Canonical Notch signaling is not required for the growth of Hedgehog pathway-induced medulloblastoma.

Current treatment for medulloblastoma is successful in more than half of all cases but results in substantial disability in survivors. Accordingly, there is considerable interest in drugs that may target specific signaling pathways activated in the tumors, with inhibitors of both the Hedgehog and Notch pathways currently proposed as possible therapeutics. Here, we tested the hypothesis that Notch pathway inhibition in vivo may block the formation of Hedgehog-dependent medulloblastoma. We took the general approach of using a cre recombinase under the control of the GFAP promoter to generate medulloblastoma in mice carrying a conditional Ptc1 allele and introduced a conditional RBP-J allele to ablate canonical Notch signaling. Loss of RBP-J from the developing cerebellum led to a modest loss of stem cells and an overall developmental delay. These phenotypes could be partially compensated by activation of the Hedgehog pathway. Hedgehog-dependent medulloblastoma were not blocked by loss of RBP-J, indicating that canonical Notch signaling is not required for tumor initiation and growth in this model.

Using videotelephony to support paediatric oncology-related palliative care in the home: from abandoned RCT to acceptability study.

Videotelephony (real-time audio-visual communication) has been used successfully in adult palliative home care. This paper describes two attempts to complete an RCT (both of which were abandoned following difficulties with family recruitment), designed to investigate the use of videotelephony with families receiving palliative care from a tertiary paediatric oncology service in Brisbane, Australia. To investigate whether providing videotelephone-based support was acceptable to these families, a 12-month non-randomised acceptability trial was completed. Seventeen palliative care families were offered access to a videotelephone support service in addition to the 24 hours 'on-call' service already offered. A 92% participation rate in this study provided some reassurance that the use of videotelephones themselves was not a factor in poor RCT participation rates. The next phase of research is to investigate the integration of videotelephone-based support from the time of diagnosis, through outpatient care and support, and for palliative care rather than for palliative care in isolation. Trial registration ACTRN 12606000311550.

Sonic Hedgehog regulates Hes1 through a novel mechanism that is independent of canonical Notch pathway signalling.

Aberrant regulation of signalling mechanisms that normally orchestrate embryonic development, such as the Hedgehog, Wnt and Notch pathways, is a common feature of tumorigenesis. In order to better understand the neoplastic events mediated by Hedgehog signalling, we identified over 200 genes regulated by Sonic Hedgehog in multipotent mesodermal cells. Widespread crosstalk with other developmental signalling pathways is evident, suggesting a complex network of interactions that challenges the often over-simplistic representation of these pathways as simple linear entities. Hes1, a principal effector of the Notch pathway, was found to be a target of Sonic Hedgehog in both C3H/10T1/2 mesodermal and MNS70 neural cells. Desert Hedgehog also elicited a strong Hes1 response. While Smoothened function was found necessary for upregulation of Hes1 in response to Sonic Hedgehog, the mechanism does not require gamma-secretase-mediated cleavage of Notch receptors, and appears to involve transcription factors other than RBP-Jkappa. Thus, we have defined a novel mechanism for Hes1 regulation in stem-like cells that is independent of canonical Notch signalling.

Improved outcomes of children with malignancy admitted to a pediatric intensive care unit.

OBJECTIVE: To assess the acute and long-term outcomes of children admitted to the intensive care unit with cancer or complications after bone marrow transplantation. DESIGN: Retrospective analysis of databases from a prospective pediatric intensive care unit (PICU) database supplemented by case notes review. SETTING: A PICU in a tertiary pediatric hospital. PATIENTS: All children with malignancy admitted to the PICU between May 1, 1987, and April 30, 1996. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 206 admissions to the PICU during a 9-yr study period of 150 children with malignancies or complications after bone marrow transplantation. Forty patents died in the PICU (27% mortality rate). The most frequent indications for PICU admission were shock and respiratory disease. Of 56 children admitted with shock, there were 16 deaths (29% mortality rate). In 24 episodes of sepsis, inotropic and ventilatory support were required and 13 patients (54%) survived. Analysis of long-term survival gave estimates of 50% survival for all oncology patients admitted to the PICU and 42% for those admitted for shock. CONCLUSIONS: A high proportion of oncology patients admitted to the PICU requiring intensive intervention survive and go on to be cured of their malignancy. Our study suggests the PICU outcome for these patients has improved.

