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Biomedical subjects

R M Higgins

Publications and source records attributed to R M Higgins.

At least 19 recordsLinked to original sources
PubMed2001

Does ethnicity influence perceived quality of life of patients on dialysis and following renal transplant?

BACKGROUND: Quality of life (QoL) as perceived by patients with end-stage renal disease (ESRD) is an important measure of patient outcome. There is a high incidence of ESRD in the Indo-Asian population in the UK and a lower rate of transplantation compared with white Europeans. The aim of this study was to determine whether perceived quality of life was influenced by treatment modality and ethnicity. METHODS: Sixty Indo-Asians treated with either peritoneal dialysis (n=20), hospital haemodialysis (n=20) or with a renal transplant (n=20) for >3 months were compared with 60 age-matched white Europeans closely matched for gender, diabetes and duration of renal replacement therapy. QoL was measured using the Kidney Disease and Quality of Life questionnaire (KDQOL-SF). The KDQOL-SF measures four QoL dimensions: physical health (PH), mental health (MH), kidney disease-targeted issues (KDI) and patient satisfaction (PS). Adequacy of treatment was measured by biochemistry, 24 h urine collection and dialysis kinetics. The number of comorbid conditions was scored. Social deprivation was calculated from the patient's postal address using Townsend scoring. RESULTS: QoL was significantly lower in Indo-Asians than white Europeans for PH, MH and KDI. This was not related to treatment adequacy, which was similar in both for each modality. Indo-Asians had a worse index of social deprivation than white Europeans (P=0.008). PH and KDI were related to social deprivation (P=0.007 and P=0.005, respectively). QoL (except PS) was inversely correlated with comorbidity. Dialysis patients had higher comorbidity than transplant patients (P<0.02). Comparing only those dialysis patients considered fit for transplantation (n=51) with transplant patients, comorbidity was similar, but differences in QoL persisted. CONCLUSION: This study demonstrates a lower perceived QoL in Asians compared with white Europeans with ESRD. Analysis of QoL indicates that Asian patients in particular perceive kidney disease as a social burden, even if successfully transplanted.

Cognition↗
PubMed2000

Conversion from tacrolimus to cyclosporin in stable renal transplant patients: safety, metabolic changes, and pharmacokinetic comparison.

BACKGROUND: Conversion from tacrolimus to cyclosporin has not previously been reported as routine clinical practice, but only as indicated by rejection or adverse effects. METHODS: The safety and metabolic outcome of elective conversion from tacrolimus to cyclosporin was examined in 19 recipients of cadaver renal transplants. Conversion was performed in stable patients at 3-6 months after transplantation. RESULTS: Patient and graft survival was 100% at 3 months after conversion, with no rejection episodes. Three patients have been subsequently converted back to tacrolimus, two for rejection and one for hirsutism. There were no significant changes in creatinine, urate, or blood sugar levels after conversion, but the mean plasma magnesium rose from 0.73 (0.63-0.97) to 0.82 (0.65-1) mmol/liter (P=0.037), and the mean plasma cholesterol rose from 5.2 (3.4-6.8) to 5.5 (3.8-7.6) mmol/liter (P=0.033). Pharmacokinetic profiles were measured before and after conversion, and showed that cyclosporin (Neoral) exhibited significantly less interpatient and intrapatient variability than tacrolimus, for area under the curve (AUC), maximum concentration postdose (Cmax), minimum concentration postdose (Cmin), time to maximum concentration (Tmax). CONCLUSION: This is the first study that has examined the outcome of conversion from tacrolimus- to cyclosporin-based immunosuppression in stable patients after renal transplantation. This conversion was performed without early immunological hazard, but there was a small rise in blood cholesterol levels after conversion. Pharmacokinetic studies showed cyclosporin in the form of Neoral showed less inter- and intrapatient variability than tacrolimus, although this is of uncertain clinical significance.

Adult↗
PubMed2000

Conversion from tacrolimus to cyclosporine in stable renal transplant patients: safety, metabolic changes, and pharmacokinetic comparison.

