Biomedical subjects

D C Linch

Publications and source records attributed to D C Linch.

At least 145 records · Page 8Linked to original sources

PubMed1994

Partial hypopituitarism following total body irradiation in adult patients with haematological malignancy.

We present the endocrine parameters of two adult patients with partial hypopituitarism documented at 6 and 8 months after chemotherapy, single fraction total body irradiation (10.5 Gy) and autologous bone marrow transplantation. The hormone profiles demonstrate severe somatotroph insufficiency and impaired adrenocorticotroph secretory capacity, despite sparing of the gonadotroph compartment. We recommend stimulatory testing of hypothalamic-pituitary function from 3 months post-transplant, as basal hormonal concentrations may be equivocal, and supplementation may significantly improve quality of life.

Adult↗

PubMed1994

Successful pregnancies in women following single autotransplant for acute myeloid leukemia with a chemotherapy ablation protocol.

Of 30 women surviving a minimum of 18 months following treatment for AML with a high-dose chemotherapy regimen with autologous bone marrow transplantation (ABMT), 24 were premenopausal at the time of transplantation. All were given a detailed questionnaire concerning menstruation, menopausal symptoms and pregnancy; 22 responded. Of these 22, 10 had received a single transplant procedure and 12 a double transplant procedure. In the 10 recipients of a single transplant, 4 women (age range 32-50 years) developed ovarian failure and 6 (age range 21-32 years) resumed spontaneous cyclical menstruation. Five of the 6 menstruating women became pregnant between 4 and 40 months following ABMT. Three pregnancies went to term and each resulted in the delivery of a full-term apparently normal infant. Of the 12 women who received a double ABMT (age range 32-47 years), 11 developed clinical and/or biochemical evidence of ovarian failure. The median age in the latter group was 35 years, however, compared with 28 years in the single ABMT group. These data show that it is possible to give a single very high-dose course of chemotherapy in younger patients without compromising fertility.

Abortion, Induced↗

PubMed1994

Detection and significance of pulmonary Hodgkin's disease at autologous bone marrow transplantation.

Pulmonary Hodgkin's disease (HD) is considered to carry a poor prognosis both at presentation and at relapse. We have therefore studied the incidence and significance of pulmonary involvement in 190 poor risk HD patients undergoing BEAM therapy and ABMT for relapsed or resistant disease. Forty-one of 190 patients (22%) had clinically diagnosed pulmonary HD at some stage of their disease prior to ABMT. In 29 patients, in whom a full set of CT scans was available, the patterns of pulmonary HD were characterised. Four of 29 patients had pulmonary disease at presentation only, 8 of 29 at presentation and ABMT and 17 of 29 developed pulmonary involvement at relapse and proceeded to ABMT with persistent pulmonary disease. The commonest pulmonary abnormalities at presentation and relapse were discrete nodules (72%), masses extending from hilar or mediastinal nodes (34%) and pleural effusion/thickening (28%); 52% had two or more patterns of involvement and 66% had coexistent mediastinal lymphadenopathy. There was no relationship between pattern or bulk of pulmonary involvement and outcome. Consideration of the outcome following ABMT in all 190 patients revealed no significant difference in progression-free survival at 5 years between the pulmonary HD group (43%) and those without lung involvement (48%). Furthermore, there was no significant difference in complete remission or transplant-related death rates between the two groups. This would suggest that pulmonary involvement is not in itself a contraindication to ABMT and some patients with bulky pulmonary disease are capable of long-term survival.

Adult↗

PubMed1994

Investigation of methylation at Hha I sites using the hypervariable probe M27 beta allows improved clonal analysis in myeloid leukaemia and demonstrates differences in methylation between leukaemic and remission samples.

The methylation-sensitive enzyme Hha I has been used to assess the differentially methylated patterns on active and inactive X-chromosomes at the DXS255 locus recognized by the hypervariable probe M27 beta. The X-chromosome inactivation ratios obtained from 37 haematologically normal females using PstI and HhaI and correlated well with results obtained using PstI Hpa II (r = 0.97), and in 19 individuals with values obtained probing for either phosphoglycerate kinase or hypoxanthine phosphoribosyl transferase (r = 0.92). At least one Hha I site was found to be unmethylated on all alleles on inactive X-chromosomes. A monoclonal or oligoclonal pattern could be obtained by digestion with Hha I in 18/22 (82%) patients with acute myeloid leukaemia who had previously shown hypermethylation of both alleles using Hpa II, although in six of these patients differences in methylation could still be demonstrated between leukaemic and remission samples.

