Campylobacter jejuni arthritis in secondary amyloidosis

We describe a case of infectious arthritis caused by C. jejuni which developed after C. jejuni enteritis in a patient with rheumatoid arthritis and hypogammaglobulinaemia. Extraintestinal infections of this enteropathogen are rare, but in patients with hypogammaglobulinaemia C. jejuni bacteriaemia is relatively common. The present patient suffered from hypogammaglobulinaemia due to a nephrotic syndrome in secondary amyloidosis. C. jejuni infection must be considered in patients with hypogammaglobulinaemia and arthritis.

Reversible nephrotic syndrome due to high renin state in renovascular hypertension

Unilateral renal artery stenosis can lead to a non-functional kidney which secretes large amounts of renin. Four cases are presented in which the high renin state resulted in hypertension, proteinuria from the intact contralateral kidney, and secondary aldosteronism. The proteinuria was in the nephrotic range, which is unusual in renovascular hypertension, but gradually disappeared after correction of the high renin state by removal of the renin-secreting kidney or administration of an ACE inhibitor. Accordingly, when there is marked proteinuria in the presence of new-onset or rapidly progressive hypertension, hypokalaemic alkalosis, and a high peripheral PRA, renal artery stenosis should be considered since the proteinuria may be reversible after nephrectomy, repair of the ischaemic kidney or medical therapy.

A model of human microvascular exchange

A compartmental model consisting of the circulation, a general interstitium, and the lymphatics, is formulated to describe the transport and distribution of fluid and plasma proteins (albumin) in the human microvascular exchange system. Transcapillary mass exchange is assumed to occur via a coupled Starling mechanism. Unknown or poorly quantified model parameters are estimated by statistical fitting of simulation predictions to five different sets of experimental data. The data consist of steady-state and transient plasma and interstitial volumes and colloid osmotic pressures measured under laboratory or clinical conditions for normal humans and for patients with nephrotic syndrome or mild heart disease. In all cases, it is assumed that the system response to perturbations imposed either artificially or through illness is due to changes in the Starling driving forces. The three best-fit parameters were found to be normal capillary hydrostatic pressure, Pc,o = 11.0 mm Hg; albumin reflection coefficient, sigma = 0.99; and lymph flow sensitivity, LS = 43.1 ml/mm Hg.hr. Three other parameters, which were unknown but related to the estimated parameters through steady-state mass balance equations, were determined to be fluid filtration coefficient, KF = 121.1 ml/mm Hg.hr; albumin permeability-surface area product, PS = 73.0 ml/hr; and normal lymph flow, JL,o = 75.7 ml/hr. The fully described model was validated by comparisons between (1) simulation predictions and data used in parameter estimation, (2) estimated transport parameters and available literature values, and (3) model predictions and an additional set of experimental data.

Activation of the renin-angiotensin system in anti-glomerular basement membrane antibody-induced glomerulonephritis

Activity of the renin-angiotensin system in the nephrotic syndrome was investigated in rats with acute nephritis induced by anti-glomerular basement membrane (GBM) antibody. Injection of anti-GBM antibody resulted in a transient 2-fold elevation of both plasma renin and angiotensinogen with a peak at 12 h. Angiotensinogen mRNA levels in the liver also rapidly and transiently increased 4-fold at 3 h. The manifestation of acute nephritis, indicated by proteinuria, hypoalbuminemia, hypercholesterolemia and an increase in serum creatinine, following injection of anti-GBM antibody, was inhibited by a single administration of the selective angiotensin II type 1 receptor antagonist TCV-116 (1 mg/kg, p.o.) 2 h before an injection with the antibody, but not by successive administration of this drug for 1 week from 3 d after the injection of antibody. These results suggested that the enhanced generation of angiotensin II by elevated levels of both renin and its substrate in the early phase of anti-GBM nephritis promotes the evolution of acute nephritis via angiotensin II type 1 receptor.

The nephrotic syndrome

In children the nephrotic syndrome is an uncommon condition characterised by heavy proteinuria, hypoalbuminaemia and oedema. It is most commonly associated with minimal glomerular changes and is usually responsive to steroids.

