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D W Galvani

Publications and source records attributed to D W Galvani.

At least 19 recordsLinked to original sources
PubMed1996

GTPgammaS-stimulated phospholipase D activation in human neutrophils occurs by protein kinase C-dependent and -independent pathways but not tyrosine kinases.

Addition of GTPgammaS to saponin-permeabilised human neutrophils activated both the NADPH oxidase and phospholipase D (PLD). This PLD activation was hardly affected by staurosporine or Ro31-8220 (at concentrations which inhibited PMA stimulated PLD activity), indicating that it was largely independent of protein kinase C (PKC). This GTPgammaS stimulated PLD activity was enhanced by 1 mM ATP, but this ATP-enhanced activity was blocked by inhibitors of PKC. Addition of GTPgammaS resulted in very low levels of phosphorylation on tyrosine residues, but higher levels of phosphorylation on serine/threonine residues. Addition of pervanadate hydroperoxides stimulated phosphorylation on tyrosine residues and activated PLD which was blocked by addition of inhibitors of tyrosine kinases. Thus, GTPgammaS can stimulate PKC-dependent and -independent pathways of PLD activation. Whilst phosphorylation on tyrosine residues can result in activation of PLD, this is regulated independently of activation via G-proteins.

Alkaloids↗
PubMed1995

The metabolic effects of interleukin 1 beta on human bone marrow adipocytes.

We have recently shown that interleukin 1 beta (IL-1 beta) directly reduces the number of adipocytes in cultures of human bone marrow (BM) stromal cells. The aim of the present study was to establish the mechanisms involved in the IL-1 effect and thereby assess its importance in BM pathophysiology. Direct morphological observation showed that individual adipocytes lost their fat in the presence of IL-1 beta and regained it when the cytokine was withdrawn. These morphological observations were supported by metabolic studies using [14]acetate as a precursor of storage fat. These metabolic studies showed that IL-1 beta inhibited the incorporation of label into triglycerides. In addition, the cytokine enhanced the release of radioactivity from prelabelled adipocytes and reduced their triglyceride stores. It was therefore concluded that IL-1 beta can both inhibit lipogenesis and stimulate lipolysis in BM adipocytes. Forskolin (an adenylate cyclase activator) produced lipolytic effect similar to those of IL-1 beta, while indomethacin (an inhibitor of prostaglandin [PG] production) fully blocked the release of radioactivity induced by IL-1 beta and greatly increased triglyceride synthesis. However, IL-1 beta was still able to decrease triglyceride synthesis in the presence of indomethacin. These results indicate that a prostaglandin-dependent increase in cAMP is important to in the lipolytic effects of IL-1 beta but that the anti-lipogenic effects of the cytokine are, at least in part, independent of PG synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1994

Phospholipase D-dependent and -independent activation of the neutrophil NADPH oxidase.

Stimulation of the respiratory burst of human neutrophils by fMet-Leu-Phe (in the absence of cytochalasin B) is largely unaffected when the activities of protein kinase C and phospholipase D are inhibited. This has been confirmed using three separate assays to measure the respiratory burst. However, whilst these enzymes are not required for the initiation or maximal rate of oxidant generation, they are required to sustain oxidase activity. In contrast, in the presence of cytochalasin B, fMet-Leu-Phe stimulated oxidase activity is much more dependent on phospholipase D activity. It is proposed that (in the absence of cytochalasin B) activation of the NADPH oxidase utilises cytochrome b molecules that are already present on the plasma membrane and activation occurs independently of phospholipase D and protein kinase C. Once these complexes are inactivated, then new cytochrome b molecules must be recruited from sub-cellular stores. This translocation and/or activation of these molecules is phospholipase D dependent. Some support for this model comes from the finding that the translocation of CD11b (which co-localises with cytochrome b) onto the cell surface is phospholipase D dependent.

