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Biomedical subjects

C G Newstead

Publications and source records attributed to C G Newstead.

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

Percentage hypochromic red cells and the response to intravenous iron therapy in anaemic haemodialysis patients.

INTRODUCTION: Iron deficiency is commonly encountered in haemodialysis (HD) patients and may be overcome by i.v. iron therapy. We have examined the percentage hypochromic red cells (%HRC) for predicting response to i.v. iron in subjects with a low serum ferritin. METHODS: Prospective study of i.v. iron saccharate (trivalent iron 200 mg/week for 8 weeks) in anaemic (Hb < 10 g/dl) HD patients with serum ferritin < 100 microg/l despite oral iron therapy. Response to i.v. iron was assessed by comparing Hb at 0 and 8 weeks according to %HRC at baseline (0-3%, 4-9%, > or = 10%). Results are mean+/-1 SD. RESULTS: For all subjects (n=82), Hb and ferritin increased between 0 and 8 weeks (8.9+/-1.0 to 10.1+/-1.4, P<0.0001; 55+/-24 to 288+/-126, P<0.0001). Patients were stratified into three groups according to %HRC at baseline (0-3%, 4-9%, > or = 10%). Hb increased significantly in all three groups. The mean increase in Hb was greater (0-3%, 0.6+/-1.2; 4-9%, 1.2+/-1.0; > or = 10%, 1.6+/-1.4; P=0.02) and the proportion of patients showing a > or = 1 g/dl increase in Hb was greater (0-3%, 27%; 4-9%, 57%; > or = 10%, 67%; P=0.02) in those with the largest %HRC pre-treatment. CONCLUSION: Intravenous iron therapy is effective in improving Hb in anaemic HD patients with a low ferritin. However, the magnitude of this response and the proportion of patients responding is related to the percentage hypochromic red cells prior to treatment.

Anemia↗
PubMed1998

Extracellular fluid volume determined by bioelectric impedance and serum albumin in CAPD patients.

AIM: To investigate the relationship between serum albumin and extracellular fluid volume, as measured by multifrequency bioelectrical impedance, in stable patients treated by CAPD. METHOD: Fifty-nine stable CAPD patients were assessed. Serum albumin (bromocresol green) and CRP, age, dialysate to plasma (D/P) creatinine ratio, normalized protein catabolic rate (nPCR), daily urine and peritoneal protein losses, and extracellular fluid volume (Vecf) were measured in each patient. Vecf was calculated as a percentage of actual body weight (Vecf% ABW), of lean body mass derived from anthropometry (Vecf% LBM) and of total body water (Vecf% Vtbw). Comparisons between those with a normal serum albumin (> or = 37 g/l) and those with a low serum albumin (< 37 g/l) were made by Mann-Whitney U test. Correlations with serum albumin were sought by Pearson's test. RESULTS: The D/P creatinine ratio, daily peritoneal and urine protein losses, and extracellular fluid volume (Vecf% LBM and Vecf% Vtbw) were all significantly greater in patients with serum albumin < 37 g/l as compared to those > or = 37 g/l; P < 0.05. Age, CRP, and nPCR were not different. Serum albumin was negatively correlated with Vecf% LBM, r = -0.25; P = 0.05, Vecf% Vtbw, r = -0.39; P = 0.002, and daily urinary albumin loss, r = -0.25, P = 0.06. CONCLUSION: Hypoalbuminaemia is partly dependent on subclinical overhydration in CAPD patients. Serum albumin is negatively correlated with increased extracellular fluid volume and the proportion of Vecf to Vtbw is increased in hypoalbuminaemic patients. Multifrequency bioelectrical impedance is able to identify these abnormalities.

Adult↗
PubMed1997

Serum albumin and survival in CAPD patients: the implications of concentration trends over time.

