International comparison of blood pressure and BMI values in schoolchildren aged 11-16 years

AIMS

This study comprised part of a larger cross-sectional survey performed in Hungary in the period 2005-2006, which was designed first to reveal the representative age-, gender- and height-specific percentile values for the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) in Hungarian children aged 11-16 years. The second aim was to determine the prevalence of overweight and obesity.

METHODS

Analyses were performed on 14,290 Hungarian children aged 11-16 years. All blood pressure (BP) measurements were made with a validated, automated, digital device. The criteria recommended by international guidelines were used.

RESULTS

The prevalence of overweight and obesity among the Hungarian children was found to be 23.4% (3347 adolescents; International Obesity Task Force criteria). Previous studies have reported that the strongest correlation is observed between the BP values and weight, and our results are in accordance with this.

CONCLUSIONS

Regional differences in morphometry (different prevalences of overweight and obesity) and the genetic background, disparate eating habits and other cultural factors may account for the differences in BP levels during childhood. As the prevalence of overweight and obesity is increasing worldwide, it is important that countries carefully monitor the weight and BP status of their children and adolescents.

Comparison of tetrahydrofuran and ethyl acetate as extraction solvents for urinary organic acid analysis

The analysis of urinary organic acids is crucial for the diagnosis of many inborn errors of metabolism. A vital part of the analytical process is the extraction procedure. The sensitivity and linearity of the analysis of 26 diagnostically important urinary metabolites with tetrahydrofuran (THF) and ethyl acetate (EtOAc) as extraction solvents were determined by gas chromatography-mass spectrometry. Good linearity (r (2) > 0.90) was observed for all of the compounds in the investigated concentration range (290-900 mumol/L) for both solvents. For less polar compounds, THF extraction yielded lower or similar sensitivities as compared with EtOAc (sensitivity ratio: 0.6-1.3). For more polar compounds, however, much higher sensitivities were observed when THF was used (sensitivity ratio: 1.8-17.2). Our results provide information concerning the use of THF for the sensitive quantitative analysis of polar urinary metabolites which are difficult to quantify using EtOAc.

Endothelin-1 gene and endothelial nitric oxide synthase gene polymorphisms in adolescents with juvenile and obesity-associated hypertension

Hypertension is an increasing public health problem all over the world. Essential hypertension accounts for more than 90% of cases of hypertension. It is a complex genetic, environmental and demographic trait. New method in molecular biology has been proposed a number of candidate genes, but the linkage or association with hypertension has been problematic (lack of gene-gene and gene-environment interaction). It is well known that genetic influences are more important in younger hypertensives, because children are relatively free from the common environmental factors contributing to essential hypertension. The association studies compare genotype ferquencies of the candidate gene between patient groups and the controls, in pathways known to be involved in blood pressure regulation. This study examined three polymorphisms of these factors encoding genes (ET-1 G+5665T (Lys198Asn), endothelial nitric oxide synthase (eNOS) T-786C promoter polymorphism and 27-bp repeat polymorphism in intron 4) in adolescents with juvenile essential and obesity-associated hypertension. Significant differences were found in the G/T genotype of the ET-1 polymorphism in the hypertensive and obese+hypertensive patients (body mass index (BMI) > 30). A strong association was detected between the BMI and the polymorphism of the ET-1 gene. It seems that ET-1 gene polymorphism plays a role in the development of juvenile hypertension associated with obesity. Although no significant differences were seen in the case of the eNOS promoter polymorphism and the eNOS 4th intron 27-bp repeat polymorphism. It seems that eNOS may play a role, but this is not the main factor in the control of blood pressure; it is rather a fine regulator in this process. This study with adolescents facilitates an understanding of the genetic factors promoting juvenile hypertension and obesity.