BACKGROUND: Although conversion between tacrolimus and cyclosporine has been performed when indicated for rejection or adverse effects, the safety and metabolic outcome of elective conversion from tacrolimus to cyclosporine has not previously been examined. METHODS: Conversion from tacrolimus to cyclosporine was performed in 19 recipients of cadaver renal transplants at 3-6 months after transplantation. Pharmacokinetic profiles and biochemical studies were performed three times, in steady state, before, and after conversion. RESULTS: Patient and graft survival was 100% at 3 months after conversion, with no rejection episodes. Three patients have been subsequently converted back to tacrolimus, two for rejection and one for hirsutism. There were no significant changes in creatinine, urate, or blood sugar levels after conversion, but the mean plasma magnesium rose from 0.73 (0.63-0.97) to 0.82 (0.65-1) mmol/L (P=0.037), and the mean plasma cholesterol rose from 5.2 (3.4-6.8) to 5.5 (3.8-7.6) mmol/L (P=0.033). Pharmacokinetic profiles were measured before and after conversion, and showed that cyclosporine (Neoral) exhibited significantly less interpatient and intrapatient variability than tacrolimus, for area under the curve (AUC), maximum concentration after dose (Cmax), minimum concentration after dose (Cmin), and time to maximum concentration (Tmax). CONCLUSION: This is the first study that has examined the outcome of conversion from tacrolimus- to cyclosporine-based immunosuppression in stable patients after renal transplantation. This conversion was performed without early immunological hazard, but there was a small rise in blood cholesterol levels after conversion. Pharmacokinetic studies showed that cyclosporine in the form of Neoral exhibited less inter- and intrapatient variability than tacrolimus, although this is of uncertain clinical significance.

Adult↗
PubMed2000

Constitutive and acquired resistance to calcineurin inhibitors in renal transplantation: role of P-glycoprotein-170.

The present study examines whether resistance to Cyclosporin A (CyA) and Tacrolimus (FK506) develops in T cells from individual patients and the role of P-glycoprotein 170 (P-gp) in mediating drug resistance. IC50s were established for CyA and FK506 in cell cultures from 46 renal allograft recipients. P-gp expression and functional activity were determined by flow cytometry. Mean ID50 for CyA was 29 microg/li (range 2.5-100) and for FK506 1.2 microg/li (range 0.085-5.5). The sensitivities to the two drugs were correlated (P = 0.0001). There was variation in the ratio of the ID50s depending on the drug used for treatment (P = 0.02). There was no difference in P-gp expression and functional activity in patients with sensitive or resistant cells. The data indicate an association between the sensitivities to CyA and FK506 and evidence of selective resistance to whichever drug was used. P-gp drug transport does not explain this variation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Serial flow cytometric analysis of T-cell surface markers can be useful in differential diagnosis of renal allograft dysfunction.

We examined changes in the circulating T-cell subsets and their activation to see if consistent changes occur following renal transplantation, during acute rejection episodes (ARE), cytomegalovirus (CMV) infection, and cyclosporine (CsA) nephrotoxicity. Serial blood samples were taken from 28 patients on standard triple immunosuppresion therapy. Using two-colour flow cytometric analysis, the percentages of CD3+, CD4+, and CD8+ T-cells were determined, and coexpression of CD25, HLA/DR, and CD45 isoforms used to define their activation status. During ARE and CMV infection, increased levels of circulating CD4+ CD25+, CD8+ HLA/DR+, CD4+ CD45RO+, CD8+ CD45RO+ were observed. The increased levels of CD45RO+ T-cells were associated with a significant decrease in the percentages of CD45RA+ of both CD4+ and CD8+ T-cells. No significant changes were seen during CsA nephrotoxicity. The pattern of marker expression seen during ARE and CMV infection was similar to that seen in Con-A stimulated T-lymphocytes from 22 normal controls. We conclude that, the increase in the levels of these surface markers do not differentiate between lymphocyte activation indicative of rejection or infection, but clearly distinguish episodes of CsA nephrotoxicity. These results could be useful in the differential diagnosis of renal allograft dysfunction.

Acute Kidney Injury↗
PubMed1998

Alkalinization and hemodialysis in severe salicylate poisoning: comparison of elimination techniques in the same patient.

