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Biomedical subjects

D de Zeeuw

Publications and source records attributed to D de Zeeuw.

At least 145 records · Page 8Linked to original sources
PubMed1991

Differential effects of enalapril and atenolol on proteinuria and renal haemodynamics in non-diabetic renal disease.

OBJECTIVE: To compare the antihypertensive, renal haemodynamic and antiproteinuric effect of enalapril and atenolol in patients with proteinuria of non-diabetic origin. DESIGN: Prospective, double blind, randomised 16 week study after a pretreatment period of at least three weeks. SETTING: Outpatient nephrology and hypertension unit. PATIENTS: 27 patients with proteinuria (greater than 300 mg protein/day) of non-diabetic origin, moderately impaired renal function (creatinine clearance 30-90 ml/min), and a pretreatment diastolic blood pressure of greater than 80 mm Hg. INTERVENTIONS: Treatment with enalapril (10 mg/day, adjusted between 5 and 40 mg, if necessary) or atenolol (50 mg/day, adjusted between 25 and 100 mg if necessary) titrated against a target fall in diastolic blood pressure to less than 95 mm Hg or of greater than 10 mm Hg, or both. MAIN OUTCOME MEASURES: Blood pressure, renal haemodynamics, and urinary protein excretion. RESULTS: No differences were detected between the two groups before treatment. The falls in systolic and diastolic blood pressures during treatment were not significantly different between both groups. Proteinuria fell slightly with atenolol but significantly more with enalapril (mean change -0.38 (95% confidence interval -0.78 to 0.03) v -1.2 (-1.70 to -0.69) g/day respectively, p less than 0.02) as did filtration fraction (mean change -1.8 (-2.9 to -0.7) v -3.8 (-4.9 to -2.8)% respectively. Serum potassium concentration increased with enalapril (mean change 0.63 (SD 0.51) v 0.19 (0.47) mmol/l, p less than 0.05). CONCLUSIONS: Enalapril lowers proteinuria more than atenolol in patients with non-diabetic renal disease despite a similar blood pressure lowering effect of both drugs, and its antiproteinuric effect seems to be associated with the characteristic renal haemodynamic effect of angiotensin converting enzyme inhibitors.

Adult↗
PubMed1991

Low molecular weight proteins as carriers for renal drug targeting: naproxen-lysozyme.

Low molecular weight proteins (LMWPs), such as lysozyme, may be suitable carriers to target drugs to the kidney. In this study the antiinflammatory drug naproxen was covalently bound to lysozyme (1:1). Pharmacokinetics of the conjugate, naproxen-lysozyme (nap-LYSO), were compared to that of an equimolar mixture of uncoupled naproxen with lysozyme in freely moving rats. Similar plasma kinetics and organ distribution for native lysozyme and the drug conjugate were observed (Clp = 1.2 and 1.1 ml/min; t1/2,beta = 85 and 75 min, respectively). In case of the uncoupled naproxen-lysozyme mixture, a monoexponential plasma disappearance of naproxen with a t1/2 of 2.8 hr was observed, coinciding with urinary excretion of naproxen metabolites (mainly 6-desmethylnaproxen sulfate; 6-DMN-S) between 2 and 8 hr after injection. Urinary recovery of total metabolites was 59% of the naproxen dose. In contrast, after injection of covalently bound naproxen, plasma levels of the parent drug were below the detection level, whereas naproxen was recovered as 6-DMN-S in urine over a period from 4 to 30 hr. However, only 8% of the administered dose was recovered as 6-DMN-S in urine, whereas 50% of the dose was recovered as naproxen metabolites in feces. Incubation experiments using purified renal tubular lysosomal lysates revealed that naproxen-lysozyme degradation ultimately results in a stable naproxen amino acid catabolite, naproxen-lysine (nap-lys). Hepatic uptake and biliary excretion of this catabolyte were demonstrated in isolated perfused rat livers. Further, an equipotent pharmacological activity relative to parent naproxen was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Angiotensin II does not acutely reverse the reduction of proteinuria by long-term ACE inhibition.

