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Mineral and bone disorder is a common complication of end-stage renal disease. Notably, hyperphosphatemia likely promotes calcification of the myocardium, valves, and arteries. Hyperphosphatemia is associated with higher risk for cardiovascular mortality and morbidity along a gradient beginning at 5.0mg/dL. Among contemporary hemodialysis (HD) patients, mean serum phosphorus level is 5.2mg/dL, although 25% of patients have serum phosphorus levels of 5.5 to 6.9mg/dL; and 13%, >7.0mg/dL. Treatment of hyperphosphatemia is burdensome. Dialysis patients consume a mean of 19 pills per day, half of which are phosphate binders. Medicare Part D expenditures on binders for dialysis patients approached $700 million in 2013. Phosphorus removal with thrice-weekly HD (4 hours per session) is ∼3,000mg/wk. However, clearance is unlikely to counterbalance dietary intake, which varies around a mean of 7,000mg/wk. Dietary restriction and phosphate binders are important interventions, but each has limitations. Dietary control is complicated by limited access to healthy food choices and unclear labeling. Meanwhile, adherence to phosphate binders is poor, especially in younger patients and those with high pill burden. Multiple randomized clinical trials show that intensive HD reduces serum phosphorus levels. In the Frequent Hemodialysis Network (FHN) trial, short daily and nocturnal schedules reduced serum phosphorus levels by 0.6 and 1.6mg/dL, respectively, relative to 3 sessions per week. A similar effect of nocturnal HD was observed in an earlier trial. In the daily arm of the FHN trial, intensive HD significantly lowered estimated phosphate binder dose per day, whereas in the nocturnal arm, intensive HD led to binder discontinuation in 75% of patients. However, intensive HD appears to have no meaningful effects on serum calcium and parathyroid hormone concentrations. In conclusion, intensive HD, especially nocturnal HD, lowers serum phosphorus levels and decreases the need for phosphate binders., (Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Diminished health-related quality of life (HRQoL) is common in dialysis patients and associated with increased risks for morbidity and mortality. Patients may present limitations in both physical and mental HRQoL. Poor physical HRQoL may be defined by limited physical function, role limitations due to physical health, dissatisfaction with physical ability, and impaired mobility. Sleep disorders such as obstructive sleep apnea, restless legs, and fatigue are typical manifestations of poor physical HRQoL in dialysis patients. Poor mental HRQoL may be defined by depressive thinking, lack of positive affect, anxiety, and feelings of social isolation. The prevalence of depression is high in dialysis patients. Intensive hemodialysis (HD) can positively address HRQoL. In 3 randomized clinical trials, relative to conventional HD, intensive HD increased physical and mental component summary scores from the 36-Item Short-Form Health Survey (SF-36), although individual treatment effects of daily nocturnal HD were not statistically significant. In another large prospective study, initiation of short daily HD therapy was followed after 12 months by improvements in all SF-36 domains, sleep quality, and restless legs symptoms. In a small study of nocturnal HD, apnea and hypopnea episodes per hour decreased by almost 70% after conversion from conventional HD. Intensive HD is also associated with a large reduction in postdialysis recovery time. In contrast, 2 randomized clinical trials failed to demonstrate statistically significant effects of intensive HD on the Beck Depression Inventory score despite a significant decrease in Beck Depression Inventory score in the prospective study of short daily HD. Furthermore, intensive HD may not improve objective physical performance and can increase burden on caregivers in the home setting. In conclusion, intensive HD potentially can address both physical and mental aspects of poor HRQoL relative to conventional HD. However, more studies are needed to understand the effects of intensive HD, including specific schedules, on HRQoL., (Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Chronic myeloid leukaemia (CML) arises after transformation of a haemopoietic stem cell (HSC) by the protein-tyrosine kinase BCR-ABL. Direct inhibition of BCR-ABL kinase has revolutionized disease management, but fails to eradicate leukaemic stem cells (LSCs), which maintain CML. LSCs are independent of BCR-ABL for survival, providing a rationale for identifying and targeting kinase-independent pathways. Here we show--using proteomics, transcriptomics and network analyses--that in human LSCs, aberrantly expressed proteins, in both imatinib-responder and non-responder patients, are modulated in concert with p53 (also known as TP53) and c-MYC regulation. Perturbation of both p53 and c-MYC, and not BCR-ABL itself, leads to synergistic cell kill, differentiation, and near elimination of transplantable human LSCs in mice, while sparing normal HSCs. This unbiased systems approach targeting connected nodes exemplifies a novel precision medicine strategy providing evidence that LSCs can be eradicated., Competing Interests: Competing Interest Declaration–The work presented in Fig. 6 was in part supported by funding from Constellation Pharmaceuticals and Roche.

Targeting the Hedgehog (Hh) pathway represents a potential leukaemia stem cell (LSC)-directed therapy which may compliment tyrosine kinase inhibitors (TKIs) to eradicate LSC in chronic phase (CP) chronic myeloid leukaemia (CML). We set out to elucidate the role of Hh signaling in CP-CML and determine if inhibition of Hh signaling, through inhibition of smoothened (SMO), was an effective strategy to target CP-CML LSC. Assessment of Hh pathway gene and protein expression demonstrated that the Hh pathway is activated in CD34(+) CP-CML stem/progenitor cells. LDE225 (Sonidegib), a small molecule, clinically investigated SMO inhibitor, used alone and in combination with nilotinib, inhibited the Hh pathway in CD34(+) CP-CML cells, reducing the number and self-renewal capacity of CML LSC in vitro. The combination had no effect on normal haemopoietic stem cells. When combined, LDE225 + nilotinib reduced CD34(+) CP-CML cell engraftment in NSG mice and, upon administration to EGFP(+) /SCLtTA/TRE-BCR-ABL mice, the combination enhanced survival with reduced leukaemia development in secondary transplant recipients. In conclusion, the Hh pathway is deregulated in CML stem and progenitor cells. We identify Hh pathway inhibition, in combination with nilotinib, as a potentially effective therapeutic strategy to improve responses in CP-CML by targeting both stem and progenitor cells.

Modelling the parameters of multistep carcinogenesis is key for a better understanding of cancer progression, biomarker identification and the design of individualized therapies. Using chronic myeloid leukemia (CML) as a paradigm for hierarchical disease evolution we show that combined population dynamic modelling and CML patient biopsy genomic analysis enables patient stratification at unprecedented resolution. Linking CD34(+) similarity as a disease progression marker to patient-derived gene expression entropy separated established CML progression stages and uncovered additional heterogeneity within disease stages. Importantly, our patient data informed model enables quantitative approximation of individual patients' disease history within chronic phase (CP) and significantly separates "early" from "late" CP. Our findings provide a novel rationale for personalized and genome-informed disease progression risk assessment that is independent and complementary to conventional measures of CML disease burden and prognosis.

