Long-term azithromycin use is not associated with QT prolongation in children with cystic fibrosis

Chronic Azithromycin (AZM) is a common treatment for lung infection. Among adults at risk of cardiac events, AZM use has been associated with cardiovascular harm. We assessed cardiovascular safety of AZM among children with CF, as a secondary analysis of a placebo-controlled, clinical trial, in which study drug was taken thrice-weekly for a planned 18 months. Safety assessments using electrocardiogram (ECG) occurred at study enrollment, and then after 3 weeks and 18 months of participation. Among 221 study participants with a median of 18 months follow-up, increased corrected QT interval (QTc) of ≥30 msec was rare, at 3.4 occurrences per 100 person-years; and incidence of QTc prolongation was no higher in the AZM arm than the placebo arm (1.8 versus 5.4 per 100 person-years). No persons experienced QTc intervals above 500 msec. Long-term chronic AZM use was not associated with increased QT prolongation.     

A clinical comparison of indices of pulmonary gas exchange with changes in the inspired oxygen concentration

Several indices have been introduced as convenient alternatives to calculation of the physiological shunt fraction (Qs/QT) for the assessment of pulmonary gas exchange. These include: the arterial-alveolar oxygen tension ratio (a/APO2), the arterial oxygen tension-inspired oxygen concentration ratio (PaO2/FIO2), the respiratory index (RI), [A-a)DO2/PaO2) and the alveolar-arterial oxygen tension difference [A-a)Do2). These indices are in use clinically despite the fact that they may not accurately predict gas exchange in situations where FIO2, Qs/QT or arterial-venous oxygen content is changing. The clinical stability of each of these indices, relative to the behaviour of the physiological shunt, was therefore investigated prospectively in ten mechanically ventilated postoperative adults as FIO2 was varied from 0.30 to 1.00. None of the indices studied reliably reflected the behaviour of the physiological shunt. As FIO2 was increased incrementally from 0.30 to 1.00, 42 to 55 per cent of the measured changes in these indices were opposite in direction to the corresponding changes in the physiological shunt. The maximum magnitudes of the opposite changes were substantial; 24 and 22 per cent for the a/APO2 and PaO2/FIO2 ratio respectively, 67 per cent for the RI and 101 per cent for the (A-a)DO2. We conclude that the use of any of these indices for clinical assessment of a patient's gas exchange defect when FIO2 is varying can be substantially misleading.     

Expanding allelic and phenotypic spectrum of ZC4H2-related disorder: A novel hypomorphic variant and high prevalence of tethered cord

ZC4H2 (MIM# 300897) is a nuclear factor involved in various cellular processes including proliferation and differentiation of neural stem cells, ventral spinal patterning and osteogenic and myogenic processes. Pathogenic variants in ZC4H2 have been associated with Wieacker-Wolff syndrome (MIM# 314580), an X-linked neurodevelopmental disorder characterized by arthrogryposis, development delay, hypotonia, feeding difficulties, poor growth, skeletal abnormalities, and dysmorphic features. Zebrafish zc4h2 null mutants recapitulated the human phenotype, showed complete loss of vsx2 expression in brain, and exhibited abnormal swimming and balance problems. Here we report 7 new patients (four males and three females) with ZC4H2-related disorder from six unrelated families. Four of the 6 ZC4H2 variants are novel: three missense variants, designated as c.142T>A (p.Tyr48Asn), c.558G>A (p.Met186Ile) and c.602C>T (p.Pro201Leu), and a nonsense variant, c.618C>A (p.Cys206*). Two variants were previously reported : a nonsense variant c.199C>T (p.Arg67*) and a splice site variant (c.225+5G>A). Five patients were on the severe spectrum of clinical findings, two of whom had early death. The male patient harboring the p.Met186Ile variant and the female patient that carries the p.Pro201Leu variant have a relatively mild phenotype. Of note, 4/7 patients had a tethered cord that required a surgical repair. We also demonstrate and discuss previously under-recognized phenotypic features including sleep apnea, arrhythmia, hypoglycemia, and unexpected early death. To study the effect of the missense variants, we performed microinjection of human ZC4H2 wild-type or variant mRNAs into zc4h2 null mutant zebrafish embryos. The p.Met186Ile mRNA variant was able to partially rescue vsx2 expression while p.Tyr48Asn and p.Pro201Leu mRNA variants were not. However, swimming and balance problems could not be rescued by any of these variants. These results suggest that the p.Met186Ile is a hypomorphic allele. Our work expands the genotypes and phenotypes associated with ZC4H2-related disorder and demonstrates that the zebrafish system is a reliable method to determine the pathogenicity of ZC4H2 variants.     

