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Biomedical subjects

E J Mees

Publications and source records attributed to E J Mees.

At least 37 records · Page 2Linked to original sources
PubMed1984

Plasma oxalate concentration in chronic renal disease.

Plasma oxalate was measured with use of the enzyme oxalate oxidase (EC 1.2.3.4; normal values 3.3 +/- 1.5 mumol/L, n = 24) in 50 patients with different degrees of renal failure. The following mean concentrations +/- SD (in mumol/L) were found: for glomerular diseases, 12.7 +/- 7.8 (n = 21); tubular diseases, 20.4 +/- 14.0 (n = 16); chronic renal failure before dialysis, 32.5 +/- 13.5, and after dialysis, 17.8 +/- 3.8 (n = 10); and primary hyperoxalemia, 72.2 +/- 14.5 14.5 (n = 2). The course of plasma oxalate was followed in one of these two patients after renal transplantation and in a patient recovering from acute tubular necrosis. No significant differences were found between patients with glomerular and tubular disorders. Overall, plasma oxalate was correlated with plasma creatinine in patients with glomerular and tubular diseases and dialysis patients (r = .84, P less than .001). Patients with primary hyperoxalemia had values outside the 95% confidence area of the regression line. It is concluded that the values obtained with this method, although probably still tending to overestimate the true oxalate concentration to some extent, provide reliable information about relative differences in plasma oxalate levels. In patients with terminal renal failure, plasma oxalate sometimes rises to levels at which deposition of calcium oxalate in tissues can occur.

Adolescent↗
PubMed1984

Plasma volume recovery after ultrafiltration in patients with chronic renal failure.

We studied the effect of standardized ultrafiltration (UF, 2 liters in 60 min) on plasma volume (PV, 131I-albumin space) and its recovery, with special reference to the tissue hydration before UF. Twenty-one UF sessions were performed in 15 patients with endstage renal failure. The PV reduction, which varied considerably, was maximal at the end of UF (range, -0.7 to -21.9%); after that PV recovered reaching a plateau in the second hour after UF. A highly significant negative correlation was found between the interstitial fluid volume (IVF, calculated from 82Br space-PV) and the PV reduction at this stage (r = -0.89, P less than 0.0001). Despite avoidance of major changes in total extracellular fluid in the next 24 hr, a further restoration of PV took place which was partial in subjects with normal tissue hydration, but complete or even excessive in grossly overfilled subjects. This PV repletion was accompanied by an increase in the intravascular mass of albumin (P less than 0.02). The negative correlation between initial IFV and PV change persisted after 24 hr (r = -0.83, P less than 0.0005). In most occasions the blood pressure fell, but only in eight occasions frank hypotension followed. Heart rate remained remarkably unaltered, even during hypotensive episodes. Changes in plasma renin activity followed no uniform pattern. Our findings indicate that the tissue hydration state has a strong influence on changes in PV during fluid removal and the subsequent repletion of PV.

Adult↗
PubMed1983

Follow up study of 70 patients with renal artery stenosis treated by percutaneous transluminal dilatation.

Between April 1978 and April 1981, 70 patients with hypertension and renal artery stenosis were treated by percutaneous transluminal arterial dilatation. Selection of the patients was based solely on arteriographic criteria. Arteriography after dilatation showed considerable widening of the stenosed area in all patients. In 65 patients the effect of treatment on the blood pressure was assessed during follow up periods of one to four years. In 14 of these patients the hypertension was cured, in 29 it was improved, and in 22 there was no change. Patients with fibromuscular lesions benefited distinctly more than did those with atheromatous stenosis, only one of the 21 patients with fibromuscular lesions showing no change as compared with 21 of the 44 patients with atheromatous lesions. The only serious complication encountered was microcholesterol emboli, which developed in two patients with severe atheromatous lesions of the aorta. In the atheromatous group age and overall renal function had no influence on the blood pressure response. In the subgroup of patients with a unilateral lesion the renal vein renin ratios and asymmetrical curves obtained by renography had only a very limited predictive value. In experienced hands percutaneous transluminal arterial dilatation is relatively safe, and this study suggests that it should be attempted in all patients with renal artery stenosis. Only in patients with severe atheromatosis of the aorta should the risk associated with the catheterisation be weighed against the 50% or so chance of benefit from the procedure.