1-Butanol↗
PubMed1994

Identification of a subgroup of myelodysplastic patients with a neutrophil stimulation-signalling defect.

f-Met-Leu-Phe-stimulated luminol-enhanced chemiluminescence was found to be repeatedly defective in some MDS patients. This defect was not attributed to myeloperoxidase deficiency, nor to a defect in NADPH oxidase function, because PMA chemiluminescence was found to be normal in these individuals. An arbitrary value of 7 mV (half the mean control value) was chosen to subdivide the group: MDS patients with values < 7 mV had a mean f-Met-Leu-Phe chemiluminescence response of 2.5 +/- 0.5 compared to MDS patients with values > 7 mV who had a mean response of 15.6 +/- 1.6 mV, P < 0.01 (healthy controls 14 +/- 2 mV). The characteristics of the f-Met-Leu-Phe receptor and initial calcium flux results suggested that the receptor itself was normal in number and function in low f-Met-Leu-Phe responders. The rate of superoxide generation, which is calcium-dependent, was also found to be in the normal range in low f-Met-Leu-Phe responders, although total superoxide production was reduced in some of these patients. When MDS neutrophils with a low f-Met-Leu-Phe response were stimulated with PMA, chemiluminescence was normal, suggesting normal activity of the NADPH-oxidase complex. Furthermore, myeloperoxidase activity was reduced in only three out of the 11 low f-Met-Leu-Phe responders. Following priming with GM-CSF, f-Met-Leu-Phe chemiluminescence was 27 +/- 1.6 mV in low f-Met-Leu-Phe responders compared to controls (87.7 +/- 11 mV, P < 0.005). Thus, although responses were improved, they were not as marked as in control neutrophils. These data suggest that a subgroup of MDS patients have a low f-Met-Leu-Phe chemiluminescence response which is not due to a defect in the f-Met-Leu-Phe receptor or oxidase activity, and in the majority of cases MPO activity is normal. Initial patient survival data suggest that these patients may have an increased risk of infective mortality. It is proposed that defective f-Met-Leu-Phe chemiluminescence results from a putative defect in cell-signalling mechanism upstream of PKC, and GM-CSF priming only partially improves responsiveness.

Blood Bactericidal Activity↗
PubMed1994

A function of CD10 on bone marrow stroma.

Bone marrow (BM) stromal cells express CD10 (cALLA), a surface antigen now known to be a neutral endopeptidase (NEP-24.11). The function of CD10 in BM stroma is unknown, although purified NEP-24.11 is known to degrade different substrates including interleukin 1 beta (IL-1 beta). We have therefore employed a CD10-positive BM stromal cell line (L2AK) which proliferates in response to IL-1 beta to test the hypothesis that degradation of this cytokine is one of the functions of stromal CD10. We first showed that [3H]thymidine incorporation by L2AK cells is enhanced by IL-1 beta in a clear dose-dependent manner. Addition of the CD10 inhibitor, phosphoramidon, together with IL-1 beta resulted in a left shift in the dose-response curve which corresponded to a 10-fold potentiation of the IL-1 beta effect. These results indicate that CD10 on bone marrow stromal cells can degrade IL-1 beta and therefore provide a local control of the effects of this, and possibly other, growth factor(s).

Bone Marrow↗
PubMed1993

The effects of GM-CSF on myeloperoxidase release in normal and myelodysplastic neutrophils.

When purified control neutrophils were primed with GM-CSF, a significant increase in FMLP-induced MPO release was observed (mean +/- S.E.M., 3.4 +/- 0.8 mU/10(7) unprimed cells compared to 6.5 +/- 1.1 mU/10(7) primed cells, p < 0.001). This MPO release was greatly augmented by Cytochalasin B (Cy B), but after the addition of Cy B the priming effects of GM-CSF became less obvious. Exposure to GM-CSF without FMLP did not enhance MPO release. Within whole blood, FMLP produced negligible MPO release, but priming with GM-CSF prior to FMLP always resulted in a significant increase in MPO release. Myelodysplastic neutrophils released similar amounts of MPO in response to FMLP, compared with control cells (3.4 +/- 0.8 mU/10(7) control cells compared to 2.7 +/- 0.3 mU/10(7) MDS cells, p > 0.05). Priming with GM-CSF produced an increase in FMLP-stimulated MPO release comparable with control cells. In terms of total MPO content, although some MDS patients exhibited low levels, as a group there was no significant difference from controls (169 +/- 21 mU/10(7) control cells compared with 157 +/- 19 mU/10(7) MDS cells). These findings suggest that MPO activity is not a universal defect in MDS and cannot account for the defects in respiratory burst activity in these neutrophils.