Acute Disease↗

PubMed1994

Effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor on neutrophil formation and function.

Work published in the past year has significantly increased our understanding of the intracellular signaling pathways that are activated following granulocyte-macrophage colony-stimulating factor or granulocyte colony-stimulating factor binding to cell surface receptors. The involvement of nonreceptor protein tyrosine kinases, in particular the JAK2 kinase, appears to be a major signal transduction pathway involved in the response to several hemopoietic cytokines. Further data continue to accrue on the clinical role of granulocyte colony-stimulating factor, in particular in the treatment of chronic neutropenia. Increased clinical experience with colony-stimulating factors has revealed side effects that may occur with chronic use. The effects of colony-stimulating factors on neutrophil function are shown increasingly to be complex and to involve significant interactions with other proinflammatory cytokines.

Agranulocytosis↗

PubMed1993

Dose intensification with autologous bone-marrow transplantation in relapsed and resistant Hodgkin's disease: results of a BNLI randomised trial.

High-dose chemotherapy and radiotherapy with autologous bone-marrow transplantation (ABMT) are increasingly used for the treatment of relapsed and resistant Hodgkin's disease, although there has been no randomised trial of this treatment. The British National Lymphoma Investigation therefore undertook a randomised comparison of high-dose chemotherapy (BEAM = carmustine, etoposide, cytarabine, and melphalan) plus ABMT with the same drugs at lower doses not requiring bone-marrow rescue (mini-BEAM) in patients with active Hodgkin's disease, for whom conventional therapy had failed. 20 patients were assigned treatment with BEAM plus ABMT and 20 mini-BEAM. All have been followed up for at least 12 months (median 34 months). 5 BEAM recipients have died (2 from causes related to ABMT and 3 from disease progression) compared with 9 mini-BEAM recipients (all disease progression). This difference was not significant (p = 0.318). However, both event-free survival and progression-free survival showed significant differences in favour of BEAM plus ABMT (p = 0.025 and p = 0.005, respectively). Recruitment to the trial became increasingly difficult because patients refused randomisation and requested ABMT. It was therefore closed early (40 patients rather than 66 intended). Nevertheless, we found a dose-response effect in these patients with relapsed and resistant Hodgkin's disease. High doses facilitated by ABMT can lead to better disease-free survival.

Adolescent↗

PubMed1993

Granulocyte-macrophage-colony-stimulating factor differentially regulates neutrophil migration across IL-1-activated and nonactivated human endothelium.

The directed migration of neutrophils across vascular endothelium to localize in inflammatory tissues is controlled by soluble mediators, including cytokines and growth factors. Granulocyte-macrophage CSF (GM-CSF) enhances and primes neutrophil functions, but its specific role in the movement and localization of neutrophils to infective sites has not been clarified. We demonstrate, using an in vitro model of the vascular endothelial barrier, that GM-CSF enhances neutrophil migration across unstimulated endothelium, increasing the percentage of migrating cells from 7.7 +/- 0.9% (mean +/- SE) in controls to 12.5 +/- 1.5% in the presence of GM-CSF (100 ng/ml) (n = 14, p < 0.0005). This effect is dose dependent, with maximal effects achieved at concentrations of 10 ng/ml or greater, and is independent of concentration gradients of GM-CSF. Transendothelial migration of neutrophils can also be increased by cytokine treatment of the endothelial cells. Preincubation of endothelial monolayers with IL-1 (10 U/ml) for 4 h increases the percentage of migrating cells to 16.8 +/- 1.4% (238 +/- 25% of base line, n = 7, p < 0.005). In the presence of GM-CSF, however, neutrophil migration across IL-1 treated endothelium (12.5 +/- 1.6%, n = 7) is no different from that across resting endothelium (11.6 +/- 1.6% in the same seven experiments). Hence GM-CSF acts to inhibit neutrophil migration across IL-1-activated endothelium, and almost completely abolishes IL-1-induced migration (n = 7, p < 0.0005). This differential effect of GM-CSF on neutrophil migration, depending upon the conditions of endothelial activation, does not relate to an effect on adhesion, because GM-CSF has no effect on the increased adhesion of neutrophils to IL-1-treated endothelium. The effect of GM-CSF on neutrophil migration across activated endothelium may be relevant to the clinical administration of human rGM-CSF.

