Bioanalysis of captopril: two sensitive high-performance liquid chromatographic methods with pre- or postcolumn fluorescent labeling.

This study describes the development and comparison of two HPLC methods for the analysis of the antihypertensive drug captopril. The first method is based on a precolumn derivatization of captopril with the fluorescent label monobromobimane (MBB). The second method is based on a postcolumn reaction with the fluorescent reagent o-phthaldialdehyde (OPA).

Modeling of cometary X-rays caused by solar wind minor ions.

X-ray emission was discovered in comet Hyakutake (C/1996 B2) by the Röntgen satellite in 1996, and these emissions were attributed to the excitation of high charge state solar wind ions due to electron capture from cometary molecules or atoms. Using the plasma flow in the coma of Hyakutake calculated by a three-dimensional adaptive magnetohydrodynamic model, the density distribution of solar wind ions in the coma and the resulting x-ray emission were computed. The calculated High Resolution Imager count rate of 4.

Proteinuria and progression of renal disease: therapeutic implications.

The relationship between proteinuria and progression of renal disease has long been an issue of debate. The present review deals with some of the recent publications on this topic. New concepts are emphasized: the possible causal role of proteinuria in the pathophysiology of progressive renal function loss, and the decrease in urinary protein loss at the beginning of renoprotective therapy as a predictor of renal function outcome during this treatment.

A short-term antihypertensive treatment-induced fall in glomerular filtration rate predicts long-term stability of renal function.

In long-term intervention studies on renal function outcome an initial decline in the glomerular filtration rate (GFR) may occur after starting therapy. If this initial GFR decline is the result of a treatment-induced hemodynamic change reflecting a fall in intraglomerular pressure, it should be reversible after treatment withdrawal, even after long-term treatment. In fact, it could be beneficial for renal function in the long term.

Measurement of glomerular charge selectivity in non-diabetic renal disease.

Background: Until now, the renal clearance index of IgG to IgG4 (IgG/IgG4) as well as pancreatic to salivary amylase (PA/SA) were separately used as parameters of renal charge selectivity in diabetic and non-diabetic albuminuria. The suitability of the IgG index may be questioned because urinary loss of IgG rather reflects a size selective defect. In contrast, the amylase index seems more appropriate to reflect renal charge selectivity because its molecular size is comparable to albumin.

Is the antiproteinuric response to inhibition of the renin-angiotensin system less effective during the night?

Background: In glomerular disease proteinuria usually has a circadian pattern with maximum excretion during the day. Blockade of the renin-angiotensin system (RAS) results in a 50% reduction of proteinuria as measured in 24-h urine collections. We questioned whether anti-proteinuric treatment by blockade of the RAS is as effective during the day as during the night.

ACE polymorphism does not determine short-term renal response to ACE-inhibition in proteinuric patients.

Background: The renal response to ACE inhibition is known to vary between individuals. The ACE genotype is a determinant of the ACE concentrations in plasma and tissue, and therefore might affect the renal response to ACE inhibition in renal patients.

Methods: To test this hypothesis we studied the short-term response to ACE inhibition (enalapril or lisinopril 10/20 mg/d) in 61 stable proteinuric patients (> 1.

Hypertension and renal disease: role of microalbuminuria.

Unlabelled: RISKS ASSOCIATED WITH HYPERTENSION: Hypertension is a risk factor for cardiovascular and possibly renal organ damage. Microalbuminuria is a newly recognized cardiovascular and renal risk factor in diabetic and non-diabetic subjects. The prevalence of microalbuminuria is enhanced in hypertensive subjects, in particular in those with blood pressure characteristics that are associated with enhanced cardiovascular risk, such as salt-sensitivity and an abnormal diurnal blood pressure rhythm.

ACE inhibitors and proteinuria.

This review discusses the clinical consequences of urinary protein loss and the effects of inhibitors of the angiotensin converting enzyme (ACE) on this clinical finding. Proteinuria appears to be an important risk factor for renal function deterioration and for cardiovascular mortality. ACE inhibitors have been shown to reduce proteinuria more effectively than other antihypertensives.

Titrating for antiproteinuric effect: the clue to renoprotection?

Proteinuria may be involved in the final common pathway of progressive renal function loss. If so, intervention treatment that reduces proteinuria might prevent or retard long-term renal function loss. In renal patients and in experimental renal disease the severity of proteinuria is associated with the rate of long-term renal function loss.

ACE inhibitors and the kidney. A risk-benefit assessment.

ACE inhibitors effectively reduce systemic vascular resistance in patients with hypertension, heart failure or chronic renal disease. This antihypertensive efficacy probably accounts for an important part of their long term renoprotective effects in patients with diabetic and non-diabetic renal disease. The renal mechanisms underlying the renal adverse effects of ACE inhibitors--intrarenal efferent vasodilation with a consequent fall in filtration pressure--are held to be involved in their renoprotective effects as well.

