"My Whole World Fell Apart": Parents Discovering Their Child Has Anorexia Nervosa

This was the first study to examine the experience of parents who discover their child was living with anorexia nervosa (AN), thus fulfilling a critical gap in the eating disorder literature. Gadamerian hermeneutic inquiry was the guiding philosophy and method used to investigate this topic. Dialogues with parents revealed the ambiguity inherent within discovery; the isolation, betrayal, and loss felt by parents; and the complicated family dynamics occurring during the process of discovering one's child has AN. As such, when discoveries are made, parents play a vital role in the development and functioning of the family's response to the situation. This research offers health care providers a better understanding of the difficult times parents and caregivers experience when discovering their child has AN.

Tackling mixed messages: Practitioner reflections on working with adolescents with atypical anorexia and their families

The treatment of atypical anorexia nervosa (AN) poses new research and practice challenges for the field of eating disorders. The objective of this study was to describe frontline practitioners' perceptions of differences between adolescents living with atypical versus typical AN, as well as the intervention challenges they experience when working with these adolescents and their families. We followed the principles of fundamental qualitative description and recruited a purposeful sample of practitioners treating adolescent eating disorders to complete a one-on-one semi-structured interview. Conventional content analysis and the constant comparison technique were used for data analysis. A total of 23 practitioners from four countries participated in this study. Practitioners described that adolescents with atypical AN present with higher pre-morbid weights and rates of weight-based teasing compared to their AN peers. Clinical challenges perceived by practitioners to be specific to working with adolescents with atypical AN included: addressing conflicting messages about eating disorders and weight loss, empathizing with a justified fear of weight gain, and increased risk for parental and therapist collusion with the eating disorder. Findings have implications for delivering interventions to adolescents seeking care for atypical AN.

A phylogeny of the temperate seabasses (Moronidae) characterized by a translocation of the mt-nd6 gene

The entire mitochondrial genome of the striped bass Morone saxatilis was sequenced together with the mitochondrial (mt) control regions of the white bass Morone chrysops, white perch Morone americana, yellow bass Morone mississippiensis, spotted seabass Dicentrarchus punctatus, European seabass Dicentrarchus labrax and the Japanese seabass Lateolabrax japonicus. The resultant 17 580 base pair circular genome of M. saxatilis contains 38 genes (13 proteins, 23 transfer RNAs and two ribosomal RNAs) and a control region bordered by the proline and phenylalanine mitochondrial tRNAs. Gene arrangement was similar to other vertebrates, except that the mt-nd6 gene was found within the control region rather than the canonical position between the mt-nd5 and mt-cyb genes. This translocation was found in all the Morone and Dicentrarchus species studied without functional copies or pseudogenes in the ancestral position. In L. japonicus, the mt-nd6 gene was found in the canonical position without evidence of an mt-nd6 gene in the control region. A Bayesian analysis of these and published mt-nd6 sequences from 45 other Perciformes grouped the Morone and Dicentrarchus species monophyletically with a probability of 1·00 with respect to L. japonicus and all other perciforms, and placed the Dicentrarchus species in the basal position. These data reinforce current placement of L. japonicus outside the Moronidae and provide a clear evolutionary character to define this family. The phylogeny of the Moronidae presented here also supports the hypothesis of an anadromous common ancestor to this family that gave rise to the North American estuarine and freshwater species. A series of tandem repeats previously reported in M. saxatilis was found in the control region of all Morone species between the mt-nd6 and mt-rnr1 genes, but not in either Dicentrarchus species, which reinforces the continued use of these two separate genera.

Hypoxia-inducible factor 2alpha regulates macrophage function in mouse models of acute and tumor inflammation

Hypoxia-inducible factor 1alpha (HIF-1alpha) and HIF-2alpha display unique and sometimes opposing activities in regulating cellular energy homeostasis, cell fate decisions, and oncogenesis. Macrophages exposed to hypoxia accumulate both HIF-1alpha and HIF-2alpha, and overexpression of HIF-2alpha in tumor-associated macrophages (TAMs) is specifically correlated with high-grade human tumors and poor prognosis. However, the precise role of HIF-2alpha during macrophage-mediated inflammatory responses remains unclear. To fully characterize cellular hypoxic adaptations, distinct functions of HIF-1alpha versus HIF-2alpha must be elucidated. We demonstrate here that mice lacking HIF-2alpha in myeloid cells (Hif2aDelta/Delta mice) are resistant to lipopolysaccharide-induced endotoxemia and display a marked inability to mount inflammatory responses to cutaneous and peritoneal irritants. Furthermore, HIF-2alpha directly regulated proinflammatory cytokine/chemokine expression in macrophages activated in vitro. Hif2aDelta/Delta mice displayed reduced TAM infiltration in independent murine hepatocellular and colitis-associated colon carcinoma models, and this was associated with reduced tumor cell proliferation and progression. Notably, HIF-2alpha modulated macrophage migration by regulating the expression of the cytokine receptor M-CSFR and the chemokine receptor CXCR4, without altering intracellular ATP levels. Collectively, our data identify HIF-2alpha as an important regulator of innate immunity, suggesting it may be a useful therapeutic target for treating inflammatory disorders and cancer.

