Ruthenium-Containing Linear Helicates and Mesocates with Tuneable p53-Selective Cytotoxicity in Colorectal Cancer Cells.

The ligands L and L both form separable dinuclear double-stranded helicate and mesocate complexes with Ru . In contrast to clinically approved platinates, the helicate isomer of [Ru (L ) ] was preferentially cytotoxic to isogenic cells (HCT116 p53 ), which lack the critical tumour suppressor gene. The mesocate isomer shows the reverse selectivity, with the achiral isomer being preferentially cytotoxic towards HCT116 p53 .

Evolution of cardiorespiratory interactions with age.

We describe an analysis of cardiac and respiratory time series recorded from 189 subjects of both genders aged 16-90. By application of the synchrosqueezed wavelet transform, we extract the respiratory and cardiac frequencies and phases with better time resolution than is possible with the marked events procedure. By treating the heart and respiration as coupled oscillators, we then apply a method based on Bayesian inference to find the underlying coupling parameters and their time dependence, deriving from them measures such as synchronization, coupling directionality and the relative contributions of different mechanisms.

Stress reactivity and cognitive performance in a simulated firefighting emergency.

Background: During emergencies maladaptive behavior can reduce survival. This study compared the effects of a basic firefighter training course on 21 volunteers (with no firefighting experience) with age and gender-matched controls.

Methods: Stress reactivity (salivary cortisol and anxiety) were monitored across the course: day 1 (classroom), day 2 (physical equipment training), and day 3 (simulated fire emergency).

Addressing a folate imbalance in fetal cerebrospinal fluid can decrease the incidence of congenital hydrocephalus.

Fetal-onset hydrocephalus (HC), which affects between 1:500 and 1:5000 live human births, results from unequal production and drainage of cerebrospinal fluid (CSF) and is associated with abnormal development of the cerebral cortex leading to severe neurological deficits. We previously found that in the hydrocephalic Texas rat, the CSF of affected fetuses induced a cell cycle arrest in neural progenitor cells. Here, we show that alterations in folate metabolism in the CSF of the developing cerebrum are likely responsible for this effect.

The effects of exposure to an acute naturalistic stressor on working memory, state anxiety and salivary cortisol concentrations.

Exposure to an acute naturalistic stressor induces both psychological and physiological changes in humans. The two studies reported here explored the impact of exposure to an acute naturalistic stressor on state anxiety, working memory and HPA axis activation (salivary cortisol). In both experiments, ten healthy male participants were exposed to an acute naturalistic stressor, helicopter underwater evacuation training (HUET), and their physiological and behavioural responses before (first study) and after (second study) the stressor were compared to ten non-stressed controls.

Differential effect of leukaemogenic tyrosine kinases on cell motility is governed by subcellular localisation.

The chemokine, stromal cell-derived factor-1 (SDF-1) is a crucial regulator of stem cell homing and tethering, and potentiation of this pathway in leukaemias may contribute to the pathogenesis of the disease. A key second messenger in SDF-1 signal/response coupling is phosphatidylinositol 3,4,5-triphosphate [PtdIns(3,4,5)P3]. SDF-1 elevated PtdIns(3,4,5)P3 levels markedly in the multipotent FDCP-mix stem cell line.

Cerebrospinal fluid supports viability and proliferation of cortical cells in vitro, mirroring in vivo development.

Background: The central nervous system develops around a fluid filled compartment. Recently, attention has turned to the potential role of the fluid (cerebrospinal fluid, CSF) in the developmental process. In particular, the cerebral cortex develops from the germinal epithelium adjacent to the CSF with regulation of cell proliferation and differentiation provided by cells adjacent to the fluid-filled subarachnoid space.

Role of the C-terminal actin binding domain in BCR/ABL-mediated survival and drug resistance.

Philadelphia chromosome-positive, chronic myeloid leukaemia (CML) stem and progenitor cells have a survival and growth advantage compared with their normal counterparts. The mechanisms through which the BCR/ABL protein tyrosine kinase (PTK) induces these effects and the important domains within this protein are not fully defined. The F- and G-actin binding region of the BCR/ABL C-terminus may be important in BCR/ABL-mediated events, and we have investigated this by expressing a C-terminus deletion mutant of the temperature-sensitive BCR/ABL PTK, in a haemopoietic progenitor cell line, which models the chronic phase of CML.

Bcr-Abl-mediated molecular mechanism for apoptotic suppression in multipotent haemopoietic cells: a role for PKCbetaII.