The stem cell paradigm was first demonstrated in hematopoietic stem cells. Whilst classically it was cytokines and chemokines which were believed to control stem cell fate, more recently it has become apparent that the stem cell niche and highly conserved embryonic pathways play a key role in governing stem cell behavior. One of these pathways, the hedgehog signaling pathway, found in all organisms, is vitally important in embryogenesis, performing the function of patterning through early stages of development, and in adulthood, through the control of somatic stem cell numbers. In addition to these roles in health however, it has been found to be deregulated in a number of solid and hematological malignancies, components of the hedgehog pathway being associated with a poor prognosis. Further, these components represent viable therapeutic targets, with inhibition from a drug development perspective being readily achieved, making the hedgehog pathway an attractive potential therapeutic target. However, although the concept of cancer stem cells is well established, how these cells arise and the factors which influence their behavior are not yet fully understood. The role of the hedgehog signaling pathway and its potential as a therapeutic target in hematological malignancies is the focus of this review.

Both acute myeloid leukemia and chronic myeloid leukemia are thought to arise from a subpopulation of primitive cells, termed leukemic stem cells that share properties with somatic stem cells. Leukemic stem cells are capable of continued self-renewal, and are resistant to conventional chemotherapy and are considered to be responsible for disease relapse. In recent years, improved understanding of the underlying mechanisms of myeloid leukemia biology has led to the development of novel and targeted therapies. This review focuses on clinically relevant patent applications and their relevance within the known literature in two areas of prevailing therapeutic interest, namely monoclonal antibody therapy and small molecule inhibitors in disease-relevant signaling pathways.

Chronic myeloid leukemia (CML) is initiated and maintained by the tyrosine kinase BCR-ABL which activates a number of signal transduction pathways, including PI3K/AKT signaling and consequently inactivates FOXO transcription factors. ABL-specific tyrosine kinase inhibitors (TKIs) induce minimal apoptosis in CML progenitor cells, yet exert potent antiproliferative effects, through as yet poorly understood mechanisms. Here, we demonstrate that in CD34+ CML cells, FOXO1 and 3a are inactivated and relocalized to the cytoplasm by BCR-ABL activity. TKIs caused a decrease in phosphorylation of FOXOs, leading to their relocalization from cytoplasm (inactive) to nucleus (active), where they modulated the expression of key FOXO target genes, such as Cyclin D1, ATM, CDKN1C, and BCL6 and induced G1 arrest. Activation of FOXO1 and 3a and a decreased expression of their target gene Cyclin D1 were also observed after 6 days of in vivo treatment with dasatinib in a CML transgenic mouse model. The over-expression of FOXO3a in CML cells combined with TKIs to reduce proliferation, with similar results seen for inhibitors of PI3K/AKT/mTOR signaling. While stable expression of an active FOXO3a mutant induced a similar level of quiescence to TKIs alone, shRNA-mediated knockdown of FOXO3a drove CML cells into cell cycle and potentiated TKI-induced apoptosis. These data demonstrate that TKI-induced G1 arrest in CML cells is mediated through inhibition of the PI3K/AKT pathway and reactivation of FOXOs. This enhanced understanding of TKI activity and induced progenitor cell quiescence suggests that new therapeutic strategies for CML should focus on manipulation of this signaling network., (© 2014 The Authors. STEM CELLS Published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

Background: Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are neoplastic disorders of hematopoietic stem cells. DNA methyltransferase inhibitors, 5-azacytidine and 5-aza-2'-deoxycytidine (decitabine), benefit some MDS/AML patients. However, the role of DNA methyltransferase inhibitor-induced DNA hypomethylation in regulation of gene expression in AML is unclear., Results: We compared the effects of 5-azacytidine on DNA methylation and gene expression using whole-genome single-nucleotide bisulfite-sequencing and RNA-sequencing in OCI-AML3 cells. For data analysis, we used an approach recently developed for discovery of differential patterns of DNA methylation associated with changes in gene expression, that is tailored to single-nucleotide bisulfite-sequencing data (Washington University Interpolated Methylation Signatures). Using this approach, we find that a subset of genes upregulated by 5-azacytidine are characterized by 5-azacytidine-induced signature methylation loss flanking the transcription start site. Many of these genes show increased methylation and decreased expression in OCI-AML3 cells compared to normal hematopoietic stem and progenitor cells. Moreover, these genes are preferentially upregulated by decitabine in human primary AML blasts, and control cell proliferation, death, and development., Conclusions: Our approach identifies a set of genes whose methylation and silencing in AML is reversed by DNA methyltransferase inhibitors. These genes are good candidates for direct regulation by DNA methyltransferase inhibitors, and their reactivation by DNA methyltransferase inhibitors may contribute to therapeutic activity.

CML (chronic myeloid leukaemia) is characterized by the presence of the oncogenic tyrosine kinase fusion protein BCR (breakpoint cluster region)-Abl, responsible for driving the disease. Current TKI (tyrosine kinase inhibitor) therapies effectively inhibit BCR-Abl to control CML in the majority of patients, but do not eliminate the LSC (leukaemic stem cell) population, which becomes quiescent following treatment. Patients require long-term treatment to sustain remission; alternative strategies are therefore required, either alone or in combination with TKIs to eliminate the LSCs and provide a cure. The embryonic morphogenetic pathways play a key role in haemopoiesis with recent evidence suggesting LSCs are more dependent on these signals following chemotherapy than normal HSCs (haemopoietic stem cells). Recent evidence in the literature and from our group has revealed that the BMP (bone morphogenetic protein) pathway is differentially expressed in CML patients compared with normal donors. In the present review, we explore the role that BMP signalling plays in oesteoblast differentiation, HSC maintenance and the implication of altered BMP signalling on LSC persistence in the BM (bone marrow) niche. Overall, we highlight the BMP pathway as a potential target for developing LSC-directed therapies in CML in the future.

Background: Over 40% of patients with end stage renal disease in the United States were treated with home hemodialysis (HHD) in the early 1970's. However, this number declined rapidly over the ensuing decades so that the overwhelming majority of patients were treated in-centre 3 times per week on a 3-4 hour schedule. Poor outcomes for patients treated in this fashion led to a renewed interest in home hemodialysis, with more intensive dialysis schedules including short daily (SDHD) and nocturnal (NHD). The relative infancy of these treatment schedules means that there is a paucity of data on 'how to do it'., Objective: We undertook a systematic survey of home hemodialysis programs in Canada to describe current practice patterns., Design: Development and deployment of a qualitative survey instrument., Setting: Community and academic HHD programs in Canada., Participants: Physicians, nurses and technologists., Measurements: Programmatic approaches to patient selection, delivery of dialysis, human resources available, and follow up., Methods: We developed the survey instrument in three phases. A focus group of Canadian nephrologists with expertise in NHD or SDHD discussed the scope the study and wrote questions on 11 domains. Three nephrologists familiar with all aspects of HHD delivery reviewed this for content validity, followed by further feedback from the whole group. Multidisciplinary teams at three sites pretested the survey and further suggestions were incorporated. In July 2010 we distributed the survey electronically to all renal programs known to offer HHD according to the Canadian Organ Replacement Registry. We compiled the survey results using qualitative and quantitative methods, as appropriate., Results: Of the academic and community programs that were invited to participate, 80% and 63%, respectively, completed the survey. We observed wide variation in programmatic approaches to patient recruitment, human resources, equipment, water, vascular access, patient training, dialysis prescription, home requirements, patient follow up, medications, and the approach to non-adherent patients., Limitations: Cross-sectional survey, unable to link variation to outcomes. Competition for patients between HHD and home peritoneal dialysis means that case mix for HHD may also vary between centres., Conclusions: There is wide variation between programs in all domains of HHD delivery in Canada. We plan further study of the extent to which differences in approach are related to outcomes.