We report the case of a man who took two overdoses of aspirin, on each occasion suffering a grand mal fit with blood levels of salicylate of over 5 mmol/l. The first event was treated with hemodialysis but without effective alkalinization, and the second with alkalinization but without hemodialysis. The rate of decline in salicylate concentration was faster with alkalinization in the first 4 hours. Similar salicylate levels were achieved with both techniques by 24 hours post-overdose. If a case of salicylate poisoning is to be treated with hemodialysis, treatment with alkalinization should still be given without delay, in order to prevent acidemia and to promote elimination of as much salicylate as possible via the kidneys.

Acute Disease↗
PubMed1997

Clinical significance of selective decline of donor-reactive IL-2-producing T lymphocytes after renal transplantation.

Limiting dilution analysis technique was used to enumerate the circulating precursor frequency of donor and third-party-reactive helper T lymphocytes (HTLpf) in 28 renal allograft recipients before (pre-tx) and at three intervals (T1: 60-90 days, T2: 120-180 days, T3: 360-1620 days) after transplantation (post-tx). Two patterns of responses were identified, in group 1 (n = 12), a five to 31-fold reduction of donor-reactive HTLpf (ranging from 1/19231-1/62500) occurred within 90-1620 days post-tx, while in group 2(n = 16), no significant changes of donor-reactive HTLpf were seen. In both groups, the third-party-reactive HTLpf in most of these patients remained largely unchanged throughout the study period. The number of HLA-DR mismatches, total number of rejection episodes, serum creatinine levels, and biopsy findings at T3 were compared in both groups using Fisher's exact probability, and the Mann-Whitney test. We found that 11 patients (92%) in group 1 were HLA-DR compatible with donors, while nine (56%) patients in group 2 were HLA-DR compatible with donors, p = 0.04. In group 1 eight rejection episodes occurred in five (41.6%) patients during the study period, compared to 33 in 13 (81%) patients in group 2, p = 0.03. Group 1 had a significantly lower serum creatinine level (at T3); median: 136 vs 165 mumol/l for group 2, p = 0.03. Biopsy indicated no rejection (at T3) in eight (66%) patients in group 1 as compared to three (18%) patients in group 2, p = 0.03. Taken together, these results indicate that the frequency of circulating HTLpf correlate with the clinical status of the graft. Therefore monitoring of HTLpf in the peripheral blood could be useful in predicting graft outcome and selecting patients for reducing immunosuppression.

Adolescent↗
PubMed1997

Steroid withdrawal and donor-specific hyporeactivity after cadaveric renal allotransplantation on maintenance triple therapy.

BACKGROUND: Even in low doses, long-term steroid immunosuppression is known to cause serious complications. However, the safety of steroid withdrawal has not been proven in randomized clinical trials. This study examines donor-specific hyporesponsive transplant recipients before and after steroid withdrawal, to see if reduction in immunosuppression was associated with consistent changes in antidonor immunological reactivity. METHODS: Using limiting dilution assays, the circulating precursor frequency of donor and third-party-reactive helper T lymphocytes (HTLpf) were determined in 21 consecutive cadaveric renal allograft recipients on standard triple therapy, before (pre-tx) and at different time points after transplantation (post-tx). Patients were selected for steroid withdrawal by clinical criteria (stable graft function and no or only one very mild rejection episode). RESULTS: Of 21 patients studied, steroids were successfully withdrawn in nine (steroid withdrawn group, SWG) for at least 187 days (mean: 380 +/- 168.5), and were not withdrawn in 12 patients (steroid continued group, SCG). In the SWG seven of nine patients developed at least fivefold reduction of post-tx donor-reactive HTLpf (range 5-17), relative to pre-tx, as compared to two of twelve patients in the SCG, P = 0.01. In both groups, the third-party-reactive HTLpf in most of these patients remained largely unchanged throughout the study period. In the SWG, no significant difference of serum creatinine level was found before and at 6 months after steroid withdrawal (mean: 138 +/- 24 versus 132 +/- 40, P = 0.45). CONCLUSION: Patients who developed donor-specific hyporeactivity as evidenced by low donor-reactive HTLpf had stable graft function and stable HTLpf levels after complete steroid withdrawal.

Adult↗
PubMed1997

Interstitial nephritis.