Adult↗
PubMed1983

Blood and extracellular fluid volume in patients with Bartter's syndrome.

Blood and extracellular fluid volumes were measured in four adult patients with Bartter's syndrome and compared with those of 21 healthy control subjects. Extracellular fluid volumes were significantly lower than in the control group (-7%), whereas blood volumes were within the normal range. Consequently, the ratio of blood volume to interstitial fluid volume was significantly elevated (0.42 v normal 0.35). The results are consistent with the concept that a tubular reabsorption defect is present in Bartter's syndrome.

Adolescent↗
PubMed1982

Plasma aldosterone concentrations in chronic renal disease.

The disagreement in the literature concerning the role of aldosterone in the maintenance of potassium homeostasis in chronic renal disease might be partially explained by differences in plasma renin activity (PRA) among individual patients. Therefore, a study was done in 28 selected patients with varying degrees of renal insufficiency whose serum potassium and PRA concentrations were within the normal range. The results indicate that at comparable serum potassium and PRA concentrations, plasma aldosterone is in most instances elevated when creatinine clearance is lower than 50% of normal.

Adult↗
PubMed1982

Renal clearance of [14C]oxalate: comparison of constant-infusion with single-injection techniques.

1. The renal clearance of [14C]oxalate was assessed by the constant-infusion technique and single-injection technique (plasma sampling only: one-compartment and two-compartment model; plasma and urine sampling). Healthy volunteers and patients with renal stones were studied. 2. Results with the constant-infusion techniques (with and without urine sampling) were not significantly different from each other. 3. The renal clearance of [14C]oxalate measured with the single-injection technique as compared with the constant-infusion technique was overestimated in the single-injection one-compartment model (52%) as well as in the two-compartment model (30%). 4. The calculated level of plasma oxalate in the healthy volunteers ranged from 1.04 to 1.78 mumol/l (mean 1.39). 5. The biological half-life of [14C]oxalate, estimated by the cumulative excretion of 14C in urine after equilibrium had been established, was 128 min (range: 113-142). 6. The oxalate/creatinine clearance ratio in the healthy volunteers ranged from 1.73 to 2.22 (mean 2.01).

Female↗
PubMed1982

Free water excretion due to suppressed vasopressin and stimulated aldosterone during sodium restriction in hypoaldosteronemic renal failure.

In two from 3 hyperkalemic patients with chronic glomerulonephritis associated with suppressed aldosterone production ("selective hypoaldosteronism") fractional free water excretion increased and urine osmolality decreased during sodium (Na) restriction. In one of the patients with severe renal concentrating defect in combination with partial vasopressin deficiency polyuria was paradoxically accentuated by lowered Na intake. Na restriction induced 1. a dramatic increase in plasma aldosterone levels, 2. a decrease in glomerular filtration rate associated with a marked disturbance in the glomerulotubular balance resembling to the effects of volume expansion, and 3. a decrease in urinary arginine vasopressin excretion. Paradoxical enhancement of water excretion was explained by increased delivery of filtrate into the distal nephron, increased abstraction of Na from the tubular fluid together with insufficient water permeability of the collecting tubules and lowered vasopressin production.

Adolescent↗
PubMed1982

Salt handling in patients with chronic renal insufficiency.

In 7 patients with moderate degrees of renal insufficiency the effect of high and low salt intake on renal NaCl handling was investigated by means of clearance techniques. After a steady state had been reached at low (1 g NaCl daily) and high (10 mmol NaCl daily for every ml X min-1 glomerular filtration rate) salt intake, proximal and distal fractional salt reabsorption (FSRprox and FSRdist) were estimated, maximal free water clearance being taken as an index of distal NaCl reabsorption. Mean FSRprox during low salt intake was 86.7% (range 80-90%) of the filtered load, and decreased to 77.9% (range 70.1-80.5%) during high salt intake. The water-loading procedure in these patients resulted in enhanced NaCl and nonelectrolyte solute excretion, especially during salt restriction. This made certain corrections obligatory for the proper calculation of FSRdist. Mean FSRdist during low salt intake was 96.5% (range 93.1-99.8%) of distal delivery, and decreased to 76.0% (range 68.0-82.1%) during high salt intake. This decrease of FSRdist also existed at comparable levels of distal delivery. It is concluded that renal response to chronic sodium loading in patients with chronic renal insufficiency is similar to that as in normal men, and consists of reduction of both proximal and distal fractional NaCl reabsorption.