Vitamin E alleviates the oxidative stress of erythropoietin in uremic children on hemodialysis

The efficacy of combined therapy with recombinant human erythropoietin (rhEPO) and vitamin E versus rhEPO alone in the treatment of anemia was examined in children (n = 10, aged 15.2 +/- 3.2 years) on chronic hemodialysis at the restart of rhEPO therapy after a 4-week interval. The results confirmed that rhEPO induced oxidative stress of the red blood cells as observed during the first rhEPO therapy. Vitamin E (15 mg/kg per day per os) was introduced after 2 weeks of rhEPO monotherapy, when the signs of acute oxidative stress appeared. The level of oxidized glutathione (GSSG) increased from 8.9 +/- 3.1 to 26.7 +/- 5.7 nmol/g hemoglobin (Hb) by that time. After 2 weeks of simultaneous vitamin E treatment, there was a significant difference in GSSG values compared with rhEPO monotherapy (10.1 +/- 3.9 vs. 56.7 +/- 15.8 nmol/g Hb, P < 0.001). A considerable decrease was observed in the previously high ratio of GSSG/reduced glutathione (GSH), an indicator of oxidative stress, and the level of carboxyhemoglobin, indicating hemolysis. A significant increase in Hb and hematocrit (P < 0.01) was achieved within 2 weeks of starting the combined therapy, while similar results occurred only at the 8th and 5th weeks without vitamin E. Antioxidant vitamin E supplementation improved the therapeutic effect of rhEPO in patients with chronic renal failure on hemodialysis.

Childhood membranous nephropathy, circulating antibodies to the 58-kD TIN antigen, and anti-tubular basement membrane nephritis: an 11-year follow-up

Childhood membranous nephropathy (MNP) with anti-tubular basement membrane (anti-TBM) nephritis is a rare disorder that may have extrarenal manifestations. This article describes a new case to be added to the 10 previously reported. A renal biopsy specimen from a 1-year-old white boy with nephrotic syndrome, microhematuria, and hypertension showed MNP (granular global IgG, IgA and C3, and segmental IgM and C1q) associated with hypercellularity and granular deposits of IgM and C1q in the mesangium, arteriolar IgA, and linear TBM IgG, IgA, and C3. A biopsy at age 4 years showed MNP (IgG and C3) and linear IgG and C3 along the TBM. Six months later, temporary glucosuria suggested a mild tubular dysfunction. Biopsy at age 8 years showed sclerosing MNP (IgG and C3), linear TBM IgG and C3, and chronic active tubulointerstitial nephritis (TIN). Indirect immunofluorescence showed circulating anti-TBM antibodies, and the enzyme-linked immunosorbent assay (ELISA) approach verified strong reactivity with the 58-kd TIN antigen. Despite trials with steroids, chlorambucil, azathioprine, and cyclosporine, end-stage renal disease developed by the age of 9 years. At age 10 years, the patient received a cadaveric kidney transplant. With the patient now aged 12 years, the graft is still functioning well, without any clinical evidence of disease recurrence. Neurological, ocular, and abdominal symptoms, including nonbacterial diarrhea, were observed during the follow-up period. The pathophysiology of these extrarenal symptoms remains unclear. Serotyping and genotyping of HLA antigens (A2, A10, B12, B41, DR5 [1101, 1103-4, 1106 or 1108-1113], DR6 [1303, 1312, or 1413], DRB3 [*0101 and 0201-2 or 0301], DQA1 [*0501 homozygous], and DQB1 [*0301 homozygous]) did not indicate any HLA association similar to those described previously in childhood MNP with anti-TBM nephritis (HLA-B7 in four patients, HLA-DR8 in two patients). The presented case is the fifth in the literature that displays reactivity with the 58-kd TIN antigen, and for which data on HLA antigens are reported.

[Thin glomerular membrane nephropathy. Clinico-pathological observations]

In two nephrology centres between 1983 and 1993 among 1545 kidney biopsies 34 cases of thin basement membrane nephropathy have been diagnosed. All patients had a varying degree of microscopic dysmorph haematuria, occasional slight proteinuria--except two nephrotic children; and normal blood pressure with one exception. 5 children and 7 adults experienced repeated bouts of macroscopic haematuria mainly after exercise or upper respiratory tract infection, one child after tonsillectomy. All patients had normal renal function and retained it during the follow-up period (mean 61 months, 3 months to 22 years), except a 46 year old patient, who was found to have the joint occurrence of light chain gammopathy and hypertension. Seven patients had positive family history for microscopic haematuria, in four family members of three patients renal biopsy disclosed mesangioproliferative glomerulonephritis with thin GBM segments. As a cut off value for thin basement membrane nephropathy we considered 264 nm. The morphometric analysis of the electron micrographs revealed a mean thickness of 210 nm. No differences in basement membrane thickness were measured regarding gender, age or the presence of macroscopic haematuria. The thin basement membrane is considered to be the pathological basis and predisposing alteration leading to haematuria.

