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Biomedical subjects

A M Davison

Publications and source records attributed to A M Davison.

At least 73 records · Page 4Linked to original sources
PubMed1993

Anticoagulation with low molecular weight heparin (Fragmin) during continuous hemodialysis in the intensive care unit.

A preparation of low molecular weight heparin (Fragmin) was administered to patients with multiorgan failure receiving continuous venovenous hemodialysis. Three patients received a high-dose regimen (35 IU/kg bolus followed by 13 IU/kg infusion), and 7 received a low-dose regimen (8 and 5 IU/kg, respectively) for 36 h. High-dose Fragmin was associated with minimal clotting in the extracorporeal circuit. Plasma fibrinopeptide A levels declined, and mean anti-Xa activity was in the range 0.47-0.79 IU/ml. The urea equilibration coefficient (UEC) (100% at initiation) remained above 90% throughout. All 3 patients had mild bleeding episodes, which led to discontinuation of Fragmin in 1. During all low-dose treatments, marked thrombus formation occurred in the extracorporeal circuit, and in 2, the circuit clotted within the study period. Fibrinopeptide A levels further increased in 4 patients, and mean anti-Xa activity was in the range 0.27-0.53 IU/ml. UEC declined appreciably in 3 treatments (including the 2 in which early circuit clotting occurred). One patient experienced a mild bleeding episode. The low-dose Fragmin regimen produced safer anticoagulation in patients at risk from bleeding and is suitable for prolonged renal support although the tendency to thrombosis may necessitate more frequent circuit changes.

Acute Kidney Injury↗
PubMed1993

The effect of treatment with recombinant human erythropoietin on the histological appearance and glycogen content of skeletal muscle in patients with chronic renal failure treated by regular hospital haemodialysis.

The effect of treatment with recombinant human erythropoietin on the histological appearance and glycogen content of the anterior tibialis muscle was studied in 10 patients with chronic renal failure treated by regular haemodialysis. Repeat muscle biopsies taken when the target haemoglobin concentration of 11 g/dl was achieved showed an increase in median glycogen content from 35 mg/g fat-free dry muscle to 51 mg/g (p < 0.05). The histological appearance showed a marked improvement in muscle fibre diameters, in particular for the type I fibres and a reduction in cytoarchitectural abnormalities. These changes would be expected to produce an increase in both muscle strength and performance and are most probably a consequence of an increase in muscle oxygen delivery.

Adult↗
PubMed1993

Membrane biocompatibility: effects on cardiovascular stability in patients on hemofiltration.

We investigated the effect of membrane bio-incompatibility on cardiovascular stability in 10 patients with combined acute hepatic and renal failure during 44 isovolemic intermittent machine hemofiltration treatments, using a polyamide membrane in 24 and a polyacrylonitrile membrane in 20. Cardiac output decreased by 14 +/- 2% during polyamide treatment compared to 8 +/- 3% during polyacrylonitrile (P < 0.05). Pulmonary artery occlusion pressure decreased by 20% or more in 65% of the polyamide treatments compared to 38% of the polyacrylonitrile (P < 0.05). Tissue oxygen delivery decreased by 16 +/- 2% during polyamide treatment compared to 6 +/- 3% during polyacrylonitrile treatment (P < 0.05). Mean arterial blood pressure declined from 80 +/- 3 mm Hg to 70 +/- 2 mm Hg during polyamide treatment (P < 0.001), whereas there was no significant change during polyacrylonitrile treatment. Thus, in this group of critically ill patients, the use of two different membranes was associated with greater cardiovascular stability with polyacrylonitrile treatment compared to polyamide, with respect to maintenance of tissue perfusion and perfusion pressure. This suggests that extracorporeal membrane bio-incompatibility may have a role in determining cardiovascular stability during treatment with extracorporeal circuits.

Acute Kidney Injury↗
PubMed1993

Effect of renal replacement therapy on patients with combined acute renal and fulminant hepatic failure.

