[The captopril test--an aid in the detection of scarring nephropathy as a cause of arterial hypertension in children]

Renal scarring with and without vesicoureteral reflux (VUR) has been now recognized as an important cause of paediatric hypertension for many years [1-5]. However, its pathogenesis has still remained uncleared. The widespread concept implicated the activation of renin-angiotensin system finding a powerfull support in higher peripheral plasma renin activity (PRA) in children with reflux nephropathy than in controls [6, 7] and in beneficial antihypertensive effects of ACE inhibitors. The latter, in form of captopril, has also been used in captopril test and in renal scintigraphy and isotope renography following the administration of captopril to provide evidence for renin dependent hypertension [8, 9]. Published studies of captopril test have centred on the identification of renovascular as opposed to essential hypertension [10-18, 20-22]. The aim of our study was to assess the usefulness of captopril test in differentiation between hypertensive children with renal scarring from those with essential hypertension. We studied blood pressure (BP) and PRA responses to a single dose of captopril in two groups of hypertensive children. Group A consisted of 29 patients, 14 boys and 15 girls, who had renal scaring as demonstrated by renal 99mTc dimercaptosuccinid acid scan (99m Tc DMSA) and/or intravenous pyelography. Group B included 19 patients, 19 boys and 10 girls who had arterial hypertension, while clinical examination excluded renal and other definable causes of BP elevation, and they were therefore considered to have essential hypertension. At the time of the study all patients had normal glomerular filtration rate and were not salt depleted. They did not receive any antihypertensive medication for at least two weeks. The test was performed in the morning in fasting sitting patients. At the start of the test a small vein in the hand or forearm was cannulated to permit blood sampling. BP was measured 10, 20, and 30 minutes before captopril administration to get baseline BP (mean of these three measurements) and to allow the children to become accustomed to the test procedure. A single oral dose of captopril 0.64 +/- 0.04 mg/kg body weight was given to patients from group A and almost the same dose of captopril, 0.63 +/- 0.05 mg/kg body weight, to patients from group B. The patients remained sitting and BP was measured every 15 minutes during an hour. Blood for PRA was drown in the sitting position (17 patients from group A and 16 patients from group B) before and one hour after the dose of captopril. Samples of blood for basal PRA were collected from 16 patients from group A and in 14 patients from in B in lying position after waking up in the morning. PRA was measured by radioimmunoassay using a commercially available kit, SB-REN 2, from CIS Bio International. According to the criteria of Muller et al. [10] the captopril test was positive if the post-captopril PRA (ng/ml/h) was greater than or equal to 12 with an increase of greater than or equal to 10 and relative increase of greater than or equal to 15% (400% if initial PRA was < 3). The results of our study are presented in Tables 1 and 2 and in Graphs 1 and 2. The age of patients, doses of captopril, initial BP and PRA before the use of captopril did not much differ between studied groups. Fall of BP and PRA increase were highly significant (p < 0.001) both in group A and group B. However, the hypotensive reaction of diastolic BP and MAP were more pronounced in group A (14.45 +/- 1.67% and 15.81 +/- 1.62%) than in group B (6.95 +/- 2.21% and 8.96 +/- 1.75%; p < 0.01), but there were no significant differences in PRA and systolic BP changes and positive results of captopril test between the studied groups. Hypotensive responses of diastolic BP and MAP greater than 10% of initial values were found to be more frequent in group A (79.32% and 79.31%) than in group B (26.61% and 31.57 degrees %; p < 0.001 and p < 0.01). Diastolic BP and MAP were directly related to the dose of cap

[Renal tubular function in children with hypercalciuria]

INTRODUCTION

Renal stone disease is commonly due to hypercalciuria [1, 2], which may be assessed either from a 24-hour urinary collection or from the fasting first morning urine. Hypercalciuria during childhood has been defined by a 24-hour calcium excretion greater than 3.5 mg/kg per day and/or calcium to creatinine ratio greater than 0.20 [3]. The alteration in the calcium transporting systems plays a pathogenetic role in promoting hypercalciuria [4, 5]. Since calcium reabsorption along the nephron is intimately related to that of other electrolytes and substances, it can be hypothesized that patients with hypercalciuria may have other renal tubular defects. The aim of the study was to investigate proximal tubular function (tubular reabsorption of sodium, potassium, phosphate and glucose) and distal tubular function (urinary concentrating capacity and acidifying capacity) in children with hypercalciuria.

PATIENTS AND METHODS

Two groups of children were studied: hypercalciuric group included 23 children with hypercalciuria (10 males, aged 11.9 +/- 4.1 years), of whom 6 with nephrolithiasis, and control group included 42 healthy children (20 males, aged 11.2 +/- 3.8 years). All subjects had normal serum values for calcium, sodium, potassium, phosphate and glucose, as well as normal renal function. The urinary excretion of calcium, sodium, potassium, phosphate, glucose and creatinine was measured in a 24-hour urine specimen by standard laboratory methods. Urine osmolality and urinary specific gravity were measured following 12-hour water-deprivation test. A short ammonium chloride loading test was performed in 3 patients with urinary pH above 5.5. The fractional excretion of sodium, tubular phosphate reabsorption and renal threshold phosphate concentration were calculated according to standard formula. Statistical analysis was performed using the t-test and analysis of variance (ANOVA). Kruskal-Wallis method was used to compare urinary phosphate excretion between two groups.

