Deciphering the heterogeneity of the Lyve1+ perivascular macrophages in the mouse brain.

Perivascular macrophages (pvMs) are associated with cerebral vasculature and mediate brain drainage and immune regulation. Here, using reporter mouse models, whole brain and section immunofluorescence, flow cytometry, and single cell RNA sequencing, besides the Lyve1+F4/80+CD206+CX3CR1+ pvMs, we identify a CX3CR1- pvM population that shares phagocytic functions and location. Furthermore, the brain parenchyma vasculature mostly hosts Lyve1+MHCII- pvMs with low to intermediate CD45 expression. Using the double Cx3cr1GFP x Cx3cr1-Cre;RosatdT reporter mice for finer mapping of the lineages, we establish that CD45lowCX3CR1- pvMs are derived from CX3CR1+ precursors and require PU.1 during their ontogeny. In parallel, results from the Cxcr4-CreErt2;Rosa26tdT lineage tracing model support a bone marrow-independent replenishment of all Lyve1+ pvMs in the adult mouse brain. Lastly, flow cytometry and 3D immunofluorescence analysis uncover increased percentage of pvMs following photothrombotic induced stroke. Our results thus show that the parenchymal pvM population is more heterogenous than previously described, and includes a CD45low and CX3CR1- pvM population.

Murine semaphorin D/collapsin is a member of a diverse gene family and creates domains inhibitory for axonal extension.

Members of the collapsin/semaphorin gene family have been proposed to act as growth cone guidance signals in vertebrates and invertebrates. To identify candidate molecules involved in axonal pathfinding during mouse embryogenesis, we isolated cDNAs encoding five new members of the semaphorin family (Sem A-Sem E). The murine semaphorin genes are differentially expressed in mesoderm and neuroectoderm before and during the time when axons select their pathways in the embryo. In explant cultures, recombinant Sem D/collapsin converts a matrix permissive for axonal growth into one that is inhibitory for neurites of peripheral ganglia. Our data demonstrate that semaphorins are a diverse family of molecules that may provide local signals to specify territories nonaccessible for growing axons.

Myeloablative therapy with autologous stem cell rescue for patients with Ewing sarcoma.

The aim of this study was to identify risk factors associated with PFS in patients with Ewing sarcoma undergoing ASCT; 116 patients underwent ASCT in 1989-2000 and reported to the Center for International Blood and Marrow Transplant Research. Eighty patients (69%) received ASCT as first-line therapy and 36 (31%), for recurrent disease. Risk factors affecting ASCT were analyzed with use of the Cox regression method. Metastatic disease at diagnosis, recurrence prior to ASCT and performance score <90 were associated with higher rates of disease recurrence/progression. Five-year probabilities of PFS in patients with localized and metastatic disease at diagnosis who received ASCT as first-line therapy were 49% (95% CI 30-69) and 34% (95% CI 22-47) respectively. The 5-year probability of PFS in patients with localized disease at diagnosis, and received ASCT after recurrence was 14% (95% CI 3-30). PFS rates after ASCT are comparable to published rates in patients with similar disease characteristics treated with conventional chemotherapy, surgery and irradiation suggesting a limited role for ASCT in these patients. Therefore, ASCT if considered should be for high-risk patients in the setting of carefully controlled clinical trials.

Growth of four tropical tree species in petroleum-contaminated soil and effects of crude oil contamination.

Under greenhouse conditions, we evaluated establishment of four tree species and their capacity to degrade crude oil recently incorporated into the soil; the species were as follows: Cedrela odorata (tropical cedar), Haematoxylum campechianum (tinto bush), Swietenia macrophylla (mahogany), and Tabebuia rosea (macuilis). Three-month-old plants were planted in soil with three treatments of heavy petroleum and a control (C0 0 mg kg-1; C1 18,000 mg kg-1; C2 31,700 mg kg-1; C3 47,100 mg kg-1) with four repetitions per treatment and species; the experiment was carried out for 245 days. Height and biomass of all species significantly diminished as petroleum concentration increased, although plant survival was not affected. The quantity of colony-forming units (CFU) of rhizospheric bacteria varied among tree species and treatments; petroleum stimulated bacterial CFU for S. macrophylla. The number of fungi CFU for S. macrophylla and T. rosea was significantly greater in C0 than in soil with petroleum, but among species and among different concentrations, no significant differences were found. The greatest percentage of total petroleum hydrocarbon (TPH) degradation was found in C1 for soil without plants (45 %). Differences from the remaining treatments (petroleum concentrations in soil and plant species) were not significant (P < 0.05). Among all trees, H. campechianum had the greatest TPH degradation (32.5 % in C2). T. rosea (C1) and H. campechianum (C2) resulted in petroleum degradation at levels ranging from 20.5 to 32.5 %. On the basis of this experiment, the tree species used did not improve TPH degradation. However, all of them showed high rates of survival and vigor. So, as tree species provide goods and services, experiments with inoculation of hydrocarbonclastic microorganisms, addition of fertilizers, and mixture of tree and grasses are recommended.