Background: Home-based renal replacement therapy (RRT) [peritoneal dialysis (PD) and home hemodialysis (HHD)] offers independent quality of life and clinical advantages compared to conventional in-center hemodialysis. However, follow-up may be less complete for home dialysis patients following a change in care settings such as post hospitalization. We aim to implement a Home Dialysis Virtual Ward (HDVW) strategy, which is targeted to minimize gaps of care., Methods/design: The HDVW Pilot Study will enroll consecutive PD and HHD patients who fulfilled any one of our inclusion criteria: 1. following discharge from hospital, 2. after interventional procedure(s), 3. prescription of anti-microbial agents, or 4. following completion of home dialysis training. Clinician-led telephone interviews are performed weekly for 2 weeks until VW discharge. Case-mix (modified Charlson Comorbidity Index), symptoms (the modified Edmonton Symptom Assessment Scale) and patient satisfaction are assessed serially. The number of VW interventions relating to eight pre-specified domains will be measured. Adverse events such as re-hospitalization and health-services utilization will be ascertained through telephone follow-up after discharge from the VW at 2, 4, 12 weeks. The VW re-hospitalization rate will be compared with a contemporary cohort (matched for age, gender, renal replacement therapy and co-morbidities). Our protocol has been approved by research ethics board (UHN: 12-5397-AE). Written informed consent for participation in the study will be obtained from participants., Discussion: This report serves as a blueprint for the design and implementation of a novel health service delivery model for home dialysis patients. The major goal of the HDVW initiative is to provide appropriate and effective supports to medically complex patients in a targeted window of vulnerability., Trial Registration: (NCT01912001).

Chronic myeloid leukemia (CML) stem cells are not dependent on BCR-ABL kinase for their survival, suggesting that kinase-independent mechanisms must contribute to their persistence. We observed that CML stem/progenitor cells (SPCs) produce tumor necrosis factor-α (TNF-α) in a kinase-independent fashion and at higher levels relative to their normal counterparts. We therefore investigated the role of TNF-α and found that it supports survival of CML SPCs by promoting nuclear factor κB/p65 pathway activity and expression of the interleukin 3 and granulocyte/macrophage-colony stimulating factor common β-chain receptor. Furthermore, we demonstrate that in CML SPCs, inhibition of autocrine TNF-α signaling via a small-molecule TNF-α inhibitor induces apoptosis. Moreover TNF-α inhibition combined with nilotinib induces significantly more apoptosis relative to either treatment alone and a reduction in the absolute number of primitive quiescent CML stem cells. These results highlight a novel survival mechanism of CML SPCs and suggest a new putative therapeutic target for their eradication.

Homologous recombination repair (HRR) protects cells from the lethal effect of spontaneous and therapy-induced DNA double-stand breaks. HRR usually depends on BRCA1/2-RAD51, and RAD52-RAD51 serves as back-up. To target HRR in tumor cells, a phenomenon called "synthetic lethality" was applied, which relies on the addiction of cancer cells to a single DNA repair pathway, whereas normal cells operate 2 or more mechanisms. Using mutagenesis and a peptide aptamer approach, we pinpointed phenylalanine 79 in RAD52 DNA binding domain I (RAD52-phenylalanine 79 [F79]) as a valid target to induce synthetic lethality in BRCA1- and/or BRCA2-deficient leukemias and carcinomas without affecting normal cells and tissues. Targeting RAD52-F79 disrupts the RAD52-DNA interaction, resulting in the accumulation of toxic DNA double-stand breaks in malignant cells, but not in normal counterparts. In addition, abrogation of RAD52-DNA interaction enhanced the antileukemia effect of already-approved drugs. BRCA-deficient status predisposing to RAD52-dependent synthetic lethality could be predicted by genetic abnormalities such as oncogenes BCR-ABL1 and PML-RAR, mutations in BRCA1 and/or BRCA2 genes, and gene expression profiles identifying leukemias displaying low levels of BRCA1 and/or BRCA2. We believe this work may initiate a personalized therapeutic approach in numerous patients with tumors displaying encoded and functional BRCA deficiency.

Most patients now receiving a haematopoietic stem cell transplant (HSCT) for chronic myeloid leukaemia (CML) have been treated with first and second line TKIs pre-HSCT, raising concerns that these patients will have more resistant disease and accumulated greater toxicity from sequential lines of therapy, potentially compromising their outcome. We outline a series of 9 patients treated with imatinib then second generation TKIs for CML followed by HSCT and compare their outcomes with patients receiving imatinib-only pre-HSCT. Our case series demonstrates that second line and sequential tyrosine kinase inhibitors followed by HSCT is a safe and effective therapeutic approach for high risk CML.