Mitochondrial mutation as a probable causative factor in familial progressive tubulointerstitial nephritis

Renal biopsy of two children and a maternal relative, diagnosed with severe progressive tubulointerstitial nephritis, has shown the presence of distorted mitochondria. Mitochondrial DNA from the blood of these patients was analysed. No major deletions were found, but an A to G mutation was detected in position 5656. It is proposed that this mutation might play a causative role in the renal disease of the patients.

Oxidative stress and antioxidant defense mechanism in glomerular diseases

The changes in red blood cell (RBC) lipid peroxidation [measured via the malonyl dialdehyde (MDA) concentration], reduced (GSH), and oxidized glutathione (GSSG) levels, hemoglobin (Hb) oxidation and antioxidant enzyme [catalase (Cat), glutathione peroxidase, and superoxide dismutase (SOD)] activities were studied in 45 pediatric patients with various glomerular diseases [minimal change nephrotic syndrome (MCNS) in relapse or in remission, lupus nephropathy (SLE), poststreptococcal glomerulonephritis (APSGN), IgA nephropathy (IGA gn)], and in 20 adult patients with IGA gn and also in 15 pediatric and 14 adult controls. The in vitro effects of hydrogen peroxide [acetyl phenylhydrazine (APH) test] on the GSH and Hb metabolisms were likewise investigated. There was an increased oxidative stress in MCNS with relapse, IGA gn, SLE gn, and APSGN, which could be detected in the GSH and Hb oxidation and in the lipid peroxidation on the peripheral RBC-s. The RBC SOD and Cat activities were significantly lower in all patients than in the controls. The RBC GSSG level was significantly elevated in all patients, with the exception of MCNS in remission. This stimulated a compensatory GSH production in MCNS with relapse and in IGA gn, but not in SLE or APSGN. The regeneration of GSH from GSSG was reduced in MCNS with relapse, SLE, and IGA gn, but not in APSGN. In remission, the GSH-GSSG redox system normalizes, but in vitro the APH test stimulates an intensive Hb oxidation. In conclusion, there is a correlation between the presence of active glomerular disease and the evidence of oxidative changes in the various parameters measured in peripheral RBCs.

Oxidative damage of red blood cells in haemolytic uraemic syndrome

Changes in red blood cell (RBC) lipid peroxidation [measured by malonyl dialdehyde (MDA) concentration], glutathione (GSH) metabolism, antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase) and haemoglobin (Hb) metabolites (metHb, carboxy Hb) were studied in six children with post-enteropathic (D+) haemolytic uraemic syndrome (HUS) and ten controls. The in vitro effect of hydrogen peroxide [acetylphenylhydrazine (APH) test] on GSH and Hb metabolism was also investigated. MDA levels were significantly higher and the antioxidant enzyme activities were lower in HUS patients than in the controls (P < 0.01). The oxidised glutathione concentration was significantly higher in the patients than in the control children (26.3 +/- 12.6 vs. 10.9 +/- 1.8 nmol/g Hb. Percentage values of carboxy Hb and metHb were also higher in HUS (P < 0.01). Incubation of RBC with APH induced a more pronounced decrease in the concentration of GSH (P < 0.001) and a significant increase (P < 0.01) in the level of metHb and carboxy Hb in the HUS patients. This suggests that there is reduced RBC GSH stability in HUS. Utilisation of GSH and antioxidant enzymes leads to increased Hb oxidation and haemolysis. The oxidative damage may have an important role in the pathogenesis of haemolytic anaemia in HUS.

