Search PubMed⌕ Search

Biomedical subjects

B Sampson

Publications and source records attributed to B Sampson.

36 records · Page 2Linked to original sources
PubMed1995

Development of an enzyme-linked immunosorbent assay for human metallothionein-1 in plasma and urine.

The development of a sensitive enzyme-linked immunosorbent assay (ELISA) for human metallothionein-1 is reported. Metallothionein was purified from postmortem human liver and used to raise high-titer antibodies in rabbits. The assay was specific for human metallothionein-1 (MT-1), and there was no significant cross-reaction with human metallothionein-2. The detection limit (sensitivity) of the assay was 5 ng/ml, and the added MT-1 could be fully recovered from plasma and urine. The normal reference range for MT-1 was 32 +/- 16 ng/ml in plasma and 10 +/- 6 ng MT-1 per micromole of creatinine in random samples of urine. No significant differences were found between the values for males and females. The concentration of MT-1 was greatly increased between 24 and 48 hours after surgery, indicating that the protein behaves like an acute phase reactant in human subjects.

Acute-Phase Proteins↗
PubMed1993

Reduced coagulation activation following infusion of a highly purified factor IX concentrate compared to a prothrombin complex concentrate.

We have looked for evidence of coagulation activation in six subjects with haemophilia B by performing a single-blind active control cross-over study comparing a recently developed factor IX concentrate with a conventional prothrombin complex concentrate (PCC). Samples were obtained before infusion and at 0.25, 0.5, 1, 2, 4, 6, 12, 24, 36 and 48 h for assay of factor IX, prothrombin time, fibrinopeptide A (FPA), prothrombin fragment F1 + 2, D-dimer, thrombin-antithrombin complexes (TAT) and antithrombin III (ATIII). Following administration of the PCC there was evidence of coagulation activation in five of the six recipients for up to 6 h after the infusion. The factor IX concentrate induced a moderate degree of coagulation activation in one subject. There was no significant difference between the two products in respect of either recovery or half-life. This study provides further evidence that the new high purity preparations of factor IX concentrates produce significantly less coagulation activation than currently available PCCs. It remains to be established whether this will result in a corresponding reduction in thromboembolic complications in clinical use.

Adolescent↗
PubMed1992

A micropuncture study of renal lithium reabsorption: effects of amiloride and furosemide.

The validity of the lithium clearance technique as a measure of end-proximal fluid delivery was assessed using micropuncture in sodium-replete, Inactin-anesthetized Sprague-Dawley rats. Three groups of animals were used: controls, amiloride treated, and furosemide treated. Diuretic-induced salt and water losses were replaced. Fractional lithium excretion (FELi) was 0.23 +/- 0.01, 0.24 +/- 0.02, and 0.40 +/- 0.03 in the control, amiloride, and furosemide groups, respectively. In each group, the tubular fluid-to-plasma lithium concentration ratio at the end of the proximal convoluted tubule (PCT) was significantly greater than unity (control, 1.16 +/- 0.03; amiloride, 1.16 +/- 0.02; furosemide, 1.17 +/- 0.02). In the control group, fractional lithium delivery (FDLi) at the late PCT was 0.50 +/- 0.02, while FDLi at the early distal tubule was 0.25 +/- 0.01; the latter did not differ significantly from FDLi at the late distal tubule or from FELi. Values in amiloride-treated rats were almost identical. Furosemide had no effect on FDLi at the late PCT, but raised that at the early distal tubule to 0.37 +/- 0.03. We conclude that 1) lithium reabsorption in the PCT lags slightly behind that of water, 2) substantial furosemide-sensitive lithium reabsorption occurs beyond the PCT, and 3) no significant lithium reabsorption occurs in nephron segments beyond the loop. These findings call into question the use of lithium clearance as a quantitative measure of end-proximal fluid delivery in sodium-replete animals.

Absorption↗
PubMed1989

Survey of blood lead and plasma aluminium concentrations in patients of a renal unit.

