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Biomedical subjects

M Bewick

Publications and source records attributed to M Bewick.

At least 19 recordsLinked to original sources
PubMed2004

The role of depletion of dimethyl sulfoxide before autografting: on hematologic recovery, side effects, and toxicity.

Cryopreservation of stem cells after collection from peripheral blood or bone marrow for autologous transplantation necessitates protection with dimethyl sulfoxide (DMSO). Unfortunately, DMSO, when infused with the thawed cell suspension, may induce serious complications and side effects. To assess whether depletion of DMSO before autografting affects safety and efficacy, 56 consenting consecutive patients treated with high-dose chemotherapy and autologous blood stem cell transplantation were assigned to obtain either an untreated or DMSO-depleted autograft. On the day of transplantation, the cryopreserved cells were thawed and infused to the patient either immediately or after washing 3 times in normal saline supplemented with 6% anticoagulant citrate dextrose solution. Cell count with viability, clonogenic assay, and phenotyping were performed before and after thawing and after washing. Hematologic recovery, side effects, and complications were recorded. The in vitro and clinical data on 56 patients show that the depletion of DMSO in vitro before autografting does not induce a significant loss of cell number, viability, colony-forming unit-granulocyte-macrophage activity, or number of CD34(+) cells. Furthermore, it leads to a safe and sustained engraftment. The complications and side effects, as recorded by continuous monitoring, were substantially less; however, the procedure takes 3 to 4 hours of laboratory work per patient.

Adolescent↗
PubMed2004

Evaluation of sICAM-1, sVCAM-1, and sE-Selectin levels in patients with metastatic breast cancer receiving high-dose chemotherapy.

Soluble forms of some cell adhesion molecules (CAM), sICAM-1, sVCAM-1, and sE-selectin, are elevated in the sera and plasma of patients with inflammation, arthritis, diabetes, and cancer. Increased levels of these soluble molecules in patients with cancer have been shown to correlate with disease progression and survival. This suggests that increased expression of the soluble forms of CAMs may play an important role in cancer cell growth and metastasis and may be prognostic and/or predictive of malignant disease. In this retrospective study, we assessed the clinical significance of sICAM-1, sVCAM-1, and sE-selectin in 95 patients with metastatic breast cancer enrolled in clinical trials of high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). The significance of soluble HER-2 (sHER-2) and sFAS status, determined in previous studies for this group of patients, was also included in this analysis. Univariate analysis showed that sICAM-1, sVCAM-1, sFas, sHER-2 positive status, and the presence of liver metastases were significant prognostic factors for both progression-free survival (PFS) and overall survival (OS) in the total patient group. In multivariable analysis, HER-2 and sFAS were shown to be independent prognostic factors for PFS and OS. Within the various treatment groups examined, sICAM-1 was a prognostic factor for clinical outcome for patients with metastatic breast cancer enrolled in trials with cyclophosphamide- and carboplatin-based or vinblastine-based HDC, but not in trials with paclitaxeland cyclophosphamide-based HDC.

Adult↗
PubMed2001

Circulating cardiac troponin-T in patients before and after renal transplantation.

BACKGROUND: The diagnostic and prognostic use of cardiac troponin T (cTnT) in patients with renal failure has been questioned. Raised serum concentrations of cTnT, with no apparent signs of cardiac damage using conventional methods of detection, have been reported. We aimed to relate circulating concentrations of cTnT to improved renal function following renal transplantation over a one-year period. METHOD: Plasma cTnT was analysed from patients with end stage renal disease before and after transplantation and subsequently at 1, 3, 6 and 12 months. Eight patients had diabetes, 14 had hyperlipidaemia, 8 were smokers and 4 were ex-smokers; all were hypersensitive. RESULTS: At the time of transplantation, 3 of the 32 patients (9.4%) had plasma cTnT concentrations above 0.1 microg/l. In addition to these three patients, five others showed raised cTnT over the one-year period. CONCLUSIONS: The overall trend in circulating cTnT concentrations did not seem to be affected by improved renal function. However, all of the patients that had raised cTnT concentrations at any stage of the one-year period had explainable pathologies or were exposed to multiple cardiac risk factors.

Adult↗
PubMed2001

HER-2 expression is a prognostic factor in patients with metastatic breast cancer treated with a combination of high-dose cyclophosphamide, mitoxantrone, paclitaxel and autologous blood stem cell support.

