In utero placement of aortopulmonary shunts reproduces the aberrant hemodynamic state of children with cogenital heart disease with left-to-right shunts; postnatal pulmonary hypertension, increased pulmonary blood flow, and vascular remodeling. In addition, the lambs have a unique paradoxical increase in pulmonary vascular volume that attenuates an increase in pulmonary vascular resistance. This experimental preparation provides a useful and consistent model for the study of the pathogenesis of pulmonary hypertension.

Persistent pulmonary hypertension of the newborn (PPHN) is associated with chronic intrauterine events. Acute nitric oxide (NO) inhibition attenuates the normal increase in pulmonary blood flow at birth. We investigated whether chronic NO inhibition in utero causes persistent pulmonary hypertension. 11 fetal lambs received either a continuous infusion of Nw-nitro-L-arginine (an NO synthesis inhibitor) or 0.9% saline. Before infusion, acetylcholine (dependent upon endogenous NO production) and sodium nitroprusside (which releases its own NO) produced potent pulmonary vasodilation. After 10.5±1.5 d of infusion, acetylcholine did not produce pulmonary vasodilation in N'-nitro-L-arginine-treated fetal lambs, but did in salinetreated fetal lambs; sodium nitroprusside produced pulmonary vasodilation in both groups. Immediately after birth, at 140 d of gestation, during the 3-h study period, mean pulmonary arterial pressure did not decrease in Nw-nitro-L-arginine-treated lambs; the increase in pulmonary blood flow and decrease in pulmonary vascular resistance were markedly attenuated compared to saline-treated lambs. These hemodynamic derangements were reversed by L-arginine. There were no anatomic abnormalities in the pulmonary circulation. Chronic NO inhibition in utero reproduces many of the physiologic derangements of PPHN. Intrauterine events which result in endothelial dysfunction and inhibition of NO may produce the physiologic derrangements of PPHN. (J. Clin. Invest. 1994. 93:2675-2683

Myocyte enhancer factor 2B (MEF2B) is a transcription factor with mutation hotspots at K4, Y69 and D83 in diffuse large B-cell lymphoma (DLBCL). To provide insight into the regulatory network of MEF2B, in this study, we analyse global gene expression and DNA-binding patterns. We find that candidate MEF2B direct target genes include RHOB, RHOD, CDH13, ITGA5 and CAV1, and that indirect target genes of MEF2B include MYC, TGFB1, CARD11, MEF2C, NDRG1 and FN1. MEF2B overexpression increases HEK293A cell migration and epithelial–mesenchymal transition, and decreases DLBCL cell chemotaxis. K4E, Y69H and D83V MEF2B mutations decrease the capacity of MEF2B to activate transcription and decrease its' effects on cell migration. The K4E and D83V mutations decrease MEF2B DNA binding. In conclusion, our map of the MEF2B regulome connects MEF2B to drivers of oncogenesis.

To investigate early endothelial function associated with increased pulmonary blood flow, vascular shunts were placed between the ascending aorta and main pulmonary artery in 18 late-gestation fetal sheep. Four weeks after delivery, the lambs were instrumented to measure vascular pressures and blood flows, and blood was collected to measure plasma concentrations of guanosine 3',5'-cyclic monophosphate [cGMP, the second messenger to nitric oxide (NO)-mediated vasodilation] and L-arginine (the precursor for NO synthesis). The responses to the endothelium-dependent vasodilators acetylcholine (ACh, 1.0 microgram/kg) and ATP (0.1 mg.kg-1.min-1), the endothelium-independent vasodilators M & B-22948 (a cGMP-specific phosphodiesterase inhibitor, 2.5 mg/kg) and inhaled NO (40 ppm), and N omega-nitro-L-arginine (an inhibitor of NO synthase, 5 mg/kg) were then compared with responses in 12 age-matched controls. Vasodilator responses in control lambs were determined during pulmonary hypertension induced by U-46619 (a thromboxane A2 mimic). Shunted lambs displayed a selective impairment of endothelium-dependent pulmonary vasodilation, an augmented pulmonary vasoconstricting response to NO synthase inhibition, increased plasma cGMP concentrations, and decreased L-arginine concentrations. Taken together, these data suggest that lambs with pulmonary hypertension and increased pulmonary blood flow have early aberrations in endothelial function, as manifested by increased basal NO activity, that cannot be further increased by agonist-induced endothelium-dependent vasodilators.