Intensive (longer and more frequent) hemodialysis has emerged as an alternative to conventional hemodialysis for the treatment of patients with end-stage renal disease. However, given the differences in dialysis delivery and models of care associated with intensive dialysis, alternative approaches to patient management may be required. The purpose of this work was to develop a clinical practice guideline for the Canadian Society of Nephrology. We applied the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach for guideline development and performed targeted systematic reviews and meta-analysis (when appropriate) to address prioritized clinical management questions. We included studies addressing the treatment of patients with end-stage renal disease with short daily (≥5 days per week, <3 hours per session), long (3-4 days per week, ≥5.5 hours per session), or long-frequent (≥5 days per week, ≥5.5 hours per session) hemodialysis. We included clinical trials and observational studies with or without a control arm (1990 and later). Based on a prioritization exercise, 6 interventions of interest included optimal vascular access type, buttonhole cannulation, antimicrobial prophylaxis for buttonhole cannulation, closed connector devices, and dialysate calcium and dialysate phosphate additives for patients receiving intensive hemodialysis. We developed 6 recommendations addressing the interventions of interest. Overall quality of the evidence was very low and all recommendations were conditional. We provide detailed commentaries to guide in shared decision making. The main limitation was the very low overall quality of evidence that precluded strong recommendations. Most included studies were small single-arm observational studies. Three randomized controlled trials were applicable, but provided only indirect evidence. Published information for patient values and preference was lacking. In conclusion, we provide 6 recommendations for the practice of intensive hemodialysis. However, due to very low-quality evidence, all recommendations were conditional. We therefore also highlight priorities for future research., (Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Patients treated with conventional hemodialysis (HD) develop disorders of mineral metabolism that are associated with increased morbidity and mortality. More frequent and longer HD has been associated with improvement in hyperphosphatemia that may improve outcomes., Study Design: Systematic review and meta-analysis to inform the clinical practice guideline on intensive dialysis for the Canadian Society of Nephrology., Setting & Population: Adult patients receiving outpatient long (≥5.5 hours/session; 3-4 times per week) or long-frequent (≥5.5 hours/session, ≥5 sessions per week) HD., Selection Criteria for Studies: We included clinical trials, cohort studies, case series, case reports, and systematic reviews., Interventions: Dialysate calcium concentration ≥1.5 mmol/L and/or phosphate additive., Outcomes: Fragility fracture, peripheral arterial and coronary artery disease, calcific uremic arteriolopathy, mortality, intradialytic hypotension, parathyroidectomy, extraosseous calcification, markers of mineral metabolism, diet liberalization, phosphate-binder use, and muscle mass., Results: 21 studies were identified: 2 randomized controlled trials, 2 reanalyses of data from the randomized controlled trials, and 17 observational studies. Dialysate calcium concentration ≥1.5 mmol/L for patients treated with long and long-frequent HD prevents an increase in parathyroid hormone levels and a decline in bone mineral density without causing harm. Both long and long-frequent HD were associated with a reduction in serum phosphate level of 0.42-0.45 mmol/L and a reduction in phosphate-binder use. There was no direct evidence to support the use of a dialysate phosphate additive., Limitations: Almost all the available information is related to changes in laboratory values and surrogate outcomes., Conclusions: Dialysate calcium concentration ≥1.5 mmol/L for most patients treated with long and long-frequent dialysis prevents an increase in parathyroid hormone levels and decline in bone mineral density without increased risk of calcification. It seems prudent to add phosphate to the dialysate for patients with a low predialysis phosphate level or very low postdialysis phosphate level until more evidence becomes available., (Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Practices in vascular access management with intensive hemodialysis may differ from those used in conventional hemodialysis., Study Design: We conducted a systematic review to inform clinical practice guidelines for the provision of intensive hemodialysis., Setting & Population: Adult patients receiving maintenance (>3 months) intensive hemodialysis (frequent [≥5 hemodialysis treatments per week] and/or long [>5.5 hours per hemodialysis treatment])., Selection Criteria for Studies: We searched EMBASE and MEDLINE (1990-2011) for randomized and observational studies. We also searched conference proceedings (2007-2011)., Interventions: (1) Central venous catheter (CVC) versus arteriovenous (AV) access, (2) buttonhole versus rope-ladder cannulation, (3) topical antimicrobial cream versus none in buttonhole cannulation, and (4) closed connector devices among CVC users., Outcomes: Access-related infection, survival, hospitalization, patency, access survival, intervention rates, and quality of life., Results: We included 23, 7, and 5 reports describing effectiveness by access type, buttonhole cannulation, and closed connector device, respectively. No study directly compared CVC with AV access. On average, bacteremia and local infection rates were higher with CVC compared with AV access. Access intervention rates were higher with more frequent hemodialysis, but access survival did not differ. Buttonhole cannulation was associated with bacteremia rates similar to those seen with CVCs in some series. Topical mupirocin seemed to attenuate this effect. No direct comparisons of closed connector devices versus standard luer-locking devices were found. Low rates of actual or averted (near misses) air embolism and bleeding were reported with closed connector devices., Limitations: Overall, evidence quality was very low. Limited direct comparisons addressing main review questions, small sample sizes, selective outcome reporting, publication bias, and residual confounding were major factors., Conclusions: This review highlights several differences in the management of vascular access in conventional and intensive hemodialysis populations. We identify a need for standardization of vascular access outcome reporting and a number of priorities for future research., (Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

A fundamental property of hematopoietic stem cells (HSCs) is the ability to self-renew. This is a complex process involving multiple signal transduction cascades which control the fine balance between self-renewal and differentiation through transcriptional networks. Key activators/regulators of self-renewal include chemokines, cytokines and morphogens which are expressed in the bone marrow niche, either in a paracrine or autocrine fashion, and modulate stem cell behaviour. Increasing evidence suggests that the downstream signaling pathways induced by these ligands converge at multiple levels providing a degree of redundancy in steady state hematopoiesis. Here we will focus on how these pathways cross-talk to regulate HSC self-renewal highlighting potential therapeutic windows which could be targeted to prevent leukemic stem cell self-renewal in myeloid malignancies.

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder that is characterized by the presence of the fusion oncogene BCR-ABL that encodes the tyrosine kinase BCR-ABL. Constitutive expression of BCR-ABL leads to the unregulated production of mature myeloid cells in the bone marrow and their subsequent release into the blood. Untreated, CML will progress from a chronic to accelerated phase over a number of years before quickly proceeding to a terminal blast crisis phase, reminiscent of acute leukemia. The advent of tyrosine kinase inhibitors has led to much improved management of the disease, but these drugs do not provide a cure as they are unable to eradicate the most primitive, quiescent fraction of CML stem cells. This review looks at recent research into targeting CML stem cells and focuses on major signalling pathways of interest.

Accumulating evidence suggests that human cancers develop through a step-wise, but nonlinear process of cellular diversification and evolution. Recent mutational analyses indicate that this process is more complex and diverse than anticipated before whole-genome sequencing methods were readily available. Examples are also emerging now of genetically abnormal clones of cells that have acquired mutations with known oncogenic potential but, nevertheless, may show no manifestations of malignant change for many years. To accommodate these diverse realities, we suggest the term neoplastic refer to clones of cells that have any type of somatic aberrancy associated with an increased propensity to become malignant, and the derivative term neoplastic stem cell be adopted to identify the cells responsible for the long-term maintenance of such clones. Neoplastic clones would thus include those that never evolve further, as well as those that eventually give rise to fully malignant populations, and all stages in between. The term cancer stem cells would then be more appropriately restricted to cells generating subclones that have established malignant properties. More precise molecular understanding of the different stem cell states thus distinguished should contribute to the development of more effective prognostic and therapeutic tools for cancer diagnosis and treatment.

Chronic myeloid leukaemia (CML) arises in a haemopoietic stem cell and is driven by the Bcr-Abl oncoprotein. Abl kinase inhibitors (protein tyrosine kinase inhibitors) represent standard treatment for CML and induce remission in the majority of patients with early disease, however these drugs do not target leukaemic stem cells (LSCs) effectively, thus preventing cure. Previously, we identified the farnesyl transferase inhibitor BMS-214662 as a selective inducer of apoptosis in LSCs of CML patients relative to normal controls; however, the mechanism underlying LSC-specific apoptosis remains unclear. To identify pathways involved in the favourable effects of BMS-214662 in CML, we employed a proteomic approach (based on iTRAQ) to analyse changes in protein expression in response to drug treatment in the nuclear and cytoplasmic fractions of CD34(+) CML cells. The study identified 88 proteins as altered after drug treatment, which included proteins known to be involved in nucleic acid metabolism, oncogenesis, developmental processes and intracellular protein trafficking. We found that expression of Ebp1, a negative regulator of proliferation, was upregulated in the nucleus of BMS-214662-treated cells. Furthermore, proteins showing altered levels in the cytosol, such as histones, were predominantly derived from the nucleus and BMS-214662 affected expression levels of nuclear pore complex proteins. Validation of key facets of these observations suggests that drug-induced alterations in protein localisation, potentially via loss of nuclear membrane integrity, contributes to the LSC specificity of BMS-214662, possibly via Ran proteins as targets., (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The mitochondrial respiratory chain (MRC) consists of protein complexes I, II, III, IV and V that support oxidative phosphorylation (OXPHOS), which depends on electron transport to generate adenosine triphosphate (ATP). Electron "leakage" from the MRC generates reactive oxygen species (ROS). Chronic myeloid leukemia in chronic phase (CML-CP) stem cells (LSCs) produce high levels of mitochondrial ROS, causing oxidative DNA damage, resulting in genomic instability, generating imatinib-resistant BCR-ABL1 kinase mutants and additional chromosomal aberrations. Using global mRNA microarray analysis combined with Ingenuity Pathway Analysis we found that LSCs display enhanced expression of genes encoding MRC complexes I, II, IV and V. However, expression of genes encoding complex III was deregulated. Treatment with imatinib did not correct the aberrant levels of MRC genes. Therefore we postulate that abnormal expression of MRC genes may facilitate electron "leakage" to promote the production of ROS and accumulation of genomic instability in LSCs in imatinib-naive and imatinib-treated patients.

