Gastrointestinal stromal tumors in patients with neurofibromatosis: imaging features with clinicopathologic correlation

OBJECTIVE: The purpose of this study was to evaluate the clinical, pathologic, and imaging features of gastrointestinal stromal tumors that occur in patients with neurofibromatosis. CONCLUSION: Gastrointestinal stromal tumors that occur in patients with neurofibromatosis commonly originate from the proximal small intestine and are often multiple. The cross-sectional imaging appearance of gastrointestinal stromal tumors that occur in patients with neurofibromatosis is similar to that of gastrointestinal stromal tumors that occur in the general population.     

Characteristics of Female Sex Workers in Southern India Willing and Unwilling to Participate in a Placebo Gel Trial

Respondent-driven sampling was used to recruit female sex workers (FSWs) for a community survey conducted in southern India. After survey completion, participants were given a brochure describing a clinical trial that entailed daily use of a placebo vaginal gel for four months. This study assessed predictors of screening among survey respondents, predictors of enrollment among those eligible for the trial, and predictors of visit attendance and retention among those enrolled. FSWs who reported having symptoms of sexually transmitted infections (STI), engaging in sex work in the past month, and living in a subdistrict easily accessible by public transportation with a high concentration of FSWs, were more likely to screen. FSWs who had never been tested for HIV were more likely to enroll. This analysis suggests that the primary reason FSWs participated in the trial was a desire for health care—not other factors hypothesized to be important, e.g., HIV risk perception and poverty status.     

High-Throughput Analysis of Antimalarial Susceptibility Data by the WorldWide Antimalarial Resistance Network (WWARN) In Vitro Analysis and Reporting Tool

Assessment of in vitro susceptibility is a fundamental component of antimalarial surveillance studies, but wide variations in the measurement of parasite growth and the calculation of inhibitory constants make comparisons of data from different laboratories difficult. Here we describe a Web-based, high-throughput in vitro analysis and reporting tool (IVART) generating inhibitory constants for large data sets. Fourteen primary data sets examining laboratory-determined susceptibility to artemisinin derivatives and artemisinin combination therapy partner drugs were collated from 11 laboratories. Drug concentrations associated with half-maximal inhibition of growth (IC₅₀s) were determined by a modified sigmoid E_max model-fitting algorithm, allowing standardized analysis of 7,350 concentration-inhibition assays involving 1,592 isolates. Examination of concentration-inhibition data revealed evidence of apparent paradoxical growth at high concentrations of nonartemisinin drugs, supporting amendment of the method for calculating the maximal drug effect in each assay. Criteria for defining more-reliable IC₅₀s based on estimated confidence intervals and growth ratios improved correlation coefficients for the drug pairs mefloquine-quinine and chloroquine-desethylamodiaquine in 9 of 11 and 8 of 8 data sets, respectively. Further analysis showed that maximal drug inhibition was higher for artemisinins than for other drugs, particularly in ELISA (enzyme-linked immunosorbent assay)-based assays, a finding consistent with the earlier onset of action of these drugs in the parasite life cycle. This is the first high-throughput analytical approach to apply consistent constraints and reliability criteria to large, diverse antimalarial susceptibility data sets. The data also illustrate the distinct biological properties of artemisinins and underline the need to apply more sensitive approaches to assessing in vitro susceptibility to these drugs.     

Criterion validity of the Duke Activity Status Index for assessing functional capacity in patients with chronic obstructive pulmonary disease

PURPOSE: This study evaluated the concurrent criterion validity of the Duke Activity Status Index (DASI) with respect to standard physiologic work capacity indices in patients with chronic obstructive pulmonary disease (COPD) and compared its performance with similar surrogates. METHODS: 119 patients with moderate to severe COPD (86 men, 33 women) completed medical and smoking histories, physical examination, pulmonary function testing (PFT), cycle ergometry (CE), arm ergometry (AE), and 6-minute walk distance (6MWD), DASI, the Sickness Impact Profile-68 (SIP-68) and the Chronic Respiratory Disease Questionnaire (CRDQ). Correlation methods were used to assess the validity of the potential surrogates DASI and the domain scores for SIP-68 and CRDQ, with the standards CE, AE, PFT, and 6MWD (as a standard). RESULTS: The mean DASI score was 33.4 +/- 13.0. Significant Pearson correlations (P <.01) were observed between the DASI and PFT outcomes maximum voluntary ventilation (r =.28); peak expiratory flow (r =.21); diffusion capacity of lung for carbon monoxide (r =.30). For CE, the correlations with DASI were oxygen consumption (VO(2))(r =.34); minute ventilation (r =.25); watts (r =.37). For AE, the correlations with DASI were VO(2) (r=.38); watts (r =.47). For 6MWD, the correlation was r =.53. Higher correlations were obtained for the distance completed during the first minute of the 6MWD and ergometric indices as well as DASI scores: watts(AE) (r =.39); VO(2AE) (r =.45); watts(CE) (r =.50); VO(2CE) (r =.44). Correlation coefficients for all SIP-68 and CRDQ domain and total scores were lower than corresponding correlations obtained for the DASI. Regression analysis demonstrated that the DASI and 6MWD were important (P <.05) for predicting VO(2) or work for CE while DASI and SIP range or CRDQ dyspnea entered for AE, when gender, age, BMI, and the FEV1 were forced into the model. In forward stepwise analyses, DASI entered first for AE, and 6MWD entered first for CE. The DASI was selected in 3 of 4 models with R(2) values ranging from.47 to.70. SIP-68 and CRDQ subscores were significant as additional predictors. CONCLUSIONS: DASI has high criterion validity for predicting CE and/or AE outcomes in the COPD population. It is warranted in addition to the 6MWD, and its predictive significance and simplicity recommends it over several other self-administered instruments for evaluating functional capacity.