Bcr-Abl protein tyrosine kinase (PTK) activity is a feature of chronic myeloid leukaemia and confers a survival advantage on haemopoietic progenitor cells. We have expressed conditional mutant of the Bcr-Abl PTK in the FDCP-Mix A4 multipotent haematopoietic cell line in order to examine the molecular mechanisms whereby Bcr-Abl PTK leads to enhanced cell survival under conditions in which normal cells die. Activation of Bcr-Abl PTK does not phosphorylate or activate either ERK-1/2 or JAK-2/STAT-5b, suggesting that these signal transduction pathways are not involved in Abl PTK-mediated suppression of apoptosis in FDCP-Mix cells.

Interleukin-3-mediated cell survival signals include phosphatidylinositol 3-kinase-dependent translocation of the glucose transporter GLUT1 to the cell surface.

Maintenance of glucose uptake is a key component in the response of hematopoietic cells to survival factors. To investigate the mechanism of this response we employed the interleukin-3 (IL-3)-dependent murine mast cell line IC2.9.

Defective cell cycle control underlies abnormal cortical development in the hydrocephalic Texas rat.

There is a significant body of evidence to suggest a physiological role for the CSF in both the developing and adult brain. Our recent studies suggest a critical role for this fluid in the developing brain of the hydrocephalic Texas (H-Tx) rat. A key feature of the foetal-onset hydrocephalus in this rat is obstruction in the flow and/or absorption of fluid that is associated with abnormal development of the cerebral cortex resulting in a reduction in the number of neuronal precursors generated.

Deficient cortical development in the hydrocephalic Texas (H-Tx) rat: a role for CSF.

The objectives of this study were to demonstrate the presence and nature of abnormal cortical development in a rat model of hydrocephalus, the hydrocephalic Texas (H-Tx) rat, and to test the hypothesis that the obstruction of CSF flow in affected animals can be linked to this effect. CSF is secreted continuously by the choroid plexus, located in the lateral, third and fourth ventricles. The fluid flows through the ventricular system, passing over all regions of germinal activity.

Glucose transport regulation by p210 Bcr-Abl in a chronic myeloid leukaemia model.

The regulation of nutrient transport by both cytokines and oncogenes has been linked to haemopoietic cell survival. In this study, we found that activation of Bcr--Abl protein tyrosine kinase was associated with the stimulation of glucose transport in the multipotent haemopoietic cell line FDCP-mix, a cell model for chronic-phase chronic myeloid leukaemia (CML). Bcr--Abl upregulation of glucose transport was mediated by phosphatidylinositol-3-kinase.

Bcr-Abl protein tyrosine kinase activity induces a loss of p53 protein that mediates a delay in myeloid differentiation.

Chronic myeloid leukaemia is a haemopoietic stem cell disorder, the hallmark of which is the expression of the Bcr-Abl Protein Tyrosine Kinase (PTK). We have previously reported that activation of a temperature sensitive Bcr-Abl PTK in the multipotent haemopoietic cell line FDCP-Mix for short periods resulted in subtle changes including, a transient suppression of apoptosis and no inhibition of differentiation. In contrast, activation of the Bcr-Abl PTK for 12 weeks results in cells that display a delay in differentiation at the early granulocyte stage.

Role of phosphatidylinositol 3-kinase and specific protein kinase B isoforms in the suppression of apoptosis mediated by the Abelson protein-tyrosine kinase.

Leukemogenic oncogenes, such as the Abelson protein-tyrosine kinases (PTK), disrupt the normal regulation of survival, proliferation, and differentiation in hemopoietic progenitor cells. In the absence of cytokines, hemopoietic progenitor cells die by apoptosis. Abl PTKs mediate suppression of this apoptotic response leading to aberrant survival.

Investigation of the molecular mechanisms underlying growth factor synergy: the role of ERK 2 activation in synergy.

Stem Cell Factor (SCF), the ligand for the c-kit proto-oncogene, has been shown to synergistically interact with other cytokines, enhancing the responsiveness of haemopoietic precursors. In this study we have examined the effects of SCF, in combination with interleukin-3 (IL-3), on FDCP-Mix A4 cells, a murine, multipotent, haemopoietic progenitor cell line. Low concentration of IL-3 act to enhance cell survival but do not stimulate proliferation in A4 cells.

p210 Bcr-Abl expression in a primitive multipotent haematopoietic cell line models the development of chronic myeloid leukaemia.