RESULTS

Table 1 summarizes urinary excretion of electrolytes in children with hypercalciuria compared with healthy controls. We found that urinary sodium excretion was significantly increased in patients with hypercalciuria when compared with controls (p < 0.05). Urinary phosphate excretion was significantly higher in patients with hypercalciuria in comparison to controls, and this was accompanied by a significant lowering of the tubular phosphate reabsorptive threshold (p < 0.05). Urinary potassium excretion tended to be lower, although not significantly, in the hypercalciuric children than in normal subjects. Table 2 shows the mean values +/- standard deviation of urinary specific gravity, urinary osmolality and urinary pH. Urinary specific gravity mean value was significantly lower in patients with hypercalciuria in comparison to controls (p < 0.05). Urinary pH was found below 5.5 in all patients. Glycosuria was detected in 3 patients (13.3%). As shown in Graph. 1, a significant correlation between the urinary excretion of calcium and sodium was demonstrated in both groups of children (r = 0.29; p < 0.01).

DISCUSSION

The present study shows that children with hypercalciuria have significantly higher urinary sodium and urinary phosphate excretion in comparison to controls, while urinary potassium excretion is normal in both groups of children. According to some recent reports [6-9], these findings may indicated defects of the renal tubular transport of sodium and phosphate which may be interpreted as a cause or a consequence of the alteration of the calcium transporting system. Defects in both proximal and distal renal tubular functions have been demonstrated in patients with nephrolithiasis, particularly those with hypercalciuria. Proximal renal tubular defects include defects in sodium, fluid, phosphate and glucose reabsorption, which were evident also in our patients. (ABSTRACT TRUNCATED)

[Continuous ambulatory measurement of blood pressure in children--personal experience]

Ambulatory blood pressure monitoring (ABPM) during normal daily activities and during night, when the patient is asleep, is a new method of measuring blood pressure (BP) in children, used for better diagnosis and treatment of hypertension. Compared to casual BP measurements, it documents normal daily BP variations, BP during sleep, the influence of emotional and physical stress on BP and is a better predictor of hypertension associated with end-organ damage. However, the experience in ABPM in children is still limited. In our country ABPM has been used since recently, and first results are referred to children with end-stage renal failure.

SUBJECTS AND METHODS

ABPM was performed in two groups of children: group A consisted of 61 children, aged 14.3 +/- 2.9 (mean +/- SD) yrs in whom intermittent outpatient BP measurements (for at least 3 months) suggested the diagnosis of hypertension (according to the data of Second Task Force); group B consisted of 52 patients (pts), aged 12.8 +/- 4.6 yr with renal disease. Four pts from group A (6.6%) and 20 pts from group B (38.5%) received antihypertensive therapy (captopril, nifedipine, furosemide and propranolol ). All children from group A and half of the children from group B had normal renal function. Eighteen pts from group B were on chronic haemodialysis (34.6%). Blood pressure was recorded during a 24-hour period except in haemodialyzed pts (48 h) (Table 1). Results of BP measurements are presented as the mean values of BP during a 24-hour period, during normal daily activities and during sleep. We used the age- and gender-appropriate 95th percentile from the Task Force Study as the daytime upper-limit of normal and 10% lower for the upper-limit at night. According to BP load (the percentage of BPs exceeding the upper limits of normal for age), children were assumed to have mild-to-moderate hypertension (BP load between 20% and 40%) or severe hypertension (BP load more than 40%). The success of antihypertensive therapy was evaluated after 1-3 months in 11 pts (twice in 10 pts and three times in one pt).

RESULTS

In group A 39.4% of pts were normotensive and 36.1% were without antihypertensive therapy, 58.4% of normotensive and 40.5% of hypertensive pts had blunted circadian BP rhythm (nocturnal BP reduction of less than 10% of diurnal values) (Graph. 1). In group B 38.5% of pts were normotensive and 27% were without antihypertensive therapy. In the group of normotensive pts alteration of circadian BP rhythm was found in 40% of pts with normal renal function, 80% of pts with chronic renal failure and in 100% of pts with terminal renal failure, while in the hypertensive group, altered circadian BP rhythm had 68%, 100% and 92% of pts, respectively (Graph 2). Mild-to-moderate hypertension had 54% of hypertensive pts from group A and 37.5% of hypertensive pts from group B. Severe hypertension was more frequent in group B (62.5%) comparing to group A (46%). The effectiveness of antihypertensive therapy was assessed in 11 pts. In 69.2% of pts BP became normal or was significantly decreased, in 23.1% of pts BP was not changed and 7.7% of pts had higher values of BP.

DISCUSSION

ABPM is very useful for diagnosing white coat hypertension. Like other authors, we have pointed out that more than one third of pts who were hypertensive according to usual BP measurements had normal 24-hour BP and we classified them as white coat hypertensives. More than a half of the pts had blunted circadian BP rhythm, and as it is not certain whether they will become hypertensive in adulthood they should be periodically controlled. There are several proofs that results of ABPM have a better correlation with hypertensive end-organ damage; therefore ABPM is used for assessing the severity of hypertension. In our former work, we showed excellent correlation of BP with left ventricular mass index in children with end-stage renal failure. (ABSTRACT TRUNCATED)

[Serum osteocalcin in children with chronic renal insufficiency]

The research of the bone metabolism has undergone a long evolution which began with the use of radioisotopes in calcium kinetic studies and went through the determination of several humoral parameters like alkaline phosphatase (ALP), hydroxyproline and intact immunoreactive parathyroid hormone (iPTH) and finally to the assay of a new serum and urinary parameters of bone metabolism, like osteocalcine (OC) and procollagen and collagen metabolites. The X-ray study of the skeleton, densitometric techniques, computerized tomography, scintigraphy and NMR are used for visualization of bone changes, but bone biopsy and histomorphometry provide the most precise evaluation [1]. Disorders of bone and mineral metabolism in children with chronic renal failure (CRF) are an almost regular occurrence; so early discovery and treatment of these changes are very important [2]. The aim of this study was to measure the serum OC level in children with CRF and terminal renal failure (TRF), treated with chronic haemodialysis, and to evaluate the significance of OC compared to other humoral parameters of renal osteodistrophy, such as ALP and iPTH.

