Association between active Wegener's granulomatosis and anticytoplasmic antibodies.

Autoantibodies reacting with the cytoplasm of granulocytes and monocytes (anticytoplasmic antibodies [ACPAs]) were found in 42 of 45 patients with active Wegener's granulomatosis (WG) (sensitivity, 93%). Specificity was tested in selected groups of patients with closely related diseases. Of 58 patients without a diagnosis of WG, 2 had ACPAs (specificity, 97%). The significance of ACPA titration for assessing or predicting disease activity was evaluated in a 16-month prospective study of 35 patients with WG. Seventeen relapses were observed and all were preceded by a significant rise of the ACPA titer. Anticytoplasmic antibodies are a specific and sensitive marker for active WG; a rising titer is a sensitive marker for the development of a relapse.

Antihypertensive effect of a 5-day infusion of atrial natriuretic factor in humans.

Atrial natriuretic factor was infused in a low dose (0.2 microgram/min) during 5 days in six patients with essential hypertension. Atrial natriuretic factor infusion caused plasma levels of atrial natriuretic factor to increase from 49 +/- 10 to 106 +/- 19 pg/ml. Within 4 hours after the start of the atrial natriuretic factor infusion, urinary sodium excretion increased in all subjects. Sodium balance was regained after 24 hours with a net loss of 72.3 +/- 14.6 mmol. However, systolic as well as diastolic blood pressure started to decrease gradually in all subjects only after 12 hours of atrial natriuretic factor infusion, reaching a stable level after 36 hours with a decrease of 11.5 +/- 1.5% and 10.3 +/- 0.8%, respectively. Heart rate increased in parallel by 12.6 +/- 3.1%. Hematocrit rose 7.1 +/- 2.3%. After cessation of atrial natriuretic factor infusion, plasma atrial natriuretic factor levels, sodium balance, and hematocrit returned to baseline within 24 hours, whereas blood pressure slowly returned toward baseline values over 3 days. These data show that chronic atrial natriuretic factor infusion in patients with essential hypertension causes a negative sodium balance and a rise in hematocrit, followed by a smooth decrease in blood pressure with a rise in heart rate until a new equilibrium is reached after approximately 2 days. Thus, atrial natriuretic factor in low doses appears intimately involved in the regulation of sodium balance and blood pressure in humans. Moreover, these data suggest that atrial natriuretic factor-like substances will eventually become useful antihypertensive drugs.

Atrial natriuretic factor influences renal diurnal rhythm in essential hypertension.

We investigated in six patients with essential hypertension the effect of a low dose atrial natriuretic factor infusion for 5 days on the diurnal rhythm of renal electrolyte excretion. Atrial natriuretic factor infusion increased the net excretion of sodium and caused a delay in its time of maximal diurnal urinary excretion. Similarly, atrial natriuretic factor caused an increase in the net excretion of chloride, calcium, and magnesium and also changed the diurnal rhythms of these electrolytes. In contrast, atrial natriuretic factor did not change the net excretion of potassium, phosphate, and uric acid, nor did atrial natriuretic factor change the diurnal rhythms of these solutes. During baseline, the time points of maximal urinary excretion of sodium and potassium overlapped, whereas atrial natriuretic factor infusion caused sodium excretion to peak 2.2 +/- 0.3 hours (p less than 0.02) after the potassium excretion peak. During baseline, the time of maximal urinary excretion of sodium did not correlate with the time of highest blood pressure, whereas it correlated negatively with mean plasma aldosterone concentration. In contrast, during atrial natriuretic factor infusion the time of maximal urinary excretion of sodium correlated positively with the time of highest blood pressure, whereas it did not correlate with mean plasma aldosterone concentration. These data suggest that atrial natriuretic factor is involved with the diurnal rhythm of the urinary excretion of sodium and that atrial natriuretic factor-induced natriuresis is mediated in part by blood pressure and plasma aldosterone.

Angiotensin converting enzyme inhibition improves diagnostic procedures for renovascular hypertension in dogs.