Priapism is a rare presenting feature of chronic myeloid leukaemia (CML). It is a urological emergency requiring urgent treatment to prevent long-term complications, in particular erectile dysfunction. In males with CML, ischaemic priapism is believed to result from hyperleucocytosis and associated leucostasis or hyperviscosity, and is seen in patients presenting with a high white cell count. Increasingly, a combined modality approach is being used to treat CML patients presenting with priapism. This includes systemic therapy with chemotherapy (hydroxycarbamide or tyrosine kinase inhibitors) and therapeutic leukapheresis to reduce the white cell count as well as local intracavernous therapy. This review will examine the literature and discuss the presenting features, investigations and management of priapism in CML., (© 2012 Blackwell Publishing Ltd.)

Patients undergoing conventional maintenance hemodialysis typically receive three sessions per week, each lasting 2.5-5.5 hours. Recently, the use of more intensive hemodialysis (>5.5 hours, three to seven times per week) has increased, but the effects of these regimens on survival are uncertain. We conducted a retrospective cohort study to examine whether intensive hemodialysis associates with better survival than conventional hemodialysis. We identified 420 patients in the International Quotidian Dialysis Registry who received intensive home hemodialysis in France, the United States, and Canada between January 2000 and August 2010. We matched 338 of these patients to 1388 patients in the Dialysis Outcomes and Practice Patterns Study who received in-center conventional hemodialysis during the same time period by country, ESRD duration, and propensity score. The intensive hemodialysis group received a mean (SD) 4.8 (1.1) sessions per week with a mean treatment time of 7.4 (0.87) hours per session; the conventional group received three sessions per week with a mean treatment time of 3.9 (0.32) hours per session. During 3008 patient-years of follow-up, 45 (13%) of 338 patients receiving intensive hemodialysis died compared with 293 (21%) of 1388 patients receiving conventional hemodialysis (6.1 versus 10.5 deaths per 100 person-years; hazard ratio, 0.55 [95% confidence interval, 0.34-0.87]). The strength and direction of the observed association between intensive hemodialysis and improved survival were consistent across all prespecified subgroups and sensitivity analyses. In conclusion, there is a strong association between intensive home hemodialysis and improved survival, but whether this relationship is causal remains unknown.

The oncogenic fusion protein BCR-ABL is produced by chronic myeloid leukemia (CML) cells and functions as an abnormal, constitutively active tyrosine kinase that interferes with normal migratory and apoptotic behaviour of cells. Small molecule tyrosine kinase inhibitors (TKIs), such as dasatinib, eliminate CML progenitor cells, but fail to target the stem cell fraction resulting in persistent disease. In order to achieve a cure for CML in the majority of patients, we need an improved understanding of intracellular signalling dynamics, including the shuttling of BCR-ABL between cytosolic and nuclear compartments. In the past, the instability of BCR-ABL in assays using conventional immunohistochemical techniques has made this difficult and has not allowed for reliable analysis at the single cell level. Here we show how the utilization of rapid on-chip cell fixation within a microfluidic platform provides a means to immunofluorescently analyze the spatiotemporal localization of both BCR-ABL and c-ABL, as well as the linked apoptosis mediator, BCL-XL, in arrays of single CD34+ CML stem/progenitor cells, without cell loss. We demonstrate this proceeds up to 4 times faster than benchtop methods. Our results indicate that whilst both BCR-ABL and c-ABL shuttle from the cytoplasm to the nucleus following dasatinib treatment, the temporal dynamics are not synchronized. The microfluidic platform has the potential to provide insights into the intracellular signalling events in single cells. The ability to examine signalling events and assess BCR-ABL expression/activity in isolated cells in "real-time" may help elucidate the characteristics of rare CML stem cell events, which lead to the resistance of CML stem cells to TKIs., (This journal is © The Royal Society of Chemistry 2012)

The Hedgehog pathway is a critical mediator of embryonic patterning and organ development, including hematopoiesis. It influences stem cell fate, differentiation, proliferation, and apoptosis in responsive tissues. In adult organisms, hedgehog pathway activity is required for aspects of tissue maintenance and regeneration; however, there is increasing awareness that abnormal hedgehog signaling is associated with malignancy. Hedgehog signaling is critical for early hematopoietic development, but there is controversy over its role in normal hematopoiesis in adult organisms where it may be dispensable. Conversely, hedgehog signaling appears to be an important survival and proliferation signal for a spectrum of hematologic malignancies. Furthermore, hedgehog signaling may be critical for the maintenance and expansion of leukemic stem cells and therefore provides a possible mechanism to selectively target these primitive cell subpopulations, which are resistant to conventional chemotherapy. Indeed, phase 1 clinical trials of hedgehog pathway inhibitors are currently underway to test this hypothesis in myeloid leukemias. This review covers: (1) the hedgehog pathway and its role in normal and malignant hematopoiesis, (2) the recent development of clinical grade small molecule inhibitors of the pathway, and (3) the potential utility of hedgehog pathway inhibition as a therapeutic strategy in hemato-oncology.

Independent dialysis therapies are as effective as in-center therapies but cost only about half as much. This project incorporated a patient focus group to better understand patient perceptions and possible barriers related to choosing independent dialysis therapies. Focus group findings included hardship related to loss of kidney function, the need for support from healthcare professionals, the need for educational materials and recruitment strategies focused on the benefits of independent dialysis, the need for peer support to encourage choice of independent dialysis modality, and support for technical issues. Themes identified by the focus group were used to create two new education tools and a nurse-delivered education program for patients with CKD. Future evaluation will determine whether these efforts lead to an increase in selection of independent dialysis therapies.

Prior small studies have shown multiple benefits of frequent nocturnal hemodialysis compared to conventional three times per week treatments. To study this further, we randomized 87 patients to three times per week conventional hemodialysis or to nocturnal hemodialysis six times per week, all with single-use high-flux dialyzers. The 45 patients in the frequent nocturnal arm had a 1.82-fold higher mean weekly stdKt/V(urea), a 1.74-fold higher average number of treatments per week, and a 2.45-fold higher average weekly treatment time than the 42 patients in the conventional arm. We did not find a significant effect of nocturnal hemodialysis for either of the two coprimary outcomes (death or left ventricular mass (measured by MRI) with a hazard ratio of 0.68, or of death or RAND Physical Health Composite with a hazard ratio of 0.91). Possible explanations for the left ventricular mass result include limited sample size and patient characteristics. Secondary outcomes included cognitive performance, self-reported depression, laboratory markers of nutrition, mineral metabolism and anemia, blood pressure and rates of hospitalization, and vascular access interventions. Patients in the nocturnal arm had improved control of hyperphosphatemia and hypertension, but no significant benefit among the other main secondary outcomes. There was a trend for increased vascular access events in the nocturnal arm. Thus, we were unable to demonstrate a definitive benefit of more frequent nocturnal hemodialysis for either coprimary outcome.

