Fetal Exposure to MR Imaging: Long-Term Neurodevelopmental Outcome.

BACKGROUND AND PURPOSE: Very few studies have investigated long-term neurodevelopment of children exposed to MR imaging antenatally. Thus, the purpose of our study was to evaluate long-term neurodevelopmental outcomes of children exposed to MR imaging during pregnancy. MATERIALS AND METHODS: We conducted a historical prospective cohort study in a single tertiary medical center. Women exposed to 1.5T noncontrast MR imaging for maternal or fetal indications were matched to unexposed controls. Long-term neurodevelopmental outcomes were evaluated of their children, 2.5 to 6 years of age, according to the Vineland-II Adaptive Behavior Scale. The Vineland-II Adaptive Behavior Scale assesses communication, daily living skills, socialization, and motor skills. A composite score summarizes these 4 domains. RESULTS: A total of 131 exposed women matched our inclusion criteria and were included in the study group, and 771 unexposed women, in the control group. No difference was identified in the Vineland-II Adaptive Behavior Scale composite score between the children of the study and control groups (mean, 110.79 versus 108.18; P = .098). Differences were also not observed between the children of the 2 groups in 3 of the 4 questionnaire domains: communication (108.84 versus 109.10; P = .888), daily living skills (109.51 versus 108.28; P = .437), and motor skills (105.09 versus 104.42; P = .642). However, the socialization score was favorable for the study group (112.98 versus 106.47; P < .001). CONCLUSIONS: Exposure to 1.5T noncontrast MR imaging during pregnancy had no harmful effects on long-term neurodevelopmental outcomes. This study contributes to understanding the safety of MR imaging during pregnancy.

Surgery and trauma care providers' perception of the impact of dual-practice employment on quality of care provided in an Andean country.

BACKGROUND: Dual-practice, simultaneous employment by healthcare workers in the public and private sectors is pervasive worldwide. Although an estimated 30 per cent of the global burden of disease is surgical, the implications of dual practice on surgical care are not well understood. METHODS: Anonymous in-depth individual interviews on trauma quality improvement practices were conducted with healthcare providers who participate in the care of the injured at ten large hospitals in Peru's capital city, Lima. A grounded theory approach to qualitative data analysis was employed to identify salient themes. RESULTS: Fifty interviews were conducted. A group of themes that emerged related to the perceived negative and positive impacts of dual practice on the quality of surgical care. Participants asserted that the majority of physicians in Lima working in the public sector also worked in the private sector. Dual practice has negative impacts on physicians' time, quality of care in the public sector, and surgical education. Dual practice positively affects patient care by allowing physicians to acquire management and quality improvement skills, and providing incentives for research and academic productivity. In addition, dual practice provides opportunities for clinical innovations and raises the economic status of the physician. CONCLUSION: Surgeons in Peru report that dual practice influences patient care negatively by creating time and human resource conflicts. Participants assert that these conflicts widen the gap in quality of care between rich and poor. This practice warrants redirection through national-level regulation of physician schedules and reorganization of public investment in health via physician remuneration.

Receptor density and recycling affect the rate of agonist-induced desensitization of mu-opioid receptor.

Previously, we reported that the time course for the rapid phosphorylation rate of mu-opioid receptor expressed in human embryonic kidney (HEK)293 cells did not correlate with the slow receptor desensitization rate induced by [D-Ala(2),N-MePhe(4), Gly-ol(5)]-enkephalin (DAMGO). However, others have suggested that receptor phosphorylation is the trigger for mu-opioid receptor desensitization. In this study, we demonstrated the relatively slow rate of receptor desensitization could be attributed partially to the recycling of internalized receptor as determined by fluorescence-activated cell-sorting analysis. However, the blockade of the endocytic and Golgi transport events in HEK293 cells with monensin and brefeldin A did not increase the initial rate of receptor desensitization. But the desensitization rate was increased by reduction of the mu-opioid receptor level with beta-furnaltrexamine (betaFNA). The reduction of the receptor level with 1 microM betaFNA significantly increased the rate of etorphine-induced receptor desensitization. By blocking the ability of receptor to internalize with 0.4 M sucrose, a significant degree of receptor being rapidly desensitized was observed in HEK293 cells pretreated with betaFNA. Hence, mu-opioid receptor is being resensitized during chronic agonist treatment. The significance of resensitization of the internalized receptor in affecting receptor desensitization was demonstrated further with human neuroblastoma SHSY5Y cells that expressed a low level of mu-opioid receptor. Although DAMGO could not induce a rapid desensitization in these cells, in the presence of monensin and brefeldin A, DAMGO desensitized the mu-opioid receptor's ability to regulate adenylyl cyclase with a t(1/2) = 9.9 +/- 2.1 min and a maximal desensitized level at 70 +/- 4.7%. Furthermore, blockade of receptor internalization with 0.4 M sucrose enhanced the DAMGO-induced receptor desensitization, and the inclusion of monensin prevented the resensitization of the mu-opioid receptor after chronic agonist treatment in SHSY5Y cells. Thus, the ability of the mu-opioid receptor to resensitize and to recycle, and the relative efficiency of the receptor to regulate adenylyl cyclase activity, contributed to the observed slow rate of mu-opioid receptor desensitization in HEK293 cells.

