PubMed Health⌕ Search

Biomedical subjects

A G Prentice

Publications and source records attributed to A G Prentice.

At least 37 records · Page 2Linked to original sources
PubMed1998

Autoimmune haemolysis in patients with B-CLL treated with chlorodeoxyadenosine (CDA).

We have treated 19 B-chronic lymphocytic leukaemia (B-CLL) patients with CDA (Leustat, Janssen-Cilag). Four patients developed severe autoimmune haemolytic anaemia, and 2 of these had severe reticulocytopenia due to red cell aplasia/hypoplasia. Two patients died as a complication of the haemolysis one during the primary episode, with a clinical course suggestive of transfusion associated graft-versus-host disease (taGVHD), and one following a relapse of haemolysis. The onset of haemolysis occurs within 4 cycles of CDA therapy and is temporally related to the T-lymphocyte nadir induced by CDA. The presence of a positive DAT prior to therapy in 3 of 4 patients developing haemolysis suggests that the CDA induced T-lymphocytopenia may exacerbate the tendency of certain CLL patients to autoimmune haemolysis.

Aged↗
PubMed1997

A prospective randomized study of three types of platelet concentrates in patients with haematological malignancy: corrected platelet count increments and frequency of nonhaemolytic febrile transfusion reactions.

We prospectively randomized 51 patients with haematological malignancy requiring platelet concentrates (PCs) to receive either single donor platelet-pheresis products (SD-PC), PCs made from pooled buffy coats (BC-PC) or pooled units of platelets made by the platelet-rich plasma method (PRP-PC). The leucocyte content of each type of PC was 0.33 (0.03-13.5), 5.68 (0.19-99.0) and 365 (65-910) x 10(6); median (range), respectively; P < 0.0001. All red cell transfusions were leucodepleted by filtration. Statistical comparison of the probability of the occurrence of a nonhaemolytic febrile transfusion reaction (NHFTR) following transfusion of PCs in patients in each group showed a significant decrease for the SD-PC and BC-PC groups (0.031 and 0.038, respectively) when compared with PRP-PC (0.171); P = 0.0001. The actual corrected platelet count increments (CCI) at 1-6 and 18-24 h post-transfusion for all three types of PC did not differ significantly. We conclude that transfusion of PRP-PC is associated with a significant increase in NHFTR.

Adult↗
PubMed1997

The distribution of leukaemia in association with domestic water quality in south west England.

This study assessed whether there is any variation in the incidence of haematological malignancies between geographical areas of differing water supplies in the South West peninsula of the United Kingdom (1984 to 1988 inclusive). The possibility of correlations existing between variation in water quality and variation in the incidence of haematological malignancies was examined. Haematological incidence data, taken from the Leukaemia Research Fund's Data Collection Study, were mapped into 46 geographical areas of differing water supply. The distribution of the mapped cases was then tested for homogeneity using the Potthoff and Whittinghill (1966) test score. The age-adjusted incidence ratios calculated during the heterogeneity testing were examined for correlations with water quality indicators using correlation and stepwise regression. Significant heterogeneity in the incidence rates among water supply areas was observed for two groups of disease-acute leukaemias and myeloproliferative disorders. Three water quality indicators-pH, nitrate concentration and aluminium concentration-varied considerably over the study period. Significant correlations were observed between the standardized incidence ratios of five disease categories and some water quality indicators, especially aluminium and trihalomethane concentrations. The standardized incidence ratios of some haematological malignancies differed between geographical areas of water supply in South West England, and the evidence suggests that this variation may be associated with variation in water quality indicators. Although this lends support to similar findings in the United States of America, the pattern of correlations are affected by disease latency and statistical methodology.

England↗
PubMed1996

Fungal infections: a survey of laboratory services for diagnosis and treatment.

A questionnaire on the services provided and the methods used for the diagnosis of fungal infections and for the support of antifungal chemotherapy was sent to members of the British Society for Medical Mycology (BSMM) and the British Society for Antimicrobial Chemotherapy (BSAC). Ninety-five responses from general microbiology laboratories in the United Kingdom were analysed, and we compared services provided by laboratories that serve a transplant unit with those offered by other laboratories. We estimate that about 150 cases of cryptococcosis, 500 to 600 of candidaemia, and 300 to 400 of invasive aspergillosis are identified by laboratories in the United Kingdom (UK) each year. The clinical laboratories are aware of the importance of fungal infection, but rely heavily on reference services. In some laboratories, however, the degree of investigation of specimens and the procedures in use are inadequate for diagnosing systemic mycoses and determining the susceptibility of isolates to antifungal agents. The balance between reference and local services requires attention and external quality assurance needs to be applied effectively. In addition, effective methods for the diagnosis of systemic mycoses, and reliable and practicable methods for determining the susceptibility of isolates to antifungal agents, are needed urgently.