Background and Objective: Acute kidney injury is a common finding among patients in the intensive care unit (ICU) and is an independent predictor of mortality. The optimal intensity and timing of continuous renal replacement therapy (CRRT), in critically ill patients remain unclear. The purpose of this study was to conduct a systematic review and meta-analysis of all prospective randomized controlled trials (RCTs) to determine the effect of intensity of CRRT on the survival of patients with acute renal failure (ARF) in ICU setting., Methods: Search strategy and data source. Electronic databases were searched on MEDLINE (through February 2010), ISIWeb of Science, and Cochrane Central Register of Controlled Trials (2010); Pub Med ''Related articles.'' Trial authors were also contacted for additional information. Study selection and data abstraction. All prospective clinical trials comparing the intensity of CRRT in adult patients with ARF and with explicit reporting of mortality were included. Three authors independently evaluated articles for eligibility and extracted data on study quality and outcomes. Meta-analysis used a random-effects model., Result: Of the 322 citations, 5 trials (n = 2402) were included in the meta-analysis, which met all the inclusion and exclusion criteria. Meta-analysis showed that in critically ill patients with acute kidney injury, the high-dose CRRT did not reduce mortality at 28 days. (risk ratio [RR], 0.88; 95% confidence interval [CI], 0.70-1.11; P = 0.28)., Conclusion: In critically ill patients with acute kidney injury, the high-dose CRRT did not reduce mortality at 28 days.

The cytotoxic farnesyl transferase inhibitor BMS-214662 has been shown to potently induce mitochondrial apoptosis in primitive CD34+ chronic myeloid leukaemia (CML) stem/progenitor cells. Here, to enhance the BMS-214662 apoptotic effect, we further targeted the extracellular signal-regulated kinase (ERK) pathway, downstream of BCR-ABL, by treating CD34+ CML stem/progenitor cells with a highly selective adenosine triphosphate (ATP) non-competitive MEK inhibitor, PD184352. PD184352 increased the apoptotic effect of BMS-214662 in a CML blast crisis cell line, K562, and in primary chronic phase CD34+ CML cells. Compared with BMS-214662, after combination treatment we observed inhibition of ERK phosphorylation, increased Annexin-V levels, caspase-3, -8 and -9 activation and potentiated mitochondrial damage, associated with decreased levels of anti-apoptotic BCL-2 family protein MCL-1. Inhibition of K-RAS function by a dominant-negative mutant resulted in CML cell death and this process was further enhanced by the addition of BMS-214662 and PD184352. Together, these findings suggest that the addition of a MEK inhibitor improves the ability of BMS-214662 to selectively target CML stem/progenitor cells, notoriously insensitive to tyrosine kinase inhibitor treatment and presumed to be responsible for the persistence and relapse of the disease.

Prospective identification of patients whose chronic myeloid leukemia (CML) will progress to blast crisis is currently not possible. PP2A is a phosphatase and tumor suppressor that regulates cell proliferation, differentiation, and survival. Cancerous inhibitor of PP2A (CIP2A) is a recently described inhibitor of PP2A in breast and gastric cancer. The aim of this study was to investigate whether CIP2A played a role in CML and whether PP2A or its inhibitor proteins CIP2A or SET could predict clinical outcome. At the time of diagnosis of CML, patients who will later progress to blast crisis have significantly higher levels of CIP2A protein (P < .0001) than patients who do not progress, suggesting that PP2A is functionally inactive. We show that the potential mechanism for disease progression is via altered phosphorylation of the oncogene c-Myc. Knockdown of CIP2A results in increased PP2A activity, decreased c-Myc levels, and a decrease in BCR-ABL1 tyrosine kinase activity. We demonstrate that CIP2A levels at diagnosis can consistently predict patients who will progress to blast crisis. The data show that CIP2A is biologically and clinically important in CML and may be a novel therapeutic target.

We discuss the ability to perform fluorescent immunocytochemistry, following cell fixation, using a microfluidic array of primary, nonadherent, single CD34+ stem cells. The technique requires small cell samples and proceeds with no cell loss, making it well-suited to monitoring these rare patient-derived cells. The chip allows us to correlate live cell dynamics across arrays of individual cells with post-translational modifications of intracellular proteins, following their exposure to drug treatments. Results also show that due to the microfluidic environment, the time scale of cell fixation was significantly reduced compared to conventional methods, leading to greater confidence in the status of the protein modifications studied.

Background and Objectives: As a result of improved clinical and quality-of-life outcomes compared with conventional hemodialysis, interest in nocturnal home hemodialysis (NHD) has steadily increased in the past decade; however, little is known about the flow of patients through NHD programs or about patient-specific predictors of mortality or technique failure associated with this modality. This study addressed this gap in knowledge., Design, Setting, Participants, & Measurements: This study included 247 NHD patients of the Canadian Slow Long nightly ExtEnded dialysis Programs (CAN-SLEEP) cohort from 1994 through 2006 inclusive. The association between program- and patient-specific variables and risk for adverse outcomes was determined using uni- and multivariable Cox regression., Results: A total of 14.6% of the cohort experienced death or technique failure. Unadjusted 1- and 5-year adverse event-free survival was 95.2 and 80.1%, respectively. Significant predictors of a composite of mortality and technique failure included advanced age (P < 0.001), diabetes (P < 0.001), central venous catheter use (P = 0.01), and inability to perform NHD independently (P = 0.009) and were adjusted for center effect. Weekly frequency of NHD was not predictive. Age and diabetes remained significant with multivariable analysis (hazard ratio 1.07 and 2.64, respectively). Unadjusted 1- and 5-year technique survival was 97.9 and 95.2%, respectively. Only age was a significant predictor of technique failure., Conclusions: NHD is associated with excellent adverse event-free survival. This study underscores the importance of modality-specific predictors in the success of home hemodialysis, as well as favorable baseline characteristics such as younger age and the absence of diabetes.

Home extended hours hemodialysis improves some measurable biological and quality-of-life parameters over conventional renal replacement therapies in patients with end-stage renal disease. Published small studies evaluating costs have shown savings in terms of ongoing operating costs with this modality. However, all estimates need to include the total costs, including infrastructure, patient training, and maintenance; patient attrition by death, transplantation, technique failure; and the necessity of in-center dialysis. We describe a comprehensive funding model for a large centrally administered but locally delivered home hemodialysis program in British Columbia, Canada that covered 122 patients, of which 113 were still in the program at study end. The majority of patients performed home nocturnal hemodialysis in this 2-year retrospective study. All training periods, both in-center and in-home dialysis, medications, hospitalizations, and deaths were captured using our provincial renal database and vital statistics. Comparative data from the provincial database and pricing models were used for costing purposes. The total comprehensive costs per patient-incorporating startup, home, and in-center dialysis; medications; home remodeling; and consumables-was $59,179 for years 2004-2005 and $48,648 for 2005-2006. The home dialysis patients required multiple in-center dialysis runs, significantly contributing to the overall costs. Our study describes a valid, comprehensive funding model delineating reliable cost estimates of starting and maintaining a large home-based hemodialysis program. Consideration of hidden costs is important for administrators and planners to take into account when designing budgets for home hemodialysis.