Angiotensin converting enzyme (ACE) inhibitors are known to lower urinary protein excretion in human renal disease. This proteinuria lowering effect of ACE inhibition has been hypothesized to be a result of renal hemodynamic changes due to the inhibition of angiotensin II (Ang II) production. To test this hypothesis we studied the short-term effects of different doses of exogenous Ang II (5%, 10% and 20% of the pressor dose) on renal hemodynamics and urinary protein excretion in comparison with placebo infusion in six non-diabetic normotensive proteinuric patients, both before and after three months treatment with the ACE inhibitor, lisinopril. Lisinopril lowered proteinuria from 7.5 +/- 1.9 to 2.7 +/- 0.6 g/24 hr and induced a fall in blood pressure, renal vascular resistance and filtration fraction, whereas plasma Ang II levels were similar to the pre-treatment values. Ang II infusion induced typical effects which appeared to be similar before and during lisinopril treatment: a dose-related fall in renal plasma flow and rise in systemic blood pressure, renal vascular resistance and filtration fraction, while the glomerular filtration rate remained relatively stable. However, neither before nor during lisinopril therapy did any changes in urinary protein loss occur during the infusions of Ang II, despite the fact that Ang II reversed the long-term systemic and renal hemodynamic changes induced by the ACE inhibitor. We conclude that the long-term antiproteinuric effect of the ACE inhibitor, lisinopril, is neither mediated through changes in circulatory Ang II levels nor influenced by acute changes in systemic and renal hemodynamics, suggesting a non-hemodynamic mechanism of action.

Adult↗
PubMed1991

Additive antiproteinuric effect of angiotensin-converting enzyme inhibition and non-steroidal anti-inflammatory drug therapy: a clue to the mechanism of action.

1. Both the angiotensin-converting enzyme inhibitor, lisinopril, and the non-steroidal anti-inflammatory drug, indomethacin, lower urinary protein excretion in renal disease and improve the selectivity of the residual proteinuria. Despite the clearly different renal haemodynamic profiles of the two drugs, we hypothesize that the antiproteinuric effect has a final common pathway that is a reduction in glomerular filtration pressure. 2. We studied the effects of lisinopril and indomethacin, separately and in combination, on urinary protein excretion, selectivity of proteinuria and renal haemodynamics in nine non-diabetic patients with overt proteinuria. 3. Urinary protein excretion was 5.4 +/- 2.5 g/24 h in the control period. Lisinopril monotherapy lowered urinary protein excretion by 53 +/- 26%. During indomethacin treatment urinary protein excretion was reduced by 63 +/- 24%. After adding indomethacin to lisinopril, urinary protein excretion fell by a further 58 +/- 23%, resulting in a 79 +/- 17% decrease during combined therapy. 4. Although both lisinopril and indomethacin monotherapy appeared to result in an improvement in glomerular protein permeselectivity, no further improvement was seen during the combination therapy. 5. The change in proteinuria were associated with changes in glomerular filtration rate, which showed a pronounced fall with combination therapy. The renal haemodynamic profiles during the different therapies suggest a post-glomerular vasodilatation by lisinopril and a pre-glomerular vasoconstriction by indomethacin, and the combination of both during the combined treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The mechanism and diagnostic value of angiotensin I converting enzyme inhibition renography.

The effect of angiotensin converting enzyme (ACE) inhibition on the sensitivity of radionuclide renography in the diagnosis of a unilateral renal artery stenosis was tested both in a conscious dog model and in the human situation. ACE inhibition (10 mg enalaprilic acid, intravenously) markedly improved the sensitivity of [123I]hippuran renography in 10 renovascular hypertensive dogs with a mild to moderate unilateral renal artery stenosis from 50 to 100%. This improved sensitivity was due to an ACE-inhibition-induced delayed tracer handling at the stenotic side without an appreciable change in the renographic curve at the contralateral side. A similar phenomenon was observed in 15 hypertensive patients with an angiographically proved unilateral renal artery stenosis. Both [123I]hippuran and 99mTc-diethylenetriaminepentaacetic acid (DTPA) handling was delayed on the stenotic side after oral enalapril treatment. However, only a moderate increase in sensitivity was observed comparing control renograms to ACE-inhibition renograms: from 87 to 93% for hippuran, and from 60 to 86% for DTPA. Eight of these 15 patients underwent either surgery or angioplasty resulting in a successful correction of the stenosis. Hypertension was more or less cured in five patients. Each of these patients had shown an ACE-inhibition-induced change in the renogram at the stenotic side, suggesting that such a response may predict the curability of the hypertension. However, of the three patients that showed no blood pressure change upon successful revascularization, two showed a positive ACE-inhibition renogram. In conclusion, in an ideal setting as obtained in animal experiments, ACE inhibition improves the sensitivity of renographic studies to 100%. However, its value in the clinical setting needs more standardization.