The endothelial transcription factor ERG mediates Angiopoietin-1-dependent control of Notch signalling and vascular stability.

Notch and Angiopoietin-1 (Ang1)/Tie2 pathways are crucial for vascular maturation and stability. Here we identify the transcription factor ERG as a key regulator of endothelial Notch signalling. We show that ERG controls the balance between Notch ligands by driving Delta-like ligand 4 (Dll4) while repressing Jagged1 (Jag1) expression. In vivo, this regulation occurs selectively in the maturing plexus of the mouse developing retina, where Ang1/Tie2 signalling is active. We find that ERG mediates Ang1-dependent regulation of Notch ligands and is required for the stabilizing effects of Ang1 in vivo. We show that Ang1 induces ERG phosphorylation in a phosphoinositide 3-kinase (PI3K)/Akt-dependent manner, resulting in ERG enrichment at Dll4 promoter and multiple enhancers. Finally, we demonstrate that ERG directly interacts with Notch intracellular domain (NICD) and ß-catenin and is required for Ang1-dependent ß-catenin recruitment at the Dll4 locus. We propose that ERG coordinates Ang1, ß-catenin and Notch signalling to promote vascular stability.

Endothelial cell survival during angiogenesis requires the pro-survival protein MCL1.

Angiogenesis is essential to match the size of blood vessel networks to the metabolic demands of growing tissues. While many genes and pathways necessary for regulating angiogenesis have been identified, those responsible for endothelial cell (EC) survival during angiogenesis remain largely unknown. We have investigated the in vivo role of myeloid cell leukemia 1 (MCL1), a pro-survival member of the BCL2 family, in EC survival during angiogenesis. EC-specific deletion of Mcl1 resulted in a dose-dependent increase in EC apoptosis in the angiogenic vasculature and a corresponding decline in vessel density. Our results suggest this apoptosis was independent of the BH3-only protein BIM. Despite the known link between apoptosis and blood vessel regression, this was not the cause of reduced vessel density observed in the absence of endothelial MCL1. Rather, the reduction in vessel density was linked to ectopic apoptosis in regions of the angiogenic vasculature where EC proliferation and new vessel growth occurs. We have therefore identified MCL1 as an essential survival factor for ECs that is required for blood vessel production during angiogenesis.

A novel class of murine semaphorins with homology to thrombospondin is differentially expressed during early embryogenesis.

The semaphorins are a family of proteins thought to be involved in axonal guidance. Most of the known semaphorins have a similar primary structure characterized by the semaphorin domain and a carboxy-terminal Ig motif. Here we report the cloning of two members (semF and G) of a novel class of membrane-bound semaphorins which contain seven carboxy-terminal thrombospondin repeats, a motif known to promote neurite outgrowth. SemF and G transcripts are expressed, together with semD and E, in specific regions of young mouse embryos, demarcating distinct compartments of the developing somites or the undifferentiated neuroepithelium. The identification of semF and G increases the number of vertebrate semaphorins to at least 20 and suggests that some semaphorins might act as positive axonal guidance cues.

A double-blind randomized placebo-controlled study of oral glutamine in the prevention of mucositis in children undergoing hematopoietic stem cell transplantation: a pediatric blood and marrow transplant consortium study.

Severe mucositis is a common cause of morbidity in hematopoietic stem cell transplant (HSCT) recipients. Glutamine has been shown to reduce mucositis in children receiving chemotherapy. Patients were randomized in a double-blind manner to receive glutamine or glycine at a dose of 2 g/m(2)/dose (maximum dose 4 g) twice daily until 28 days post transplant or discharge if sooner. Mucositis was graded by use of a modified Walsh scale. A total of 120 children were evaluable: 57 children received glutamine and 63 received glycine. The mean mucositis score was 3.0+/-0.3 vs 3.9+/-0.4 (P=0.07) in the glutamine and glycine groups, respectively. The glutamine group demonstrated a reduction in mean number of days of intravenous narcotics use (12.1+/-1.5 vs 19.3+/-2.8 in the glycine group, P=0.03) and total parenteral nutrition (17.3+/-1.7 vs 27.3+/-3.6 in glycine group, P=0.01). There was no statistically significant difference in toxicity between the two groups. Glutamine appears to be safe and beneficial in reducing the severity of mucositis. Strong consideration should be given to include oral glutamine supplementation as a routine part of supportive care of SCT patients.

Eph receptors and ephrin ligands. essential mediators of vascular development.

The molecular and cellular mechanisms governing vascular development are still poorly understood. Prominent among the intercellular signals that control the initial establishment of the vascular network (termed vasculogenesis) and the subsequent remodeling process (called angiogenesis) are soluble ligands that signal through receptor tyrosine kinases (RTKs). Recent reports have added cell-bound ephrin ligands and their cognate Eph RTKs to the list of key players in vascular development.

