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Biomedical subjects

F D Thompson

Publications and source records attributed to F D Thompson.

15 recordsLinked to original sources
PubMed1992

High resolution proton magnetic resonance spectroscopy of cyst fluids from patients with polycystic kidney disease.

High field 1H-NMR spectra of fluid collected from the cysts of six renal transplant recipients with autosomal dominant polycystic kidney disease (ADPKD) have been measured and the major metabolite signals assigned. Quantitative NMR measurements have revealed a combination of unusual biochemical features of the cystic fluids that shows them to be distinct from both blood plasma and urine. Isoleucine, lysine, threonine and valine were present at mM concentrations, in cyst fluid and in some cases levels up to 2 orders of magnitude higher than normal plasma or urine were recorded. Mean glucose concentrations in the cyst fluids ranged from 3.4-9.6 mM and a number of organic acids and bases, including acetate, lactate, succinate, creatinine and dimethylamine were also present at high concentration and in different ratios to those found in either plasma or urine. The majority of cyst fluids examined also contained significant quantities of glycoproteins with characteristic 1H-NMR signals from N-acetyl groups of amino-sugar and sialic acid side chains which had a high degree of molecular mobility (as indicated by their relatively long T2 relaxation times, greater than 120 ms). High levels of ethanol (0.5-12.6 mM/l) were found in all fluid samples from the six transplanted patients (confirmed by conventional analysis). In general there was little variation in the 1H-NMR spectral patterns of either the intra- or interpatient cyst fluids, although the contribution of the protein macromolecules to individual spectra was lower in a few cysts. This constancy of biochemical composition probably reflects the chronic nature of the accumulation of cyst fluid and a long turnover of the cystic fluid components which has the effect of averaging composition. These findings suggest that the dynamic composition of cyst fluid from ADPKD patients is unique among the other body fluids and that the unusual composition may be related to epithelial polarity reversal of the cystic epithelium which could also contribute to the growth of the cysts.

Amino Acids↗
PubMed1990

Cardiac output and oxygen uptake in patients with renal failure.

1. Cardiac index, oxygen uptake and haemoglobin concentration have been measured in eight patients with end-stage renal failure, and the values compared with those in eight healthy control subjects. Assuming the arterial blood to be 97% saturated, the oxygen saturation of mixed venous blood has been calculated. 2. Cardiac index was lower in the patients (2.45 +/- 0.42 litres min-1 m-2) compared with the control subjects (3.74 +/- 0.17 litres min-1 m-2). Oxygen uptake was reduced from 147 +/- 16 ml STP min-1 m-2 in the control subjects to 112 +/- 9 ml STP min-1 m-2 in the patients. 3. Oxygen saturation of mixed venous blood was 53 +/- 8% in the patients compared with 79 +/- 2% in the control subjects, suggesting some degree of tissue hypoxia. If oxygen uptake were not reduced in renal failure, then the mixed venous blood oxygen saturation would be as low as 40%. 4. The oxygen saturation of blood sampled from the superior vena cava of patients with renal failure was 57 +/- 6%. 5. The data on oxygen uptake and venous oxygen saturation suggest that in the patients with end-stage renal failure, the low values of cardiac index, previously measured by impedance cardiography, are accurate.

Adult↗
PubMed1990

Hemodynamic responses to head-up tilt in uremic patients.

The hemodynamic responses to 45 degrees C head-up tilt for 30 min were compared between a group of 13 normal healthy subjects, 16 patients with end-stage renal failure (Group 1) and 9 hypertensive patients (Group 2). In the normal subjects there was no change in systolic blood pressure (SBP), a significant increase in diastolic blood pressure (DBP) (9 +/- 1 mmHg, mean + SEM, p less than 0.01), heart rate (HR) (11 +/- 2 beats/min) and derived peripheral resistance (PR) (66 +/- 8%, p less than 0.001). Stroke volume (SV) and cardiac output (CO) fell significantly by 42 +/- 3% and 33 +/- 3%, respectively. The responses in Group 2 patients were similar to those of the controls. However in Group 1 patients, though there was a rise in heart rate (9 +/- 2, p less than 0.001), SBP fell significantly accompanied by no change in either DBP or PR. The decrease in SV was only 12 +/- 4% while there was no change in derived CO. The results suggest that there was a lack of vasoconstriction during postural stress in patients with endstage renal failure, which was probably due to a functional defect in the baroreceptor reflex. Concomitantly, the small decrease in SV suggests stiffness of the veins and/or active venoconstriction which may help to prevent a bigger fall in blood pressure.

