Diagnostic and prognostic value of circulating D-Dimers in patients with acute aortic dissection

OBJECTIVE: We sought to determine whether assessing D-Dimer might be helpful for the management of acute aortic dissection (AAD). DESIGN: Single-center retrospective case-control study. SETTING: University Hospital of Strasbourg France. PATIENTS: Patients were 94 consecutive patients admitted to our institution with confirmed AAD and in whom D-Dimer test had been performed at presentation. These patients were matched with 94 controls presenting with clinical suspicion of dissection, which was later ruled out. INTERVENTIONS: Patient characteristics and clinical course were analyzed. MEASUREMENTS AND MAIN RESULTS: Ninety-three (99%) patients with AAD had elevated D-Dimer (>400 ng/mL) with a median D-Dimer value of 8610 ng/mL (interquartile range, 2982-20,000 ng/mL). Receiver operating characteristic curves analysis showed that D-Dimer, but not C-reactive protein, troponin, lactate dehydrogenase, or leukocyte count, was predictive of a diagnosis of AAD, with a sensitivity and specificity of 99% and 34%, respectively. D-Dimer concentration positively correlated with the anatomical extension of the dissection to the different segments of the aorta (R = .47, p < .0001). A positive relationship was observed between D-Dimer and in-hospital mortality rate among patients with AAD (p = .037). On multivariate analysis, the independent predictors of in-hospital mortality were the presence of pericardial effusion (odds ratio, 6.80; confidence interval, 1.87-27.60), D-Dimer >5200 ng/mL (odds ratio, 5.38; confidence interval, 1.27-30.87), and female gender (odds ratio, 4.96; confidence interval, 1.39-19.95). CONCLUSIONS: D-Dimers are elevated in patients with AAD and provide valuable diagnostic and prognostic information. In patients with acute chest pain and elevated D-Dimer, a diagnosis of AAD should also be considered. D-Dimer might be a useful complementary tool to the current diagnostic work-up of patients with suspected AAD.     

Mathias Duval on placental development in mice and rats

Mathias Duval (1844-1907) was one of the pioneers in elucidating the intricate placental histology of different mammalian groups, notably the rodents. Using a well-dated series of mouse conceptuses, he described in detail the successive steps in placental development, and for confirmation he included observations on a (undated) collection of rat specimens. Not only was he able to identify correctly the different extra-embryonic cell layers, but he was also the first to recognize trophoblast invasion in rodents. Not all his interpretations are still valid, however. Re-reading his extensive and detailed work "Le placenta des rongeurs" (1890-1892) confronts us with still existing gaps in our present understanding of placental development, notably the morphogenesis of the different placental layers and the differentiation of invasive trophoblast. His understanding of uteroplacental blood flow was still limited, and he failed to recognize the complexity of the maternal decidua and its vasculature, which is essential for correctly understanding the pathways and extent of trophoblast invasion. Although Duval was active in promoting Darwin's evolutionary ideas, he refrained from extrapolating too quickly his findings in rodents to other mammalian groups including humans. In his view detailed histological studies on complete series of specimens had to come first, and thus provide a firm basis for a proper understanding of placental function and evolution.     

Bullying involvement,psychological distress,and short sleep duration among adolescents

Purpose

Previous research has found links between involvement in bullying and sleep duration in adolescents. However, little is known about the factors that might mediate these relationships. This study examined the associations between cyberbullying victimization and school bullying involvement (bully, victim, bully–victim) with short sleep duration in a large sample of middle and high school students and tested whether psychological distress mediates these relationships.

Methods

Data on 5061 students (49% females; mean age?=?15.1 years) from the 2015 Ontario Student Drug Use and Health Survey were used. Participants self-reported their sleep duration and their levels of bullying involvement over the past year. Psychological distress was assessed using the Kessler 6 (K6) scale. Covariates in multiple linear regression analyses included age, sex, racial background, socioeconomic status, and substance use.

Results

Being a victim of cyberbullying (β?=???1.179; 95% CI ??0.238; ??0.120) or school bullying (β?=???0.119; 95% CI ??0.190; ??0.049) was associated with short sleep duration. Mediation analyses suggested that psychological distress fully mediates the relationships between being cyberbullied, a school bullying victim or bully–victim with short sleep duration. There was a complementary mediation by psychological distress on the relationship between being a bully at school and short sleep duration.

Conclusions

These results suggest that higher levels of bullying involvement place adolescents at risk of developing higher psychological distress which, in turn, can lead to short sleep duration. Longitudinal research is necessary to confirm the mediating role of psychological distress on the relationship between bullying involvement and short sleep duration among adolescents.