MATERIALS AND METHODS

We studied the fasting levels of OC in three different groups of children: group A consisted of 18 patients with TRF; group B consisted of 12 patients at different stages of CRF, and group C consisted of 32 healthy children, all of the approximately same age. Clinical characteristics of the examinded children are presented in Table 1. Of 30 patients, 26 were treated with calcium carbonate and 21 with vitamin D analogues. None were treated with aluminium hydroxide. Additional parameters included serum calcium, phosphate, ALP and body height, while serum concentrations of iPTH and ionized serum calcium were measured only in group A. Serum OC was measured by radioimmunoassay using OSTK PR RIA (CIS), while ELISA-PTH (CIS) radioimmunoassay was used to determine iPTH plasma levels. Statistical analyses were performed using Kolmogorov-Smirnov test to confirm normal distribution, the Pearson and Spearman rank sum test for correlation between variables of interest, while analysis of variance was used to compare the findings.

RESULTS

Serum OC levels were significantly different in all groups (p < 0.01); they were three times higher in group A than in group C. Similar increase was noticed in plasma iPTH, assuming that "normal" uremic iPTH was raised up to threefold above normal range (between 10 and 60 pg/ml) [2]. However, the total serum ALP activity was not sensitive as OC and iPTH, since ALP increases were less as compared to them. OC was age related only in group A (p < 0.01), with a positive correlation between OC and duration of haemodialysis (p < 0.05), as well as between OC and serum phosphate (p < 0.05), but there was no correlation between OC and growth retardation (expressed by SDS), bone age and current therapy for renal osteodistrophy. A direct correlation between OC and ALP was found only in healthy children (p < 0.01), while in groups A and B it was remarkable, although not statistically significant (p = 0.08) (Graphs 1, 2, 3). In group A, ALP and iPTH were directly correlated (p < 0.001), but the correlation of OC with iPTH was less significant (p = 0.06). In patients with CRF no correlation was found between glomerular filtration rate and OC.

DISCUSSION

OC is a bone-derived noncollagenous protein of low molecular weight (about 5800 D), containing residues of the vitamin K dependent amino acid gamma-carboxyglutamic acid and is synthesized by osteoblasts and odontoblasts. Calcitriol is a potent stimulator of OC synthesis, acting at the transcriptional level and increasing mRNA severalfold. OC is found mainly in bone, but nanomolar concentrations circulate in the blood. Its serum levels are an expression of the bone formation process and are age related (higher in the neonatal and adolescent period). ABSTRACT TRUNCATED.

Endothelin-1 in acute renal failure

To study the pathological significance of circulating endothelin (ET) in ARF, we measured plasma ET in seven children (mean age 8.8 +/- 4.4 years) with ARF in the most severe phase and 3.7 +/- 3.5 months later in the recovery period. Twenty-seven healthy children were included in the study as controls. Plasma ET level was measured by highly sensitive and specific radioimmunoassay for ET-1 and ET-2 (ET-1/2, Biomedica, Vienna). Plasma ET was significantly higher in the most severe phase of ARF (4.75 +/- 4.08 fM/ml) than in the recovery period (0.78 +/- 0.24 fM/ml; p < 0.01), but comparing to plasma ET in the healthy children, the difference was only of borderline statistical significance (Pf, 0.0573). Since plasma concentrations of creatinine did not correlate with plasma ET in patients, either in acute or in the recovery phase of disease, we concluded that decreased GFR is not the main factor determining an increased ET in ARF. We suggest that elevated plasma ET in ARF may be secondary to vascular endothelial dysfunction and speculate that enhancement synthesis of endothelial relaxing factor (EDRF) inhibits ET synthesis during the recovery period. We did not find any relationship between plasma ET and blood pressure (BP) in patients with ARF, so we conclude that circulating ET is not the main factor determining BP in ARF.

[Kidney transplantation in children]

During the last 14 years, since the opening of the Center for Childrens' Hemodialysis the University Children's Hospital of Belgrade, 174 children with terminal renal failure were treated by chronic hemodialysis. Of these, only 35 patients (20.1%), 14 girls and 21 boys, mean age 12.6 +/- 4.9 years, were transplanted. The average waiting time for transplantation was 24.6 months (range 0-120 months). Twenty-five patients were transplanted with paternal kidney, the others were cadaveric transplantations. More than half of transplantations were done abroad. Of 35 patients, 20 were under follow-up for over 6 months (45.7 +/- 7.2 range 6 to 102 months). Five year patient survival was 94.1% and the graft survival over the same period was 76.4%. 45.7 +/- 7.2 months after transplantation the outcome was the following: 11 patients (55%) had GFR over 60 ml/min/1.73 m2, 5 patients (25%) had GFR from 25 to 60 ml/min/1.73 m2, 2 patients (10%) returned to chronic hemodialysis, 1 patient was retransplanted and 1 patient died. All patients with GFR of over 60 ml/min/1.73 m2 are well psychosocially rehabilitated, 62.4% are normotensive without antihypertensive therapy, and only 9.9% are growth retarded.