The expression levels of a circulating extracellular domain of HER-2 can be detected in the plasma and serum of patients with metastatic breast cancer using an enzyme immunoassay (ELISA) method. In this study, we evaluated the clinical significance of high and low levels of HER-2 in the plasma of 46 patients with metastatic breast cancer enrolled in a clinical trial of high-dose chemotherapy (HDCT) using cyclophosphamide, mitoxantrone, and paclitaxel with autologous stem cell transplantation (ASCT). Using 2500 U/ml as the cut-point, 20 patients (46%) had elevated HER-2 levels (HER-2 positive). Our results suggest that patients with metastatic breast cancer and high soluble plasma HER-2 have a significantly poorer overall (OS) and progression-free survival (PFS) following high-dose chemotherapy with paclitaxel and ASCT. The median OS of patients with low levels of HER-2 was significantly longer (P < 0.01) than the median OS of patients with high levels of HER-2 (29.8 months vs 15.9 months). PFS was also significantly longer (P < 0.01) for patients who were HER-2-negative, than for patients who were HER-2-positive (13.0 vs 8.6 months). Univariate analysis showed that patients with liver or lung metastases had significantly reduced OS and PFS. Patients with metastases to two or more sites also had a significantly reduced time to disease progression, but not OS. In multivariable analysis, lung metastases contributed along with HER-2-positive status to determine a group of patients with significantly poorer OS. However, HER-2-positive status remained the only independent predictor of PFS.

Adult↗
PubMed2001

Soluble Fas (CD95) is a prognostic factor in patients with metastatic breast cancer undergoing high-dose chemotherapy and autologous stem cell transplantation.

The Fas/Fas ligand (FasL) system plays an important role in cellular apoptosis and is involved in cancer cell death induced by the immune system and anticancer drugs. Increased serum levels of soluble Fas (sFas) are associated with a number of different disease states and with tumor progression and metastasis in patients. In this study, we examined the plasma levels of sFas in 94 women with metastatic breast cancer undergoing high-dose chemotherapy (HDCT) treatment with autologous stem cell transplantation (ASCT) using a quantitative enzyme-linked immunosorbent assay (ELISA) method. Thirty-one patients (31/94, 33%) had plasma sFas levels greater than the optimum cut point of 1.90 ng/ml (median 2.47, range 1.98-13.54 ng/ml) and were designated as sFas positive. Sixty-three patients (63/94, 67%) had sFas levels below 1.90 ng/ml (median 1.14, range 0.47-1.89 ng/ml). In univariate analysis, patients with sFas-positive status, HER-2 overexpression, and the presence of liver metastases had a significantly shorter time to disease progression (PFS) and significantly decreased overall survival (OS). Multivariable analysis (Cox proportional hazards model) for PFS determined that sFas status significantly predicted disease progression (p = 0.004) with an adjusted hazard ratio (HR) of 2.0 (95% CI, 1.3-3.3). HER-2 status and liver metastases were also significant independent predictors of disease progression (p < 0.001) for both. sFas level was also an independent prognostic factor for OS with an adjusted HR of 2.0 (p = 0.006; 95% CI, 1.2-3.4). HER-2 status and liver metastases also remained highly significant independent prognostic factors for OS (HER-2: p < 0.001, HR 2.3, and liver metastases: p = 0.001, HR 2.7). In conclusion, these results suggest that plasma levels of sFas may be a valuable clinical prognostic factor in predicting outcome (PFS and OS) for patients with metastatic breast cancer undergoing HDCT with ASCT.

Adult↗
PubMed2001

Cardiac troponin T and creatine kinase MB are not increased in exterior oblique muscle of patients with renal failure.

BACKGROUND: Serum cardiac troponin T (cTnT) concentrations may be increased in patients with renal dysfunction without evidence of cardiac damage, as assessed by conventional methods. It has been suggested that these positive measurements result from the expression in skeletal muscle of fetal isoforms of cTnT, which are detected by the cTnT immunoassay. METHODS: Skeletal muscle (exterior oblique) biopsies were taken from healthy living kidney donors (n = 5) and transplant recipients (n = 19). The amounts of cTnT and creatine kinase (CK) isoenzymes in skeletal muscle of healthy controls were compared with those in patients with renal failure (Wilcoxon-Mann-Whitney test). cTnT was measured quantitatively by a second-generation assay, with a limit of detection of 1 microg/g of protein, and qualitatively by immunohistochemistry and immunoblotting. CK-MB was measured by quantitative electrophoresis. RESULTS: Minute quantities of cTnT were detected in 2 of the 5 (40%) control samples and 9 of the 19 (47%) renal failure samples, respectively, at mean concentrations of <5 microg/g of protein for both subject groups. This was <1/6000th that found in heart muscle. There was no significant difference in cTnT or CK-MB content in skeletal muscle between healthy controls and patients with renal failure. Increased serum cTnT did not predict detectable cTnT in skeletal muscle. cTnT was not detected qualitatively by immunoblotting or immunohistochemistry in any skeletal muscle samples. CONCLUSIONS: Uremia does not affect the content of cTnT or CK-MB in exterior oblique muscle, suggesting that cTnT detected in serum from patients with renal failure does not originate from skeletal muscle.