Adult↗
PubMed1989

Treatment of resistant CAPD peritonitis by temporary discontinuation of peritoneal dialysis.

Resistant continuous ambulatory peritoneal dialysis (CAPD) peritonitis (recurrent or persistent infection) is traditionally treated by removal of the CAPD catheter and a period off peritoneal dialysis. In a pilot study we have treated 8 patients with recurrent staphylococcal peritonitis and 3 patients with persistent staphylococcal peritonitis by stopping CAPD for a 2-week period, the CAPD catheter being left in-situ. All 8 patients with recurrent peritonitis and 2 of the 3 patients with persistent peritonitis had resolution of their infection; the third patient required catheter removal to clear the infection. There were no acute problems associated with stopping CAPD, and there was no evidence of loss of peritoneal filtration capacity on restarting CAPD. This novel approach to the treatment of resistant CAPD peritonitis should reduce the number of CAPD catheters replaced and therefore diminish the risks and inconvenience to patients that such replacements entail.

Catheters, Indwelling↗
PubMed1979

Single sample estimates of renal clearances.

Thirty adult patients were investigated with 36 125I Hippuran and 40 51Cr EDTA single injection clearance studies. "Volumes of distribution" obtained from single samples have been correlated with the slope clearances and regression equations have been determined. From these equations it is possible to determine glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) from single plasma samples and the method is sufficiently accurate for routine application.

Adult↗
PubMed1979

Hyponatraemia.

Explore the source record for details and available documents.

Extracellular Space↗
PubMed1979

Monotherapy with labetalol for hypertensive patients with normal and impaired renal function.

1 Labetalol was given to 41 hypertensive patients in a divided dosage of 150--2,400 mg daily for periods ranging from 1--64 months. 2 Monotherapy with labetalol was adequate in 12 out of 19 patients with essential hypertension and in 15 out of the 22 with renal hypertension. 3 Following a single dose of labetalol 200 mg orally a hypotensive response was seen between 1.5 and 2 hours. 4 In the doses used there was no exercise or postural hypotension. 5 No reduction in overall renal function attributable to labetalol was seen.

Blood Pressure↗
PubMed1976

Acute haemodynamic effects of labetalol and its subsequent use of an oral hypotensive agent.

1 Fourteen patients whose lying diastolic blood pressure was persistently 110 mmHg or greater were given labetalol 0.5--1 mg/kg intravenously. 2 The maximum hypotensive effect developed between 20 and 40 min, and on average lasted 3 h. The lying systolic mean blood pressure fell by 30 mmHg and the lying diastolic blood pressure by 17 mmHg (P less than 0.001). 3 This acute hypotensive effect was associated with a significant reduction in the peripheral resistance (P less than 0.02). The hypotension was not associated with significant secondary changes in the stroke volume or pulse rate. 4 The above 14 patients plus 1 additional subject received labetalol orally at a daily dose ranging from 150-2400 mg. The mean lying systolic blood pressure fell by 22 mmHg (P less than0.01) and the mean lying diastolic blood pressure by 26 mmHg (P less than 0.001). The standing values were similar and postural hypotension at this dose did not develop. There was no significant change in the pulse rate. 5 Renal function was monitored by estimates of plasma creatinine and creatinine clearance. Some patients were followed for 2 yr and others for a few months. With the long-term patients, there was no significant reduction in either measurement although in a few patients a slight reduction in creatinine clearance was observed.

Administration, Oral↗