Antifungal Agents↗
PubMed1996

Modulation of apoptosis with cytokines in B-cell chronic lymphocytic leukaemia.

In B chronic lymphocytic leukaemia (B-CLL) non-proliferating peripheral blood (PB) B cells have a long life span in vivo. In cultures, these cells die spontaneously by apoptosis. Interleukin (IL) 4 inhibits spontaneous apoptosis (SA) and promotes survival of B-CLL B cells in vitro. No such effect is observed in PB B cells from normal healthy donors. The anti-apoptotic effect of IL4 is independent of mitogen-induced cell activation but depends on the concentration of IL4. The protective effect of IL4 is specific and it is significantly reduced or abolished with anti-IL4 antibody. Interferon (IFN)-gamma and alpha- IFN also protect B-CLL B cells from apoptosis in vitro. Sera from B-CLL patients have increased levels of IFN-gamma when compared with sera from healthy donors. In addition, B-cells in B-CLL express detectable levels of IFN-gamma mRNA. Other cytokines, namely ILl, IL2, IL6 and IL7 do not affect SA of B-CLL B cells. By contrast, IL5 and antibody to apolipoprotein-1 (APO- 1) receptor increase SA significantly and in a dose-dependent manner. Interleukin 4 protects B-CLL B cells from IL5-, anti(alpha) APO-1- and steroid-induced apoptosis. The mode of action of the cytokines inducing apoptosis or protecting B-CLL B cells from dying is largely unknown. Recently the bcl-2 proto-oncogene has been associated with prolonged cell survival. However, the involvement of bel-2 in spontaneous, cytokine-induced or steroid-induced apoptosis in B-CLL has been controversial. Some authors have reported down-regulation of bcl-2 protein expression in B-CLL B-cells undergoing SA or in steroid-treated cells with IL4 preventing this down-regulation. By contrast, others observed no significant loss of bcl-2 protein expression in steroid-, alpha-APO-1 - and IL5-treated cells when compared with untreated or fresh cells. Also, no correlation between bcl-2 protein expression and protection with IL4 has been reported. In conclusion, in B-CLL IL4, IFN-gamma and alpha-IFN promote the survival of the leukaemic cells. These cytokines may therefore be involved in the pathogenesis of the B-CLL.

Apoptosis↗
PubMed1996

Severe intravascular hemolysis due to autoantibodies stimulated by blood transfusion.

Autoantibodies may cause severe hemolytic anemia, but only rarely are they the cause of a hemolytic transfusion reaction due to the destruction of transfused allogeneic blood. In two patients, autoantibody was detected shortly after blood transfusion. The first case was a D-negative patient who produced an autoanti-Ce and subsequently developed hemoglobinuria and hyperbilirubinemia. The second case was a patient who developed an autoanti-Wrb that caused severe hemolysis that resulted in death.

Journal Article↗
PubMed1995

Multiple dose pharmacokinetics of an oral solution of itraconazole in patients receiving chemotherapy for acute myeloid leukaemia.

The multiple dose pharmacokinetics of a solution of itraconazole given orally were measured in an open study of 20 patients undergoing remission induction chemotherapy for acute myeloid leukaemia. Patients were given itraconazole 5 mg/kg od, 2.5 mg/kg bd, 2.5 mg/kg od or 1.25 mg/kg bd. The mean daily dose of itraconazole was 407 mg for patients receiving 5 mg/kg/day and 148 mg in patients receiving 2.5 mg/kg/day. Mean concentrations of 493 and 495 micrograms/L were achieved on day 8 in patients who received 5 mg/kg/d od or 2.5 mg/kg bd itraconazole respectively. However, mean concentrations were significantly lower for those who received 2.5 mg/kg od itraconazole being 110 micrograms/L on day 8. Mean areas under the serum-concentration time curves were also markedly higher in patients receiving 5 mg/kg/day than in those receiving 2.5 mg/kg/day itraconazole and were 22,382 and 5615 micrograms.h/L on day 15 respectively. These findings suggest that the serum concentrations attained with an oral solution of 5 mg/kg itraconazole either once daily or in two divided doses are suitable for antifungal prophylaxis in patients receiving chemotherapy for acute myeloid leukaemia.