Impact of switching laboratory tests on reported trends in Chlamydia trachomatis infections.

Improvements in the sensitivity and specificity of laboratory testing methods for Chlamydia trachomatis infections in recent years have created potential problems with interpreting data on chlamydia prevalence trends. A switch to a more sensitive test can result in an increase in chlamydia positivity even with no increase in the true disease prevalence. To examine the impact of switching laboratory testing methods on chlamydia positivity trends among women, the authors analyzed data from chlamydia screening programs in family planning clinics in two geographic areas of the United States. Data from 7,287 tests performed in Philadelphia, Pennsylvania, indicated a 46% increase in positivity (from 4.1% to 6.0%) when the clinics switched from a nucleic acid probe assay to a ligase chain reaction test. Data from 35,306 tests performed in Oregon and Washington State laboratories showed a 21% increase in positivity (from 3.3% to 4.0%) when clinics switched from a direct immunofluorescent antibody testing procedure to an enzyme immunoassay with negative gray zone confirmation. These increases were within ranges consistent with the variability of the testing methods and occurred primarily in asymptomatic women and in women over age 20 years. Any switch in laboratory testing methods must be considered when interpreting data on chlamydial infection trends.

The risk of serious cardiac arrhythmias among cisapride users in the United Kingdom and Canada.

PURPOSE: Serious, although rare, ventricular arrhythmias and deaths have been reported in patients taking cisapride monohydrate. Without quantification of the risk involved, it is impossible to develop rational therapeutic guidelines. SUBJECTS AND METHODS: Arrhythmic events (sudden deaths and other events compatible with serious ventricular arrhythmias) were sought among 36,743 patients prescribed cisapride in the United Kingdom and Saskatchewan, Canada. Prescriptions and cases were identified from computerized medical claims data and physicians' office records. We compared rates of events between periods of recent cisapride use and nonrecent use, using cohort analysis. Potential confounding factors, including concomitant treatment with agents that inhibit CYP3A4 metabolism or that prolong the QT interval, were assessed in a nested case-control study. RESULTS: In the cohort analysis, the incidence of the arrhythmic events was 1.6 times greater (95% confidence interval [CI]: 0.9 to 2.9) in periods of recent use. With adjustment for clinical history, use of CYP3A4 inhibitors, and use of drugs that prolong the QT interval, the odds ratio for cisapride and cardiac outcomes was 1.0 (95% CI: 0.3 to 3.7). There was no identifiable increase in risk when cisapride was dispensed at about the same time as QT-prolonging drugs or CYP3A4 inhibitors. QT-prolonging agents were associated with a 2.5-fold increase in the risk of arrhythmic events (95% CI: 1.1 to 5.8). CONCLUSIONS: Serious rhythm disorders were not associated with cisapride use, although the upper confidence bounds do not rule out an increase in risk.

A metaregression analysis of the dose-response effect of aspirin on stroke.

BACKGROUND: We evaluated whether the risk of stroke depends on aspirin dose in patients with a previous transient ischemic attack or stroke. METHODS: We conducted a metaregression analysis of stroke by using published randomized, placebo-controlled trials. We analyzed studies of patients who had recently had a transient ischemic attack or stroke (ie, secondary prevention). We abstracted data on the treatment regimen and stroke. To evaluate the dose-response relationship, we conducted a metaregression analysis of study-specific risk ratios by means of weighted linear regression. RESULTS: Eleven randomized, placebo-controlled trials contributed a total of 5228 patients randomized to aspirin only and 4401 patients randomized to placebo only. The slope of the dose-response curve was virtually flat across a wide range of aspirin doses from 50 to 1500 mg/d (P = .49 for test of slope not =0). Summarizing across studies, aspirin decreases the risk of stroke by about 15% (risk ratio, 0.85;95% confidence interval, 0.77-0.94). CONCLUSIONS: Aspirin reduces the risk of stroke by approximately 15%, and this effect is uniform across aspirin doses from 50 to 1500 mg/d. The lowest effective aspirin dose has not yet been identified, but it could be lower than 50 mg/d.

Human immunodeficiency virus partner notification. Cost and effectiveness data from an attempted randomized controlled trial.