[Cystic tumefaction in the minor pelvis--the agenesis-dysplasia syndrome (case report)]

Ectopic kidney often shows signs of parenchyma maldifferentiation. Multicystic or dysplastic kidney is usually associated with congenital urogenital and skeletal system anomalies. In the Unilateral form of the agenesia-dysplasis syndrome, the kidney, if it is present, is small dysplastic and usually cystically changed. Ipsilateral uterus horn or vaginal agenesia are the most frequently associated anomalies. Case report. A six years old girl was clinically examined due to recurrent urinary tract infections. On ultrasound, the left kidney was enlarged, while the right kidney was absent in normal position. Cystic mass 4x5 cm was seen in the pelvis. The right kidney was not seen on IVP. CT scan showed a cystic formation in the pelvis, described as cystically changed dysplastic kidney. Pelviceal mass was extirpated. Exploration of the genital system revealed vaginal arch blinded in the hypoplastic right uterus horn. On pathohystology tumefaction corresponded to the dysplastic kidney.

IN CONCLUSION

unilateral renal aplasia or dysplasia may indicate genital anomalies having in mind the hereditary character of unilateral form of the agenesia-dysplasia syndrome therefore, it could be helpful in prenatal diagnosis of cystic pelvic mass of fetus in families with this syndrome.

[Jeune's syndrome (3 case reports)]

Jeune's syndrome or asphyxiating thoracic dystrophy is an autosomal recessive osteochondrodysplasia with multisystem involvement. In patients who survive neonatal period in the main clinical feature progressive renal failure is. Renal lesions are variable but is familial juvenile nephronophtisis the most frequent one. We present three patients with Jeune's syndrome phenotype and chronic tubulointerstitial disease. All patients developed terminal renal failure in the eyrly childhood. Renal histology, examined in two cases, was consistent with juvenile nephronophtisis in one case and with renal dysplasia in other case. All our patients had hepatic fibrosis and two of them had pigmentary retinophaty. We want to underline the importance of regular check-up of children with typical phenotype by pediatrician-nephrologist as wel as possibility of prenatal diagnosis of Jeune's syndrome.

[Vesicoureteral reflux as a familial disease]

Vesicoureteral reflux and reflux nephropathy are causes of end-stage renal failure in 43 percent of our patients on haemodialysis. Aiming at early discovering of vesicoureteral reflux and preventing reflux nephropathy, we started an investigation of the familial character or the primary vesicoureteral reflux in the families of 44 our patients with the diagnosed anomaly. Investigations which consist of urinalysis, urine culture and ultrasound of kidneys have so far been carried out for siblings of our patients in ten families. Complete investigations, including voiding cystourethrogram where indicated, have been carried out in five families. Familial vesicoureteral reflux ascertained in three families.

[Cystic kidney disease--genetics, pathogenesis and clinical aspects in children]

This paper reviews recent studies producing insight into genetics and cellular abnormalities causing kidney cysts, their growth and development. Clinical features of various cystic kidney diseases in our patients are described. Special attention has been paid to those rarely reported in our literature. Important discovery concerns location of the gene for autosomal dominant polycystic kidney disease (ADPKD) 1 and 2 on the short arms of chromosome 16 and 4 respectively, as well as for autosomal recessive polycystic kidney disease (ARPKD) on chromosome 6 and for juvenile nephronophtisis on the short arm of chromosome 2. Two basic abnormalities necessary for cyst formation are increased: epithelial cell proliferation and altered fluid transport. Mitogenic action of epidermal growth factor (EGF) is significantly increased and EGF receptors have been demonstrated on apical as well as on basal surface of cyst lining epithelium. TGF-beta shows marked loos of inhibitory activity with regard to EGF. Cystic epithelium has altered polarity; Na-K-ATP-ase is located exclusively on the apical cell membrane. Tubular basement membrane shows alteration in structural components. Complex medullar cystic disease--nephronophtisis, complex as well as the hepatorenal complex of nephoronophtisis--congenital hepatic fibrosis are emphasized in this paper. The later has proved to be rather frequent in our population. We described a distinctive variant of hepato-renal disorder in 4 patients and reviewed 5 similar patients in the literature. The main characteristics are progressive tubulointerstitial nephritis and cholestatic liver disease. We strongly suggest that this variant represents a new syndrome (Popović-Rolović M, Kostić M, Sindić M. et al Progressive tubulointerstitialnephritis and chronic cholestatic liver disease.

[Urinary bladder dysfunction and vesicoureteral reflux in patients with enuresis]

We present preliminary results of prospective study on 38 children (aged 4-15 y.) with enuresis. The aim of the study was to document the association between bladder disfunction and urinary tract abnormalities. Enuresis was more common in girls (71%). Twenty one children (44.7%) suffered from secondary, and 17 (55.3%) from primary enuresis. High incidence of enuresis (31.6%) or voiding dysfunction, renal lithiasis, constipation of other kidney disease (42%) were disclosed among family members of children with enuresis. Urodynamic studies revealed bladder dysfunction in 84.0% of children with enuresis mostly in the form of dyssingeric (45.5%) or unstable/hyperactive bladder (45.5%). In 9% of patients bladder dysfunction as in the form of inadequate bladder with small and poor detrusor contractions often associated with large residue. Ultrasonography revealed dilatation of pyelocaliceal system in 13.2%, and vesicoureteral reflux was confirmed in 10.5% of patients. We stress out high incidence of bladder dysfunction among children with enuresis as well as among their family members.