Abstract C67: Hypoxia-inducible factor-2α regulates macrophage functions in both acute and tumor inflammation

Hypoxia and inflammation in the tumor microenvironment profoundly influence carcinogenesis and tumor progression. In order to connect hypoxic signaling to inflammatory responses and their roles in oncogenesis, we investigated how one of the master regulators of hypoxic hypoxia-inducible factor (HIF)-2α, adaptations, regulates macrophage functions in both acute inflammatory diseases and cancer (a disease involving various inflammatory components). Myeloid-specific deletion of HIF-2α results in defective expression of a panel of proinflammatory cytokines in macrophages responding to innate stimuli. Also, mice lacking myeloid HIF-2α are resistant to lipopolysaccharide-induced endotoxemia and display a marked inability to mount inflammation in response to several other acute irritants, revealing that this transcription factor is essential for macrophage inflammatory responses. Tumor-associated macrophages (TAMs) represent the major inflammatory cell type within tumors and HIF-2α is robustly expressed in these cells. Clinically, increased TAM HIF-2α level correlates with high tumor grade and poor prognosis in breast and uterine cervical cancer, respectively. To characterize roles of HIF-2α in TAMs, we induced hepatocellular carcinoma (HCC) and colitis-associated cancer (CAC), two established inflammation-associated tumor models, in mice lacking myeloid HIF-2α expression. Interestingly, we found that HIF-2α -deficient TAMs migrate less efficiently into tumors, leading to reduced tumor cell proliferation and decreased malignancy in mutant mice. Further studies revealed that the deficient macrophages were attributable to compromised migration capacity of HIF-2α to insufficient expression of M-CSF receptor, CXCR4 and extracellular fibronectin-1. Therefore, our study demonstrated HIF-2α as an important regulator in both acute inflammation and cancer, suggesting that the myeloid HIF-2α pathway could be exploited as therapeutic targets for treating these diseases.

Citation Information: Cancer Res 2009;69(23 Suppl):C67.

Hematopoietic cell regulation by Rac1 and Rac2 guanosine triphosphatases

The Rho guanosine triphosphatases (GTPases) Rac1 and Rac2 are critical signaling regulators in mammalian cells. The deletion of both Rac1 and Rac2 murine alleles leads to a massive egress of hematopoietic stem/progenitor cells (HSC/Ps) into the blood from the marrow, whereas Rac1-/- but not Rac2-/- HSC/Ps fail to engraft in the bone marrow of irradiated recipient mice. In contrast, Rac2, but not Rac1, regulates superoxide production and directed migration in neutrophils, and in each cell type, the two GTPases play distinct roles in actin organization, cell survival, and proliferation. Thus, Rac1 and Rac2 regulate unique aspects of hematopoietic development and function.

Differential transduction efficiency of SCID-repopulating cells derived from umbilical cord blood and granulocyte colony-stimulating factor-mobilized peripheral blood

The gene transfer efficiency into nonobese diabetic/severe combined immunodeficient (NOD/SCID)-repopulating cells (SRCs) derived from umbilical cord blood (UCB) (n = 11 NOD/SCID mice) and granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood (MPB) (n = 64 NOD/SCID mice) was compared using a clinically relevant protocol and a retrovirus vector expressing the enhanced green fluorescent protein (EGFP). At 6-9 weeks after transplantation, the frequency of transduced human cells in the bone marrow (BM) (40.5% +/- 2.4% [mean +/- SE]) and spleen (SPL) (36.4% +/- 3.2%) in recipients of UCB cells was significantly higher (p < 0.001) than that observed in the BM (2.2% +/- 1.8%) and SPL (2.0% +/- 2.6%) in recipients of MPB. In subsequent studies, MPB was cultured for 2-8 days in cytokines prior to transduction to determine if longer prestimulation was required for optimal gene transfer. A significant increase in gene transfer into CD45(+) human cells and clonogenic cells derived from MPB SRCs was observed when cells were prestimulated for 6 days compared to 2 days prior to transduction (p = 0.019). However, even after 6 days of prestimulation, transduction was still significantly less than UCB. A substantial discrepancy exists in the ability to introduce genes effectively via retrovirus vectors into SRCs derived from MPB as compared to UCB.