Chronic myeloid leukemia (CML) is a hematopoietic stem cell disorder maintained by cancer stem cells. To target this population, we investigated the mechanism of action of BMS-214662, developed as a farnesyl transferase inhibitor (FTI) and unique in inducing apoptosis in these cells. By contrast, a related congener and equally effective FTI, BMS-225975 does not induce apoptosis, indicating a novel mechanism of action. BMS-214662 significantly and selectively induced apoptosis in primitive CD34(+)38(-) CML compared with normal cells. Apoptosis proceeded via the intrinsic pathway: Bax conformational changes, loss of mitochondrial membrane potential, generation of reactive oxygen species, release of cytochrome c, and caspase-9/3 activation were noted. Up-regulation of protein kinase Cbeta (PKCbeta), down-regulation of E2F1, and phosphorylation of cyclin A-associated cyclin-dependent kinase 2 preceded these changes. Cotreatment of CML CD34(+) and CD34(+)38(-) cells with PKC modulators, bryostatin-1, or hispidin markedly decreased these early events and the subsequent apoptosis. None of these events was elicited by BMS-214662 in normal CD34(+) cells or by BMS-225975 in CML CD34(+) cells. These data suggest that BMS-214662 selectively elicits a latent apoptotic pathway in CML stem cells that is initiated by up-regulation of PKCbeta and mediated by Bax activation, providing a molecular framework for development of novel therapeutics.

Stem cells hold great promise as a means of treating otherwise incurable, degenerative diseases due to their ability both to self-renew and differentiate. However, stem cell damage can also play a role in the disease with the formation of solid tumors and leukaemias such as chronic myeloid leukaemia (CML), a hematopoietic stem cell (HSC) disorder. Despite recent medical advances, CML remains incurable by drug therapy. Understanding the mechanisms which govern chemoresistance of individual stem cell leukaemias may therefore require analysis at the single cell level. This task is not trivial using current technologies given that isolating HSCs is difficult, expensive, and inefficient due to low cell yield from patients. In addition, hematopoietic cells are largely non-adherent and thus difficult to study over time using conventional cell culture techniques. Hence, there is a need for new microfluidic platforms that allow the functional interrogation of hundreds of non-adherent single cells in parallel. We demonstrate the ability to perform assays, normally performed on the macroscopic scale, within the microfluidic platform using minimal reagents and low numbers of primary cells. We investigated normal and CML stem cell responses to the tyrosine kinase inhibitor, dasatinib, a drug approved for the treatment of CML. Dynamic, on-chip three-color cell viability assays revealed that differences in the responses of normal and CML stem/progenitor cells to dasatinib were observed even in the early phases of exposure, during which time normal cells exhibit a significantly elevated cell death rate, as compared to both controls and CML cells. Further studies show that dasatinib does, however, markedly reduce CML stem/progenitor cell migration in situ.

Background: As the population with stage 5 CKD grows, the associated costs of providing dialysis care increase. Due to the high costs of these therapies, home haemodialysis is enjoying a renaissance in many jurisdictions. However, concerns persist as to whether home haemodialysis programmes grow at the expense of other home therapies such as peritoneal dialysis. This study attempts to look at the impact of a new home haemodialysis programme on an existing peritoneal dialysis programme in the province of British Columbia., Methods: Using the provincial renal database in British Columbia (PROMIS), all patients receiving dialysis were tracked over the years preceding the implementation of a home haemodialysis programme and following its implementation. Rate of growth by specific dialysis modality (hospital haemodialysis, community haemodialysis, home haemodialysis, and peritoneal dialysis) were tracked., Results: When comparing the provincial growth rates in the peritoneal dialysis programme, using the 4 years before and following the introduction of the home haemodialysis programme, they were unchanged both annually (7.84% versus 7.34%) and overall (25.27% versus 23.62%). The growth within the home haemodialysis programme appears to have come from the community haemodialysis programme (annual growth rate 12.28% versus 5.87%) and in-hospital haemodialysis (annual growth rate 4.61% versus 1.3%). Incident rates of dialysis were similar both prior to and following the introduction of the home haemodialysis programme.Finally, only 6.4% of the total patients entering the home haemodialysis programme had discontinued peritoneal dialysis within the 6 months preceding home haemodialysis training, indicating a low frequency of movement from peritoneal dialysis to home haemodialysis., Conclusions: Successful implementation of a home haemodialysis programme can be done at a provincial level without having an adverse impact on the growth rate of existing peritoneal dialysis programmes.

A mounting body of clinical data and purported quality of life benefits has been primarily responsible for a renewed interest in programs providing longer more frequent home hemodialysis. As novel forms of home hemodialysis (HHD) like nocturnal (nightly) home hemodialysis (NHD) move from strictly the academic "experimental" arenas to potentially the preferred renal replacement modality for patients, it will be necessary for programs to plan and evaluate standardized metrics for program quality. This will be essential for smaller, less experienced centers to gauge their outcomes against larger, more established programs. Driven by market forces primarily in the United States, conventional hemodialysis programs have begun to explore optimal strategies for reporting quality of care in their respective dialysis centers. Extrapolating this to home hemodialysis modalities the question remains which criteria do we use as measures of quality? The evidence is limited to small, observational studies and one small randomized controlled trial. Extrapolating existing quality indices from conventional hemodialysis seems reasonable however may miss many of the true clinically significant advantages of HHD as a modality. Although definitive evidence does not yet exist for intensive home hemodialysis strategies, clearly clinicians, payers and patients are convinced enough of this approach for programs to justify the expansion of these modalities. We have laid the groundwork for the CANadian Slow Long nightly ExtEnded dialysis Programs (CAN-SLEEP), a multicenter cohort aimed to investigate the clinical and programmatic outcomes of NHD. This will allow for the assessment of numerous outcomes on a global scale for this state-of-the art dialysis modality in the form of a multidimensional programmatic evaluation.

Chronic myelogenous leukemia (CML) is a clonal myeloproliferative disorder that arises in the hematopoietic stem cell compartment. CML is one of the best-understood malignancies, as it results from a single genetic mutation, the fusion oncogene BCR-ABL, which has been widely studied. Specific tyrosine kinase inhibitors have been developed to target BCR-ABL in CML, but these agents fail to eliminate the CML stem cell population and thus are unlikely to cure CML. This article reviews recent developments in the biology and treatment of CML, specifically focusing on CML stem cells. Significant progress continues to be made in our understanding of CML stem cell biology, which has wider implications within the cancer stem cell field. We are also beginning to see the identification of novel therapies that specifically target the CML stem cell. These are exciting times in the quest to cure CML.