Blue toe syndrome from a “coral reef” aorta

An endoaortic calcified mass, sometimes referred to as a coral reef aorta, is an unusual cause of distal leg microembolization. When discovered it is usually in the suprarenal aorta. We present an unusual case of infrarenal coral reef aorta with symptoms of distal atheroembolism. A review of the literature is also presented.     

Use of Professional Associate Ratings to Assess the Performance of Practicing Physicians: Past, Present, Future

The American Board of Family Practice (ABFP) is developing a computer-based testing system that will create realistic clinical encounters using an adaptation of an item generation process. Simulated patients' entire lives will be stochastically produced from a knowledge base, with constraints applied to prevent implausible simulations. The constraint mechanisms include knowledge acquisition decisions about grouping closely related medical concepts and widespread use of Bayesian networks to manage dependencies between concepts. Bayesian networks and fuzzy definitions provide stochastic variability between simulations produced from the same data. Examinees will interact with these patients using a large and stable set of queries and interventions. Multiple management plans associated with patient simulations provide a framework for scoring performance. All major components, including Health States, history generating "Lead To" objects, and Plans are reusable and often substitutable. Although initial knowledge acquisition demands are enormous, the system has good potential for low cost maintenance of content areas, and economies of scale as simulations and components are reused.     

On the use of survival analysis techniques to estimate medical care costs.

Measurement of treatment costs is important in the evaluation of medical interventions. Accurate cost estimation is problematic, when cost records are incomplete. Methods from the survival analysis literature have been proposed for estimating costs using available data. In this article, we clarify assumptions necessary for validity of these techniques. We demonstrate how assumptions needed for valid survival analysis may be violated when these methods are applied to cost estimation. Our observations are confirmed through simulations and empirical data analysis. We conclude that survival analysis approaches are not generally appropriate for the analysis of medical costs and review several valid alternatives.     

Spatio-temporal progression of the AEP P300 component using the cortical imaging technique

Summary The cortical imaging technique (CIT), a mathematical method for simulating the potential fields on the surface of the brain, was used to analyze the spatio-temporal progression of the AEP P300 component (as well as the preceding and subsequent N2a and N3 components) from thirty normal adult subjects recorded in a standard oddball paradigm. Comparisons were made between the progressions of the endogenous event-related cognitive potentials and the exogenous stimulus-dependent potentials (Nl component). Cortical imaging results suggest that different and multiple generator sites are involved in the production of exogenous and endogenous evoked responses. We particularly note the asymmetric development of the P300 component and the apparent anterior generator sites for the N2a component. This last result is interesting because the N2a precedes the P300 component and supports an earlier frontal contribution.     

Abortion as “deviance”

Summary The paper focuses on the relationship between changing societal norms toward women's roles and actual, emotional acceptance of them for oneself, specifically as the norms relate to abortion and sexual behavior. Elective abortion still is regarded by many as a deviant activity. Such a view has sprung from an uncritical acceptance of the traditional role of women. The implications are that women who have abortions accept traditional norms for sexual behavior, in spite of their own sexual activity, and have a generally traditional view of women's roles. They are considered to behave stereotypically and to have failed. Traditional norms for women's roles have been challenged in recent years, however, especially by the feminist movement. The authors hypothesized that women who sought early abortions would tend to have feminist orientations. The paper is based on a study of 1598 women with problem pregnancies, part of a larger study conducted throughout Michigan during 1974–75. The women studied showed little lag in emotional acceptance of changing norms about women's roles. They indicated a non-traditional female role orientation, and seemed to see themselves as competent, selfdirected, and legitimately sexual persons. Most did not have any great conflict over the decision to have an abortion. The findings by and large substantiated the authors' hypotheses.This research is supported by Grant Number 1 RO 1 HD0773901, National Institute of Child Health and Human Development, Washington, D. C.