Antibodies, Monoclonal↗

PubMed1993

The place of high-dose BEAM therapy and autologous bone marrow transplantation in poor-risk Hodgkin's disease. A single-center eight-year study of 155 patients.

Although high-dose chemotherapy and autologous bone marrow transplantation (ABMT) are increasingly being used for the treatment of relapsed and resistant Hodgkin's disease, there have been few large, single-center studies reported with adequate follow-up to allow full evaluation of this therapeutic modality. We present 155 poor-risk Hodgkin's disease patients who received high-dose BEAM (BCNU, etoposide, cytosine arabinoside, and melphalan) chemotherapy and ABMT who have been studied over a period of 8 years. All patients had either not attained a remission on mechlorethamine, vincristine, procarbazine, prednisone-type therapy and had poor prognostic features at presentation, not attained a complete remission or relapsed within 1 year of an initial alternating regimen, or not attained remission with two or more lines of treatment. At the time of ABMT the relapse status of the patients was as follows: 46 patients were primarily refractory to induction therapy, 7 were good partial responders, 52 were in first relapse, 37 in second relapse, and 13 in third relapse. Seventy-eight patients had chemoresistant disease, 33 had chemosensitive disease at the time of ABMT, and 44 were untested for chemosensitivity at latest relapse. The procedure related mortality in the first 90 days post-ABMT of 10% overall. At 3 months 43 patients (28%) were assessed as complete responders, 72 patients had a partial response (46%), and 24 patients (16%) had no response or progression of disease. However, by 6 months, 53 (24%) patients were assessed as complete responders and 51 (33%) patients had nonprogressive disease. Forty-five patients had received radiotherapy post-ABMT to residual masses (41 patients) or to previous sites of bulk disease (4 patients). The actuarial overall and progression-free survival at 5 years was 55% and 50%, respectively. On multivariate analysis patients with bulk (masses > 10 cm), heavily pretreated patients (those receiving three or more lines of treatment) and females had a significantly poorer prognosis. Relapse status was also significant for progression-free survival in that patients in second (60%) and third relapse (70%) had a better prognosis than those in first relapse (44%) or with primary refractory disease (33%). Response to prior chemotherapy did not predict for progression-free survival. These results enable comparisons to be made between high-dose chemotherapy with ABMT and conventional dose salvage therapy. Furthermore, although the results as a whole are highly encouraging, certain groups carry an unfavorable prognosis.

Adolescent↗

PubMed1993

Frequency of clonal remission in acute myeloid leukaemia.

Analysis of X-chromosome inactivation patterns in females has been used to assess clonality of various tumours and for prenatal diagnosis of X-linked disorders. Studies with these methods in acute myeloid leukaemia suggest that a significant proportion of cases have clonal remissions (ie, persistence of the malignant clone), which may represent return to a preleukaemic state. We therefore analysed X-chromosome inactivation patterns with differential methylation patterns of heterozygotes for three DNA probes, HPRT, PGK, and M27 beta, in leukaemic patients and normal controls. As expected, blast cells from 67 of 68 analysable samples (99%) were monoclonal or had a skewed X-inactivation pattern. A skewed pattern in remission was also found in 26 of 77 patients (34%), proportion only slightly greater than control (16/75, 21%). In 7 of 10 patients with a skewed pattern in myeloid cells there was similar skewing in the T cells, which is compatible with the concept of a constitutively skewed X-chromosome inactivation pattern of haemopoietic cells in these patients. Our study illustrates the difficulty of interpreting clonality in individual tumour samples and emphasises the importance of comparisons with non-malignant tissue of the same cell type from that individual and from normal control populations.

Acute Disease↗

PubMed1993

Idiopathic thrombocytopenic purpura in Hodgkin's disease: a report of eight cases.