HYPOTHESIS: Trends in serum albumin concentration over time provide a better prediction of clinical outcome in CAPD patients than a single mean value. METHODS: This was a retrospective review of outcome at 36 months in 225 adult CAPD patients. Mean serum albumin was determined for the first (SA1) and second (SA2) 6 months of treatment and patients grouped according to SA1 (group I, > 37; group II, 34-37; group III, < 34 g/l) and according to the change in serum albumin (delta SA) between the first and second 6 months (increased/static or decreased). Patient (PS) and technique (TS) survival were determined by Kaplan-Meier survival analysis. The effect of SA1 and delta SA on survival were determined in a multivariate Cox regression analysis model that included age and presence or absence of a systemic disease. RESULTS: By SA1 group, PS and TS survival at 36 months were 94 and 76% (group I), 64 and 53% (group II) and 70 and 52% (group III). If delta SA increased/remained static, then SA1 did not predict PS (group I, 100%; group II, 96%; group III, 74%; P = n.s.) or TS (group I, 72%; group II, 63%; group III, 65%; P = n.s.). If delta SA decreased, PS was worse in groups II and III, both as compared to group I (PS group I, 88%; group II, 52%; group III, 34%; P = 0.02) and as compared to the groups II and III when delta SA increased (PS group II, 74 vs 52%, P = 0.05; group III, 82 vs 34%, P = 0.005) The same trend was seen for TS. In the multivariate Cox regression model, age, direction of change in serum albumin, and presence of a multisystem disease were significant predictors of survival, whereas SA1 was not. CONCLUSION: Early hypoalbuminaemia in CAPD only predicts a worse patient and technique survival if mean serum albumin decreases further from the first to second 6 months of dialysis therapy. Change in serum albumin between the first and second 6 months of CAPD and the mean serum albumin over the first 6 months together offer better discrimination of outcome than either alone.

Adult↗
PubMed1997

Assessment of nutritional status in CAPD patients: serum albumin is not a useful measure.

INTRODUCTION: In CAPD patients serum albumin is frequently used as an index of nutritional status, although it is recognized that hypoalbuminaemia may be caused by many factors. We have further examined the relationship between serum albumin and nutrition. METHODS: Nutritional status was assessed by biochemistry, anthropometry, mid-arm muscle circumference, muscle strength (hand grip and back), and lean body mass (from anthropometry, creatinine kinetics and bioimpedance) in a group of 76 stable CAPD patients. Correlations between biochemical and nutritional parameters were sought and data were compared between patient groups defined by serum albumin (> or = 37 vs < 37 g/l on two occasions 2 months apart) and separately according to subjective global assessment score (normal nutrition, A vs mild to moderate, B, and severe, C, malnutrition). RESULTS: In patients with a low SGA score, actual body weight, body mass index, mid-arm muscle circumference, lean body mass, subscapular skinfold thickness, hand grip strength (males and females) and iliac and triceps skinfold thicknesses and back strength (females only) were all significantly less than in patients with a normal SGA score. In contrast, none of these variables differed in either gender when patients were compared according to serum albumin. Serum albumin was correlated with serum creatinine (r = 0.45, P = 0.01), daily urine protein excretion (r = -0.42, P = 0.02) and uncorrected weekly creatinine clearance (r = -0.39) in females, but not with any index of body composition in either gender. CONCLUSION: Whilst SGA identified a patient group with significantly abnormal body mass, muscle mass and muscle strength, serum albumin did not. Serum albumin is not a useful marker of malnutrition in stable patients on CAPD.

Adolescent↗
PubMed1995

Evaluation of dopexamine hydrochloride as a renoprotective agent during aortic surgery.

Thirty-two patients undergoing elective infrarenal aortic surgery were randomly assigned to receive a perioperative infusion of either dopexamine hydrochloride at a rate of 2 micrograms/kg/min (n = 15) or 0.9% saline solution as placebo (n = 17). Renal function was monitored by regular measurements of serum creatinine levels. There were significant mean percentage increases in serum creatinine (p < 0.001) at all time points up to 3 days postoperatively in the placebo group but only at 2 and 12 hours in the dopexamine group. It was concluded that dopexamine hydrochloride confers renal protection in patients undergoing aortic reconstruction.