Anemia↗
PubMed1993

IL-1 beta inhibits adipocyte formation in human long-term bone marrow culture.

Addition of recombinant interleukin-1 beta (IL-1 beta) to human long-term bone marrow culture (LTBMC) was found to have a profound effect on adipocyte formation. Control cultures developed 133 +/- 58 adipocytes/flask compared with 3 +/- 2 adipocytes/flask in IL-1 beta-treated flasks (mean +/- SEM, n = 6 for both groups). In terms of cell number, morphology and colony forming cell, IL-1 beta did not have significant effects on LTBMC, although IL-1 beta slightly enhanced colony-stimulating activity of LTBMC-conditioned medium. To further analyze the effect of IL-1 beta on adipocytes, stromal cells were passaged to reduce hemopoietic cell content, and marrow fibroblasts were converted to adipocytes following addition of hydrocortisone. In both types of assay, IL-1 beta again reduced adipocyte formation: control 1095 +/- 76 adipocytes/flask, IL-1 beta-treated 7 +/- 2 adipocytes/flask (n = 3 for both groups). When preformed adipocytes were treated with IL-1 beta for 1 week, the number of lipid-laden cells decreased to 41 +/- 13% of its value before treatment compared to 87 +/- 9% for untreated controls. The addition of neutralizing concentrations of anti-TNF did not inhibit these effects of IL-1 beta. These results suggest that 1) adipocyte formation is not essential for healthy LTBMC growth, or at least IL-1 beta is an effective substitute for adipocytes; 2) IL-1 beta by itself does not significantly enhance hemopoiesis in LTBMC, and this has implications for clinical trials with this cytokine; 3) IL-1 beta produces major changes in stromal cell development, and 4) overgrowth of fat in marrow may reflect defective cytokine regulation in vivo.

Adipose Tissue↗
PubMed1992

Endolymphatic delivery of IL2 in patients with melanoma and lymphoma.

UNLABELLED: During this phase I/II study, enodolymphatic cannulae were placed in the iliac lymphatics under general anaesthesia. IL2 was then infused via this route at escalating doses until the highest tolerated dose was achieved; then, continuous infusion was maintained for 2 to 3 weeks. Seven patients with advanced cancer (3 lymphoma, 4 melanoma), resistant to all other modalities of treatment received such therapy. Most patients tolerated 4 to 5 x 10(6) u/day of IL2 for 2 to 3 weeks with less toxicity as compared to the equivalent dosage given intravenously. No severe perioperative morbidity was experienced. One melanoma patient had a minor clinical response. Changes in circulating lymphocyte numbers and cytotoxicity demonstrated a systemic effect of endolymphatic IL2 therapy. CONCLUSIONS: The endolymphatic administration of IL2 is associated with less toxicity than the intravenous route but still achieves a systemic effect; a lower tumour burden may prove more responsive to this therapy.

Adult↗
PubMed1992

Combination of GM-CSF and cytosine in myelodysplasia results in improved neutrophil function.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was given concurrently with low-dose cytosine arabinoside for 3 weeks to patients with myelodysplasia. Neutrophil activation as evidenced by increased chemiluminescence and reduced surface expression of CD16 was consistently seen during therapy. An attendant fall in chemotaxis was also observed. These effects occurred even when neutrophil counts did not rise significantly at lower doses of GM-CSF. Although no improvement in anaemia or thrombocytopenia was observed, the neutrophil counts became normal during therapy without significant expansion of marrow cellularity or colony-forming ability. No major toxicities were observed, even at higher dosages of GM-CSF.

Antigens, CD↗
PubMed1991

The current status of myeloid growth factor therapy.

Supralethal chemotherapy has been used in an attempt to cure certain malignancies by employing doses of cytotoxic agents beyond conventional limits. The resulting damage to the bone marrow requires rescue with an infusion of autologous or allogenic marrow to repopulate the haemopoietic system. The recent availability of marrow stimulants for clinical use may prove to be a major advance in oncology as early evidence suggests that they can reduce cytotoxic drug induced myelosuppression and possibly allow escalation of chemotherapy with improved tumour responsiveness. Such growth factors may also improve primary marrow disorders. This article outlines the properties of the myeloid growth factors and then reviews the important clinical conditions in which they have been employed so far. Erythropoietin and lymphoid growth factors are not dealt with.