The effect of erythropoietin on the cellular defence mechanism of red blood cells in children with chronic renal failure

The glutathione redox system, haemoglobin (Hb) oxidation, the activity of antioxidant enzymes and the lipid peroxidation product malonyl dialdehyde (MDA) were studied in red blood cells (RBCs) during administration of recombinant human erythropoietin (rhEPO) over 12 weeks in ten children maintained on haemodialysis. A rapid increase in the reticulocyte count was accompanied by a slower rise in total Hb concentration. The mean level of oxidized glutathione (GSSG) increased from 13.2 +/- 5.3 nmol/g Hb to 56.7 +/- 15.8 nmol/g Hb 4 weeks after the start of rhEPO (P < 0.001), followed by a fall to the basal value. Reduced glutathione (GSH) levels showed a smaller though constant elevation during rhEPO therapy (P < 0.001). Before rhEPO treatment, incubation of RBCs for 1 h with acetylphenylhydrazine induced a decrease in GSH concentration compared with controls (P < 0.001), which became more pronounced in the first few weeks of rhEPO therapy (P < 0.001). In addition, the percentage of Hb derivatives (metHb and haemichrome) increased in the first 4 weeks of rhEPO therapy (P < 0.001). Although there was no significant difference between the values obtained preEPO and during EPO treatment, MDA levels were continuously higher and superoxide dismutase, catalase and glutathione peroxidase concentrations were lower than in the controls (P < 0.001). These results are compatible with oxidative damage to the RBCs in the early period of rhEPO therapy in children with end-stage renal failure. The GSH-GSSG system, as an important cellular defence mechanism of the RBCs, appears to be severely affected.

[Successful treatment of acute tubulointerstitial nephritis associated with infectious mononucleosis and causing severe uremia]

A ten years old boy with severe acute renal failure was presented. The development of acute uremia was proceeded by infectious mononucleosis. Renal biopsy revealed acute tubulointerstitial nephritis. Peritoneal- and haemodialysis was completed by steroid therapy and cytostatic treatment when glomerular proteinuria was observed. Following a 2 months uremic period the patient cured completely.

Hereditary nephritis, platelet disorders and deafness-Epstein's syndrome

A 14-year-old boy with persistent proteinuria (1.6-4.0 g/day), microscopic haematuria, moderate hypertension, macrothrombocytopenia (giant platelets, platelet number 30 x 10(9)/l) and a familial sensorineural hearing loss (the father and the brother were also affected) was studied. Kidney biopsy revealed a diffuse mesangial proliferation, and a focal thickening of the glomerular basement membrane was seen on electron microscopy. A normal number of megakaryocytes was observed in bone marrow aspirates. The aggregation response of the platelets to collagen, epinephrine and adenosine diphosphate (ADP) was decreased. The platelet number was slightly diminished, platelets were of normal size in both parents and the brother, and showed a decreased aggregability in response to collagen, epinephrine and ADP in the brother and mother. No functional abnormality of the platelets was observed in the father. Urinalysis and kidney function were normal in the family members. This boy with nephritis, platelet disorders and hearing loss corresponds to Epstein's syndrome.

[Macrothrombopenia, nephritis and hearing loss--a new case of Epstein syndrome]

A 14 years old boy with persistent proteinuria (1.6-4.0 g/day), microscopic haematuria, macrothrombocytopenia (giant platelets, platelet number 30 G/l), and a familial sensorineural hearing loss (the father and the brother were also affected) was studied. Kidney biopsy presented a diffuse mesangial proliferation, and a focal thickening of the glomerular basement membrane was seen on electron microscopy. With bone marrow aspiration normal number of megacaryocytes was observed. The aggregation response of the platelets was decreased on collagen, epinephrine and ADP but it was normal on aggristin. The presented case with nephritis, platelet disorders and hearing loss corresponds to Epstein syndrome, a variant of Alport's syndrome.

[Comparative study of acetate and bicarbonate hemodialysis in children with chronic uremia]

Comparative studies on 5 children suffering from chronic uremia were performed regarding the efficacy of acetate and bicarbonate hemodialysis. Clinical symptoms, acid-base and blood gas analysis, serum osmolality, blood pressure and EEG were examined. On authors experience the patients tolerated better the bicarbonate dialysis. Laboratory data and blood pressure were found to be closer to the normal values too. The abnormality of EEG made after bicarbonate dialysis were not so expressed than that of acetate dialysis. On the basis of this examinations the authors suggest the bicarbonate hemodialysis in uremic patients with severe cardiovascular and/or neurological complications.