Blood lead and plasma aluminium concentrations have been measured in patients with end-stage chronic renal failure treated by haemodialysis (HD) or by continuous ambulatory peritoneal dialysis (CAPD) and in a control group of non-dialysed patients with chronic renal failure (CRF). Data on a group of subjects with normal renal function is included for comparison. We have found significantly increased mean blood lead and plasma aluminium concentrations in all patients with chronic renal failure compared to a group with normal renal function. All blood lead concentrations were within the accepted safe exposure range of less than 1.8 mumol/l (380 micrograms/l]. There were significant differences among the patient groups: home HD, 0.60 +/- 0.25 mumol/l (124 +/- 52 micrograms/l); hospital HD, 0.39 +/- 0.31 mumol/l (81 +/- 64 micrograms/l); CAPD, 0.32 +/- 0.17 mumol/l (66 +/- 35 micrograms/l); CRF, 0.38 +/- 0.20 mumol/l (79 +/- 41 micrograms/l); normal, 0.24 +/- 0.11 mumol/l (50 +/- 23 micrograms/l). Correction of the blood lead results for haemoglobin accentuates these differences (i.e. hospital HD, 4.61 +/- 3.25 nmol/g (0.96 +/- 0.67 micrograms/g); CRF, 3.05 +/- 1.46 nmol/g (0.63 +/- 0.30 micrograms/g); normal, 1.65 +/- 0.70 nmol/g (0.34 +/- 0.14 micrograms/g). Plasma aluminium concentrations show a similar pattern: home HD, 1.09 +/- 0.70 mumol/l (29.4 +/- 18.9 micrograms/l); hospital HD, 0.81 +/- 0.58 mumol/l (21.9 +/- 15.7 micrograms/l); CAPD, 0.34 +/- 0.34 mumol/l (9.2 +/- 9.2 micrograms/l); CRF, 0.18 +/- 0.09 mumol/l (4.9 +/- 2.4 micrograms/l); normal, 0.09 +/- 0.07 mumol/l (2.4 +/- 1.9 micrograms/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Aluminium kinetics during haemodialysis with the Redy 2000 Sorbsystem.

Aluminium kinetics of the Redy 2000 Sorbsystem using D3260 cartridges and the latest pre-treatment protocol have been studied in vitro and in vivo. In 7 patients, aluminium kinetics were studied during haemodialysis using the Redy 2000 Sorbysystem, D3260 cartridges. S557 acetate concentrate and Gambro hollow fibre dialyser (cuprophane 120M). The same patients were also studied during conventional haemodialysis using the Gambro AK10 proportionating system with acetate dialysate and Gambro hollow fibre dialyser (cuprophane 120M). There was no significant rise in plasma aluminium concentration during dialysis on the Redy 2000 Sorbsystem. The post-dialysis plasma aluminium concentrations were significantly higher after conventional haemodialysis, however, and the explanation for this is not clear but is not accounted for by differences in the degree of ultrafiltration during the studies. A significant rise in dialysate aluminium concentration was observed after 4 hours of dialysis on the Redy 2000 Sorbsystem. The manufacturer's ammonia test papers appear to be too insensitive as indicators of cartridge exhaustion and dialysate pH may be better. The D3260 cartridges should be used for a maximum of 4 hours only. Further long-term studies of aluminium kinetics using this system are justified.

Aluminum↗
PubMed1987

Is selenium deficiency the cause of uraemic cardiomyopathy?

We studied the relationship between serum selenium (Se) and left ventricular performance in 33 patients on maintenance haemodialysis. Low serum Se was frequent. However, there were no significant differences in echocardiographic indices of left ventricular function between patients with serum Se less than 0.9 umol/l and those with serum Se greater than 0.9 umol/l. We conclude that Se deficiency is not an important cause of cardiac failure in uraemia.

Adolescent↗
PubMed1985

Lack of effect of oral magnesium on high blood pressure: a double blind study.