Are cytotoxic agents beneficial in idiopathic membranous nephropathy? A meta-analysis of the controlled trials

The use of cytotoxic agents for the treatment of idiopathic membranous nephropathy is controversial. Although several controlled trials have been published, both the comparison groups and the study findings have varied, resulting in clinical uncertainty. To explore this uncertainty, a meta-analysis of controlled trials of treatment with cyclophosphamide or chlorambucil was performed in patients with idiopathic membranous nephropathy and nephrotic-range proteinuria. Patients in the control groups received only symptomatic treatment or corticosteroids. Descriptive and quantitative data from each trial were abstracted independently. Outcomes included effects of treatment on renal function and proteinuria, with a complete remission (CR) or partial remission (PR) defined as the complete or partial resolution of proteinuria without deterioration of renal function. For patients having either any response (CR or PR) or only a CR, both the relative risk (RR) and the number needed to be treated were calculated. The five trials that satisfied criteria for inclusion in the analysis were clinically and statistically homogeneous. There were no placebo-controlled trials that met the criteria for inclusion. Among the 228 patients in these studies, the RR of achieving any response with cytotoxic agents was 2.3 (95% confidence interval, 1.7 to 3.2) and the RR for a CR was 4.6 (95% confidence interval, 2.2 to 9.3), with respective numbers needed to be treated of 2.9 and 4.7, meaning that between three and five patients would need to be treated with cytotoxic agents to achieve one response. Exclusion of the only nonrandomized trial had no significant effect on the results. Both chlorambucil and cyclophosphamide showed similar beneficial effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful treatment of Finnish congenital nephrotic syndrome with captopril and indomethacin

Two infants with biopsy-proven microcystic Finnish congenital nephrotic syndrome (onset at birth) were treated with a combination of captopril and indomethacin for 2 1/2 and 2 years, respectively; they had a marked reduction of urinary protein excretion without further need for albumin infusions. One infant has end-stage renal disease; the other infant's glomerular filtration rate has remained within normal limits.

The influence of chronic ethanol administration on adriamycin-induced nephrotic syndrome in rats

Alcoholic liver disease may be frequently complicated by mesangial proliferation with the deposition of IgA in glomeruli and glomerulosclerosis, but these glomerular lesions are usually mild and without greater impact on renal function. To evaluate the putative role of ethanol in glomerular pathology we studied the influence of chronic ethanol administration on the development of experimental adriamycin nephropathy in rats. Nephrotic syndrome was induced by a single i.v. dose of adriamycin (5 mg/kg body wt) both in rats given ethanol at a dose of 4 g/day for 3 months and control rats given standard chow. Further controls on both diets without adriamycin administration were also studied. Blood and urine were examined before and 3 and 6 weeks after adriamycin administration. All rats were killed and examined histologically 6 weeks after adriamycin administration. Ethanol fed nephrotic rats were more catabolic than control nephrotic rats (with higher free fatty acids, lower glycaemia, higher urea with similar creatinine) and had lower proteinuria (0.55 +/- 0.34 versus 5.79 +/- 3.15 g of protein/nmol of creatinine, P < 0.05), higher albuminaemia (5.41 +/- 2.62 versus 1.92 +/- 1.94 g/l, P < 0.01), lower plasma cholesterol (6.54 +/- 2.6 versus 10.57 +/- 2.92 mmol/l, P < 0.01) and triglycerides. The development of nephrotic syndrome and renal morphological changes after adriamycin administration in rats seemed to be ameliorated, or at least delayed by chronic ethanol feeding with much milder and focal glomerulosclerosis as compared with more severe and diffuse glomerulosclerosis in control nephrotic animals. The mechanism of this effect of chronic ethanol feeding remains to be elucidated.(ABSTRACT TRUNCATED AT 250 WORDS)

Nephrosis in childhood

Succinct aspects of clinical features, pathophysiology and prognosis of nephrotic syndrome in childhood, and indications for performing renal biopsy are enumerated in this review. Orthodox treatment of the nephrotic syndrome with more recent therapeutic approaches, and the role of diuretics, albumin infusions and immunizations in patients with the nephrotic syndrome are reviewed. The etiology of peritonitis, acute renal failure, and renal transplantation are re-examined to update nephrologists on the associated complications of this common childhood disease.