Animals↗
PubMed1990

Additive antiproteinuric effect of the NSAID indomethacin and the ACE inhibitor lisinopril.

Both angiotensin-converting enzyme (ACE) inhibitors like lisinopril and nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin have been shown to lower urinary protein excretion in renal disease. If this effect is caused by different mechanisms of action, the combination of these agents could have an additive antiproteinuric effect. We studied the effects of lisinopril and indomethacin separately and in combination in 10 patients with the nephrotic syndrome. Proteinuria was lowered from 10.5 +/- 1.8 g/24 h in the control period to 4.5 +/- 1.1 g/24 h on indomethacin, 4.3 +/- 1.0 g/24 h on lisinopril and to 2.4 +/- 0.8 g/24 h on the combination. Glomerular filtration rate (GFR) fell on either monotherapy, but particularly on the combination of drugs. The renal hemodynamic changes suggested a preglomerular vasoconstriction by indomethacin and a postglomerular vasodilation by lisinopril. Severe hyperkalemia occurred in 3 patients on the combination therapy. We conclude that the combination of indomethacin and lisinopril has an additive antiproteinuric effect. This, as well as the more pronounced fall in GFR on the combination, may suggest that both drugs lower proteinuria by decreasing intraglomerular capillary pressure but via different mechanisms. Combining these drugs may be useful in the symptomatic treatment of nephrotic syndrome, but renal function and serum potassium should be monitored carefully.

Adult↗
PubMed1990

Lisinopril in hypertensive patients with renal function impairment.

The antihypertensive and renal effects of the angiotensin-converting enzyme inhibitor lisinopril were studied in a group of patients with moderate-to-severe hypertension and impaired renal function. After 12 weeks of treatment, most patients had good blood pressure response to lisinopril monotherapy. During this period, correlations between antihypertensive effect, drug dose, and serum drug level were observed. These correlations were no longer evident after prolonged treatment. During a 1-year follow-up period, the drug dose was lowered gradually without losing antihypertensive effect. Hyperkalemia occurred in one third of the patients. During the 1-year follow-up, the glomerular filtration rate (GFR) decreased in two thirds of the patients and remained stable in the other third. In this latter group, the pretreatment GFR was higher, and the effective renal plasma flow had increased, whereas in the patients with a decreased GFR no renal vasodilation had occurred during lisinopril therapy. Thus, lisinopril is an effective antihypertensive drug for patients with impaired renal function. The dose should be adjusted to the pretreatment GFR, and a decrease in dosage should be considered with prolonged treatment.

Blood Pressure↗
PubMed1989

Angiotensin converting enzyme inhibitors and progressive renal insufficiency. Current experience and future directions.

STUDY OBJECTIVE: To review the rationale for using angiotensin converting enzyme (ACE) inhibitors in progressive renal disease, and to evaluate the experience with these agents in patients with hypertension and renal insufficiency. DATA IDENTIFICATION: Experimental and clinical studies published from January 1977 to November 1988 were identified by searching the literature and by extensive hand searching of bibliographies of identified articles. STUDY SELECTION: Experimental studies of glomerular function during therapy with ACE inhibitors or other antihypertensive regimens were reviewed. Series using ACE inhibitors for treating hypertensive patients with renal disease were evaluated and reports of adverse events were studied. RESULTS OF DATA SYNTHESIS: Experimentally, ACE inhibitors seem to decrease glomerular injury by reducing both systemic and glomerular hypertension. Clinically, ACE inhibitors reduce systemic blood pressure in hypertensive patients with diabetic and nondiabetic renal disease without causing dramatic changes in glomerular filtration rate or renal blood flow. Most studies of nondiabetic renal insufficiency suggest that proteinuria is reduced in most patients. However, no long-term controlled study on the effect of ACE inhibitors on the progression rate of nondiabetic renal disease has been completed. ACE inhibitors have not yet been approved by the Food and Drug Administration (FDA) for treating or preventing progressive renal disease. Such use would therefore be considered "innovative" therapy. CONCLUSIONS: ACE inhibitors are tolerated by azotemic patients, although transient reductions in renal function can occur. Patients with bilateral renal insufficiency or low cardiac output are at increased risk for developing reversible acute renal insufficiency. Hyperkalemia may occur, particularly in patients with diabetes or severe renal insufficiency. In many patients with renal disease, ACE inhibitors dramatically reduce proteinuria, but whether they also reduce the rate of progression of renal disease remains unproved.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1989

Unilateral renal parenchymal disease with contralateral renal artery stenosis of the fibrodysplasia type.