[The effect of hemodialysis on endothelin-1 plasma levels in children with terminal renal insufficiency]

We analysed the effect of hemodialysis (HD) on endothelin (ET) plasma level in children with terminal renal failure. Twenty-five patients (pts) and 27 healthy children as controls were included in the study. There was no difference in ET plasma levels in pts before HD (1.97 +/- 1.45) and controls (2.08 +/- 1.47), but ET increased in plasma of pts after HD (4.10 +/- 3.66). To estimate the relationship of volume depletion or depuration on ET plasma level changes in pts during HD, ET was measured at three time points of HD (before ultrafiltration-UF, after UF, and after HD without fluid removal) in 10 pts. ET level was not significantly changed after UF (1.93 +/- 2.25 vs 1.71 +/- 1.50; ns), but was significantly increased after depuration (4.46 +/- 3.56; p < 0.05). There was no correlation between ET and blood pressure in controls and pts in either period of testing, neither with plasma renin activity, left ventricular mass index, and body weight changes during HD.

[Continuous blood pressure monitoring over a 24-hour period in children with terminal renal failure treated with hemodialysis]

Recent evidence suggests that circadian blood pressure changes are common in patients with impaired renal function and has excellent correlation with end-organ damage. The aim of this paper was to: 1) evaluate if children with end-stage renal failure have altered circadian blood pressure rhythm; 2) assess whether pre- or postdialytic blood pressure is representative for the average interdialytic blood pressure; 3) assess whether pre- or postdialytic blood pressure is representative for the average interdialytic blood pressure; 3) determine influence of pre-, post and interdialytic blood pressure. Ambulatory blood pressure monitoring was performed in two groups of patients: group A-13 children with end-stage renal failure, aged 15.15 +/- 5.58 years, on chronic haemodialysis from 2 to 156 (mean 45.3) months, 4 of whom were hypertensive and 9 normotensive; group B-19 children with chronic hypertension (essential or renal hypertension) aged 15.28 +/- 2.27 years. 84.62% of children from group A and 31.58% from group B (p = 0.0037) had blunted circadian blood pressure rhythm (a nocturnal reduction of blood pressure is less than 10% of daytime values). Pre- and postdialytic systolic, diastolic and mean arterial blood pressure did not differ significantly and were in correlation with interdialytic blood pressure (r = 0.9; p < 0.01). Pre-, post- and interdialytic blood pressures correlated well with left ventricular mass index (r = 0.6; p < 0.05), but were not in correlation with the degree of hypervolemia (p < 0.05).

[Treatment of duodenal ulcer with famotidine and proglumide]

In an open study the clinical efficacy of famotidine 40 mg on a duodenal ulcer was compared to that of proglumide 1600 mg. The study included 106 patients with acute duodenal ulcer, divided into two groups: A-famotidine and B-proglumide. There were no significant differences between the groups in baseline characteristics. Due to different reasons nine patients were excluded from analysis. Duodenal ulcer diagnosis and healing were determined exclusively by endoscopy. Ulcer healing was observed after four weeks in 40/49 (81.6%) patients in group A and 35/48 (72.9%) patients in group B and in 46/49 (94%) and 40/48 (83.3) after eight weeks, respectively. There were no statistically significant differences between the healing rates for both groups (p > 0.05). The reduction of ulcer related symptoms and antacid consumption was equal in both groups. No adverse effects were reported in the group A, but there were three patients with transient skin rush in the group B. Reported adverse effects were minor and did not merit exclusion from the study. It was concluded that the efficacy of famotidine 40 mg vs. proglumide 1600 mg was similar, although famotidine had proportionally better effect than proglumide. These findings supported the hypothesis that famotidine suppressed acid secretion stronger than proglumide.

[Significance of endothelin in arterial hypertension in children]

Concentration of plasma endothelin and the activity of Na(+)-K(+)-ATP-ase were determined in 3 different groups of children: the 1st group comprised 13 children with essential hypertension, aged 12.9+/-4.8; the 2nd group concerned 16 children with renal hypertension, but with preserved global renal function, aged 13.7+/-2.8, and the 3rd group consisted of 27 healthy children, aged 11.6+/-6.3 years. Plasma endothelin concentrations were measured by radioimmunological method, using a set manufactured by "Biomedica". The activity of Na(+)-K(+)-ATPase was determined in erythrocyte haemolysate by measuring the quantity of released inorganic phosphate in samples with and without ouabaine. Concentration of plasma endothelin was not significantly different between the children with arterial hypertension and healthy children, and there was no significant correlation between endothelin concentration and blood pressure in either of the 3 groups of children. The activity of Na(+)-K(+)-ATP-ase was significantly decreased only in the 1st group of children. There was no evidence of correlation between the Na(+)-K(+)-ATPase activity and blood pressure or plasma endothelin either in healthy, or in hypertensive children.

CONCLUSION

Endothelin in blood circulation has no significance in regulating blood pressure in healthy children. It also has no direct role on the development of essential and renal hypertension in children. The activity of Na(+)-K(+)-ATP-ase is decreased in children with essential hypertension, but it seems that it has no direct impact on hypertension. Endothelin in circulation and Na(+)-K(+)-ATP-ase activity are not interdependant.