Considerations on the sodium retention in nephrotic syndrome

Renin-angiotensin-aldosterone system, plasma atrial natriuretic peptide (PANP), and blood volume (BV) have been investigated in 20 nephrotic patients with normal renal function and with (group 1; n = 12) or without (group 2; n = 8) sodium retention. Patients of group 1 had a plasma albumin (PALB) concentration < 1.7 g/dl, low BV and PANP levels, a reduced fractional excretion of lithium (FELi), and high plasma angiotensin II levels. Patients of group 2 had PALB > 1.7 g/dl, and the other parameters were normal. The spontaneous intake of dietary sodium was lower in group 1 than in group 2. In all patients the BV was directly correlated with PALB, and the plasma renin activity (PRA) was inversely correlated with both BV and PALB. A nonlinear inverse relationship was present between plasma aldosterone (PALD) levels and fractional excretion of sodium (FENa). The acute expansion of the BV in patients of group 1 normalized PRA, PALD, PAII, FENa, and FELi and increased PANP. The administration of spironolactone to the patients of both groups had variable effects on FENa, did not modify PRA and PALD, and reduced body weight, PANP, and FELi, thus suggesting that the reduction of BV induced by the drug increased the proximal reabsorption of sodium. Three additional patients who had sodium retention, PALB of 2.3-2.4 g/dl, normal PRA and PALD, elevated urinary excretion of aldosterone, and a slightly low PANP showed a spontaneous normalization of urinary aldosterone and PANP associated with natriuresis and weight loss, but thereafter urinary aldosterone increased, PANP decreased, and the sodium retention began again. Our data suggest that in nephrotic patients with severe hypoalbuminemia, contraction of BV plays a major role in promoting the sodium retention through the activation of compensatory hormonal mechanisms. On the other hand, when PALB is not severely reduced, the patients have normal BV, but they are very sensitive to small changes of BV which are better evidenced by modifications of the urinary excretion of aldosterone and PANP rather than by the profiles of PRA and PALD.

Reduced natriuretic effect of atrial natriuretic peptide in nephrotic syndrome: a possible role of decreased cyclic guanosine monophosphate

To evaluate therapeutic and side effects, atrial natriuretic peptide (ANP) was administered as a pharmacological bolus dose (2 micrograms/kg body weight) to 7 patients with nephrotic syndrome and to 13 age- and gender-matched control subjects. The basal glomerular filtration rate was similar, but the blood pressure was slightly higher in the patients than in the controls. Injection of ANP induced a significant increase of sodium excretion in controls (from 0.21 to 0.52 mmol/min, medians, p < 0.01), but not in nephrotics (from 0.21 to 0.32 mmol/min). Urinary output and free water clearance after ANP had been given were also lower in the patients. The natriuretic effect was mediated through inhibition of distal tubular fractional sodium reabsorption, as estimated by the lithium clearance technique, and through an increase of glomerular filtration rate, both effects only significant in the healthy subjects. The blood pressure was reduced to the same extent in the two groups. Although similar levels of ANP were reached in the groups after injection, cyclic guanosine monophosphate (GMP)/ANP was less in the patients, both basally and after ANP injection, and the urinary excretion of cyclic GMP did not increase in the nephrotics (from 478 to 1,220 pmol/min, ns) as in the controls (from 389 to 2,500 pmol/min, p < 0.01). The urinary albumin excretion rate increased significantly in patients, whereas the prostaglandin E2 excretion increased after ANP administration only in controls. Endothelin, angiotensin II, aldosterone, and arginine vasopressin were unchanged in the two groups. Basal aldosterone was lower and ANP higher in patients than in controls. In conclusion, the natriuretic effect of ANP was reduced in nephrotic patients. This could not be attributed to counterregulatory haemodynamic or hormonal factors, but probably to reduced second messenger cyclic GMP.

[Fibrinolytic and lipid disturbances in patients with nephrotic syndrome]

Some fibrinolytic parameters (euglobulin clot lysis time, activities and antigens of tissue plasminogen activator and inhibitor), serum lipids and their mutual relations were studied in 31 patients with nephrotic syndrome. Euglobulin clot lysis time was found to be significantly prolonged in patients with nephrotic syndrome when compared to control group. Activity and antigen of tissue plasminogen activator were significantly higher in healthy volunteers, whereas nephrotic patients activity of tissue plasminogen activator inhibitor was significantly higher than in controls. Cholesterol, LDL and VLDL were elevated in patients with nephrotic syndrome when compared to controls. LDL was found to be positively related to both tissue plasminogen activity and antigen in nephrotic patients. Serum cholesterol correlated positively with albuminemia in these patients.

[Disorders of oxidation-reduction processes in nephrotic syndrome]

Reduction capacity of the blood and its fractions was studied by potentiometry in 68 patients with the nephrotic syndrome. The type of renal injury was identified by kidney biopsy in all the patients. Control group consisted of 30 donors. Changes of blood reduction capacity were detected in all the patients with the nephrotic syndrome in comparison with the controls. A correlation could be traced between blood reduction capacity and functional compensation of the nephrotic syndrome. Disordered redox equilibrium was not associated in patients with the nephrotic syndrome with increased levels of lipid peroxidation products. The method used to assess reduction capacity is highly informative, rapid, and simple.