In patients who have hypertension and a unilateral small kidney, hypertension may have either a vascular (renal artery stenosis) or nonvascular (urologic) cause. Generally, the hypertension can be attributed to the abnormal-sized kidney, and nephrectomy of the shrunken kidney or correction of the stenotic artery will result in the normalization of blood pressure. We report eight cases of hypertension in young women shown to have a small kidney by intravenous urography. The abnormal-sized kidney was considered to be due to either agenesis or dysplasia and reflux. Although the diseased kidney was thought to be the cause of the high blood pressure, these patients were unique in that they had a stenosis of the contralateral renal artery of the fibrodysplasia type, which was predominantly localized in the distal part of the artery and frequently extended into the peripheral branches. Successful anatomic correction of the stenotic artery without surgery on the contralateral small kidney resulted in the normalization of blood pressure. This previously unrecognized combination of parenchymal disease of one kidney and renal artery stenosis of the fibrodysplasia type on the contralateral side should be considered in patients with hypertension and a unilateral small kidney. Such recognition could prevent the unnecessary treatment of these patients with an angiotensin-converting enzyme inhibitor or nephrectomy.

Adolescent↗
PubMed1989

Human plasma contains low molecular weight factors which stimulate active sodium transport in erythrocytes.

The aim of this study was to establish whether differences in sodium efflux rate constants (ke) in human erythrocytes occur when artificial media are compared with plasma. Using a 22Na tracer method, a mean total ke of 0.49 +/- 0.10 h-1 and significantly (p less than 0.05) lower ke values in Hanks' solution (0.43 +/- 0.08 h-1) and Basic Salt Solution (0.37 +/- 0.07 h-1) were observed. Exhaustive dialysis of plasma against Hanks' solution over a membrane with relative molecular mass cut-off of 1000 Da resulted in a decrease of the plasma total ke value to that measured in Hanks' solution. After equilibrium dialysis of plasma against Hanks' solution a decrease of total ke was found in plasma and an increase of the ke in Hanks' solution was measured. The data suggest the presence of an excess of dialyzable, active sodium transport stimulating plasma factor(s) with relative molecular mass below 1000 Da.

Adult↗
PubMed1989

Efficacy and variability of the antiproteinuric effect of ACE inhibition by lisinopril.

We studied the efficacy of the ACE inhibitor lisinopril in treating overt proteinuria in comparison with the NSAID indomethacin, and evaluated some of the conditions that could influence this antiproteinuric effect. In 12 patients with a proteinuria varying from 3.2 to 10.5 g/24 hr, a diastolic BP ranging from 64 to 105 mm Hg, and a GFR varying from 34 to 127 ml/min, the effect of different lisinopril doses and of changing dietary sodium intake was evaluated. Proteinuria fell by 27 +/- 20% from 6.1 +/- 2.1 to 4.5 +/- 1.9 g/24 hr on a low dose (median 5 mg/day) lisinopril and by 50 +/- 17% to 3.1 +/- 1.4 g/24 hr on a higher dose (median 10 mg/day), irrespective of initial proteinuria, BP, or GFR. This antiproteinuric effect was abolished by increasing salt intake from 50 to 200 mmol/day, and was recovered again by re-instituting the sodium restricted diet. The antiproteinuric effect of 10 mg/day lisinopril was comparable to the reduction in proteinuria (by 57 +/- 21% to 2.8 +/- 2.0 g/24 hr) on 150 mg/day indomethacin, while adverse effects were less and renal hemodynamic effects were more favorable during lisinopril. In some patients it took several weeks before the effect of the ACE inhibitor on proteinuria was stabilized. Thus, the antiproteinuric effect of the ACE inhibitor lisinopril appears to be dose and time related, and is strongly dependent on dietary sodium restriction, whereas it does not depend on initial proteinuria, BP, or GFR. The effect is comparable to that of indomethacin, while adverse effects are less.

Adult↗