Absorption↗
PubMed1979

Measurement of cardiac output by impedance cardiography under various conditions.

The suitability of impedance cardiography as a method to follow changes in cardiac output (CO) was investigated by comparing it with thermodilution and by measurements in conditions with predictable effects on CO. The correlation between absolute CO values obtained by impedance and thermodilution techniques was moderate (r = 0.61), but the percentage changes showed a good correlation (r = 0.84). Head-up tilting decreased CO by 25% in 5 normal subjects. Bloodletting in three subjects caused a 20% decrease, reinfusion in one subject a 16% increase. Occlusion of artificial large flow arteriovenous shunts in 6 dialysis patients caused a 12% decrease in CO, whereas the effect was less with moderate and absent with small flow shunts. Ultrafiltration caused a 28% decrease in two dialysis patients. In 20 hypertensive patients CO dropped 25% after salt depletion; propranolol administered intravenously gave a 15% decrease (n = 13), diazoxide intravenously a 30% increase (n = 6). It is concluded that, provided conditions are strictly defined, impedance cardiography is a reproducible method and suitable for the measurement of intrapatient changes in cardiac output.

Adult↗
PubMed1979

Increase of serum potassium in the upright posture in selective hypoaldosteronism.

The effect of a 4 hr upright posture on serum potassium (SK) levels was investigated in a certain group of hospitalized renal patients with selective hypoaldosteronism and in healthy subjects. Significant (p less than 0.001) postural increase in SK (0.4 MMol/L) was found only in the 3 young patients with chronic glomerulonephritis and hypoaldosteronism who presented with hyperkalemia (5.84 +/- 0.13 mMol/L) as outpatients, but showed a marked improvement toward normokalemia (4.95 +/- 0.13 mMol/L; p less than 0.001) within the hospital without any specific treatment. In healthy persons in the fastqng condition the influence of the upright position of short duration (45 min) was also studied on SK and a very small but significant increase (0.15 mMol/L) was found. It was concluded: 1. the postural SK INCREASE MAY OFFER AN--AT LEAST PARTIAL--EXPLANTATION FOR THE "OUTPATIENT HYPERKALEMIA", 2. The normal activity of renin-angiotensinaldosterone system may play a role in the counteraction of the trend for SK rise in the upright posture.

Adolescent↗
PubMed1979

Oxalic acid concentration in serum measured by isotopic clearance technique. Experience in hyper- and normo-oxaluric subjects.

In a family from which two children suffered from primary hyperoxaluria the renal clearance of (14C) oxalate was studied. The (14C) oxalate/creatinine clearance ratio ranged from 1.76-2.63 (mean: 2.03) and appeared to be independent of glomerular filtration rate (GFR). The calculated plasma oxalate concentrations in normo-oxaluric subjects ranged from 0.1-0.9 mumol/L, whereas in hyperoxaluric subjects values between 3.2-16.3 mumol/L were found. The mean biological half-life of (14C) oxalate was 2.7hr in subjects with normal renal function and increased proportionally with renal functional impairment. Recovery of (14C) oxalate ranged from 87-112% (mean: 101%). All urine (14C) activity was found in the oxalate fraction.

Adolescent↗
PubMed1976

Occurrence of vascular IgA deposits in clinically normal skin of patients with renal disease.