Eight patients with idiopathic thrombocytopenic purpura (ITP) in association with Hodgkin's disease (HD) are reported from the British National Lymphoma Investigation (BNLI) registry. The patients were heterogeneous for initial stage of HD, histology and treatment received. The median time from diagnosis of HD to diagnosis of ITP was 23 months (range 3-57). Six of eight were in complete remission at diagnosis of ITP, one was in relapse, and one was undergoing first line chemotherapy. Of those patients developing ITP in remission, only one subsequently relapsed. The ITP responded in six of the eight patients to a single course of oral prednisolone. Thus the occurrence of ITP in patients with HD appears to be independent of the activity of the lymphoma, and responds to therapy as for primary ITP. The development of ITP in remission has no prognostic significance.

Adult↗

PubMed1993

The effects of interleukin-8 on neutrophil fMetLeuPhe receptors, CD11b expression and metabolic activity, in comparison and combination with other cytokines.

The effect of the chemotactic cytokine, IL-8, on neutrophil function was compared with that of of other cytokines, GM-CSF, G-CSF TNF alpha and IFN-gamma. IL-8 rapidly stimulated a three-fold enhancement of the fMLP-stimulated respiratory burst, but this priming effect was transient compared with the slower and sustained effects of GM-CSF and IFN gamma. Apart from G-CSF, IL-8 was the weakest priming agent and was weaker than GM-CSF in priming arachidonic acid metabolism stimulated by calcium ionophore. When incubated in combination, IL-8 and TNF alpha were highly synergistic in their effects on respiratory burst priming, whereas IL-8 and GM-CSF showed little synergy. In contrast, IL-8 was as potent as GM-CSF at increasing the expression of neutrophil chemotactic peptide receptors and the beta 2 integrin, CD11b. The latter was maximally upregulated within 5 min of stimulation with IL-8, whereas the effect of GM-CSF was much slower. The kinetics of neutrophil respiratory burst priming by IL-8 were the same when measured in whole blood samples and in purified cell suspensions, and IL-8 dose-response curves were similar, showing that the low affinity IL-8 receptors on erythrocytes do not rapidly sequester circulating IL-8. The data suggest that IL-8 plays a minor role in priming neutrophil function and that a more major activity is the regulation of neutrophil adhesion and migration.

Antigens, CD↗

PubMed1993

Expression and dynamic modulation of the human granulocyte colony-stimulating factor receptor in immature and differentiated myeloid cells.

In this study we have examined the expression and modulation of the human granulocyte colony-stimulating factor (G-CSF) receptor (R) in immature and differentiated myeloid cells using a 125I labelled human G-CSF analogue (TG50). Equilibrium binding data revealed a single affinity class of receptor on all cell types expressing G-CSFR (KD 235-606 pM) with neutrophils expressing 2883 +/- 672 Rs/cell. Rapid internalization of surface receptor-bound ligand at 37 degrees C was detected in both immature cells (U937) and neutrophils with > 70% of specifically bound ligand internalized within 5 min. Concentration-response data showed that the level of occupancy of neutrophil G-CSFRs by ligand at 37 degrees C was approximately 5-fold greater than predicted by equilibrium binding data and correlated closely with concentration-response data for biological activity. Re-expression of G-CSFRs following down-regulation by internalization was not detected. Down-regulation of the neutrophil G-CSFR by several agents including granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor (TNF), lipopolysaccharide (LPS), f-met-leu-phe (fMLP), phorbol ester (TPA) and C5a was observed at 37 degrees C but not at 4 degrees C. In contrast, G-CSFRs on immature myeloid cells were significantly down-regulated by TPA only. Differentiation of myeloid leukaemic cell line HL-60 with DMSO, a frequently used model of granulocytic differentiation, was associated with a significant reduction in G-CSFR expression (11 +/- 5% of control) whereas treatment with retinoic acid led to increased G-CSFR expression (161 +/- 3%).

Binding, Competitive↗

PubMed1993

Acute hepatitis C infection in patients undergoing therapy for haematological malignancies: a clinical and virological study.