In renovascular hypertension adaptive mechanisms in the poststenotic kidney are a probable cause of the 20 to 25% false-negative findings during rapid sequence urography or [123I]o-iodohippurate renography. We blocked the renin-angiotensin system in an effort to increase the yield of these diagnostic procedures. Chronically instrumented, salt-depleted conscious dogs were used in which a light (n = 5), moderate (n = 4), or severe (n = 2) renal artery stenosis was induced. Before stenosis 10 of the dogs showed no left-right differences with either diagnostic procedure, and angiotensin converting enzyme (ACE) inhibition did not change this result. Two to 3 weeks after induction of a renal artery stenosis, all dogs showed signs of renovascular hypertension. However, only 50% of the renograms and 22% of the urograms showed differences between the two kidneys indicative of the presence of stenosis. After ACE inhibition, all previously negative test results became positive (abnormal) and previously existing left-right differences became more evidence. Electromagnetically measured renal blood flow on the stenotic side did not change during ACE inhibition (146 +/- 13 vs 145 +/- 21 ml/min), whereas contralateral blood flow showed a distinct increase (207 +/- 18 vs 282 +/- 20 ml/min, p less than 0.01). In conclusion, ACE inhibition markedly improves the sensitivity of rapid sequence urography and hippurate renography in the diagnosis of renovascular hypertension in the two-kidney, one clip Goldblatt hypertensive dog. The effects of ACE inhibition on the handling of the different tracers do not appear to be related to its effects on renal blood flow or systemic blood pressure.

Effects of nonsteroidal anti-inflammatory drugs on proteinuria.

Most nonsteroidal anti-inflammatory drugs are anti-proteinuric agents, especially if the patient is sodium-depleted. The decline in urinary protein excretion induced by these agents always markedly exceeds the decrease in glomerular filtration rate. Moreover, the remaining proteinuria appears to be more selective. Together, these findings suggest that the anti-proteinuric effect of nonsteroidal anti-inflammatory drugs is hemodynamically mediated. Nonsteroidal anti-inflammatory agents that reduce renal prostaglandin E2 excretion also decrease proteinuria, whereas sulindac decreases neither prostaglandin E2 nor protein excretion. In a retrospective study, it appeared that administration of indomethacin improved renal survival of nephrotic patients with an initial serum creatinine concentration of less than 110 mumol/liter. The anti-proteinuric effect of indomethacin itself or indomethacin-induced hemodynamic changes might explain this observation.

Renal tubular sensitivity to atrial natriuretic factor in essential hypertension.

OBJECTIVE: To study the tubular site or sites of the natriuretic action of atrial natriuretic factor and the possible differences between healthy subjects and patients with essential hypertension. DESIGN: Nine healthy volunteers and six patients with essential hypertension were studied on four test days under standard conditions, water loading and hydropenia with mannitol or saline loading. On each test day baseline, atrial natriuretic factor infusion (1 microgram/min) and recovery measurements were performed after equilibrium had been reached. The measurements included the atrial natriuretic factor (ANF) plasma levels, blood pressure, glomerular filtration rate (GFR), effective renal plasma flow, urinary osmolality and the (fractional) excretions of (free) water, sodium and potassium. METHODS: Fractional free-water excretion and free-water reabsorption (as a function of osmolar clearance) were calculated during water loading and hydropenia with mannitol or saline loading, respectively, using standard formulae. [125I]-iothalamate and [131I]-hippuran were infused continuously for the measurement of GFR and effective renal plasma flow, respectively. RESULTS: The plasma ANF concentration rose five- to eightfold during the infusion of ANF, which induced an increase in urinary sodium excretion, a small increase in GFR and a decrease in the effective renal plasma flow. Moreover, ANF induced an increase in fractional free-water excretion and a decrease in fractional free-water reabsorption. These changes did not correlate with changes in GFR. The blood pressure and potassium excretion were not affected. The effects of ANF on the plasma ANF levels, natriuresis and renal haemodynamics did not differ between the normotensive and the essential hypertensives. However, the increase in fractional free-water excretion was significantly greater in the patients with essential hypertension and correlated significantly with blood pressure (r = 0.56, P < 0.05). CONCLUSIONS: These results indicate that the infusion of ANF at a low dose induces a similar natriuretic response in normotensive subjects and in patients with essential hypertension. This natriuresis is probably the result of both a glomerular and a tubular effect of ANF. Proximal as well as distal tubular sites seem to be involved. In essential hypertension an enhanced proximal as well as an impaired distal tubular action of ANF can be hypothesized.