Ustekinumab, a human anti-interleukin (IL)-12/IL-23p40 monoclonal antibody has demonstrated significant efficacy in patients with moderate-to-severe psoriasis. Skin lesion biopsies, cell surface markers on peripheral blood lymphocytes, and ex vivo T-helper (Th)1/Th2 cytokine responses from peripheral blood mononuclear cells (PBMC) from patients receiving ustekinumab 45 or 90 mg, or placebo were evaluated at baseline and week 12. Inflammatory serum protein levels were measured at baseline, week 2 and week 12. At week 12, median epidermal thickness decreased from 312.1 to 132.7 microm, and median levels of cellular proliferation (Ki67) and T-cell infiltration (CD3) decreased by 84.3% and 70.7%, respectively, in the combined ustekinumab group (all P < or = 0.002). Serum levels of tumor necrosis factor (TNF)-alpha, C-C motif ligand 27 (CCL27) and other inflammatory cytokines remained unchanged. Minimal variation in the percentage of T cells expressing cutaneous lymphocyte antigen (CLA) was observed following ustekinumab treatment, with no significant variation in the percentage of cells expressing CD45RA, CD45RO, CD25, human leukocyte antigen-DR (HLA-DR), and C-X-C motif receptor 3 (CXCR3). No apparent effect on the magnitude of Th1/Th2 responses to external stimuli in PBMC was observed following placebo or ustekinumab treatment. Ustekinumab improves histological psoriasis measures, with minimal impact on the systemic immune system.

Increased concentrations of endothelin-1 (ET-1) are found in children with congenital heart diseases that produce increased pulmonary blood flow and pulmonary hypertension, but the role of ET-1 in the pathophysiology of pulmonary hypertension is unclear. Therefore, we investigated ET-1-induced vasoactive responses and ET-1 concentrations in an animal model of pulmonary hypertension and increased pulmonary blood flow. Vascular shunts were placed between the ascending aorta and main pulmonary artery in seven late-gestation fetal sheep. Four weeks after spontaneous delivery, ET-1 increased pulmonary vascular resistance by 29.7 +/- 34.4% (P < 0.05), the ETb-receptor agonist [Ala1,3,11,15]ET-1 (4AlaET-1) had no effect, and the ETa-receptor antagonist cyclo(D-Asp-L-Pro-D-Val-L-Leu-D-Trp) (BQ-123) decreased pulmonary vascular resistance by -16.0 +/- 5.6% (P < 0.05). In contrast, in six control lambs with a similar degree of pulmonary hypertension induced by U-46619, ET-1 and 4AlaET-1 decreased pulmonary vascular resistance by 24.8 +/- 17.6, and 20.0 +/- 13.8%, respectively (P < 0.05). In addition, systemic arterial concentrations of immunoreactive ET-1 were elevated in lambs with pulmonary hypertension (29.2 +/- 9.6 vs. 15.2 +/- 10.7 pg/ml, P < 0.05). Pulmonary hypertension and increased pulmonary blood flow alters the response of ET-1 from pulmonary vasodilation to vasoconstriction. These altered responses suggest a role for ET-1 and its receptors in the pathogenesis of pulmonary hypertension secondary to increased pulmonary blood flow.

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A double-blind randomized placebo-controlled trial was conducted to investigate the efficacy of 3 months' inhaled steroids delivered via a spacer device with face mask attachment to infants recovering from bronchiolitis. Forty-eight previously healthy infants recovering from their first documented episode of acute bronchiolitis were randomized to receive 150 microg fluticasone propionate (FP) b.i.d. or placebo delivered via the Babyhaler spacer. Longitudinal assessments were performed on seven occasions over 1 yr based on symptom diaries and health records, clinical examinations, overnight cough recordings and oxygen saturation readings. Lung function was measured 6 months after hospital discharge. Forty-three infants completed the trial (FP 21, placebo 22). There were no significant differences in the three objective end-points measured, recorded night cough, oxygen saturation and lung function test results. Symptom scores were low in both the FP and placebo groups with the absence of (0) or mild (1) symptoms > or =90% of the trial days. No statistical differences in symptom frequency, use of rescue respiratory medications or hospital admissions between treatment groups were found throughout the trial or follow-up periods. In conclusion, the use of inhaled fluticasone propionate in infants recovering from acute bronchiolitis cannot be recommended.