Hemodynamics and baroreflex function in rats with nephrotic syndrome

The excess renal sodium retention leading to edema formation in the nephrotic syndrome (NS) is substantially dependent on increased efferent renal sympathetic nerve activity (RSNA). This study examined whether the hypoalbuminemia in NS is reflected as a decrease in cardiac output or cardiac function and whether the increased RSNA in NS is due to alterations in arterial and/or cardiopulmonary baroreflex function. NS was induced in rats with adriamycin (3.5 mg/kg i.v.), and they were studied 4 wk after injection. Mean arterial pressure (MAP) was similar in control (C) and NS rats. Cardiac indexes (CIs; cardiac output/body wt) were 29 +/- 1 and 26 +/- 1 ml.min-1.100 g-1 in C and NS rats, respectively. Total peripheral resistance indexes were significantly greater in NS than in C rats (4.7 +/- 0.2 vs. 4.1 +/- 0.1 mmHg.100 g.min.ml-1). Cardiac function during increases in cardiac filling pressure was not different between C and NS rats. The afferent limb of the arterial baroreflex was assessed by measuring aortic depressor nerve activity (ADNA) while the efferent limb was assessed by measuring RSNA in C and NS rats during increases in MAP. The central component of the arterial baroreflex was assessed from plots of RSNA (output) vs. ADNA (input). Comparisons between C and NS rats before and after vagotomy revealed no differences in the gains of any component of the arterial baroreflex. The cardiopulmonary baroreflex was assessed in a similar manner by measuring afferent vagus nerve activity (VGNA) and efferent RSNA during volume expansion before and after sinoaortic denervation (SAD). Before SAD, gains were similar in C and NS rats. After SAD, gains of the total (-1.59 +/- 0.44 vs. -3.64 +/- 0.65%/mmHg) and the central/efferent limb (-0.26 +/- 0.07 vs. -0.67 +/- 0.14 %/%) were significantly reduced (P < 0.05) in NS compared with C rats while the gain of the afferent limb of the reflex was similar in C and NS rats. These results indicate that NS rats with significant hypoalbuminemia maintain an arterial pressure similar to C rats by increasing total peripheral resistance, which serves to offset the tendency to a lower CI. Arterial baroreflex function in NS does not differ from that in C, but decreased cardiopulmonary baroreflex inhibition of RSNA in NS may contribute to the increased RSNA.

Thyroid function in children with nephrotic syndrome

The thyroid function of seven children with untreated nephrotic syndrome who had a normal serum creatinine concentration was compared with that of the same patients in remission and age-matched controls. There was a significant decrease in serum thyroxine (T4), tri-iodothyronine (T3) and thyroid-binding globulin (TBG) concentrations in untreated nephrotic children compared with the same patients in remission and age-matched controls. Most values for serum free T4, free T3 and thyroid-stimulating hormone (TSH) in the patients with nephrosis were within the normal range. However, the mean serum free T4 and free T3 concentrations were significantly (P < 0.05) lower in the untreated patients than in the same patients in remission, and the mean serum TSH concentrations were significantly (P < 0.05) higher in the untreated patients than in the same patients in remission. There were massive urinary losses of T4, T3, TBG, free T4 and free T3 in the untreated nephrotic children compared with the same patients in remission and age-matched controls. The daily urinary protein excretion showed a positive correlation with the urinary T4, T3, free T4, free T3 and TBG excretion. Furthermore, the urinary protein excretion showed a negative correlation with the serum T4, T3, free T4, free T3 and TBG levels. There was a negative correlation between serum albumin and serum TSH. These findings provide evidence of mild hypothyroidism in children with untreated nephrotic syndrome, partly because of losses of T4, T3, free T4, free T3 and TBG into the urine.

The combination of lovastatin and enalapril in a model of progressive renal disease

Puromycin-induced nephrotic syndrome is an animal model of progressive renal disease. Both angiotensin converting enzyme inhibitors and lipid-lowering agents have been used to preserve renal structure and function in this model, although neither completely prevents progression. We tested the hypothesis that the combination of the two agents would be more protective than either alone. Rats were divided into five groups; all were uninephrectomized. Four groups were given puromycin at a dose of 10 mg/100 g body weight (BW) with additional doses of 4 mg/100 g BW given intraperitoneally at 4, 5, and 6 weeks thereafter. One group was given enalapril (EN) 50 mg/l dissolved in the drinking water; the second received lovastatin (L) 15 mg/kg given daily by gavage; the third received both agents; the fourth was left untreated, and the final group received no puromycin and served as the control group. Eight weeks after the initial dose of puromycin, glomerular filtration rate (GFR), as inulin clearance, and protein excretion were determined and blood was collected for cholesterol and triglycerides. Blood pressure was not different between any of the groups. At the end of the study period, serum cholesterol [mean +/- SD, 252 +/- 185 mg/dl (L), 135 +/- 101 mg/dl (L + EN)] and triglycerides (239 +/- 200, 148 +/- 158 mg/dl) were significantly lower (P < 0.001) in the lovastatin-treated groups than in the untreated puromycin group (535 +/- 255 mg/dl and 579 +/- 561 mg/dl, cholesterol and triglyceride, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