Complement activation associated with active cytomegalovirus infection in renal transplant patients, and its absence in transplant rejection episodes.

In 20 patients with a cadaveric renal allograft, serial measurements were made of the serum complement factors C3, C4, factor B (FB), and C3d, the stable conversion product of C3. Measurements were started immediately before transplantation and continued thereafter once a week to investigate whether these assays help to differentiate between acute allograft rejection (R) and an active cytomegalovirus (CMV) infection. Fifteen patients had one or more R episodes, and 9 patients suffered from an active CMV infection. Six patients had an R episode and subsequently a CMV infection 13-64 days after R. No significant changes were found in the levels of C3, C4, and FB during R or CMV infection. C3d levels remained unchanged or decreased slightly during R. However, there was a 43-500% increase in the C3d level during CMV infection. This difference in the behavior of levels of C3d during R and CMV infection is significant (P less than 0.01), and suggests that serial measurements of C3d may be useful in differentiating CMV infection from R after renal transplantation.

Diagnostic use of angiotensin converting enzyme inhibitors in radioisotope evaluation of unilateral renal artery stenosis.

Iodine-123 hippurate renography, [99mTc]diethylenetriaminepentaacetic acid (DTPA) renography, and [99mTc]dimercapto succinic acid (DMSA) renal scintigraphy were performed before and during angiotensin converting enzyme (ACE) inhibition in a group of 15 hypertensive patients with angiographically "significant" unilateral renal artery stenosis. Visual and quantitative evaluation of the three radioisotope methods before ACE inhibition already disclosed abnormalities suggestive of renal artery stenosis in a high percentage (87%, 60%, and 60%, respectively) in this group of patients, but ACE inhibition further improved the diagnostic yield in all three methods (93%, 86%, and 80%). Iodine-123 hippurate renography was at least as useful as [99mTc]DTPA renography in this respect, while [99mTc]DMSA scintigraphy can be used particularly in segmental stenosis. Despite a large drop in blood pressure after ACE inhibition little adverse reactions were seen and overall renal function was fairly well maintained, the exceptions noted in patients with initially a more impaired renal function.

Renal handling of technetium-99m DMSA: evidence for glomerular filtration and peritubular uptake.

The finding of an enhanced excretion of [99mTc]dimercaptosuccinic acid (DMSA) in patients with tubular reabsorption disorders prompted us to investigate the role of filtration in the renal handling of [99mTc]DMSA. Our studies in human serum indicated that binding to serum proteins was approximately 90%. Chromatography of human urine and studies in rats showed that the complex was excreted unaltered into the urine. Renal extraction of [99mTc]DMSA in a human volunteer was 5.8%. Continuous infusion of [99mTc]DMSA in 13 individuals with normal renal function gave the following results (mean +/- s.d.): plasma clearance of [99mTc]DMSA 34 +/- 4 ml/min, urinary clearance of [99mTc]DMSA 12 +/- 3 ml/min. The calculated filtered load of [99mTc]DMSA closely resembled the urinary clearance, whereas the plasma clearance was about three times faster. This indicates that peritubular uptake accounts for approximately 65% and filtration for approximately 35% of the renal handling of [99mTc]DMSA.

Protein-restricted diets in chronic renal failure: a four year follow-up shows limited indications.