Seventeen unselected patients with mild to moderate essential hypertension and whose average supine blood pressure after two months' observation with no treatment was 154/100 mm Hg were entered into a double blind randomised crossover study of one month's treatment with magnesium aspartate (15 mmol magnesium/day) and treatment with placebo for a further month. This preparation of magnesium was well tolerated and did not cause diarrhoea. Despite a significant increase in plasma magnesium concentration and a significant increase in urinary excretion of magnesium while taking magnesium aspartate there was no fall in blood pressure compared with either treatment with placebo or values before treatment. The results provide no evidence for a role of dietary magnesium in the regulation of high blood pressure and are contrary to recent speculations.

Adult↗
PubMed1984

Early plasma protein and mineral changes after surgery: a two stage process.

Sequential changes in albumin, transferrin, alpha 1-acid glycoprotein, C reactive protein, fibrinogen, copper, iron, and zinc in plasma up to 24 h after hysterectomy were measured. No increases in the concentrations of the acute phase proteins alpha 1-acid glycoprotein, C reactive protein, and fibrinogen were observed until 6 h after the skin incision. These increases were preceded by significant falls at 2-4 h, and this was shown also by albumin, transferrin, iron, zinc, and copper. The ratios of iron and zinc to their binding proteins, transferrin and albumin, did not decrease until 4-6 h and their concentrations remained low for at least 24 h. These patterns suggest that at least two mechanisms operate after trauma. The early fall in the concentrations of the proteins in plasma is consistent with a prompt increase in microvascular permeability. The later decrease in binding of the metals iron and zinc to their transport proteins and the increase in concentrations of the acute phase proteins could be initiated by a common mediator.

Adult↗
PubMed1984

Urinary iron loss in the nephrotic syndrome--an unusual cause of iron deficiency with a note on urinary copper losses.

Two patients with long-standing nephrotic syndrome are described in whom urinary iron losses may have contributed towards an iron deficiency state. Seven other nephrotic patients were also studied. Increased urinary iron excretion was found in six out of nine patients and increased urinary copper excretion in all eight patients in whom it was measured. Trace metal losses in the urine in nephrotics may be important clinically.

Adult↗
PubMed1983

Manganese balance studies in infants after operations on the heart.

Manganese balance studies have been performed on 16 infants, aged 3 days to 8 months, in the period following operation for the correction of congenital heart defects. Samples were analyzed by flameless atomic absorption spectroscopy or by solvent extraction with 8-hydroxyquinoline followed by flame atomic absorption spectroscopy. A higher manganese content was found in either whole blood (710 +/- 320 nmole X litre-1) or purified plasma protein (1130 +/- 770 nmole X litre-1) compared with fresh frozen plasma (215 +/- 35 nmole X litre-1) used in intravenous drips. The manganese content of the milks used in oral feeding was 200-300 nmole X litre-1.

Diet↗
PubMed1980

Separation of peptides and amino acids by ion-exchange chromatography of their copper complexes.

The method of separating peptides and amino acids using their copper (II) complexes has been reexamined by studying model compounds. A marked improvement in the separation was achieved on DEAE Sephadex columns by variation of the ionic strength of the eluting buffers. The use of the method is illustrated by an examination of a protein hydrolysate used in intravenous feeding (Aminosol).

Amino Acids↗
PubMedDate not supplied

Acquired type 2a von Willebrand's disease: response to immunoglobulin infusion.

A 75-year-old male presented with new symptoms of a bleeding diathesis associated with a decline in the functional activity of von Willebrand factor (type 2a von Willebrand's disease). Replacement therapy was ineffective and he was subsequently treated with intravenous immunoglobulin (IvIg). IvIg not only caused symptomatic improvement but was shown to transiently restore the depleted von Willebrand factor intermediate and high molecular weight multimers. Subsequent periodic IvIg infusions have been used successfully to treat bleeding complications in this patient over the past 3 years. A secondary cause for the acquired von Willebrand's disease has not been identified.

Aged↗