Adult↗
PubMed2000

Pharmacokinetics of mycophenolate mofetil in patients with end-stage renal failure.

BACKGROUND: Mycophenolate mofetil (MMF) acts as a prodrug for the immunosuppressive drug mycophenolic acid (MPA). It is rapidly converted to MPA following oral ingestion. MPA is metabolized to MPA glucuronide (MPAG), which is renally excreted. This study examines the pharmacokinetics of MPA and MPAG in patients with end-stage renal failure who were on hemodialysis (N = 10) or peritoneal dialysis (N = 10) treatment. METHODS: After an overnight fast, a single oral dose of 1 g MMF was given. Plasma concentrations of MPA and MPAG were measured from 0 (predose) to 36 hours after administration, using high-performance liquid chromatography (HPLC). The area under the concentration time curve (AUC) from 0 to 36 hours was calculated using the trapezoidal rule. RESULTS: Mean (+/- SD) AUC for MPA was 55.7 +/- 32.6 mg/L.h for hemodialysis patients and 44.7 +/- 14.7 mg/L.h for peritoneal dialysis patients, which is similar to expected values for subjects with normal renal function. The mean (+/- SD) maximum plasma concentration (Cmax) for MPA was lower than would be expected for subjects with normal renal function (16.01 +/- 10.61 mg/L for hemodialysis, 11.48 +/- 4.98 mg/L for peritoneal dialysis). MPAG clearance was prolonged with AUC approximately five times what would be expected in subjects with normal renal function (1565 +/- 596 mg/L.h for hemodialysis, 1386 +/- 410 mg/L.h for peritoneal dialysis). There was no significant difference for any of the pharmacokinetic parameters between subjects on hemodialysis and those on peritoneal dialysis. Plasma concentrations of MPA and MPAG did not fall significantly during hemodialysis. No MPA was detectable in hemodialysis or peritoneal dialysis fluid, but small amounts of MPAG were detected in hemodialysis fluid in 1 out of 10 subjects and in peritoneal dialysis fluid in 3 out of 10 subjects. CONCLUSIONS: The accumulation of MPAG may be responsible for the poor gastrointestinal tolerance of this drug in dialysis patients and probably limits the maximum dose of MMF that can be tolerated.

Adult↗
PubMed1999

Expression of C-erbB-2/HER-2 in patients with metastatic breast cancer undergoing high-dose chemotherapy and autologous blood stem cell support.

C-erbB-2/HER-2 (designated HER-2) is overexpressed in both primary and metastatic breast cancer and predicts poor prognosis. We investigated the expression of HER-2 in patients with metastatic breast cancer undergoing high-dose chemotherapy (HDCT) with autologous blood stem cell (ABSC) support and correlated the presence (positive) or absence (negative) of HER-2 overexpression in these patients with response to treatment, progression-free survival (PFS) and overall survival (OS). The level of HER-2 expression was analyzed in 57 patients with metastatic breast cancer undergoing HDCT with ABSC support. Plasma from peripheral blood was taken at three different time points during the course of treatment and was analyzed using an enzyme immunoassay (EIA) to detect circulating levels of the extracellular portion of HER-2. HER-2 levels were elevated (>0.2 U/mg protein) in 27/57 (47.4%) patients at one or more time points during treatment. The level of HER-2 varied during the course of treatment. Following induction chemotherapy (ICT), five patients who were negative initially, showed overexpression of HER-2. Three patients overexpressed HER-2 only after HDCT/ABSC. Response to treatment was similar in patients independent of plasma HER-2 levels. Overexpression of HER-2 was associated with a significantly shorter PFS (P = 0.004, log rank) and OS (P = 0.003, log rank) after HDCT/ABSC. HER-2 overexpression, patient age, estrogen receptor status, progesterone receptor status, and previous hormone treatment were assessed by univariate and multivariate analysis. Univariate analysis determined that only HER-2 overexpression correlated significantly with decreases in progression free survival (P = 0.005, Cox regression). Decreased overall survival correlated significantly with HER-2 overexpression (P = 0.004) and decreased expression of both estrogen receptor (P = 0.032) and progesterone receptor (P = 0.039). In multivariate analysis of these variables, only HER-2 expression levels proved to be of independent statistical significance in predicting outcome for both PFS (P = 0.007) and OS (P = 0.002). These results suggest that overexpression of HER-2, measured by EIA in plasma may predict a shorter PFS and OS in patients with metastatic breast cancer treated with HDCT and ABSC support.