OBJECTIVE: Determine the cost and effectiveness of partner notification for human immunodeficiency virus (HIV) infection. METHODS: Persons testing HIV positive in three areas were randomly assigned one of four approaches to partner notification. Analysis plans changed because disease intervention specialists notified many partners from the patient referral group. We dropped the patient referral group and combined the others to assess the cost and effectiveness of provider referral. RESULTS: The 1,070 patients reported 8,633 partners. Of those 1,035 were located via record search or in person. A previous positive test was reported by 248 partners. Of the 787 others, 560 were tested: 438 were HIV negative and 122 were newly identified as HIV positive. The intervention specialist's time totaled 197 minutes per index patient. The cost of the intervention specialist's time, travel, and overhead was $268,425: $251 per index patient, $427 per partner notified, or $2,200 per new HIV infection identified. No demographic characteristic of the index patient strongly predicted the likelihood of finding an infected partner. CONCLUSION: We could not compare the effectiveness of different partner notification approaches because of frequent crossover between randomized groups. The cost of partner notification can be compared with other approaches to acquired immunodeficiency syndrome prevention, but the benefits are not easily measured. We do not know the number of HIV cases prevented or the value of fulfilling the ethical obligation to warn partners of a potential threat to their health.

Chlamydia positivity versus prevalence. What's the difference?

BACKGROUND: Data on chlamydia screening collected as part of Regional Infertility Prevention Projects often do not include personal identifiers, therefore repeat tests for patients during a year cannot be identified. Consequently, positivity is calculated and used to monitor chlamydia prevalence. GOALS: To assess how well positivity can estimate prevalence in family planning and sexually transmitted disease (STD) clinic settings. STUDY DESIGN: Analyzed data from chlamydia screening programs in three geographic areas of the United States that used unique patient identifiers. RESULTS: The relationship between positivity and prevalence is related to both the percentage of tests that are repeat tests and the percentage of repeat tests that are positive. On average, the percentage of positive repeat tests was the same as or higher than prevalence in family planning clinics; thus, positivity was the same as or higher than prevalence. In STD clinics, the percentage of positive repeat tests was consistently lower than prevalence; thus, positivity underestimated prevalence. However, the absolute difference between positivity and prevalence was less than 0.5% in family planning and STD clinics. CONCLUSIONS: Positivity can be used to monitor chlamydia prevalence in women screened in family planning and STD clinic settings.

PIP: Data collected from US family planning (FP) and sexually transmitted disease (STD) programs that offer screening for chlamydia are used to monitor trends in chlamydia prevalence and identify high-risk groups. Because personal identifiers are often not collected and repeat tests for patients during the year cannot be identified, the proportion of total tests that are positive is used to estimate prevalence. To determine how well positivity estimates prevalence, data that used personal identifiers was analyzed from 16 states that are part of US Regional Infertility Prevention Projects in 3 geographic areas. In 1988-96, a total of 880,069 chlamydia tests were performed in FP clinics in the 3 regions; the percentage of women having a repeat test in a given year ranged from 2.7% to 11.9%. On average, the percentage of positive repeat tests was the same as or higher than the chlamydia prevalence in FP clinics. Over 26,000 tests for chlamydia infection were performed in STD clinics in 1 of these regions (VIII) in 1994-96; about 11% of women were tested more than once. In STD clinics, the percentage of positive repeat tests was much lower than chlamydia prevalence. Overall, however, the absolute difference between positivity and prevalence was less than 0.5% in both settings, confirming that positivity can be used to monitor chlamydia prevalence. As the positivity of initial and repeat tests diverges and the percentage of repeat tests increases, the difference between positivity and prevalence will widen.

Partner notification for syphilis: a randomized, controlled trial of three approaches.

OBJECTIVE: To determine the cost and effectiveness of three approaches to partner notification for infectious syphilis. STUDY DESIGN: People with syphilis were randomly assigned to: (1) notification of partners by patients themselves within 2 days or disease intervention specialists would notify them; (2) immediate notification by intervention specialist; or (3) immediate notification by intervention specialists, who had the option of drawing blood in the field. Costs of intervention specialists' time, travel, and overhead were measured. Intention-to-treat analysis measured outcomes per randomized index patient. RESULTS: From December, 1990 through March, 1993, 1,966 index patients with syphilis (primary 9%; secondary 18%; and early latent 73%) were randomized in Broward County (Ft. Lauderdale), Florida (1,191); Tampa, Florida (569); and Paterson, New Jersey (206). Index patients reported 11,272 potentially exposed partners and sufficient information to initiate investigations for 2,761. Of these, 2,236 were located, 367 had newly identified infections, and 870 others received preventive treatment. The three partner notification approaches had similar success locating partners (1.1-1.2 per index patient) and treating partners (0.61-0.67 per index). The cost was $317 to $362 per partner treated; the optimal strategy differed by study site. CONCLUSIONS: Partner notification identified many infected and potentially infected people. The cost and effectiveness of the three types of provider notification were similar. Alternative approaches are needed to reach infected partners who could not be notified.

Airborne asbestos measurement: preliminary findings identify a new source of variability in the membrane filter method.

Significant quantities of asbestos fibers have been found on the inside surfaces of the filter cassettes using the current membrane filter method (P&CAM-239). This introduces a major new source of random error not previously recognized in these measurements. This phenomenon is apparently due to the presence of electrostatic charges generated within the plastic filter cassettes.