US and MR imaging findings to detect placental adhesion spectrum (PAS) in patients with placenta previa: a comparative systematic study

Purpose

To compare the performance US and MR in identifying placental adhesion spectrum (PAS) in placenta previa (PP) and to establish a potential method of image interpretation.

Methods

US and MR examinations of 51 patients with PP were selected. The presence of imaging signs commonly used to detect PAS was assessed. Penalized logistic regression was performed considering histology as standard of reference; only signs statistically significant (p < 0.05) were considered for ROC and multivariate analysis. The probability of PAS according to the presence of US and/or MR signs was then assessed.

Results

At univariate analysis, loss of retroplacental clear space, myometrial thinning (MT) and placenta lacunar spaces on US, intraplacental dark bands (IDBs), focal interruption of myometrial border (FIMB) and abnormal vascularity (AV) on MR were statistically significant (p < 0.01). Three diagnostic methods for PAS were then developed for both US and MR when at least one (Method 1), two (Method 2) or three (Method 3) imaging signs occurred, respectively. Method 2 for MR showed a significantly (p < 0.05) higher accuracy (91%) compared to the other methods. When MR IDBs and AV as well as IDBs and FIMB were present in combination with US MT the probability of PAS increased from 75 to 90% and from 80 to 91%, respectively.

Conclusion

MR demonstrated a higher diagnostic accuracy than US to detect PAS. However, since the combination of MR and US signs could improve the probability to detect PAS, a complementary diagnostic role of these techniques could be considered.

     

Generation and functional characterization of human dendritic cells derived from CD34+ cells mobilized into peripheral blood: comparison with bone marrow CD34+ cells

Dendritic cells (DCs) are the most powerful professional antigen-presenting cells (APC), specializing in capturing antigens and stimulating T-cell-dependent immunity. In this study we report the generation and characterization of functional DCs derived from both steady-state bone marrow (BM) and circulating haemopoietic CD34⁺ cells from 14 individuals undergoing granulocyte colony-stimulating factor (G-CSF) treatment for peripheral blood stem cells (PBSC) mobilization and transplantation. Clonogenic assays in methylcellulose showed an increased frequency and proliferation of colony-forming unit-dendritic cells (CFU-DC) in circulating CD34⁺ cells, compared to that of BM CD34⁺ precursors in response to GM-CSF and TNF-α with or without SCF and FLT-3L. Moreover, peripheral blood (PB) CD34⁺ cells generated a significantly higher number of fully functional DCs, as determined by conventional mixed lymphocyte reactions (MLR), than their BM counterparts upon different culture conditions. DCs derived from mobilized stem cells were also capable of processing and presenting soluble antigens to autologous T cells for both primary and secondary immune response. Replacement of the early-acting growth factors SCF and FLT-3L with IL-4 at day 7 of culture of PB CD34⁺ cells enhanced both the percentage of total CD1a⁺ cells and CD1a⁺CD14^? cells and the yield of DCs after 14 d of incubation. In addition, the alloreactivity of IL-4-stimulated DCs was significantly higher than those generated in the absence of IL-4. Furthermore, autologous serum collected during G-CSF treatment was more efficient than fetal calf serum (FCS) or two different serum-free media for large-scale production of DCs. Thus, our comparative studies indicate that G-CSF mobilizes CD34⁺ DC precursors into PB and circulating CD34⁺ cells represent the optimal source for the massive generation of DCs. The sequential use of early-acting and intermediate-late-acting colony-stimulating factors (CSFs) as well as the use of autologous serum greatly enhanced the growth of DCs. These data may provide new insights for manipulating immunocompetent cells for cancer therapy.     