Acquired Immunodeficiency Syndrome↗
PubMed1990

The effects of alpha interferon on human long-term bone marrow culture.

The effect of alpha IFN on normal long term bone marrow culture (LTBMC) was assessed by measuring haemopoietic progenitor formation and stromal cell number and composition over the course of 5 weeks. When alpha IFN was added at the initiation of LTBMC, there was a marked inhibition of CFU-GEMM, BFU-E and CFU-GM formation from both adherent and non-adherent compartments of culture. There was a profound inhibition of stromal layer formation, especially the reticulo-fibroblast component, and this was not a result of TNF release from macrophages. When alpha IFN was added to established normal LTBMC, although haemopoietic progenitor formation was inhibited, there was little effect on the stromal layer in terms of number or composition. This suggests that the cytostatic effects of alpha IFN when added at commencement of LTBMC result from the anti-proliferative effects of alpha IFN on these actively dividing cells. It is concluded that in addition to the established inhibitory effects of alpha IFN on haemopoietic progenitors as previously demonstrated in semi-solid culture systems, alpha IFN has profound effects upon the marrow microenvironment. This is of particular relevance to bone marrow transplantation where such cytokines may be considered for clinical use.

Bone Marrow Cells↗
PubMed1990

gamma IFN receptor expression in haemic malignancies.

gamma Interferon receptor (gamma IFNR) expression was examined by Scatchard analysis in 49 patients with various haemic malignancies. In chronic lymphocytic leukaemia (CLL) (20 cases) expression was variable but generally low (0-1600 receptors/cell) and was not related to clinical stage. In hairy-cell leukaemia (HCL) (n = 6), prolymphocytic leukaemia (PLL) (n = 1) and acute lymphoblastic leukaemia (ALL) (n = 4) expression was again variable but was significantly higher than in CLL (500-4500 receptors/cell). In the myeloid proliferations (n = 18) receptor numbers were significantly higher than in the lymphoproliferative disorders as a whole (1000-30,000) and the highest level of expression was observed in primitive monocytoid proliferations.

Cell Differentiation↗
PubMed1990

The current status of interferon alpha in haemic malignancy.

Interferon-alpha (IFN alpha) has been extensively studied, both in clinical trials and in the laboratory. The cytokine has proved most effective in haemic malignancy, in particular hairy cell and chronic granulocytic leukaemia. This article deals with the current status of IFN alpha in these conditions and the possible basis of this sensitivity. Other less responsive haemic malignancies are also discussed.

Humans↗
PubMed1989

Mechanism of action of alpha interferon in chronic granulocytic leukaemia: evidence for preferential inhibition of late progenitors.

The effect of alpha interferon (alpha IFN) on colony forming unit, granulocyte-macrophage (CFU-GM) formation by normal bone marrow (BM) as compared with chronic granulocytic leukaemia (CGL) BM and peripheral blood (PB) was tested in semi-solid assay systems employing either 5637CM or recombinant granulocyte-macrophage colony stimulating factor (GM-CSF) to support growth. alpha IFN (greater than 125 U/ml) caused consistent inhibition (P = 0.02) of day-7 (late progenitor) colonies, but had little or no effect on either day-7 clusters or day-14 colonies/clusters. This selective effect on day-7 colonies was quantitatively similar for both normal and CGL (P greater than 0.5). Similar results were obtained whether or not the mononuclear preparations were depleted of potential accessory cells, suggesting that the alpha IFN-suppression is directly mediated. Morphological examination of colonies and clusters showed that IFN had no effect on cell maturation and that colony inhibition is not, therefore, a consequence of blocked maturation. Since the late-progenitor compartment is preferentially expanded in CGL, we suggest that our demonstration that alpha IFN selectively inhibits this compartment is relevant to the clinical effects of the cytokine in the disease.

Bone Marrow↗