Patients receiving multiple transfusions are at risk of acquiring hepatitis C (HCV) infection from a donor population which is unscreened for hepatitis C antibodies (anti-HCV). Prior to the introduction of blood donor screening for anti-HCV in the U.K., a group of patients undergoing therapy for haematological malignancies, with repeatedly abnormal liver function tests, were investigated for acute HCV infection. Thirty-two patients had repeatedly raised serum transaminases, and eight of these (25%) had evidence of an acute HCV infection. The diagnosis was made by the detection of HCV-RNA in the patients' serum using a complementary DNA/polymerase chain reaction (cDNA/PCR) procedure. All eight patients had received myeloablative chemotherapy and three had undergone bone marrow transplantation. HCV infection contributed significantly to the morbidity of this group of patients in the short term whilst they were undergoing treatment for their underlying haematological condition. The long-term effects have yet to be evaluated. In an attempt to decrease hepatic damage due to HCV, three patients were placed on interferon therapy. None showed a sustained reduction in serum transaminases or HCV viraemia. It is hoped that the introduction of anti-HCV screening of blood donors, will reduce the frequency of transfusion-acquired HCV infections. Early observations suggest that this is the case, as we have seen no new cases of HCV infection in our unit since the introduction of donor screening in September 1991.

Acute Disease↗

PubMed1993

Dynamic modulation of the cell surface expression of the granulocyte-macrophage colony-stimulating factor receptor.

The GM-CSF receptor (GM-CSFR) is composed of alpha and beta subunits. Surface expression of the alpha chain alone leads to low affinity GM-CSF binding and of both subunits to high affinity binding; the beta chain is required for transducing a proliferative signal. Studies of GM-CSFR expression have concentrated largely on static events occurring under conditions of binding equilibrium. We have examined the dynamic regulation of high and low affinity GM-CSFR expression in neutrophils (1100 +/- 200 R/cell, KD 50 +/- 15 pM) and a GM-CSF dependent human leukaemic cell line, TF-1 (2000 +/- 450 R/cell KD 15 +/- 5 pM) and 8600 +/- 1150 R/cell KD 1.8 +/- 0.3 nM). The addition of GM-CSF to TF-1 cells (350 pM, 4 h at 37 degrees C) caused a reduction in subsequent binding of 125I-GM-CSF at low ligand concentration (100 pM) (following a low pH wash to remove surface bound ligand) to 16 +/- 4% and a reduction in binding at high ligand concentration (2 nM 125I-GM-CSF) to 36 +/- 9% of control. Scatchard analysis showed complete down-regulation of high affinity GM-CSFR and a significant reduction in low affinity GM-CSFR. In neutrophils, concentration-response curves of ligand induced receptor down-regulation at 37 degrees C showed that observed down-modulation was more than 10-fold greater than predicted by static equilibrium binding data and correlated closely with GM-CSF priming of the neutrophil respiratory burst. The addition of IL-3 to TF-1 cells at 37 degrees C reduced 100 pM 125I-GM-CSF binding to 18 +/- 4% and 2 nM 125I-GM-CSF binding to 46 +/- 5% of control. TF-1 cells, but not neutrophils, were able to re-express GM-CSFR following removal of GM-CSF from medium. TF-1 proliferation assays showed that pulsed GM-CSF (0.35-3.5 nM) for up to 4 h did not cause a significant increase in 3H-thymidine incorporation which required the continued presence of GM-CSF (control 2875 +/- 208 cpm, pulsed GM-CSF 5 ng/ml 4972 +/- 1344, continuous GM-CSF 5 ng/ml 17249 +/- 2982). Therefore, proliferation of TF-1 cells required the continued presence of GM-CSF at a time when there was no detectable surface high affinity GM-CSFR.(ABSTRACT TRUNCATED AT 400 WORDS)

Cells, Cultured↗

PubMed1993

Pentoxifylline at clinically achievable levels inhibits FMLP-induced neutrophil responses, but not priming, upregulation of cell-adhesion molecules, or migration induced by GM-CSF.

Pentoxifylline (PTX) administered after bone-marrow transplantation reduces procedure-related organ damage mediated by TNF alpha. GM-CSF is also given post-transplant to stimulate earlier neutrophil recovery. Because PTX has been shown to inhibit neutrophil function, we sought to determine whether it also inhibited the effects of GM-CSF on neutrophil activity. The study confirmed that PTX at clinically achievable concentration (5-10 mumol/l) attenuated the responses of human neutrophils to chemotactic peptide, whereas it did not inhibit the effect of GM-CSF on neutrophil function even at high concentrations. In experiments with human neutrophils, neither the direct effects of GM-CSF such as stimulation of migration and increased expression of CD11b, nor the priming effects of GM-CSF on the respiratory burst, were inhibited by PTX. In experiments with monkeys, intravenous administration of PTX did not block subsequent GM-CSF-induced neutrophil CD11b upregulation or phagocyte margination, even when near millimolar plasma levels of pentoxifylline were obtained. The retention of cytokine-stimulated activities suggests that PTX will not compromise the response of neutrophils to stimuli from infectious foci.