[Determination of the level of urinary tract infection in children by antibodies coating bacteria from urinary sediment]

The article deals with the evaluation of the significance of surface antibodies in urinary sediment bacteria by direct immunofluorescence in children with urinary tract infection caused by Escherichia coli (E. coli), so as of determination of location of the infection. Sixty five children were studied, aged from 1 to 16.5 years. Based on the recognized criteria in literature, all patients were classified into three groups: chronic pyelonephritis (CP)--10 patients, acute pyelonephritis (AP)--34 patients, and lower urinary tract infections (LUTI)--21 patients. On the basis of the analysis of the relationship among the three groups of patients in relation to the absence or various presence rates (up to 5%, 6-10% and 11-15% respectively) of fluorescent antibodies in urine sediment, and using the Fischer's test of absolute probability, we obtained a highly significant difference (p = 0.00006) only between the groups AP and LUTI. This difference caused the presence of fluorescence in the AP group and its absence in the LUTI group. By adding the positive fluorescence findings we found that it was present in 80% of CP patients, in 91.17% of AP patients, and in 14.28% of LUTI patients. chi2 test showed a highly significant difference (chi2 = 34.79; p < 0.01), which confirmed that bacterial fluorescence was most often present in the urine of AP patients and absent in LUTI patients. Bacterial fluorescence was significantly more frequent in CP patients in relation to LUTI patients. These results indicate that the method for detecting surface antibodies in urine bacteria, aimed at determinig the location of infection, is more reliable and noninvasive as compared to other methods.

[The influence of protein and phosphorous restricted diet supplemented with essential aminoacids (EAA) and their alpha-keto-analogues (KAA) on nutritional status of children with chronic renal failure (CRF)]

The purpose of the study was to establish the influence of protein restricted diet supplemented with EAA/KAA on nutritional status of children with CRF. Seven childredn (four girls and three boys), aged from 7 years and eight months to 14 years and two months, with glomerular filtration rate of 42.6-9.2 ml/min/1.73 m2 and proteinuria of 0.025-1.125 g/24 h, who were on conservative treatment and who lived at home, were observed for six months. In prescribing energy value and protein intake WHO recommendations were used for healthly children (age for height). Through food 80-90% of energy and 80-85% of protein needs were provided. The remaining energy and proteins were provided by glucodextrin and EAA/KAA supplements respectevely. Average daily phosphorous intake amounted to about 550-800 mg. The obtained results showed that stunting and kwashiorkor like aminoacid disbalance were the prominent nutritional problems. This dietary regimen had a beneficial effect on all studied parameters. especially on height standard deviation score which increased from 1.71 +/- 2.6 to 1.5 +/- 4.3 (t = 2.809, p < 0.05); total essential/nonessential aminoacid score increased from 0.38 +/- 0.2 to 0.56 +/- 0.2 (t = 2.763, p < 0.05). The ratio between plasma concentration of four nonessential (glycine+serinet glutamine+taurine) to four essential (leucine+isoleucine+valine+methionine) amino acids decreased from 3.82 +/- 1.2 to 2.7 +/- 0.4 (t = 2.528, p < 0.05). Lymphocyte count increased from 1.809 x 10(9) +/- 0.268 x 10(9)/l to 2.314 x 10(9) +/- 0.922 x 10(9)/l (t = 2.431, p < 0.05). No significant changes were found in the values of relative body weight, arm circumpherence, triceps skinfold thickness, total plasma protein, albumin, transferine, complement C3 and plasma valin/glycin and phenylalanine/thyrosine ratio. It should be noted that the significant changes were not found in the results of these latter anthropometric biochemical parameters in relation to their primary almost insignificant values.

[Clinical significance of serotypization of Escherichia coli isolated in children urinary tract]

The paper deals with the study of 65 children, aged from 1 to 16,5 years (7 years and 5 months +/- 2 years and 7 months), with urinary tract infection caused by Escherichia coli (E. coli). All patients were classified into three groups according to accepted criteria from literature (clinical features, urographic characteristics, immunological analyses and laboratory signs of inflammatory reaction: (1) 10 patients with chronic pyelonephritis (CP); (2) 34 patients with acute pyelonephritis (AP), and (3) 21 patients with lower urinary tract infection (LUTI). Using 7 antisera antigen preparations O1, O2, 04, O7, O11, O15 and O18, 46 (70.8%) isolated strains were serotyped, while 19 (29.2%) isolated strains of E. coli remained unserotyped. None of the patients showed the presence of more than one serotype in urine. Due to the small number of cases in some groups and low number of serotype strains within the groups, break-down of serotype by patient groups was not done. The prevalent serogroup was O7 found in 22 (47.8%) patients, then O11 in 9 (19.6%), O1 in 4 (8.7%), O15 in 4 (8.7%), O4 in 3 (6.5%), O2 in 2 (4.3%) and O18 in 2 (4.3%) patients. Serogroup O7 was present in all three groups of patients. Statistical analysis showed that the incidence of serogroup O7 was not significantly different (p > 0.05); this suggests that a specific serogroup does not cause only one type of infection. Having in mind that all existing antisera were not used, the possibility of intra-hospital infection provoked by O7 serogroup should be taken into consideration.

Characteristics of thiamin transport in the isolated perfused guinea pig heart

The cellular uptake of (14C)-thiamin hydrochloride was studied in the isolated perfused guinea pig heart, using the rapid single circulation, paired-tracer technique, in which D-(3H)-mannitol serves as an extracellular marker. Cellular uptake of this vitamin was estimated by directly comparing venous dilution profiles of (14C) and (3H) radioactivities in the absence and presence of unlabelled thiamin hydrochloride and pyrithiamin hydrobromide. The maximal cellular uptake (Umax) of thiamin was very low (5.31 +/- 1.79%), while in the presence of 10 mM unlabelled thiamin and 1 mM pyrithiamin, Umax was significantly greater (9.71 +/- 1.57% and 12.30 +/- 0.82%, respectively). Our data suggest that there is a saturable mechanism of sarcolemmal thiamin transport out of myocardial cell, while this transport into the cell is unsaturable.