Chronic myeloid leukaemia (CML) is a clonal disorder of the pluripotent haemopoietic stem cell, the hallmark of which is the constitutively activated Bcr-Abl protein tyrosine kinase. During the initial chronic phase of CML the primitive multipotent leukaemic progenitor cells remain growth factor dependent and are capable of producing terminally differentiated cells. Although the available evidence suggests that Bcr-Abl directly affects signalling pathways involved in controlling the development of primitive haemopoietic progenitors the identification of the specific biological consequences of Bcr-Abl activity in these progenitors has been hampered by the lack of suitable systems modelling CML.

The growth inhibitory role and potential clinical value of macrophage inflammatory protein 1 alpha in myeloid leukaemias.

The control of primitive haemopoietic progenitor cell proliferation in vitro can be achieved with combinations of growth stimulatory cytokines. Acting in apparent opposition to these growth stimulators are growth inhibitory substances, including prostaglandins, cytokines and chemokines which bind to specific cognate cell surface receptors and promote signal transduction events that interfere with cellular proliferation. Within the bone marrow microenvironment, significant quantities of both growth inhibitors and growth promoters can be detected.

Ectopic interleukin-5 receptor expression promotes proliferation without development in a multipotent hematopoietic cell line.

The interleukin-5 (IL-5) receptor is a heterodimer that consists of an IL-5 specific alpha subunit and a common ssc chain that is shared with the receptors for granulocyte macrophage colony stimulating factor (GM-CSF) and interleukin-3 (IL-3). In contrast to IL-5, which acts mainly as an eosinophil lineage specific factor in vivo, IL-3 and GM-CSF stimulate the survival, proliferation and development of various hematopoietic cell lineages and also multipotent progenitor cells. IL-5 has little effect on the survival or proliferation of the multipotent stem cell line FDCP-Mix A4 but does promote some eosinophil development.

An activated protein kinase C alpha gives a differentiation signal for hematopoietic progenitor cells and mimicks macrophage colony-stimulating factor-stimulated signaling events.

Highly enriched, bipotent, hematopoietic granulocyte macrophage colony-forming cells (GM-CFC) require cytokines for their survival, proliferation, and development. GM-CFC will form neutrophils in the presence of the cytokines stem cell factor and granulocyte colony-stimulating factor, whereas macrophage colony-stimulating factor leads to macrophage formation. Previously, we have shown that the commitment to the macrophage lineage is associated with lipid hydrolysis and translocation of protein kinase C alpha (PKCalpha) to the nucleus.

The effect of the chemokine rhMIP-1 alpha, and a non-aggregating variant BB-10010, on blast cells from patients with acute myeloid leukaemia.

The effects of recombinant macrophage inflammatory protein 1 alpha (rhMIP-1 alpha) on the proliferation of leukaemic blast cells from patients with acute myeloid leukaemia was assessed. Using the previously described [3H]thymidine incorporation index assay, the response of autonomous and growth factor responsive AML blast cells to the chemokine rhMIP-1 alpha was measured. In the case of autonomous proliferators, rhMIP-1 alpha had no inhibitory effect on [3H]thymidine incorporation and in 4/6 cases [3H]-thymidine incorporation was stimulated by rhMIP-1 alpha.

Macrophage inflammatory protein-1 alpha receptors are present on cells enriched for CD34 expression from patients with chronic myeloid leukemia.

The response of normal and chronic myeloid leukemia (CML), CD34+ cells to human macrophage inflammatory protein-1 alpha (MIP-1 alpha or LD78) was assessed. In tritiated thymidine incorporation assays, stem cell factor plus granulocyte-macrophage colony-stimulating factor stimulated thymidine incorporation in normal CD34+ cells was reduced to 72% of control values in the presence of MIP-1 alpha, whereas incorporation by CML CD34+ cells exposed to the same factors was not altered. In clonogenic assays, the presence of MIP-1 alpha gave a level of colony formation that was 71% of control values for normal progenitor cells, whereas for CML CD34+ cells colony formation was enhanced by 25%.

Suppression of apoptosis by v-ABL protein tyrosine kinase is associated with nuclear translocation and activation of protein kinase C in an interleukin-3-dependent haemopoietic cell line.

We previously demonstrated that activation of v-ABL protein tyrosine kinase resulted in suppression of apoptosis following interleukin-3 removal using an interleukin-3-dependent haemopoietic cell line transfected with a temperature-sensitive mutant of the v-abl oncoprotein (IC.DP). Cellular signalling events associated with the activation of v-ABL included increased levels of sn-1,2-diacylglycerol, an activator of protein kinase C.