Skin and kidney biopsies were performed on 262 patients with various nephropathies. In 45 skin biopsy specimens finely granular deposits of predominantly IgA and late-acting complement factors were detected in the walls of superficial capillaries, sometimes concomitantly with IgM, IgG, C4 or a combination of these proteins. Twelve of the 45 patients presented with anaphylactoid purpura and the majority of the other 33 patients had either recurrent macroscopic or microscopic hematuria. The renal lesions in 32 of these 45 patients consisted of focal segmental intracapillary proliferation. In 35 the kidney biopsy specimen showed mesangial deposits of IgA; in one case IgA was deposited along the glomerular basement membrane. In only three of the remaining 217 patients without cutaneous IgA deposits were typical mesangial IgA deposits found. The close correlation between IgA deposits in cutaneous vessels and focal segmental intracapillary proliferation with mesangial IgA deposits suggests that immunofluorescence examination of skin biopsy specimens could prove of diagnostic value. The results provide additional evidence for a close pathogenic relationship between IgA-associated glomerulonephritis and anaphylactoid purpura.

Adult↗
PubMed1975

Comparison of the antihypertensive effect of propranolol and practolol combined with chlorthalidone.

A double blind cross-over trial of fixed doses of propranolol (640 mg/day) and the cardioselective drug practolol (1600 mg/day) was performed in 28 patients with essential hypertension whose blood pressure was not adequately controlled by chlorthalidone (100 mg 3 times weekly) alone. Chlorthalidone alone was given during the first (control) period, and it was continued throughout the propranolol and practolol treatment periods, each of 10 weeks. The systolic and diastolic blood pressures were lowered significantly by both the beta blocking drugs. The changes in blood pressure caused by altering the patient's position were the same after both beta blockers. Propranolol produced slightly lower values than practolol, but the difference was significant only for diastolic blood pressure in the sitting and supine positions. In individual patients the final blood pressure after propranolol was correlated with the final blood pressure after practolol. Only minimal side-effects of either drug were noticed. It is concluded that the doses employed both of propranolol and practolol had a good and approximately equal antihypertensive effect when combined with chlorthalidone treatment. There was no correlation between the final blood pressure and plasma renin activity.

Antihypertensive Agents↗
PubMed1975

Effect of salt depletion and propranolol on blood pressure and plasma renin activity in various forms of hypertension.

The effect of propranolol therapy on the mean arterial pressure (MAP) and plasma renin activity (PRA) was studied in three groups of hypertensive patients who were also treated with saliuretics. Group A: In 14 patients with essential hypertension on chlorthalidone treatment, an additional daily dose of 640 mg propranolol for two months led to a significant reduction of the MAP (from 124 to 105 mm Hg) and PRA (from 5.3 to 2.0 ng AI/ml/hr standing). There was no correlation between MAP reduction and either the original levels or change in PRA. Group B: In 14 patients with essential hypertension and 5 with renal artery stenosis studied on a fixed salt intake, the plasma and extracellular volumes, PRA, and blood pressures were recorded before and after three days of diuretic induced salt depletion and, with maintenance of the depleted state, after three days of propranolol. Salt depletion resulted in a decrease in MAP from 132 to 128 mm Hg (NS), and PRA increased from 3.4 to 22.3 ng AI/ml/hr (P less than 0.01). There was no correlation between change in MAP and PRA control values, PRA change, or any of the volume parameters. Addition of propranolol was followed by a rapid MAP decrease to 111 mm Hg (P less than 0.01), and the PRA dropped to a mean of 8.5 (P less than 0.01). No correlation was found between change in MAP and change in PRA. The patients with renal artery stenosis did not differ in their reactions from those with essential hypertension. Group C: In five patients with moderate renal failure and normal to expanded 82-Br distribution volume, propranolol lowered MAP by 10% and lowered the PRA in all five. Salt depletion by furosemide to 82-Br volumes below normal resulted in a 10% decrease of MAP and a marked rise in PRA. In this state propranolol was followed by a further MAP reduction of 18% and a decrease in PRA. There was no quantitative relationship between MAP and PRA change during either of the treatment regimes. It is concluded that in various forms of hypertension, the blood pressure can be effectively lowered by combining diuretics and propranolol regardless of the pretreatment PRA level.

Adult↗