Effects of antenatal betamethasone on preterm human and mouse ductus arteriosus: comparison with baboon data.

BackgroundAlthough studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.MethodsWe used preterm baboons, mice, and humans (≤276/7 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.ResultsIn mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K+ channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤256/7 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.ConclusionsWe speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth

Comparison of an oscillometric method with cardiac magnetic resonance for the analysis of aortic pulse wave velocity.

OBJECTIVES:Pulse wave velocity (PWV) is the proposed gold-standard for the assessment of aortic elastic properties. The aim of this study was to compare aortic PWV determined by a recently developed oscillometric device with cardiac magnetic resonance imaging (CMR). METHODS:PWV was assessed in 40 volunteers with two different methods. The oscillometric method (PWVOSC) is based on a transfer function from the brachial pressure waves determined by oscillometric blood pressure measurements with a common cuff (Mobil-O-Graph, I.E.M. Stolberg, Germany). CMR was used to determine aortic PWVCMR with the use of the transit time method based on phase-contrast imaging at the level of the ascending and abdominal aorta on a clinical 1.5 Tesla scanner (Siemens, Erlangen, Germany). RESULTS:The median age of the study population was 34 years (IQR: 24-55 years, 11 females). A very strong correlation was found between PWVOSC and PWVCMR (r = 0.859, p < 0.001). Mean PWVOSC was 6.7 ± 1.8 m/s and mean PWVCMR was 6.1 ± 1.8 m/s (p < 0.001). Analysis of agreement between the two measurements using Bland-Altman method showed a bias of 0.57 m/s (upper and lower limit of agreement: 2.49 m/s and -1.34 m/s). The corresponding coefficient of variation between both measurements was 15%. CONCLUSION:Aortic pulse wave velocity assessed by transformation of the brachial pressure waveform showed an acceptable agreement with the CMR-derived transit time method

Linear correlation between PWV, clinical characteristics, oscillometric measures and CMR-derived parameters.

<p>PWV_OSC: pulse wave velocity assessed by transformation of oscillometrically defined brachial pressure wave form, PWV_CMR: pulse wave velocity assessed by cardiac magnetic resonance, RR_sys: systolic blood pressure, RR_dia: diastolic blood pressure, DC_aA: distensibility coefficient of the ascending aorta, DC_dA: distensibility coefficient of the descending thoracic aorta, DC_abA: distensibility coefficient of the abdominal aorta, DC mean: mean DC of all three aortic levels, DC central: DC at different aortic levels calculated using central aortic pulse pressure.</p><p>Linear correlation between PWV, clinical characteristics, oscillometric measures and CMR-derived parameters.</p

Study population characteristics.

<p>RR_sys: systolic blood pressure, RR_dia: diastolic blood pressure.</p><p>Study population characteristics.</p

Methods´ agreement.

<p>Bland-Altman plots representing the agreement between the oscillometric method and cardiac magnetic resonance for the assessment of aortic pulse wave velocity. Corresponding coefficient of variation was 15%.</p

Assessment of aortic pulse wave velocity.

<p>Evaluation of aortic pulse wave velocity using (a1) a transfer function from (a2) brachial pressure wave analysis and (b) the cardiac magnetic resonance-derived transit time method based on phase-contrast imaging. R1 and R2 indicate the aortic region.</p

Correlation of aortic pulse wave velocity assessed by the two methods.

<p>Linear correlation between aortic pulse wave velocities assessed by brachial oscillometry (PWV_OSC) and cardiac magnetic resonance (PWV_CMR).</p

Oscillometric measures and CMR-derived parameters of the study cohort.

<p>PWV_OSC: pulse wave velocity assessed by transformation of oscillometrically defined brachial pressure wave form, RR_sys: systolic blood pressure, RR_dia: diastolic blood pressure, DC_aA: distensibility coefficient of the ascending aorta, PWV_CMR: pulse wave velocity assessed by cardiac magnetic resonance, DC_aA: distensibility coefficient of the ascending aorta, DC_dA: distensibility coefficient of the descending thoracic aorta, DC_abA: distensibility coefficient of the abdominal aorta, DC mean: mean DC of all three aortic levels, DC central: DC at different aortic levels calculated using central aortic pulse pressure, R1: aortic arch, R2: descending thoracic to abdominal aorta, R3: R1 + R2 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116862#pone.0116862.g001" target="_blank">Fig. 1b</a>).</p><p>Oscillometric measures and CMR-derived parameters of the study cohort.</p

Avoidance of Fiber Is Associated With Greater Risk of Crohn’s Disease Flare in a 6-Month Period

BACKGROUND & AIMS: Chronic inflammatory bowel diseases (IBDs) have been associated with an abnormal mucosal response to the gastrointestinal microbiota. Although dietary fiber affects the gastrointestinal microbiota, there is limited information on the role of fiber on IBD activity. We investigated factors associated with fiber consumption and whether it was associated with flares in patients with IBD. METHODS: We collected a completed 26-item dietary survey from 1619 participants in the Crohn’s and Colitis Foundation of America Partners Internet cohort (Crohn’s disease, 1130; ulcerative colitis/indeterminate colitis, 489). Eligible individuals were in remission based on disease activity index at baseline and completed a follow-up survey 6 months later. Fiber and whole grain consumption were categorized into quartiles and deciles. Disease flare at 6 months was defined as a disease activity index score exceeding remission cut-off values, and/or an IBD-related surgical procedure or hospitalization since baseline. RESULTS: Participants with longer duration of disease, past history of surgery and past IBD hospitalization ate less fiber. The risks for disease flare differed by disease type. Compared to those in the lowest quartile of fiber consumption, participants with Crohn’s disease in the highest quartile were less likely to have a flare (adjusted odds ratios [OR], 0.58, 95% confidence interval [CI], 0.37–0.90). Participants with Crohn’s disease who reported that they did not avoid high fiber foods were ~40% less likely to have a disease flare than those who avoided high fiber foods (adjusted OR, 0.59; 95% CI, 0.43–0.81). There was no association between fiber intake and flares in patients with ulcerative colitis (adjusted OR, 1.82; 95% CI, 0.92–3.60). CONCLUSIONS: Intake of dietary fiber is associated with reduced disease flares in patients with Crohn’s disease, but not UC. Recommendations to limit dietary fiber should be reevaluated