Adult↗
PubMed1997

Evaluation of three rapid RNA extraction reagents: relevance for use in RT-PCR's and measurement of low level gene expression in clinical samples.

Although peripheral blood and bone marrow are usually readily available from patients, present techniques of RNA extraction are tedious, require millilitres of starting material and removal of red blood cells before RNA purification. Further, successful reverse transcriptase polymerase chain reaction (RT-PCR) amplification requires the removal of haemoglobin derivatives which interfere with the PCR process. Recently, one step rapid use reagents have become available, claiming to be useful for obtaining high quality RNA from microlitre quantities of whole blood drawn directly from the patient. Their use to date in clinical samples appears limited with little information in the literature documented. In an attempt to overcome this, we tested the Trizol-LS, RNA-STAT-50 and Ultraspec-3 reagents upon a statistically significant number of clinical isolates of fresh and cryopreserved peripheral blood, bone marrow, blood apheresis products and a breast cancer cell line (MCF7) in order to evaluate whether these methods could be applied to routine laboratory use in an RT-PCR method capable of detecting rare gene expression. Our findings showed that there was some variation in the quality of RNA extracted which was indicated by absorbance spectrophotometry at 260 and 280 nm. 1% agarose gel electrophoresis showed that each of these methods could yield total RNA capable of generating the signature 18S and 28S rRNA bands. Using the Kruskal-Wallis non-parametric anova test combined with Dunn's multiple comparison test, the only statistically significant difference (p<0.05) indicated that Trizol-LS was more reliable than RNA-STAT-50-LS and Ultraspec-3 at extracting RNA from fresh peripheral blood. RNA extracted with the Trizol-LS and RNA STAT-50 reagents was successfully amplified in a multiplex RT-PCR reaction for detection of the multi-drug resistance related genes MDR1, the multi-drug resistance related protein (MRP) and topoisomerase IIalpha. Low level MDR1 gene expression could be detected in frozen whole blood. However, PCR products were only seen when the anti-coagulant heparin was removed from all samples prior to cDNA production. RT-PCR amplification was not 100% successful with RNA extracted with Ultraspec-3 reagent. In conclusion, we found that the RNA extracted from whole blood with the Trizol-LS and the RNA-STAT-50 are suitable for use in clinically relevant molecular biology protocols that analyze rare event genes without further purification. Our results indicated that the Trizol-LS reagent was generally more consistent in obtaining a pure and sufficient quantity of RNA from patient material as shown by the mean result of purity and quantity in comparison to either Ultraspec-3 or RNA-STAT-50-LS reagents. Ultraspec-3 is not easily suited for direct use with whole blood products.

Evaluation Studies as Topic↗
PubMed1996

Prevention of hyperacute rejection by removal of antibodies to HLA immediately before renal transplantation.

BACKGROUND: Many patients with circulating antibodies to human leucocyte antigens (anti-HLA) are highly sensitised against renal transplantation and are liable to immediate graft loss through hyperacute rejection. Our aim was to find out whether removal of anti-HLA immediately before renal transplantation prevented hyperacute graft rejection. METHODS: 13 highly sensitised patients underwent cadaveric renal transplants immediately after immunoadsorption (IA) treatment to remove anti-HLA. Before IA, 12 patients had a positive crossmatch against donor cells either by cytotoxic or flow-cytometric assay; results for one patient were equivocal. FINDINGS: Renal biopsy samples were obtained 20 min after removal of the vascular clamps in nine patients. There was no evidence of hyperacute rejection in six of the nine patients; the other three patients showed glomerular thrombosis but no other evidence of hyperacute rejection. Two of these three grafts were functioning at 31 months of follow-up. Six episodes of acute rejection occurred in five patients during the first month after transplantation and overall there were 13 rejection episodes in nine patients. At latest follow-up (median 26 months, range 9-42), 12 of 13 patients were alive and seven of 13 grafts were surviving with a median plasma creatinine concentration of 185 mumol/L (range 106-296) in the functioning grafts. No graft was lost as a result of classic hyperacute rejection. INTERPRETATION: Immediate pretransplant IA can prevent hyperacute rejection and provide an opportunity for successful transplantation in highly sensitised patients.

