Analysis of Pregnancy Outcomes Following Exposure to Intramuscular Interferon Beta-1a: The AVONEX® Pregnancy Exposure Registry.

BACKGROUND AND OBJECTIVES: There is a lack of well-controlled US studies of intramuscular (IM) interferon beta (IFNß)-1a use in pregnant women with multiple sclerosis; however, in the European Medicines Agency region, IFNß formulations may be considered during pregnancy if clinically needed based on data from European Union cohort registries. The AVONEX Pregnancy Exposure Registry was established to prospectively study the effects of IM IFNß-1a on the risk of birth defects and spontaneous pregnancy loss in a US population. METHODS: Pregnant women with multiple sclerosis exposed to IM IFNß-1a within ~ 1 week of conception or during the first trimester were included. Participants were followed until there was a pregnancy outcome, live-born infants were followed until age 8-12 weeks. Data were collected on IM IFNß-1a exposure, demographics, patient characteristics, medical history, and pregnancy outcomes, including live births (with or without birth defect), spontaneous abortions/miscarriages and fetal death/stillbirth, elective abortions (with and without birth defect), and ectopic pregnancies. A population-based birth defect surveillance program, the Metropolitan Atlanta Congenital Defects Program (MACDP), served as the primary external control group for evaluating the risk of birth defects. RESULTS: Three-hundred and two patients with a median (range) age of 31.0 (16-48) years and a median (range) gestational age at the time of enrollment of 10.1 (4-39) weeks were evaluable. Most patients (n = 278/302; 92%) reported IM IFNß-1a exposure in the week before conception and most (n = 293/302; 97%) discontinued treatment before the end of the first trimester. Of 306 pregnancy outcomes, there were 272 live births, 28 spontaneous abortions of 266 pregnancies enrolled before 22 weeks' gestation (rate 10.5%; 95% confidence interval 7.2-15.0), five elective abortions, and one stillbirth. There were 17 adjudicator-confirmed major birth defects of 272 live births (rate 6.3%; 95% confidence interval 3.8-10.0); the pattern of birth defects observed was not suggestive of a relationship to prenatal IM IFNß-1a exposure. CONCLUSIONS: This large US registry study suggests IM IFNß-1a exposure during early pregnancy was not clinically associated with adverse pregnancy outcomes in women with multiple sclerosis. These findings help inform clinicians and patients in weighing the risks and benefits of IM IFNß-1a use during pregnancy. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT00168714, 15 September, 2005.

Detection of Acoustic Plasmons in Hole-Doped Lanthanum and Bismuth Cuprate Superconductors Using Resonant Inelastic X-Ray Scattering.

High T_{c} superconductors show a rich variety of phases associated with their charge degrees of freedom. Valence charges can give rise to charge ordering or acoustic plasmons in these layered cuprate superconductors. While charge ordering has been observed for both hole- and electron-doped cuprates, acoustic plasmons have only been found in electron-doped materials. Here, we use resonant inelastic x-ray scattering to observe the presence of acoustic plasmons in two families of hole-doped cuprate superconductors (La_{1.84}Sr_{0.16}CuO_{4} and Bi_{2}Sr_{1.6}La_{0.4}CuO_{6+δ}), crucially completing the picture. Interestingly, in contrast to the quasistatic charge ordering which manifests at both Cu and O sites, the observed acoustic plasmons are predominantly associated with the O sites, revealing a unique dichotomy in the behavior of valence charges in hole-doped cuprates.

Mechanism for Unconventional Superconductivity in the Hole-Doped Rashba-Hubbard Model.

Motivated by the recent resurgence of interest in topological superconductivity, we study superconducting pairing instabilities of the hole-doped Rashba-Hubbard model on the square lattice with first- and second-neighbor hopping. Within the random phase approximation, we compute the spin-fluctuation-mediated pairing interactions as a function of filling. Rashba spin-orbit coupling splits the spin degeneracies of the bands, which leads to two van Hove singularities at two different fillings. We find that, for a doping region in between these two van Hove fillings, the spin fluctuations exhibit a strong ferromagnetic contribution. Because of these ferromagnetic fluctuations, there is a strong tendency towards spin-triplet f-wave pairing within this filling region, resulting in a topologically nontrivial phase.

Translation-Invariant Parent Hamiltonians of Valence Bond Crystals.

We present a general method to construct translation-invariant and SU(2) symmetric antiferromagnetic parent Hamiltonians of valence bond crystals (VBCs). The method is based on a canonical mapping transforming S=1/2 spin operators into a bilinear form of a new set of dimer fermion operators. We construct parent Hamiltonians of the columnar and the staggered VBCs on the square lattice, for which the VBC is an eigenstate in all regimes and the exact ground state in some region of the phase diagram. We study the departure from the exact VBC regime upon tuning the anisotropy by means of the hierarchical mean field theory and exact diagonalization on finite clusters. In both Hamiltonians, the VBC phase extends over the exact regime and transits to a columnar antiferromagnet (CAFM) through a window of intermediate phases, revealing an intriguing competition of correlation lengths at the VBC-CAFM transition. The method can be readily applied to construct other VBC parent Hamiltonians in different lattices and dimensions.

Pseudogap in cuprates driven by D-wave flux-phase order proximity effects: a theoretical analysis from Raman and ARPES experiments.