Aortic Aneurysm, Abdominal↗
PubMed1994

Transforming growth factor beta 1 in renal allograft recipients.

Transforming growth factor beta (TGF beta 1) is a prosclerotic cytokine implicated in several disease processes. Recent reports have demonstrated a role for TGF beta 1 in experimental models of glomerulonephritis, focusing attention on the relevance of TGF beta to renal fibrogenesis in human disease. The study reported here was designed to investigate whether circulating, active TGF beta 1 could be detected in renal allograft recipients, and whether plasma levels correlated with episodes of rejection, a process involving both inflammation and fibrosis. We have developed an ELISA assay for active TGF beta 1 using commercially available antibodies, and measured plasma levels in 43 healthy controls, 11 patients with membranous nephropathy (MN) and impaired renal function, 17 transplant recipients with stable renal function, 27 patients with acute cellular rejection, 7 patients with chronic vascular rejection, and 10 patients with acute tubular necrosis and/or cyclosporine toxicity. In the last three groups diagnoses were biopsy-proved, and all samples were collected at the time of biopsy. TGF beta 1 was also measured in urine samples from 8, 11, 0, 9, 4, and 7 individuals, respectively, from each group. TGF beta 1 was not detected in plasma from any of the healthy controls or any of the MN patients, (detection limit of assay 0.1 ng/ml). By comparison, it was significantly increased in all groups of transplant recipients (unpaired t test, P < 0.01), but there were no significant differences between the transplant groups. Plasma TGF beta 1 level did not correlate with renal function (estimated by either serum creatinine or reciprocal creatinine), kidney donor age, recipient age, time since transplantation, or cyclosporine plasma trough level. TGF beta 1 was found in every urine sample tested from healthy controls, with a range from 1 ng/ml to 35 ng/ml. Among the 20 transplant patient urines tested, 2 were negative, 18 were positive but within the range determined for the healthy controls. There were no significant differences between the groups.

Acute Disease↗
PubMed1993

Case report: sonographic detection of renal transplant cortical calcification.

Cortical calcification in a transplanted kidney was detected by high resolution ultrasound, not visible on plain abdominal radiography. Early recognition of these sonographic appearances should lead to a more accurate diagnosis and institution of appropriate treatment in patients with post-operative transplant dysfunction.

Adult↗
PubMed1993

Serum and urine IL-6 and TNF-alpha in renal transplant recipients with graft dysfunction.

The object of the study presented here was to test whether measurement of blood or urine IL-6 or TNF-alpha could discriminate between the most common causes of renal allograft dysfunction, thus avoiding a biopsy. We present data here in which serum and urine IL-6 and TNF-alpha levels were measured at the same time as a diagnostic renal biopsy was performed. TNF-alpha and IL-6 were measured by sandwich ELISA. Thirty patients had acute cellular rejection, 18 had acute tubular necrosis/CsA toxicity, and 9 had chronic vascular rejection. There was no difference in the levels of IL-6 measured in serum and urine among the three categories of graft dysfunction (t < 1.31; P > 0.20). A similar result with considerable overlap between the groups was seen with TNF-alpha (t < 0.78; P > 0.44). Stratifying the results according to the precise immunosuppressive therapy, CsA dose, body weight, CsA level, body temperature, serum creatinine, the number of previous rejection episodes, original cause of renal failure, or the time elapsed since the transplant did not alter the results. The ratio of serum IL-6 divided by trough CsA level was compared among the three groups and there was no significant difference among them (t < 1.79; P > 0.09). In the light of our results, we therefore suggest that previously published reports of the clinical value of serum and or urine IL-6 and or TNF-alpha in relatively small numbers of patients, not all of whom had been biopsied and in whom rigorous clinical and statistical criteria had not been met, should be viewed with caution.

Antibodies, Monoclonal↗