Adolescent↗
PubMed1996

Transplant renal artery stenosis in 77 patients--does it have an immunological cause?

Transplant renal artery stenosis (TRAS) is a common complication after transplantation and is an important cause of graft dysfunction. Damage from graft rejection, trauma, and atherosclerosis have been implicated as possible causes. We reviewed all 917 patients transplanted in our unit since 1978 to study the prevalence, clinical features, and possible causes of TRAS. Seventy-seven patients with TRAS were identified. The detected incidence was 2.4% before the introduction of color doppler ultrasonography (CDU) and rose to 12.4% after CDU was introduced in 1985, giving an overall incidence of 8.4% during a mean follow-up period of 6.9 years. The TRAS group was compared with a control group of 77 transplanted patients matched for age, year of transplant, sex, and number of previous grafts. Mean ages for the study and control groups were 43.6 +/- 15 and 44.8 +/- 13.7 yr. A total of 25% of cases of TRAS were diagnosed within the first 8 wk of transplantation and in 60% within the first 30 wk (median = 23 wk). All patients were treated with angioplasty, 28 patients had recurrence of TRAS requiring multiple angioplasties (maximum 5) and 1 went on to have surgery. Angioplasty resulted in a significant fall in plasma creatinine. Patient and graft survival were significantly worse in the TRAS group: 69% vs. 83% (P < 0.05) and 56% vs. 74% (P < 0.05) (TRAS vs. Control), respectively. There was a significantly higher incidence of rejection, especially cellular rejection in the TRAS group, 0.67 vs. 0.35 episodes per patient (P < 0.01) (TRAS vs. Control). Recurrence but not occurrence of TRAS was associated with the use of cyclosporine.

Adult↗
PubMed1996

Anticipation of highly sensitised renal patients' immunoadsorption requirements by prescreening using protein A minicolumns.

We are able to subdivide highly sensitised renal patients who wish to enter our immunoadsorption programme into two groups; those who will require acute pretransplant immunoadsorption only and those requiring regular immunoadsorption prior to transplantation. This division of patients is based on the results obtained from laboratory assessment using protein A minicolumns. Patient's plasma is passed down a minicolumn for 6 x 10 min cycles, a sample of plasma is kept after each cycle for analysis by cell flow cytometric cross-match (FCXM). The samples are screened against cells from two normal volunteers, one expressing a previously mismatched Class I HLA antigen (MMA) to which the patient has raised persistent IgG antibodies, the other, whilst not expressing any MMAs, should express a cross-reactive HLA Class I antigen (XRA) to which the patient has formed persistent IgG antibodies. Patients are allocated into the acute pretransplant immunoadsorption group if, after 6 minicolumn cycles, the T cell FCXM vs XRA and MMA is reduced to less than 1 Log median fluorescence intensity shift above the negative control and that both these values have been reduced by at least 15% from the preimmunoadsorption figure. If these criteria are not met, regular immunoadsorption is required under cover of cyclophosphamide. Eleven patients who have been allocated by these criteria have subsequently been transplanted without any incidence of hyperacute rejection.

Adolescent↗
PubMed1996

Antibody removal and subsequent transplantation of a highly sensitised paediatric renal patient.

We report a successful renal transplant in a highly sensitised paediatric recipient following removal of HLA-specific antibodies by extracorporeal immunoadsorption. The immediate pretransplant cytotoxic titre against the donor was greater than 1:512; this was reduced to negativity by two immunoadsorption sessions prior to transplant surgery. We also describe the presence of unexpected non-HLA-specific antibody activities in this immunoadsorbed patient.

Autoantibodies↗
PubMed1996

5-year follow-up of patients successfully transplanted after immunoadsorption to remove anti-HLA antibodies.

The function of renal allografts in patients who had received pretransplant immunoadsorption in order to remove cytotoxic anti-HLA antibodies was studied. We reviewed 6 patients who received a graft which functioned beyond 3 months; the mean follow-up period was 76 (range 62-89) months. Two grafts have been lost from chronic rejection, at 12 and 62 months, respectively. The mean plasma creatinine levels at 1 and 5 years were 169 (range 143-211) mumol/l and 155 (range 92-235) mumol/l, respectively (1.91, range 1.62-2.39, mg/dl and 1.75, range 1.04-2.66 mg/dl, respectively). The major source of morbidity during long-term follow-up has been the occurrence of renal artery stenosis in 5 patient and renal vein stenosis in 1. In conclusion, the 5-year graft survival and function was good in patients who received immunoadsorption and whose grafts survived beyond the first 3 months after transplantation.

Aged↗