Several retrospective and prospective studies confirmed the beneficial effect of dietary protein restriction (DPR) on the downhill course of renal function in chronic kidney disease. The long-term results of this therapeutic modality may be different than the short-term effects. In our nephrology outpatient department, a prospective randomized trial has been in progress since April, 1982. In 1984, we reported a general beneficial effect of our diet after two years of follow-up. Two hundred and forty-eight patients with initial creatinine clearances between 10 and 60 ml/min entered the trial. Patients were stratified for sex, age and degree of renal insufficiency. One hundred and twenty-nine patients were randomly assigned to a DPR-group (0.4 to 0.6 g/kg/day); 118 patients to a control group. Patients on DPR visited the dietitian every three months during the first 24 months of the study; thereafter, as with the controls, the dietitian visits were only for specific needs. Urea excretion decreased significantly in DPR patients as a sign of good compliance and stayed at that level, even without frequent visits to the dietitian. Biochemical parameters showed no signs of malnutrition. Amino acid profiles were related to the degree of renal failure. The diet appeared to have a selective effect on the progression rate of renal failure: only patients with primary glomerular disease responded to the diet. Furthermore, there were striking intersex differences. Males showed a more rapid decline towards end-stage renal failure, but responded in a positive way to the diet, whereas female patients did not benefit from the dietary manipulation at all.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effects of cis-diamminedichloroplatinum (CDDP) on renal function.

Ten previously untreated patients with metastatic non-seminomatous testicular carcinoma received cis-diamminedichloroplatinum (CDDP). Renal function studies were performed before and following the first CDDP infusion. A decrease in effective renal plasma flow (ERPF) and an increase in filtration fraction (FF) was found in all patients. These findings suggest primary changes in renal hemodynamics during CDDP infusion.

Nephrotoxicity of cis-diamminedichloride platinum (CDDP) during remission-induction and maintenance chemotherapy of testicular carcinoma.

We studied renal function in nine patients with disseminated testicular carcinoma before and after remission-induction and maintenance therapy with a drug combination containing cis-platinum. The median glomerular filtration rate (GFR) decreased during remission-induction therapy from 146 to 118 ml/min. No effect of cumulative toxicity on the median GFR was found during maintenance therapy, nor did the median GFR improve. The median effective renal plasma flow (ERPF) decreased during the total period from 705 to 514 ml/min. No significant changes in median filtration fraction (FF) and serum creatinine were observed. It is suggested that intrarenal hemodynamic effects are important in the nephrotoxicity of cis-diamminedichloride platinum (CDDP).

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.

Differences in erythrocyte sodium transport between human plasma and artificial medium: the role and character of sodium efflux and influx stimulating plasma factors.

The main objective of this study was to further characterize the plasma factor(s) which stimulate sodium efflux from erythrocytes, which we reported previously. Dialysis of plasma against an artificial medium using membranes with varying molecular mass cut-off points revealed relative molecular mass(es) of the factor(s) of 100-1000 Da. The factor(s) could be absorbed on Dowex at pH 1.5 and Amberlite at pH 11.0, indicating 'Zwitterionic' character. They are hydrophilic and resistant to acid hydrolysis. These characteristics and direct measurements of contents made amino acids likely candidates for the efflux stimulating properties of the factor(s). Indeed, plasma amino acids added to artificial medium could abolish the sodium efflux difference between plasma and the artificial medium. The efflux stimulating effect of amino acids appeared not to be the result of sodium influx stimulation. A coincident finding was that plasma also contains dialyzable sodium influx stimulating factor(s) which are not amino acids.

Loss of amino acids during hemodialysis: quantitative and qualitative investigations.

In three patients the total amino acid losses (free plus peptide-bound) in dialyzate have been assayed by means of gas-liquid chromatography. During a period 3--4 months the average losses varied from 115--178 mg per kg of body weight per dialysis treatment. The weekly mean essential amino acid losses amounted to 3--4% of the dietary intake. The concentrations in the dialyzate of non-essential amino acid fell considerably during the dialysis procedure, whereas the concentrations of most of the essential amino acids remained at a fairly constant level. It is concluded that considerable quantitative but no qualitative differences exist between the patients with respect to amino acid losses.

Impaired lymphocyte function and neutrophil damage during the first hours of hemodialysis.

Tests of T lymphocyte function, as lymphocyte stimulation by phytohemagglutinin (PHA) and concanavalin A (Con A), decreased during the first 2 hours of dialysis to approximately 20% of the predialysis value but returned to near normal within 4 hr. No change in the percentage of T cells was noted. Lymphocyte function in blood obtained from the arterial side fo the dialyzer 1 hour after the start of dialysis was better than that in blood from the venous side, though lower than before dialysis. Neutrophils in blood from the venous side of the dialyzer showed decreased density and decreased carbonyl iron phagocytosis. These changes were not found in blood from the arterial side of the dialyzer, suggesting that damaged neutrophils were retained in the patient. Neutrophil damage persisted during the first 4 hours of hemodialysis.