Antigens, CD↗

PubMed1993

Randomised vehicle-controlled dose-finding study of glycosylated recombinant human granulocyte colony-stimulating factor after bone marrow transplantation.

A multicentre, randomised vehicle-controlled single-blind dose ranging trial of intravenous recombinant granulocyte colony-stimulating factor (rhuG-CSF) administration after BMT has been performed in 121 patients with non-myeloid malignancies. All the doses of rhuG-CSF used (2-20 micrograms/kg/day) resulted in significant acceleration of neutrophil recovery, and a dose-response effect was apparent (p < 0.05). At the 20 micrograms/kg/day dose of rhuG-CSF the median time taken to achieve a neutrophil count of > 0.5 x 10(9)/1 was reduced from 19 to 13 days (p < 0.001) and the time to achieve a neutrophil count > 1.0 x 10(9)/1 on the first of 3 consecutive days, from 26 to 14 days (p < 0.001). There was a trend to less antibiotic use in the rhuG-CSF recipients and the median time in hospital was markedly reduced by 11-15 days (p < 0.01). There was no toxicity in this study attributable to rhuG-CSF.

Adolescent↗

PubMed1993

Efficacy of delayed granulocyte colony-stimulating factor after autologous BMT.

Granulocyte colony-stimulating factor (G-CSF) has been shown to be effective in accelerating neutrophil recovery after BMT. In this single centre study, we have examined the effect of delaying the start of treatment with G-CSF (5 micrograms/kg) until 8 days after BM infusion in a cohort of 17 patients with malignant lymphomas undergoing autologous BMT. In comparison with historical controls, neutrophil recovery to > 0.5 x 10(9)/l was shortened from 22 to 14 days (p < 0.01). Patients receiving G-CSF required iv antibiotics for a median 13 days (control 17, p < 0.05) and were discharged a median 28 days post-ABMT (control 32.5, p = NS). Patients received G-CSF for a median of 10 days only. Although these results require confirmation in a randomised trial they suggest that G-CSF administration could be delayed until 8 days after BMT without compromising efficacy and with an accompanying reduction in treatment costs.

Adult↗

PubMed1992

Human macrophage colony-stimulating factor levels are elevated in pregnancy and in immune thrombocytopenia.

Plasma macrophage colony-stimulating factor (M-CSF) levels were measured by enzyme immunosorbent assay (ELISA) using horse and rabbit polyvalent antibodies raised against human M-CSF purified from urine (hM-CSF). Plasma M-CSF levels in nonpregnant female controls were 364 +/- 69 U/mL (mean +/- SD, n = 20). Pregnancy results in significant elevation of circulating M-CSF levels (541 +/- 164 U/mL, n = 46, P < .0005). M-CSF levels were increased by 28 weeks' gestation and did not increase further in later pregnancy. M-CSF levels were also measured in 20 female controls before and after commencing on the oral contraceptive pill. There was no effect of the contraceptive pill on plasma M-CSF levels (364 +/- 69 U/mL before v 373 +/- 66 U/mL after commencing on the pill). In 28 nonpregnant patients with untreated immune thrombocytopenic purpura, (ITP), plasma M-CSF levels were significantly increased (797 +/- 402 U/mL, n = 28, v 364 +/- 69 U/mL in controls, N = 20, P < .0005). Pregnant ITP patients had higher levels of plasma M-CSF (929 +/- 327 U/mL, n = 25) than nonpregnant patients, but this difference was not significant. Elevated levels of M-CSF in ITP may reflect activation of the reticuloendothelial system (RES), which could result in positive feedback to increase the destruction of platelets. The increase in M-CSF associated with pregnancy could contribute to the exacerbation of latent ITP in pregnancy.

Adult↗