Adolescent↗
PubMed1995

Antifungal drug susceptibility testing. Working Party of the British Society for Antimicrobial chemotherapy.

This article describes the current situation with regard to intrinsic and acquired resistance to antifungal compounds and progress with the development of standardized methods of susceptibility testing for amphotericin B, flucytosine, and the azoles. Recommendations for testing of isolates from patients destined to receive antifungal drug treatment, or in whom therapeutic failure or relapse is suspected, are presented.

Antifungal Agents↗
PubMed1995

Fludarabine-related autoimmune haemolytic anaemia in patients with chronic lymphocytic leukaemia.

We have treated 52 patients with chronic lymphocytic leukaemia (CLL) with fludarabine; 12 developed severe autoimmune haemolysis. Only three had a previous history of haemolytic anaemia. Six out of eight patients retreated with fludarabine after control of their haemolysis developed an exacerbation of the haemolytic anaemia. The cause of autoimmune phenomena in CLL is not known, but our findings reinforce the view that they are caused by a disturbance in immunoregulatory T cells. Fludarabine is a known suppressor of T-cell function.

Adult↗
PubMed1995

Effect of interleukins on the proliferation and survival of B cell chronic lymphocytic leukaemia cells.

AIMS: To investigate the effects of interleukin (IL) 1, 2, 4, and 5 on the proliferation and survival of peripheral blood B cells from patients with B chronic lymphocytic leukaemia (B-CLL) and compare them with the effects on normal peripheral blood B cells. METHODS: The proliferation and survival of pokeweed mitogen (PWM) activated B cells from B-CLL (n = 12) and normal peripheral blood (n = 5) were studied in vitro in response to IL-1, IL-2 IL-4, and IL-5. Survival of cells in cultures with or without added interleukins was studied by microscopic examination of cells and DNA agarose gel electrophoresis. RESULTS: Proliferation was observed in both B-CLL and normal peripheral blood cells on culture with IL-2 alone and also in some, but not all, B-CLL and normal peripheral blood cells with IL-1 and IL-4. However, there was greater variability in B-CLL cell responses than in normal peripheral blood cells. Il-5 did not affect normal peripheral blood cell proliferation but it increased proliferation in two B-CLL cases. Synergistic effects of these cytokines were not detected. IL-4 inhibited normal peripheral blood and B-CLL cell proliferation after the addition of IL-2. Inhibition of B-CLL cell responses to IL-2 was also observed with IL-5 and Il-1. Survival of B-CLL cells in cultures was enhanced with IL-4 not by an increase in proliferation but by reduced apoptosis. No such effect was seen in normal peripheral blood cells. IL-2 had a less noticeable antiapoptotic effect; IL-5 enhanced apoptosis in B-CLL cells. CONCLUSIONS: B-CLL and normal peripheral blood cells proliferated equally well in response to IL-2. IL-4 had a much lower effect on B-CLL cell proliferation, but had noticeable antiapoptotic activity. IL-5 enhanced cell death by apoptosis.

Apoptosis↗
PubMed1995

Effect of anti-APO1 on spontaneous apoptosis of B cells in chronic lymphocytic leukaemia: the role of bcl-2 and interleukin 4.