Vascular permeability increasing factor (VPF) in IgA nephropathy.

Peripheral blood mononuclear cells (PBC) from non-nephrotic and nephrotic patients with different glomerulopathies were tested for their potential to produce vascular permeability increasing factor (VPF) after stimulation with Concanavalin-A (Con-A) in vitro. Supernatants from cultures of PBC from patients with IgA nephropathy were injected intradermally into the skins of normal Wistar rats which were given Evans blue dye solution intravenously. The mean extravasation of dye after 60 minutes was taken as a standard for the induction of local vascular permeability. Using a routine vascular permeability assay based on this principle similar studies were done with supernatants from cultures of PBC from nephrotic subjects with minimal change disease (MCD), or membranous nephropathy (MGN) and from healthy donors. The results show that cultures of PBC from non-nephrotic subjects with IgA nephropathy as well as from nephrotic MCD patients produced VPF in their supernatants whereas lymphocytes from nephrotic MGN subjects or normal donors did not. It is concluded that the production of VPF in stimulated PBC cultures from patients with IgA nephropathy or MCD might reflect altered T-cell function in these diseases, and that there is no direct relationship between VPF production and increased glomerular permeability.

Reduction of urinary protein and prostaglandin E2 excretion in the nephrotic syndrome by non-steroidal anti-inflammatory drugs.

Seven salt depleted patients with the idiopathic nephrotic syndrome were treated with various non-steroidal anti-inflammatory drugs. Indomethacin, diclofenac-sodium and flurbiprofen decreased proteinuria, glomerular filtration rate, plasma renin activity and renal prostaglandin E2 excretion by 59%, 19%, 55% and 68% respectively. Sulindac induced no major changes in proteinuria, glomerular filtration rate, plasma renin activity and renal prostaglandin E2 excretion. The relative change in proteinuria and glomerular filtration rate during non-steroidal anti-inflammatory drug treatment correlated strongly with that of the renal prostaglandin E2 excretion (r = 0.89 and r = 0.70, respectively p less than 0.05). It is likely that the anti-proteinuric effect of non-steroidal anti-inflammatory drugs is dependent on their potency to inhibit renal prostaglandin synthesis and it is suggested that this effect is mediated by lowering transcapillary glomerular hydraulic pressure.

Subentities within adult primary IgA-nephropathy.

Since its definition is purely descriptive, IgA-nephropathy (IGAN) may comprise more disease entities which share the (epi)phenomenon of mesangial IgA-depositions. IGAN patients with macroscopical hematuria (macro-H) differ from the other IGAN patients in 9 aspects: history, HLA-DR, Gm-allotypes, actuarial kidney survival, initial creatinine clearance, initial proteinuria, initial microhematuria, age at presentation and light microscopy of the renal biopsy. The difference in the last five parameters may either be explained by the existence of subentities or by earlier detection of patients with macro-H. The dissimilarity in the first four parameters can only be due to the former theory. Therefore, we conclude that IGAN probably comprises at least two disease entities.

Decreased filtration fraction during active proliferative lupus nephritis: relation to disease activity and reversibility of renal function.

Nine consecutive patients with systemic lupus erythematosus (SLE) were studied longitudinally for glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) during ten exacerbations of severe proliferative glomerulonephritis. At the onset of exacerbation, GFR decreased significantly whereas ERPF did not fall; the latter even increased in some patients. As a consequence mean filtration fraction (FF), the ratio of GFR and ERPF, fell from 0.20 to 0.10. At maximum exacerbation, both GFR and ERPF had decreased without change in FF. During remission FF rose to pre-exacerbation values as a result of increase in GFR without change in ERPF. We conclude that changes in FF reflect changes in renal haemodynamics in patients with SLE and active proliferative glomerulonephritis. Determination of FF may be of some value in assessing renal disease activity and the degree of reversibility of renal function in those patients.