One of the puzzling characteristics of the pseudogap phase of high-Tc cuprates is the nodal-antinodal dichotomy. While the nodal quasiparticles have a Fermi liquid behaviour, the antinodal ones show non-Fermi liquid features and an associated pseudogap. Angle-resolved photoemission spectroscopy and electronic Raman scattering are two valuable tools which have shown universal features which are rather material-independent, and presumably intrinsic to the pseudogap phase. The doping and temperature dependence of the Fermi arcs and the pseudogap observed by photoemission near the antinode correlates with the non-Fermi liquid behaviour observed by Raman for the B(1g) mode. In contrast, and similar to the nodal quasiparticles detected by photoemission, the Raman B(2g) mode shows Fermi liquid features. We show that these two experiments can be analysed, in the context of the t-J model, by self-energy effects in the proximity to a D-wave flux-phase order instability. This approach supports a crossover origin for the pseudogap, and a scenario of two competing phases. The B(2g) mode shows, in an underdoped case, a depletion at intermediate energy which has attracted renewed interest. We study this depletion and discuss its origin and relation with the pseudogap.

Evidence for two competing order parameters in underdoped cuprate superconductors from a model analysis of Fermi-Arc effects.

Preformed pairs above T{c} and the two-gap scenarios are two main proposals for describing the low-doping pseudogap phase of high-T{c} cuprates. Very recent angle-resolved photoemission experiments have shown features which were interpreted as evidence for preformed pairs. Here it is shown that those results can be explained also in the context of the two-gap scenario if self-energy effects are considered. The discussion is based on the d charge-density wave theory or the flux phase of the t-J model.

Intracellular signaling via ERK/MAPK completes the pathway for tubulogenic fibronectin in MDCK cells.

A classic in vitro model of branching morphogenesis utilizes the Madin-Darby canine kidney (MDCK) cell line. MDCK Strain II cells form hollow monoclonal cysts in a three-dimensional collagen matrix over the course of 10 days and tubulate in response to hepatocyte growth factor (HGF). We and our colleagues previously showed that activation of the extracellular-signal regulated kinase (ERK, aka MAPK) pathway is necessary and sufficient to induce tubulogenesis in MDCK cells. We also showed in a microarray study that one of the genes upregulated by HGF was the known tubulogene fibronectin. Given that HGF activates a multitude of signaling pathways, including ERK/MAPK, to test the intracellular regulatory pathway, we used two distinct inhibitors of ERK activation (U0126 and PD098059). Following induction of MDCK Type II cells with HGF, tubulogenic fibronectin mRNA was upregulated fourfold by real-time PCR, and minimal or no change in fibronectin expression was seen when HGF was added with either U0126 or PD098059. We confirmed these results using an MDCK cell line inducible for Raf, which is upstream of ERK. Following activation of Raf, fibronectin mRNA and protein expression were increased to a similar degree as was seen following HGF induction. Furthermore, MDCK Strain I cells, which originate from collecting ducts and have constitutively active ERK, spontaneously initiate tubulogenesis. We show here that MDCK Strain I cells have high levels of fibronectin mRNA and protein compared to MDCK Strain II cells. When U0126 and PD098059 were added to MDCK Strain I cells, fibronectin mRNA, and protein levels were decreased to levels seen in MDCK Strain II cells. These data allow us to complete what we believe is the first description of a tubulogenic pathway from receptor/ligand (HGF/CMET), through an intracellular signaling pathway (ERK/MAPK), to transcription and, finally, secretion of a critical tubuloprotein (fibronectin).

Chromophobe renal cell carcinoma in a pediatric living-related kidney transplant recipient.

Renal cell carcinoma can occur in children who have received renal allografts from adults. Chromophobe renal cell carcinoma is a rare variant of renal carcinoma with distinct histochemical, ultrastructural, and genetic characteristics. We describe the incidental finding of a chromophobe renal cell carcinoma in a 13 1/2-year-old boy 5 years after receiving a living-related renal transplant. This tumor was found by serendipity during the evaluation of fever and inguinal lymphadenopathy, with the presumptive diagnosis of posttransplantation lymphoproliferative disorder. The patient was found to have cat-scratch disease. A renal cell carcinoma should be considered in the differential diagnosis of a pediatric recipient of an adult kidney with an incidental finding of a tumor in the graft.

Activated extracellular signal-regulated kinases are necessary and sufficient to initiate tubulogenesis in renal tubular MDCK strain I cell cysts.

A classic in vitro model of renal cyst and tubule formation utilizes the Madin-Darby canine kidney (MDCK) cell line, of which two strains exist. Most cyst and tubule formation studies that utilized MDCK cells have been performed with MDCK strain II cells. MDCK strain II cells form hollow cysts in a three-dimensional collagen matrix over 10 days and tubulate in response to hepatocyte growth factor, which increases levels of active (phosphorylated) ERK1/2. In this study, we demonstrate that MDCK strain I cells also form cysts when grown in a collagen matrix; however, MDCK strain I cell cysts spontaneously initiate the primary steps in tubulogenesis. Analysis of time-lapse microscopy of both MDCK strain I and strain II cell cysts during the initial stages of tubulogenesis demonstrates a highly dynamic process with cellular extensions and retractions occurring rapidly and continuously. MDCK strain I cell cysts can spontaneously initiate tubulogenesis mainly because of relatively higher levels of active ERK in MDCK strain I, compared with strain II, cells. The presence of either of two distinct inhibitors of ERK activation (UO126 and PD09059) prevents tubulogenesis from occurring spontaneously in MDCK strain I cell cysts and, in response to hepatocyte growth factor, in strain II cell cysts. The difference between MDCK strain I and strain II cell lines is likely explained by differing embryological origins, with strain I cells being of collecting duct, and hence ureteric bud, origin. Ureteric bud cells also have high levels of active ERK and spontaneously tubulate in our in vitro collagen gel system, with tubulogenesis inhibited by UO126 and PD09059. These results suggest that a seminal event in kidney development may be the activation of ERK in the mesonephric duct/ureteric bud cells destined to form the collecting tubules.