The mortality of patients with combined acute hepatic and renal failure remains high. Previous studies have reported both patient morbidity and mortality directly attributable to the use of extracorporeal circuits used to treat renal failure. We investigated the effect of various modes of renal replacement therapy in 30 consecutive patients referred with both fulminant hepatic and acute renal failure. Cardiac output decreased during the first hour of 30 intermittent machine haemofiltration treatments, by 15 +/- 3%, as did tissue oxygen delivery, 16 +/- 3% and tissue oxygen uptake, 13 +/- 4%, whereas there was no significant change during 30 continuous hemofiltration and/or dialysis treatments. Intracranial pressure remained stable during the continuous modes but increased from 9 +/- 2 mm Hg to 17 +/- 2 mm Hg, P < 0.01, during intermittent machine hemofiltration, with the greatest increase of 55 +/- 9% within the first hour. Mean arterial blood pressure was stable during treatment with the continuous modes, but decreased by 20 +/- 3% during the first hour of intermittent machine hemofiltration, resulting in a maximum reduction in cerebral perfusion pressure of 35 +/- 8%. In this group of critically ill patients continuous modes of renal replacement therapy resulted in superior cardiac and intracranial stability compared to standard intermittent modes of treatment.

Acute Kidney Injury↗
PubMed1993

Clinical features of benign hypertensive nephrosclerosis at time of renal biopsy.

Although hypertension accounts for approximately 15-20% of end-stage renal disease and renal impairment occurs in 15% of patients with essential hypertension, there are few data available on the clinical features of patients with benign hypertensive nephrosclerosis, the histological consequence of hypertension on the kidney. To determine its prevalence on renal biopsy and its clinical features (including proteinuria and renal function), we used the U.K. MRC Glomerulonephritis Registry of 7339 biopsies from 20 centres to define all patients with benign hypertensive nephrosclerosis. In patients with no co-existing disease, 185 biopsies were classified solely as benign hypertensive nephrosclerosis (2.5%). Sixty-nine percent of patients were male and 72% aged over 50 years. Sixty-four percent had diastolic blood pressure above 90 mmHg and severe hypertension (diastolic > 120 mmHg) was present in 9%. Protein excretion of > 1.5 g/day was noted in 40%, with 22% excreting > 3 g/day. Eighteen percent had serum albumin values under 30 g/l. Eighty-one percent had serum creatinine > 120 mumol/l; in 51% this was > 250 mumol/l. There was significant correlation between serum creatinine and systolic blood pressure at time of biopsy (p = 0.01) and between serum creatinine and serum albumin (p = 0.001). Benign hypertensive nephrosclerosis accounts for 2.5% of all registered biopsies. Significant proteinuria is a common finding and proteinuria within the nephrotic range does occur. Systolic blood pressure appears to influence serum creatinine levels. Hypertensive nephropathy should be considered in all patients with heavy proteinuria and renal impairment.

Adult↗
PubMed1993

Aluminium mobilization following renal allograft transplantation may have an immunomodulatory role by reducing the incidence of graft rejection.

Urinary aluminium excretion was prospectively monitored during the first year following first cadaver renal allograft transplantation in 79 consecutive patients. Plasma and urinary aluminium concentrations steadily declined with time. Thirty-five patients had 0-1 episodes of acute graft rejection compared to 44 with two or more rejections; more of the former group had been prescribed aluminium-containing phosphate binders (74% versus 56%, P < 0.02), and following transplantation this group had a persistently greater urinary aluminium excretion, suggesting a greater aluminium body burden. There were no significant differences in terms of gender distribution, blood transfusion, or HLA matching between the groups, thus suggesting that either the subsequent mobilization of aluminium body stores following transplantation and/or the accumulation of aluminium in the reticulo-endothelial system prior to transplantation may have had an immunomodulatory effect in reducing the incidence of renal allograft rejection.

Adolescent↗
PubMed1992

Preparation and use of the poly-L-lysine-gold probe: a differential marker of glomerular anionic sites.

The conditions required for the production of a polylysine-coated gold (PL-G) complex, which shows optimal sensitivity for the demonstration of tissue anionic sites, expressed under different conditions of pH have been investigated. Problems encountered with this complex have been compared with those found with other methods of conjugation of polylysine to colloidal gold. The performance of a bovine serum albumin (BSA)-stabilized PL-G complex was examined against other PL-G conjugates, including complexes that are commercially available, for the detection of heterogeneous glomerular anionic site populations, expressed at pH 2.5 and pH 7.0.

Anions↗
PubMed1992

Childhood lymphoma in Yorkshire.