[Emergencies in arterial hypertension in children]

From March 1982 to March 1992 at the Nephrology Department of Belgrade University Children's Hospital 25 patients (16 females and 9 males, aged from 1.5 to 14 years) were treated for hypertensive emergency. Twenty patients had chronic severe hypertension of whom in 19 it was of renal origin. Five patients had acute hypertension during acute poststreptococcal glomerulonephritis. In 15 patients hypertensive emergency was manifested by neurologic disorders, while in the other patients signs of cardiac failure prevailed. Deterioration of renal function was observed in 9 patients and 2 had sec. haemolytic-uremic syndrome. Three patients died during hypertensive crisis, and the others were successfully treated. The fact that in 50% of patients chronic hypertension could not be revealed until the occurrence of hypertensive emergency, suggests the need of its early detection during systemic check-up.

Progressive tubulointerstitial nephritis and chronic cholestatic liver disease

We report the clinical and morphological features of a distinctive hepatorenal disorder in four patients and review the five similar patients in the literature. The main clinical characteristics were early onset of cholestatic liver disease and progressive tubulointerstitial nephritis leading to renal death in early childhood. Liver histology showed disturbed architecture with nodular and acinar formations and portal fibrosis and bile duct proliferation. Histological abnormalities in the kidney were severe interstitial fibrosis and tubular atrophy and dilatation, while the typical features of nephronophthisis were lacking. These clinical and morphological characteristics distinguish our patients from the majority described, as having nephronophthisis and congenital hepatic fibrosis or any other known syndrome with concomitant hepatorenal involvement. We suggest that the association of cholestatic liver disease and progressive tubulointerstitial nephritis represents a new syndrome.

[Viral hepatitis C--a problem in the treatment of children with renal insufficiency on hemodialysis]

The aim of the study was to assess the frequency of positive anti HCV in the haemodialysis unit (staff and patients) of the University Children's Hospital in Belgrade. Twenty four patients, 14 girls and 10 boys, on chronic haemodialysis from 1 to 164 months, and ten staff members who worked for an average of 9.3 years in the haemodialysis unit, were examined. Patients were screened for HCV antibody in November 1990 (15 pts), July 1992 (14 pts) and September 1992 (13 pts) using the Hepatitis C virus (HCV) 1st generation test for the first check up, and 2nd generation tests for the following ones. Five patients were tested 3 times and 8 twice. Staff members were tested in September 1992 by the HCV 2nd generation test. Complete screening for Hepatitis B virus (HBV) was done by ELISA at the same time as the tests for HCV antibody. All patients and staff members were Hbs Ag negative. Eleven patients and 9 staff members had one or more HBV antibodies due to HBV infection or HBV vaccine. None of staff members had HCV antibody while overall prevalence in patients was high, reaching 50%. It raised with duration of dialysis, and was more frequent in polytransfused and/or patients with positive HBV infection anamnesis.

[IgA nephropathy in children with various clinico-histologic features and therapy]

Clinical and hystological features of IgA nephropathy were evaluated in 17 children (age range 6 to 14 years). Hematuria was present in all patients (macroscopic hematuria in 10 patients, microscopic hematuria in 7). Mild to moderate proteinuria was present in 10, nephrotic syndrome in two cases. The majority of renal biopsy showed normal picture of mild mesangial proliferation, with crescents in only one patient. Transient impairment of renal function developed in two patients. One of patients progressed to chronic renal failure. Four patients were treated (two with persistent proteinuria, one with nephrotic syndrome, one with nephritic syndrome). Corticosteroid treatment resulted in aggravation of proteinuria in two patients with persistent proteinuria. Patient with nephrotic syndrome demonstrated only diminution of proteinuria during different treatments: corticosteroids, ciclophosphamid and Ciclosporin A. Ciclophosphamid was beneficial in patient with nephritic syndrome.

[Levels of immunoreactive atrial natriuretic peptide in the blood of children on hemodialysis therapy]

Expansion of extracellular fluid volume,--increasing right atrial pressure,--appears to be a major stimulus for the rise in plasma atrial natriuretic peptide (ANP). End-stage renal disease (ESRD) is associated with significant changes of several hormone systems. Recent studies have shown that plasma ANP concentration is significantly increased in patients with ESRD and that the concentration of the hormone declines following haemodialysis (HD). In patients with ESRD treated by HD "dry weight" for each individual patient is the body weight at which the patients has normal hydration status. The aim of the present study was to determine changes of plasma concentrations of ANP during haemodialysis. We also attempted to check whether the baseline levels of ANP were related to weight loss during dialysis. Eleven children (7 females, 4 males) participated in the study. The patients age related from 8 to 20 years. Plasma concentrations were markedly elevated (p < 0.01) before haemodialysis (251 ae 119) pg/ml) in comparison with control values (61 ae 23 pg/ml), but remained above normal range in all except 4 cases. During HD body weight was reduced in all but one patient. This patient was infused isotonic fluid during HD and did not show weight loss. The four patients who had normal plasma ANP levels at the end of treatment appeared to be in better overall condition than the other patients. In summary, plasma ANP measurements may be of value in establishing the volume status in patients with ESRD. Plasma ANP levels after HD may help to adjust the right dry body weight for each patient.