The cell surface protein apolipoprotein 1 (APO1) is expressed on various cell types including malignant lymphoid cells. Triggering of APO1 protein with antibody (Ab) induces apoptosis in APO1-expressing cells. We examined the effect of anti (alpha) APO1 Ab on spontaneous apoptosis (SA) and bcl-2 expression in B cell chronic lymphocytic leukaemia (B-CLL) in vitro. We also investigated the anti-apoptotic activity of interleukin 4 (IL4) on the aAPO1-induced apoptosis in B-CLL cells. Although expression of APO1 on B-CLL cells was not detectable by immunofluorescence, alpha APO1 Ab induced apoptosis in these cells. At 24 hours in culture the number of apoptotic cells was increased by a mean percentage (%) of 27% (range: 21-38) in only half of the cases studied. But in all twelve cases studied, at 48 hours alpha APO1 increased SA by a mean of 72% (range: 26-114) (P < .001) and at 72 hours, the mean % increase was 69% (range: 31-96) in 6/7 cases (P < .001). This effect was alpha APO1 concentration dependent. Interleukin 4 significantly protected B-CLL cells against alpha APO1-induced apoptosis by a mean of 53% (range: 28-76) (P < .001). This protection was specific to IL4 and it was significantly reduced or abolished with alpha IL4 Ab. Expression of bcl-2 protein in untreated cultures was not significantly different from that of the alpha APO1-treated cells; the mean equivalent of soluble fluorochrome (MESF) (range) was 4.9 (3.0-6.8) and 5.2 (3.5-6.0) respectively (P > 0.2). In fresh B-CLL cells the MESF (range) was 4.5 (2.4-6.6). Thus alpha APO1 Ab induced apoptosis in B-CLL cells by a pathway that is independent of bcl-2 expression and partially blocked by IL4.

Apoptosis↗
PubMed1994

Interleukin-5 (IL-5) increases spontaneous apoptosis of B-cell chronic lymphocytic leukemia cells in vitro independently of bcl-2 expression and is inhibited by IL-4.

During hematopoiesis, viability factors that suppress apoptosis are required throughout the differentiation process. Some of these factors may also function as growth factors. Interleukin-5 (IL-5) is recognized as a growth factor in hematopoiesis. We examined the involvement of IL-5 as a viability factor of B-CLL in vitro. In 13 B-CLL cases studied, IL-5 at 20 U/mL increased spontaneous apoptosis by a mean percentage of 53% (range, 20% to 129%) (P < .05) after 2 days in culture. On the third day, the mean percentage increase was 37% (range, 18% to 50%). In all cases, IL-4 protected B-CLL cells against IL-5-induced apoptosis by a mean percentage of 47% (range, 18% to 81%) (P < .001). This protection was specific to IL-4 and it was reduced with anti-IL-4 antibody. In addition, expression of bcl-2 protein in untreated cultures was not significantly different from that of the IL-5-treated cells; mean equivalent of soluble fluorochrome (MESF) was 5.2 (range, 3.0 to 6.8) and 4.9 (range, 3.0 to 6.3), respectively (P > .2). In freshly isolated B-CLL cells, the MESF was 4.5 (range, 2.4 to 6.6). These results show that IL-5 induced apoptosis in B-CLL cells by a pathway that is independent of bcl-2 expression. IL-4 partially protects against this effect.

Apoptosis↗
PubMed1994

Randomised trial of intravenous immunoglobulin as prophylaxis against infection in plateau-phase multiple myeloma. The UK Group for Immunoglobulin Replacement Therapy in Multiple Myeloma.

Patients with plateau-phase multiple myeloma have an increased risk of life-threatening bacterial infections and polyclonal humoral immune suppression. We conducted a randomised, double-blind, placebo-controlled, multicentre trial of intravenous immunoglobulin (IVIg) as prophylaxis against infection. 82 patients with stable multiple myeloma received monthly infusions of IVIg at 0.4 g/kg body weight or an equivalent volume of placebo (0.4% albumin) intravenously for 1 year. Other interventions, including chemotherapy, were not affected; no patient received prophylactic antibiotics. There were no differences at entry or on study in clinical or laboratory variables between patients in the two groups. There were no episodes of septicaemia or pneumonia in patients receiving IVIg compared with 10 in placebo patients (p = 0.002). There were 57 serious infections; 38 occurred in 470 patient-months on placebo, compared with 19 in 449 patient-months on IVIg (p = 0.019). IVIg also protected against recurrent infections (p = 0.021) in 60 patients who completed a year. Before treatment, 54 patients were immunised with Pneumovax and specific IgG responses were measured. A poor pneumococcal IgG antibody response (less than 2-fold increase) identified patients who had maximum benefit from IVIg. Mild adverse reactions were noted in 12% of IVIg infusions and 5% of placebo infusions. IVIg can be given safely to plateau-phase myeloma patients. It protects against life-threatening infections and significantly reduces the risk of recurrent infections. The individuals who benefit most can be identified prospectively by measuring IgG antibody responses to pneumococcal immunisation.

Aged↗