AIMS: A histopathological review of 43 cases of childhood non-Hodgkin's lymphoma (NHL) in an attempt to identify histological variables of prognostic importance. METHOD: Each case was reclassified according to the Working Formulation and an attempt made to allocate an immunophenotype using a panel of monoclonal antibodies. Results were correlated with clinical data on site and survival. RESULTS: Of the 43 cases, 30 were males and 13 females. There were 17 cases of lymphoblastic lymphoma, 15 cases of small non-cleaved cell lymphoma (SNCC), and four cases of large cell lymphoma. The SNCC group was subdivided into 10 cases of Burkitt's lymphoma and five cases of non-Burkitt's lymphoma. An immunophenotype was allocated in 65.1% of cases (23 B, 5 T). The SNCC cases were spread throughout the 0-16 year age range while the lymphoblastic lymphoma cases tended to occur in older children. Most mediastinal tumours were lymphoblastic lymphoma and most abdominal tumours were SNCC. Statistical analysis failed to show a significant difference in survival among histological subgroups or immunophenotypes. CONCLUSION: No histological variables of prognostic importance were identified partly due to the great variation in treatment regimens, standard of supportive care, and prognosis over the period of the study (1972 to 1988).

Adolescent↗
PubMed1992

Blood lactate is reduced following successful treatment of anaemia in haemodialysis patients with recombinant human erythropoietin both at rest and after maximal exertion.

The effect of increasing haemoglobin by erythropoietin therapy on exercise capacity was investigated in 11 regular haemodialysis patients, previously transfusion dependent. Exercise work load increased from a median of 100 W (95% confidence limit, 25-135) to 120 (45-180; p < 0.05) following erythropoietin, and the duration of the exercise test from 13 (3.5-20) to 15.5 min (4-22; p < 0.05). Resting blood lactate concentration decreased from 0.8 (0.6-1.6) to 0.3 mmol/l (0.3-0.4), p < 0.05, following treatment with erythropoietin, as did blood lactate concentration at maximal exertion from 2.0 (1.0-4.1) to 1.8 mmol/l (0.5-2.8; p < 0.05). In association with the increase in haemoglobin from a median of 6 (5.1-6.8) to 11.1 g/dl (11-11.9) following erythropoietin therapy, patients were able to achieve greater exercise capacity both in terms of maximum work load and duration of exercise in association with a reduced resting arterial lactate and a similar exercise-induced lactate production. This suggests that treatment had improved muscle function in terms of lactate production and/or utilisation. This was probably due to the increase in tissue oxygen delivery, as there was an increase in the median arterial oxygen content from 79 (65-85) to 150 ml O2 (144-157) following erythropoietin treatment.

Adult↗
PubMed1992

Use of the urinary protein creatinine index to assess proteinuria in renal transplant patients.

The use of 24-h urine protein collections for the assessment of proteinuria in renal transplant patients has been compared with the protein creatinine index (PCI) obtained from spot urine samples. Paired data from 148 patients showed a correlation of 0.77 (P less than 0.001) between 24-h protein excretion and the PCI. A PCI of 750 identified proteinuria of greater than 1.0 g/24 h with a sensitivity of 89% and a specificity of 93%. The predictive value of a positive test was 81% and that of a negative test 96%. Similar performance was observed for the detection of proteinuria of differing severities ranging from 0.5 g/24 h to 2.0 g/24 h. The use of spot testing was popular with both patients and staff, and reduced the sample handling cost to 15% of that of 24-h urine collection. We recommend that PCI be adopted as the standard outpatient test for the assessment of proteinuria following renal transplantation.

Adolescent↗
PubMed1992

Clinico-pathological correlations and long-term follow-up of 253 United Kingdom patients with IgA nephropathy. A report from the MRC Glomerulonephritis Registry.

The Medical Research Council's Glomerulonephritis Registry was used to study clinicopathological correlations and renal survival in patients with IgA nephropathy reported between 1978 and 1985. IgA nephropathy was the histological diagnosis in 9.3 per cent of all renal biopsies reported to the registry during this period, and in 18.1 per cent of those with a primary glomerulonephritis. The 10-year cumulative renal survival rate accounting for censored data (Kaplan-Meier) was 83.3 per cent. Univariate analysis of survival curves (log-rank test) found the following parameters to be significantly correlated with poor renal survival: serum creatinine > 120 mumol/l (p < 0.001), hypertension (p < 0.001), serum albumin < 40 g/l (p < 0.005), proteinuria > 1 g (p < 0.025), age > 30 years (p < 0.025), and focal mesangial proliferation (p < 0.05). There was no significant difference in renal survival between males and females. Multivariate analysis (Cox's proportional hazards model) revealed that only a serum creatinine of > 120 mumol/l and a serum albumin of < 40 g/l were independently predictive of outcome. These findings indicate marked similarities between the UK experience of IgA nephropathy and the published European experience. IgA nephropathy is not a benign condition in the UK and patients with impaired renal function and/or those with a reduced serum albumin are significantly more likely to progress to end-stage renal failure within 10 years.

Adult↗