Homocysteine plasma concentration is related to severity of lung impairment in scleroderma

OBJECTIVE: To investigate the correlation between plasma concentration of total homocysteine and pulmonary involvement in patients with limited or diffuse scleroderma (systemic sclerosis, SSc). METHODS: Seventy-one patients with scleroderma were divided into 3 groups based on pulmonary involvement: Group A comprised patients without lung involvement (9 cases); Group B patients with lung involvement of mild and moderate stages (44 cases); and Group C patients with lung involvement of severe stage and endstage (18 cases). At the time of evaluation of lung involvement all patients underwent determination of plasma homocysteine concentration. Homocysteine concentration was also measured in 30 healthy controls homogeneous for sex and age. RESULTS: In patients with scleroderma the homocysteine concentration was significantly higher than in controls (11.1 and 6.9 micromol/l, respectively; p < 0.001). We found a significant association between plasma homocysteine concentration and severity of lung involvement that was not modified by correction for age, time from the diagnosis, type of scleroderma pattern, and serum creatinine and folate levels. Homocysteine concentration progressively increases in scleroderma patients with more severe pulmonary involvement. Subjects with high homocysteine concentration (i.e., > or = 75th percentile of homocysteine concentration in patients with scleroderma without lung involvement) were mostly present in the group with the greatest lung involvement. CONCLUSION: High level of homocysteinemia is associated with an increased risk of pulmonary disease in patients with scleroderma. We hypothesize that hyperhomocysteinemia may worsen injury of the endothelium, a key lesion in scleroderma disease, favoring the development of lung involvement. Our data support the hypothesis that homocysteine could be involved in the pathogenetic process of scleroderma pulmonary involvement.     

The effects of recombinant-DNA-derived interferons on the growth of myeloid progenitor cells

Interferons (IFNs) have been shown to have significant effects on hematopoietic cell growth. Previous studies defining these effects have utilized mouse and human alpha-, beta-, and gamma-IFN isolated from supernatants of stimulated cells. Despite purification, the possible presence of other lymphokines and soluble factors remains a concern. In this study, the effects of gene-cloned alpha- and gamma-IFN on colony- forming units of granulocyte/macrophage (CFU-GM) progenitors cultured from the peripheral blood of normal volunteers were examined. In addition, blast cell colonies from one patient with acute myelogenous leukemia (AML) were studied. The growth of normal CFU-GM and AML blast cell colonies was inhibited in a dose-dependent manner by gamma- and alpha-IFN. gamma-IFN was ten to 100 times more potent than alpha-IFN in that this species of IFN reduced colony formation by greater than 50% at concentrations of less than 15 antiviral U/mL. The effects of gamma- IFN were neutralized by a monoclonal antibody specific for gamma-IFN. These in vitro studies indicate that human gamma-IFN may be an important modulator of myelopoiesis. Although these data indicate a possible efficacy of gamma-IFN in the treatment of AML, the in vitro results should be considered for their in vivo significance.     

Simple method for stapled low colorectal or coloanal anastomosis

A technique of stapled low colorectal or coloanal anastomosis is described, which follows eversion through the anus and stapled closure of the anorectal or anal remnant. The procedure is rapid and safe, and allows a secure distal clearance under direct visual control when dealing with tumors of the lower third of the rectum.     

Cerebral vein thrombosis in patients with Philadelphia‐negative myeloproliferative neoplasms An European Leukemia Net study