The histopathology of kidney uriniferous tubules as revealed by noninvasive confocal vital microscopy

Tandem scanning confocal microscopy (TSCM) permits the noninvasive microscopic viewing of unstained, living, solid organs in real time. This article provides an overview of recent studies conducted by the author and other scientists, using TSCM and demonstrating its advantages in evaluating the histopathology of uriniferous tubules associated with normothermic renal ischemia, the nephrotic syndrome, and extracorporeal cold-storage preservation of kidneys.

The effect of betamethasone on intraocular pressure in nephrotic children

Intraocular pressure (IOP) was measured by Goldmann's or Schiotz's method in 46 nephrotic children, who were treated with betamethasone, and in 40 age-matched normal controls at the Taipei Municipal Chung-Hsin Hospital, from July 1, 1987 to June 30, 1990. We found the difference in mean IOP between patients treated at the end of a full-dose course of betamethasone and normal controls or patients before treatment, was statistically significant. This difference was also found between the measurement of IOP at the end of a full-dose course of betamethasone, and after stopping betamethasone therapy two to four weeks later. Although six of all patients had high IOP and suffered from headache or ocular pain, clinically, at the end of full-dose betamethasone therapy, the symptoms disappeared quickly after tapering or stopping of the drug. Therefore, we believe it is very safe to treat the nephrotic syndrome with betamethasone. On the other hand, these observations indicate that corticosteroid is a causative factor in increasing IOP. Susceptibility to full-dose betamethasone is firmly recognized, and patients need to be monitored on an individual basis. Nephrotic syndrome is a chronic disease which often requires long-term corticosteroid treatment. Children with the syndrome are at risk of developing steroid-induced increasing IOP. Careful ophthalmological examination of nephrotic children, as well as other pediatric patients who received corticosteroid therapy, is highly recommended.

[The interaction of atrial natriuretic peptide with other bioregulators of kidney function in chronic glomerulonephritis in children]

A study was made of renin-angiotensin-aldosterone system activity and plasmic concentrations of atrial natriuretic peptide (NUP) as well as antidiuretic hormone in children with primary glomerulonephritis. A close relationship was established of these parameters in regulation of water-salt homeostasis. The above systems are involved in pathogenesis of childhood glomerulonephritis. This finding should be considered in development of pathogenetically validated therapy of glomerulonephritis, including introduction of synthetic NUP.

Determinants of glomerular hypofiltration in nephrotic patients with minimal change nephropathy

Physiologic and morphologic techniques were used to elucidate the determinants of the GFR in 25 nephrotic patients with minimal change nephropathy. They were divided into two groups according to the finding of either a normal (Group 1, N = 13) or a depressed (Group 2, N = 12) inulin clearance. RPF, afferent oncotic pressure, and dextran sieving coefficients were determined. Mathematical models of glomerular ultrafiltration were then used to compute likely upper bounds for the ultrafiltration coefficient and pore area/length ratio (a measure of pore density). The upper bounds for each measure of intrinsic ultrafiltration capacity were depressed below estimated normal values in healthy controls by 55 and 47% in Group 1 patients and by 86 and 83% in Group 2 patients with minimal change nephropathy. A corresponding excess of ultrafiltration pressure (versus control), attributable solely to reduced intracapillary oncotic pressure, was by 10.8 and 11.5 mm Hg, respectively. Glomerular morphometry revealed peripheral capillary filtration surface area to be preserved in both minimal change nephropathy groups. However, a significant reduction in filtration slit frequency due to epithelial podocyte broadening correlated with the computed ultrafiltration coefficient across the two minimal change nephropathy groups (r = 0.65; P < 0.001). It was concluded that podocyte deformation invariably lowers the ultrafiltration coefficient and pore area/length ratio in minimal change nephropathy but that an offsetting reduction in intracapillary oncotic pressure prevents the GFR from declining in many cases. However, the models presented here predict that the depression of capillary oncotic pressure is insufficient to compensate when the ultrafiltration coefficient is lowered by substantially more than half and that it is in this circumstance that minimal change nephropathy is most likely to be accompanied by glomerular hypofiltration.