Bcr-Abl tyrosine kinase inhibitors (TKI) are effective in inducing remissions in chronic myelogenous leukemia (CML) patients but do not eliminate primitive CML hematopoietic cells. There is a need to identify mechanisms that contribute to retention of CML progenitors. Src family tyrosine kinases have been identified as potential mediators of Bcr-Abl-induced leukemogenesis. Dasatinib (BMS-354825) is a potent dual Abl/Src kinase inhibitor approved for clinical use in CML patients. We evaluated Src activity in primitive human CML progenitors from different stages of disease and investigated effects of Dasatinib on Src activity and downstream signaling pathways. P-Src expression was increased in CD34+ cells and CD34+CD38- cells in all phases of CML. Dasatinib showed potent Src inhibitory activity in CML progenitors, inhibiting both Bcr-Abl-dependent and -independent Src activity. In contrast, Imatinib inhibited only Bcr-Abl-dependent Src activity. Dasatinib inhibited P-mitogen-activated protein kinase (MAPK), P-Akt, and P-STAT5 levels in CML progenitors in the absence of growth factors but not in the presence of growth factors. A marked increase in P-MAPK levels seen in the presence of growth factors with Imatinib was much less prominent with Dasatinib. Dasatinib significantly suppressed CML colony-forming cells and long-term culture-initiating cells but did not significantly alter the level of apoptosis-regulating proteins in CML CD34+ cells. Our results indicate that Dasatinib, in addition to potent anti-Bcr-Abl kinase activity, effectively inhibits Src kinase activity and downstream signaling pathways in CML progenitors but does not induce a strong proapoptotic response. These observations argue against a prominent role for Src kinases in persistence of primitive CML cells in TKI-treated patients.

Nocturnal home hemodialysis (NHD) is the most intensive dialysis strategy among dialytic renal replacement options and is receiving increased attention as more research reveals its physiologic restorative potential compared with conventional hemodialysis; however, a significant gap in knowledge remains concerning the predictors of program success and the clinical outcomes of NHD. This review aims to highlight the methodologic strengths and pitfalls of various study designs as they pertain to NHD research and lays the foundation for the CANandian Slow Long nightly ExtEnded dialysis Programs (CAN-SLEEP), a multicenter NHD research network aimed to facilitate investigation of NHD.

Introduction: The province of British Columbia has the only coordinated provincial programme for home-based haemodialysis (HHD) in Canada. The centrally coordinated and locally administered programme was initiated in 2002 as a pilot project, and was firmly established with secured funding in 2004. HHD programmes have reported successful outcomes with respect to patients' well-being, haemodynamic stability and improvement of clinical and biochemical parameters in small selected groups of patients., Methods: This report describes the 2-year outcomes of a provincial programme, in which more liberal criteria for patient selection have been applied, and multiple sites have trained and managed the patients over a large geographic area. As a 'newer' modality, it is important to review outcomes objectively so as to determine the true value of this home-based programme as an alternative to other home-based therapies such as peritoneal dialysis., Results: One hundred and five patients who completed training and commenced home therapy between April 2004 and March 2006 were followed, for a total of 163.23 patient-years (PY). The average age was 52; 71% were male and the majority (58%) were Caucasian. Mean biochemical and clinical parameters were all within provincial and national target ranges at baseline and at the time of study follow-up cessation. Overall, 34 individual patients required hospital admission and 95% of the cohort required at least one in-centre run after training was completed (0.5 hospital admissions and 11 in-centre run per PY of HHD delivered). One- and 2-year technique survivals were 81% and 61% respectively, which were 85% and 74% when censored for transplantation. We were unable to demonstrate any significant predictors of technique survival using demographic, biochemical or other variables., Conclusion: This is the first report of HHD programme technique survival in a large provincial cohort. The 2-year technique survival of this cohort is comparable to reports of technique survival in peritoneal dialysis. These data can be used to benchmark programmes, and to foster further research to determine factors that may improve HHD technique survival.

Patients with newly diagnosed chronic phase chronic myeloid leukemia were treated with imatinib mesylate (IM) for 6 to 12 months to establish disease control, before reduced intensity stem cell transplantation (RISCT). Escalating doses of donor lymphocyte infusions were given from 6 months after transplantation to eradicate residual disease. A total of 18 patients entered the study and 15 received RISCT (median follow-up, 31 months). RISCT was well tolerated with rapid engraftment, short inpatient stays, and few readmissions. Viral reactivation was common, although extensive graft-versus-host disease occurred infrequently. Donor lymphocyte infusions were given as part of the RISCT protocol in 13 of 15 patients. BCR-ABL transcripts continued to decrease after RISCT, and 8 (53%) patients achieved sustained undetectable levels. All patients are currently off IM. Although IM is now established as first-line therapy for chronic phase chronic myeloid leukemia, this protocol is a safe, well-tolerated, and effective strategy in these patients. This study is registered at http://www.controlled-trials.com as ISRCTN86187144.

Chronic myeloid leukemia (CML), a hematopoietic stem-cell disorder, cannot be eradicated by conventional chemotherapy or the tyrosine kinase inhibitor imatinib mesylate (IM). To target CML stem/progenitor cells, we investigated BMS-214662, a cytotoxic farnesyltransferase inhibitor, previously reported to kill nonproliferating tumor cells. IM or dasatinib alone reversibly arrested proliferation of CML stem/progenitor cells without inducing apoptosis. In contrast, BMS-214662, alone or in combination with IM or dasatinib, potently induced apoptosis of both proliferating and quiescent CML stem/progenitor cells with less than 1% recovery of Philadelphia-positive long-term culture-initiating cells. Normal stem/progenitor cells were relatively spared by BMS-214662, suggesting selectivity for leukemic stem/progenitor cells. The ability to induce selective apoptosis of leukemic stem/progenitor cells was unique to BMS-214662 and not seen with a structurally similar agent BMS-225975. BMS-214662 was cytotoxic against CML blast crisis stem/progenitor cells, particularly in combination with a tyrosine kinase inhibitor and equally effective in cell lines harboring wild-type vs mutant BCR-ABL, including the T315I mutation. This is the first report of an agent with activity in resistant and blast crisis CML that selectively kills CML stem/progenitor cells through apoptosis and offers potential for eradication of chronic phase CML.

Chilocorus nigritus is currently considered one of the most successful biological control agents of armoured scale insects. However, establishment of this beetle in crop pest situations has not always been successful and there are still gaps in our knowledge of its ecology and behaviour. The research involved an examination of tritrophic effects on the survival and development of this common diaspid predator. The effect of a forced change in host plant on the developmental time of the juvenile stages was also examined. The prey and host plants used were the armoured scales Aspidiotus nerii Bouché Homoptera: Diaspididae and Abgrallaspis cyanophylli (Signoret) Homoptera: Diaspididae, on potatoes (Solanum tuberosum L.) and Butternut squashes (Cucurbita moschata Duchesne ex Lamarck). C. nigritus eggs were incubated on four treatments of scales on potatoes or squashes for ten days, half the second instar larvae were then switched to the same scales on the other host plant. Daily observations were made during development to adult emergence. C. nigritus larvae survived and completed development on two species of diaspid scales and the two host plants examined with varying levels of success. Larvae were able to switch from feeding on A. nerii on potatoes to A. nerii on squashes or A. cyanophylli on potatoes to A. cyanophylli on squashes and vice versa with little or no deleterious effects when compared to those beetles reared on one prey and host plant throughout. There were significant differences in survival of larvae reared to the adult stage on both A. nerii and A. cyanophylli on potatoes when compared to larvae reared on these scales on squashes. Squash appears to be a less desirable and potato a more favourable host plant for survival and development. The results have implications for rearing programmes, and the release and establishment of C. nigritus, in fields and glasshouses where scale pests may be present on a variety of host plants, or may be on host plants different to those used in the insectary.