To investigate the characteristics and clinical course of cerebral vein thrombosis (CVT) in patients with myeloproliferative neoplasms (MPN) we compared 48 patients with MPN and CVT (group MPN‐CVT) to 87 with MPN and other venous thrombosis (group MPN‐VT) and 178 with MPN and no thrombosis (group MPN‐NoT) matched by sex, age at diagnosis of MPN (±5 years) and type of MPN. The study population was identified among 5,500 patients with MPN, from January 1982 to June 2013. Thrombophilia abnormalities were significantly more prevalent in the MPN‐CVT and MPN‐VT than in MPN‐NoT group (P = 0.015), as well as the JAK2 V617F mutation in patients with essential thrombocythemia (P = 0.059). Compared to MPN‐VT, MPN‐CVT patients had a higher rate of recurrent thrombosis (42% vs. 25%, P = 0.049) despite a shorter median follow‐up period (6.1 vs. 10.3 years, P = 0.019), a higher long‐term antithrombotic (94% vs. 84%, P = 0.099) and a similar cytoreductive treatment (79% vs. 70%, P = 0.311). The incidence of recurrent thrombosis was double in MPN‐CVT than in MPN‐VT group (8.8% and 4.2% patient‐years, P = 0.022), and CVT and unprovoked event were the only predictive variables in a multivariate model including also sex, blood count, thrombophilia, cytoreductive, and antithrombotic treatment (HR 1.97, 95%CI 1.05–3.72 and 2.09, 1.09–4.00, respectively). Am. J. Hematol. 89:E200–E205, 2014. © 2014 Wiley Periodicals, Inc.     

Central role for hydrogen peroxide in P2Y1 ADP receptor-mediated cellular responses in vascular endothelium