Haemophagocytic lymphohistiocytosis in children.

OBJECTIVE: To evaluate the clinical and diagnostic features of children presenting with haemophagocytic lymphohistiocytosis (HLH), evolution of the disease and outcomes in response to treatment. METHODOLOGY: The medical records of 12 children, aged 5 weeks to 13 years at diagnosis, with HLH managed at a single institution were reviewed. RESULTS: Presenting features were fever, hepatosplenomegaly, pancytopenia and hypertriglyceridemia or hypofibrinogenemia. Nine patients (75%) developed central nervous system (CNS) disease. Only one child with CNS disease survived. Five children had complete responses to therapy (42%), but all relapsed at a median of 1.5 months after starting treatment (range 2 weeks to 5 months). Two of the children treated are long-term survivors (17%), both after allogeneic bone marrow transplantation. All deaths occurred in the context of active disease. CONCLUSIONS: Haemophagocytic lymphohistiocytosis is a disease with a poor prognosis. Central nervous system complications are common and response to treatment usually is transient. This study provides support for the use of immunomodulatory therapy for remission introduction followed by consideration of allogeneic bone marrow transplantation.

Products of neutrophils and eosinophils increase the responsiveness of human isolated bronchial tissue.

This study examines the possibility that products of neutrophils and eosinophils could increase the responsiveness of human isolated bronchial tissue. Neutrophils and eosinophils were isolated from the peripheral blood of healthy volunteers. The cells were incubated with 1 microM calcium ionophore A23187 for 10-15 min then centrifuged, the supernatant collected and stored at -70 degrees C. Human bronchial rings (2-3 mm diameter, 3-4 mm long) were prepared from specimens resected at thoracotomy. The tissues were suspended in organ baths under a 1 g load and changes in tension measured isometrically. Stable contractions to bolus doses of histamine (0.1-10 microM) or to electrical field stimulation (40-100 V, 4-16 Hz, 1 ms for 20 s) were established. Supernatant from 106 neutrophils or 105 eosinophils was then added and tissue responsiveness reassessed. Neutrophil supernatant increased tissue responsiveness to histamine and electrical field stimulation by 54 +/- 17% (n = 5, p less than 0.05) and 18 +/- 7% (n = 6, p less than 0.05), respectively. Eosinophil supernatant increased the histamine response by 60 +/- 23% (n = 8, p less than 0.05) while tissue responsiveness to electrical field stimulation was unchanged (n = 3). Thus, as neutrophils and eosinophils can change the responsiveness of human bronchus in vitro it is possible that they do this in vivo and may not simply be temporally related to the development of bronchial hyperresponsiveness.

Flow cytometric measurement of glutathione content of human cancer biopsies.

Rice et al. (1986) have described a flow cytometric method where the non-fluorescent probe monochlorobimane (mBCl) forms a fluorescent adduct with cellular glutathione (GSH) under the action of glutathione-S-transferase. We show here that for EMT6 carcinosarcoma cells there is a close correlation between mean cell fluorescence, expressed as a ratio to that of fluorescence calibration beads, and biochemically determined GSH content over the range 0.2-2.0 fmol cell-1. Single cell suspensions from 14 human cancers were prepared by 23-gauge needle aspiration or mechanical disaggregation of surgical specimens, stained using mBCl and examined by flow cytometry. There was a wide range in individual cell fluorescence, which in contrast to EMT6 cells was not strongly correlated with Coulter volume. By comparing tumour cell fluorescence to that of calibration beads, and assuming that the relationship with GSH content for EMT6 holds for other cells, a mean GSH content of 0.95 fmol cell-1 was derived for nine carcinomas, and 0.21 fmol cell-1 for five non-Hodgkin's lymphomas. Although this semi-quantitation needs further validation, the method used here is rapid, gives an indication of heterogeneity of tumour cell GSH content, and can be applied to fine needle biopsy samples. It therefore shows promise as a means for studying prospectively the relationship of GSH content to clinical drug and radiation sensitivity, and for monitoring the effects of agents such as buthionine sulphoximine which are intended to improve treatment results through tumour cell GSH depletion.