Renal 131I-hippurate clearance overestimates true renal blood flow in the instrumented conscious dog.

We evaluated renal 131I-hippurate clearance (ERPFhip) as a measure of renal blood flow (RBF) in chronically instrumented conscious dogs. When adjusted for renal hippurate extraction (Ehip, 0.77 +/- 0.

The serum lathosterol to cholesterol ratio, an index of cholesterol synthesis, is not elevated in patients with glomerular proteinuria and is not associated with improvement of hyperlipidemia in response to antiproteinuric treatment.

The hypothesis that increased cholesterol synthesis provides a mechanism that contributes to nephrotic syndrome-associated hyperlipidemia is mainly based on experimental evidence. The serum level of the cholesterol precursor, lathosterol (expressed per millimole cholesterol), is a reliable marker of whole-body cholesterol synthesis in normocholesterolemia and primary hypercholesterolemia. Serum lathosterol and lipoprotein levels were measured in 11 moderately hyperlipidemic patients with nephrotic-range proteinuria and 22 matched controls.

Antiproteinuric effect predicts renal protection by angiotensin-converting enzyme inhibition in rats with established adriamycin nephrosis.

1. The mechanism of renal protection by angiotensin-converting enzyme inhibition is still the subject of debate. Inhibition of proteinuria might play a role.

Precision of glomerular filtration rate determinations for long-term slope calculations is improved by simultaneous infusion of 125I-iothalamate and 131I-hippuran.

In studies on the progression of chronic renal failure the measurement of GFR must be very reliable. Sequential determination of GFR using the renal clearances of exogenous tracers such as inulin or iothalamate is the most accepted method. However, because of inaccuracies in urine collection, intratest variation, and thus intertest variation, of these clearances is considerable.

Angiotensin-converting enzyme inhibition-induced changes in hippurate renography and renal function in renovascular hypertension.

Unlabelled: We studied the mechanism of angiotensin-converting enzyme (ACE) inhibition-induced changes in hippurate renography of the poststenotic kidney.

Methods: Ten male mongrel dogs, six with unilateral and four with bilateral renal artery stenosis, were equipped with renal artery blood flow probes and catheters in the aorta, atrium and both renal veins.

Results: Enalaprilat (10 mg intravenously) in conscious dogs with renal artery stenoses produced changes in all stenotic (n = 11) but not in nonstenotic kidney 123I-hippurate renograms (n = 6).

Does the renin-angiotensin system determine the renal and systemic hemodynamic response to sodium in patients with essential hypertension?

Many patients with essential hypertension respond to a high dietary sodium intake with a rise in blood pressure. Experimental evidence suggests that the renal hemodynamic response to sodium determines, at least partially, this rise in blood pressure. Our aim was to clarify the role of the renin-angiotensin system in the renal and systemic adaptation to a change in dietary sodium.

Association between angiotensin-converting-enzyme gene polymorphism and failure of renoprotective therapy.

Background: Polymorphism in the gene for angiotensin-converting enzyme (ACE), especially the DD genotype, is associated with risk for cardiovascular disease. Glomerulosclerosis has similarities to atherosclerosis, and we looked at ACE gene polymorphism in patients with kidney disease who were in a trial of long-term therapy with an ACE inhibitor or a beta-blocker.

Methods: 81 patients with non-diabetic renal disease had been entered into a randomised comparison of oral atenolol or enalapril to prevent progressive decline in renal function.

Prognostic value of the short-term antiproteinuric response to ACE inhibition for prediction of GFR decline in patients with nondiabetic renal disease.

In chronic renal disease, the severity of proteinuria is associated with the rate of renal function loss. Proteinuria, therefore, was postulated to play a role in the final common pathway of chronic renal function loss. If so, reduction of proteinuria would improve long-term renal outcome.

Blood pressure reduction initiates the antiproteinuric effect of ACE inhibition.

Several observations question the role of blood pressure and renal hemodynamic changes in the long-term antiproteinuric effect of ACE inhibition. To differentiate blood pressure and renal effects in the initial antiproteinuric response, the placebo-controlled acute effects of the ACE inhibitor enalaprilat (10 mg i.v.

Antiproteinuric effect of blood-pressure-lowering agents: a meta-analysis of comparative trials.

Whether ACE inhibitors (ACEi) differ from other antihypertensives in their efficacy to lower proteinuria is controversial. We therefore performed a meta-analysis of articles on this subject. The secondary objective in our meta-analysis was to study whether there is any difference between diabetic and non-diabetic patients in antiproteinuric response to blood pressure reduction.