Interstitial nephritis is an inflammatory process within the renal interstitium, and was one of the first observations made in the description of renal histopathology. Many different conditions are associated with an interstitial nephritis, and as a clinical diagnosis the term has little use unless causation is defined. However, there has been recent interest in the possibility of a common mechanism causing irreversible renal damage and eventually renal failure in many different types of interstitial nephritis. Such damage could take place due to blood-borne inflammatory mediators, or could be due to renal tubular inflammation related to abnormal components of the glomerular filtrate in renal failure, such as proteins or lipids. If such research were to result in effective therapy for interstitial nephritis, the progression of many forms of renal disease to end stage renal failure could be ameliorated.

Acute Disease↗
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

Randomised controlled trial of steroid withdrawal in renal transplant recipients receiving triple immunosuppression.

BACKGROUND: The combination of cyclosporin, azathioprine, and prednisolone (triple immunosuppression) is the most commonly used immunosuppressive regimen early after renal transplantation, but the risks and benefits of maintaining the steroid component of this regimen in the long term are uncertain. METHODS: A randomised controlled trial of steroid withdrawal was conducted among renal transplant patients receiving triple immunosuppression. Between one and six years after transplantation, 100 such patients were randomised either to reduce prednisolone treatment to zero over about four months or to maintain their triple immunosuppression unchanged. Outcome was analysed according to "Intention-to-treat". FINDINGS: In 42 (86%) of 49 patients allocated to steroid withdrawal, complete steroid withdrawal was achieved. Although these patients did not experience defined acute rejection episodes, insidious increases in plasma creatinine were observed more frequently in this group than in the controls. In 97 patients surviving one year after trial entry, plasma creatinine exceeded the baseline by more than 25% at some time in the first year in 25 (53%) of 47 in the steroid withdrawal group compared with 9 (18%) of 50 in the control group (p < 0.001, chi-square test). In some cases these increases were transient. However, when corrected for the baseline (entry) value significant differences between groups were apparent in both mean plasma creatinine and mean creatinine clearance; mean (SD) plasma creatinine values at entry, immediately after withdrawal, and at one year were 138 (27), 151 (36), and 150 (36) mumol/L in the steroid withdrawal group versus 138 (34), 140 (51), and 139 (47) mumol/L in the control group (p = 0.017, analysis of covariance). Steroid withdrawal patients showed a further rise in mean plasma creatinine to 160 (44) and 161 (65) mumol/L at two and three years from trial entry. Changes in several clinical and metabolic indices were also observed in association with steroid withdrawal. Blood pressure declined but the reduction was incompletely sustained, being more evident immediately after steroid withdrawal than at one year. Total cholesterol declined about 1 mmol/L in the steroid withdrawal group. Other changes associated with steroid withdrawal were reductions in white cell count and haemoglobin and increases in plasma phosphate and alkaline phosphatase. INTERPRETATION: Late steroid withdrawal is feasible in most patients with stable graft function on triple immunosuppression and has potentially beneficial metabolic effects. However, a substantial proportion of patients show a reduction in graft function, indicating a need for caution in considering the long term outcome.

Adult↗
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

Cyclosporin A and multiple fibroadenomas of the breast.

Multiple bilateral fibroadenomas are uncommon. This finding in four women who had received renal transplants prompted further inquiry. A prospective study was performed on 39 women under the age of 55 years who had received a renal transplant at least 1 year earlier. Clinical examination and breast ultrasonography were performed. Factors considered included immunosuppressive therapy, concurrent medication and renal function. Blood was taken for estimation of oestradiol, prolactin, follicle-stimulating hormone (FSH) and sex hormone binding globulin levels. Fibroadenomas were found in 13 of 29 women who had received cyclosporin A: multiple in ten and bilateral in five. No abnormal breast findings were seen in 10 patients immunosuppressed with steroids and azathioprine alone (chi 2 = 7.30, 1 d.f., P < 0.01). Serum oestradiol concentration was raised in women with fibroadenomas compared with that in those with normal breasts (P < 0.05) and the level of FSH was lower (P < 0.01). Cyclosporin A may act on breast fibroblasts by humoral mechanisms and direct action.

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↗