ADP activates a family of cell surface receptors that modulate signaling pathways in a broad range of cells. ADP receptor antagonists are widely used to treat cardiovascular disease states. These studies identify a critical role for the stable reactive oxygen species hydrogen peroxide (H₂O₂) in mediating cellular responses activated by the G protein-coupled P2Y1 receptor for ADP. We found that ADP-dependent phosphorylation of key endothelial signaling proteins—including endothelial nitric oxide synthase, AMP-activated protein kinase, and the actin-binding MARCKS protein—was blocked by preincubation with PEG-catalase, which degrades H₂O₂. ADP treatment promoted the H₂O₂-dependent phosphorylation of c-Abl, a nonreceptor tyrosine kinase that modulates the actin cytoskeleton. Cellular imaging experiments using fluorescence resonance energy transfer-based biosensors revealed that ADP-stimulated activation of the cytoskeleton-associated small GTPase Rac1 was independent of H₂O₂. However, Rac1-dependent activation of AMP-activated protein kinase, the signaling phospholipid phosphatidylinositol-(4, 5)-bisphosphate, and the c-Abl–interacting protein CrkII are mediated by H₂O₂. We transfected endothelial cells with differentially targeted HyPer2 H₂O₂ biosensors and found that ADP promoted a marked increase in H₂O₂ levels in the cytosol and caveolae, and a smaller increase in mitochondria. We performed a screen for P2Y1 receptor-mediated receptor tyrosine kinase transactivation and discovered that ADP transactivates Fms-like tyrosine kinase 3 (Flt3), a receptor tyrosine kinase expressed in these cells. Our observation that P2Y1 receptor-mediated responses involve Flt3 transactivation may identify a unique mechanism whereby cancer chemotherapy with receptor tyrosine kinase inhibitors promotes vascular dysfunction. Taken together, these findings establish a critical role for endogenous H₂O₂ in control of ADP-mediated signaling responses in the vascular wall.Beyond their established roles in intracellular energy flux and nucleic acid metabolism, purine nucleotides also serve as intercellular messenger molecules that regulate signal transduction pathways in a broad range of cells and tissues (1–3). The purine nucleotide ADP binds to G protein-coupled P2Y purinergic cell surface receptors, which are expressed in diverse mammalian cells, including blood platelets and vascular endothelial cells (reviewed in refs. 2 and 4). ADP is a critical determinant of platelet aggregation, blood vessel tone, and vascular wall integrity. Platelet granules contain high concentrations of ADP, which is released during platelet aggregation. The released ADP binds to P2Y12 and P2Y1 cell surface receptors for ADP on platelets and further potentiates platelet aggregation. P2Y receptor antagonists play a central role in cardiovascular therapeutics (2, 4): The P2Y12 blocker clopidogrel is one of the most commonly prescribed drugs in the United States, and other P2Y1 and P2Y12 blockers are being actively developed and tested for treatment of cardiovascular and cerebrovascular disease states. ADP also binds to P2Y1 receptors in vascular endothelial cells and rapidly activates endothelial nitric oxide synthase (eNOS) (5). Endothelium-generated nitric oxide (NO) inhibits platelet aggregation (3, 6) and provides an important feedback loop between endothelial cells and platelets that serves to attenuate the direct proaggregatory effects of ADP on platelets. ADP may also be released from the vascular endothelium and act in an autocrine or paracrine fashion to exert longer-term effects on vascular cell migration and barrier function (1, 3, 7–9). Clearly, a deeper understanding of P2Y receptor pharmacodynamics could inform current efforts in the development of novel purinergic antagonist drugs.Purinergic receptors for ADP can be classified by their structure and mode of action into two distinct receptor families, P2X and P2Y. P2X receptors are ligand-gated ion channels, whereas members of the P2Y receptor family are G protein-coupled receptors. ADP signaling pathways in platelets have been extensively characterized, yet the roles of ADP in the modulation of endothelial responses are less well understood. The current studies have focused on exploring the signaling pathways activated by P2Y1 receptors in vascular endothelial cells. We have shown (6) that ADP acts via P2Y1 receptors to activate the endothelial isoform of nitric oxide synthase (eNOS) in cultured endothelial cells and also modulates the activation of key signaling protein kinases including the AMP-activated protein kinase (AMPK). We also found that ADP promotes the P2Y1 ADP receptor-dependent endothelial cell migration through activation of the small GTPase Rac1 (6, 10). Discovering the involvement of Rac1 provided an important clue to the mechanisms whereby ADP exerts its influence on endothelial cell responses.Rac1 is an actin-binding cytoskeletal regulatory protein and is a member of the Rho GTPase protein family. The activation of eNOS by P2Y1 receptors for ADP depends on Rac1 (1, 6). Rac1 has been identified as a critical determinant of endothelial cell migration and barrier function, at least in part by modulating the levels of intracellular NO and hydrogen peroxide (H₂O₂) (11–15). H₂O₂ is a stable reactive oxygen species (ROS) that has been identified in recent years as a physiologically important intracellular messenger molecule (11–14), belying the classical concept of ROS functioning solely as deleterious molecules responsible for pathological states such as aging and neurodegeneration (14, 16). We reported (17, 18) that endogenous H₂O₂ regulates endothelial cell migration via dynamic signaling pathways involving the MARCKS protein, a ubiquitous phosphoprotein that translocates from the cell membrane to the actin cytoskeleton. The MARCKS protein also reversibly sequesters the signaling phospholipid phosphatidylinositol-(4, 5)-bisphosphate (PIP₂). PIP₂ is an important activator of proteins that initiate actin nucleation, including the phosphoprotein c-Abl, a nonreceptor tyrosine kinase that has been implicated in the dynamic cytoskeletal rearrangements that modulate endothelial barrier function. Endogenous H₂O₂ induces changes in cellular phospholipid metabolism via the phosphorylation and translocation of MARCKS in endothelial cells, yet the connections between receptor activation and intracellular modulation of H₂O₂ levels are incompletely understood.The roles of H₂O₂ as a physiological intracellular messenger molecule were initially discovered through studies of growth factor-dependent activation of their cognate receptor tyrosine kinases (19, 20), which then signal to redox-regulated phosphoprotein phosphatases via H₂O₂ (20). In contrast to the widespread involvement of H₂O₂ in receptor tyrosine kinase signaling, only a handful of G protein-coupled receptors have been shown to directly modulate H₂O₂ levels (11, 16, 21, 22). Indeed, the roles of H₂O₂ in modulation of physiological responses have not yet been clearly defined for G protein-coupled receptors. In these studies, we present observations that establish that the G protein-coupled P2Y1 receptor for ADP modulates key H₂O₂-dependent signaling responses in the vascular endothelium via transactivation of the receptor tyrosine kinase Flt3.