Clinical characteristics of haemorrhagic fever with renal syndrome in children

From January 1988 to September 1989, seven patients (4 girls and 3 boys, aged 3-12 years) with haemorrhagic fever with renal syndrome (HFRS) were hospitalised at the University Children's Hospital in Belgrade. In four patients the disease appeared as a family outbreak, the others were sporadic cases. In six patients the clinical presentation was suggestive of HFRS, as they had fever with headache, myalgia, sore throat and gastrointestinal illness followed by renal abnormalities. However, severe haemorrhagic syndrome with petechia, haematoma, haematemesis and melaena was present in one patient only. Renal disease presented as nephritic syndrome and/or acute renal failure. Five patients recovered after 2-3 weeks without sequellae, one patient had decreased renal function 17 months after the start of the disease and the remaining patient died. In six patients the diagnosis of HFRS was confirmed serologically by a significant rise in antibody titres against hantaviruses, while in the patient with the fetal and fulminant course of the disease, the diagnosis was established on the basis of epidemiological and autopsy findings. We suggest that children living in endemic areas who develop an ill-defined, febrile and gastrointestinal disease with renal dysfunction should be evaluated for HFRS.

[Use of erythropoietin in children with terminal renal insufficiency treated with chronic hemodialysis]

Nine pts, aged 4-20 years (mean 12) with chronic uremic anaemia (mean Hb 5.8 g/dl, range 5.0-7.0 g/dl) on regular thrice-weekly haemodialysis, were treated with human recombinant erythropoietin (rh-uEPO) for a mean of 28.11 weeks (range 4-48). To attain a target Hb concentration (9.6-11.2 g/dl) RH-uEPO (Cilag) was administered i.v. after each dialysis in increasing doses within the range (51-300 U/kg/week). All pts were treated with persantine. Five pts needed iron supplementation. All pts showed increased Hb concentration and none of 6 previously transfusion dependent pts needed further transfusions after the first week of rH-uEPO. Pretreatment long-term dialyzed, polytransfused and iron overloaded pts, even when treated with lower doses of rH-EPO, responded better, reaching target Hb level from the 8th- to the 16th week. Three of 4 highly sensitized pts on rH-EPO treatment had a significant decrease of cytotoxic antibody titre, and 2 were successfully transplanted. rH-EPO also significantly improved the life quality in all pts. No pts developed any serious side affects. There was a transient increase in BP (2 pts) and transaminase with eosinophilia (4 pts).

[Cyclosporine in the treatment of glomerular diseases in children]

From June 1987 to June 1991 at the Belgrade University Children's Hospital 10 patients, 5 males and 4 females, aged 2-16 years, with chronic glomerular disease, were treated with CyA. Seven patients had INS, 2 lupus nephritis and one IgA nephritis. Before initiation of CyA, all but one, were treated with classic immunosuppressive therapy, which had no effect (8/10) and/or had serious adverse effects (9/10). CyA dosage was initiated at 4-6 mg/kg/BW, and was subsequently adjusted to achieve CyA concentrations in blood at range 50-100 ng/ml. Treatment duration was 2-17 months. Patient compliance to CyA therapy was observed in 5/7 INSs: 2 cortico-sensitive (1 with FSGS was cortico-dependent and 1 had frequent relapses) and 3 cortico-resistant patients (2 with FSGS and 1 with minimal histologic changes). After drug withdrawal, only one of the patients who responded, had no relapse. One of the two patients with SLE showed improvement during CyA administration, while no response was observed in the patient with IgA nephritis. Adverse experiences with CyA therapy involved decreased renal function (2/10), arterial hypertension (1/10), hyperbilirubinaemia (1/10), transient LDH increase and hyperuricaemia (1/10).

Medium- and long-term prognosis of patients with acute poststreptococcal glomerulonephritis

The prognosis of acute poststreptococcal glomerulonephritis (APSGN) is still a matter of considerable debate. In an attempt to elucidate this controversy, the medium-term prognosis was evaluated in 40 patients 5-9 years after the onset of the disease, and the long-term prognosis in 88 patients 10-17 years after the onset of the disease. All were sporadic cases. In the medium-term follow-up study, abnormalities were revealed in 5.0% (2/40) of the patients. Hypertension and proteinuria were the only abnormalities detected. In the long-term follow-up study, abnormalities were revealed in 6.8% (6/88) of the patients. Hypertension was found in 3.4, proteinuria in 2.3, and microhaematuria in 2.3% of the patients. In both studies, all patients had normal creatinine clearance. We conclude that the medium- and long-term outcome of patients with APSGN is excellent.

Aldehyde and nucleotide separations by high-performance liquid chromatography. Application to phenylhydrazine-induced damage of erythrocytes and reticulocytes

High-performance liquid chromatographic (HPLC) techniques were used for the determination of aldehydes as lipid peroxidation products and of nucleotide concentrations in rabbit red blood cells exposed to phenylhydrazine hydrochloride. Aldehydes were determined by derivatization to dinitrophenylhydrazones, followed by thin-layer chromatographic and HPLC separation with methanol-water on an ODS column. Nucleotides and their derivatives were measured by ion-pair reversed-phase HPLC gradient elution with 10 mM ammonium phosphate buffer containing 2 mM tetrabutylammonium phosphate on ODS columns. The sensitivity of mature erythrocytes was compared with that of reticulocytes against the toxicological effects of phenylhydrazine. For both cell types an increase in aldehyde concentrations, especially of 4-hydroxynonenal, and a decline in both energy-rich nucleoside triphosphate and NAD+ were demonstrated.

Effects of dibutyryl-cANP on glycolysis in washed human erythrocytes

The experiments were carried out with washed human erythrocytes in order to study the effects of dibutyryl-cAMP (DB-cAMP) on glycolysis. 5 mM DB-cAMP significantly increases glucose consumption and lactate production in incubated erythrocytes. The cross-over plot of glycolytic intermediates shows that increased glycolysis is probably the result of activation of phosphofructokinase by DB-cAMP. Under the same condition DB-cAMP significantly protects the 2,3-diphosphoglycerate level in incubated erythrocytes.