Treatment of severe Evans syndrome with an allogeneic cord blood transplant.

Immunosuppressive therapy is commonly used in the management of autoimmune disorders. As marrow-derived lymphocytes appear to play a key role in these diseases, lymphoid ablation followed by replacement with autologous or allogeneic stem cells may be a therapeutic option. We report a 5-year-old boy with severe Evans syndrome which consists of immune thrombocytopenia and Coombs-positive hemolytic anemia. He was rendered into complete remission with marrow ablation followed by rescue with an HLA-identical sibling cord blood transplant. He unexpectedly died 9 months following transplant from acute hepatic failure of unknown etiology.

Successful treatment of JMML relapsed after unrelated allogeneic transplant with cytoreduction followed by DLI and interferon-alpha: evidence for a graft-versus-leukemia effect in non-monosomy-7 JMML.

Relapse is the major cause of treatment failure after allogeneic transplantation of children with juvenile myelomonocytic leukemia (JMML), and the role of post-transplant immunomodulation is poorly understood. We report a 12-month-old child with JMML relapsed after unrelated marrow transplantation who received cytoreduction followed by donor lymphocyte infusion (DLI) with improvement, and after addition of interferon-alpha (IFN) achieved complete donor chimerism. He was weaned from IFN and has maintained complete remission for 19 months. This is the first published report of a patient with non-monosomy-7 JMML responding to post-transplant immunomodulation and suggests a role for DLI plus IFN in these patients.

Psychosocial supportive care for children receiving stem cell transplantation: practice patterns across centers.

Although pediatric stem cell transplantation is associated with elevated risks for quality-of-life (QOL) deficits, morbidity, and late effects, little is known about how supportive care needs are addressed across different pediatric centers. This study examined practice patterns among centers enrolled in the Pediatric Blood and Marrow Transplant Consortium. In all, 65 centers (response rate=82.2%) were surveyed regarding QOL screening, psychosocial intervention services, and long-term follow-up care. Approximately 80% of centers provided routine screening for psychological difficulties and pain. A smaller number screened for fatigue (69.2%), cognitive deficits (52.3%), sleep difficulties (60.0%) or spiritual concerns (38.5%). Screening was conducted predominantly via interview; little use was made of standardized measures. Community-based centers screened some deficits more frequently than did academic ones (all P's

Bacillus cereus infections among oncology patients at a children's hospital.

BACKGROUND: Bacillus cereus can cause severe infections in immunocompromised persons. METHODS: We report 3 cases of bacteremia/septicemia (1 fatal) among oncology patients in a children's hospital. Because all cases occurred during a 10-day period, a common source outbreak was suspected. An epidemiologic investigation was performed. Molecular comparison of patient and environmental isolates was performed by using pulsed-field gel electrophoresis. RESULTS: After an extensive investigation, no common hospital source could be found. Pulsed-field gel electrophoresis proved that the isolates were not related. CONCLUSION: Sporadic infections in immunocompromised persons do occur and can be associated with significant morbidity.

Surgical suite reconstruction. Infection control.

Careful literature review revealed little information on the safety of using an operating room during major renovation. This study sought to determine if an operating room under renovation increases infectious morbidity in the surgical wound. The observations of this study indicate that it is possible to use a properly ventilated operating room undergoing renovation if the precautions of controlling construction traffic, sealing off the construction area from the OR in use, fastidious housekeeping, environmental culturing, and careful surveillance of wound infections are used.

Kidins220/ARMS mediates the integration of the neurotrophin and VEGF pathways in the vascular and nervous systems.

Signaling downstream of receptor tyrosine kinases controls cell differentiation and survival. How signals from different receptors are integrated is, however, still poorly understood. In this work, we have identified Kidins220 (Kinase D interacting substrate of 220 kDa)/ARMS (Ankyrin repeat-rich membrane spanning) as a main player in the modulation of neurotrophin and vascular endothelial growth factor (VEGF) signaling in vivo, and a primary determinant for neuronal and cardiovascular development. Kidins220(-/-) embryos die at late stages of gestation, and show extensive cell death in the central and peripheral nervous systems. Primary neurons from Kidins220(-/-) mice exhibit reduced responsiveness to brain-derived neurotrophic factor, in terms of activation of mitogen-activated protein kinase signaling, neurite outgrowth and potentiation of excitatory postsynaptic currents. In addition, mice lacking Kidins220 display striking cardiovascular abnormalities, possibly due to impaired VEGF signaling. In support of this hypothesis, we demonstrate that Kidins220 constitutively interacts with VEGFR2. These findings, together with the data presented in the accompanying paper, indicate that Kidins220 mediates the integration of several growth factor receptor pathways during development, and mediates the activation of distinct downstream cascades according to the location and timing of stimulation.