The effects of bicarbonate and acetate haemodialysis on platelet cyclic AMP concentration, thromboxane B2 release and aggregation

The effects of chronic uraemia and serial acetate (HDA) or bicarbonate (HDB) haemodialysis on the aggregation, thromboxane B2 (TXB2) release and cyclic AMP (cAMP) concentration of platelets from arterial blood were studied in 14 uraemic patients (6 dialysed and 8 conservatively treated) and 10 controls. Platelets from uraemic patients, either dialysed or treated conservatively, exhibited a significantly higher cAMP level (P less than 0.005), a lower TXB2 level (P less than 0.01), and a lower aggregability (P less than 0.001) than the controls. The platelet cAMP level was more markedly decreased after HDB than after HDA (P less than 0.05). Greater increases in platelet aggregation (P less than 0.05) and TXB2 formation were observed after HDB than after HDA. The concentration of platelet cAMP and aggregability, and also the platelet cAMP and the TXB2 level showed a significantly negative correlation (r = -0.7, P less than 0.05 and r = -0.60, P less than 0.05, respectively). There was a positive correlation between the platelet-derived TXB2 and the aggregability (r = 0.67, P less than 0.05). Although most patients had secondary hyperparathyroidism, the serum parathyroid hormone level did not correlate closely with the cAMP, TXB2 or aggregation results. The dysfunction of uraemic platelets accompanied by a reduced TXB2 release may be explained by an increased cAMP and a decreased arachidonic acid availability. HDB improves the platelet function to a greater degree than does HDA.

The effects of vitamin E on tissue oxidation in nephrotoxic (anti-glomerular basement membrane) nephritis

The effects of vitamin E on tissue oxidation, kidney function and morphology were studied in rats with nephrotoxic nephritis (NTN). Thirty-six nephritic animals received no treatment (group 1), while 36 were treated with vitamin E (group 2). Twenty-four hours after the administration of anti-glomerular basement membrane antibody, sulfhydryl-containing renal protein was significantly lower in group 1 than in group 2 (0.70 +/- 0.16 and 1.08 +/- 0.06 mmol/100 g kidney tissue, respectively), suggesting a free oxygen radical scavenging effect of vitamin E in group 2. The difference was similar on day 14. The creatinine clearance was significantly lower in group 1 than in group 2 on day 1 (40 +/- 30 and 204 +/- 60 microliter/min per 100 g body weight, respectively). The protein excretion was initially high in both groups, but a significant decrease was detected in group 2 relative to group 1 on day 14 (25 +/- 18 and 92 +/- 38 mg/24 h, respectively). The morphological changes were less severe in group 2. Vitamin E treatment did not alter any of the above values significantly in healthy animals. The release of oxygen free radicals in NTN might play an important role in the pathogenesis, which can be influenced by free radical scavengers through changes in kidney function and morphology.

Erythrocyte defense mechanisms against free oxygen radicals in haemodialysed uraemic children

Changes in erythrocyte lipid peroxidation (measured as the concentration of malonyl dialdehyde), glutathione metabolism, antioxidant enzyme activities (glutathione peroxidase, catalase, and superoxide dismutase), the oxidized products of haemoglobin (Hb), and hydrogen peroxide (H2O2)-induced haemolysis were studied in six children with chronic renal failure treated with serial acetate and bicarbonate haemodialysis (HD). Ten age- and sex-matched children acted as controls. Malonyl dialdehyde levels were significantly higher and antioxidant enzyme activities lower in uraemic red blood cells (RBCs) compared with controls (P less than 0.05). Incubation of RBCs for 1 h with acetylphenylhydrazine induced a decrease in the concentration of reduced glutathione (P less than 0.001) and an increase in the level of oxidized products of Hb (P less than 0.001), but only in the uraemic patients. The H2O2 haemolysis test revealed a mild (n = 3) to increased (n = 3) haemolysis in the uraemic RBCs. Oxidative haemolysis is probably a multifactorial process in uraemic patients, and may be an important risk factor in HD therapy.

Long-term follow-up of patients with persistent/recurrent, isolated haematuria: a Hungarian multicentre study

A retrospective multicentre study of 341 children with persistent/recurrent, isolated haematuria is described. The haematuria was isolated for at least 6 months at the beginning of observation. The duration of follow-up was 2-5 years in 201, 5-10 years in 119, 10-15 years in 19, and over 15 years in 2 cases. Of these patients 47.8% became symptom-free. In 18.4% the haematuria remained isolated; in 13.8% it was combined with proteinuria over 250 mg/day more than 2 years later. The occurrence of associated proteinuria increased progressively with time. It was 8.6% between the 3rd and 5th years, and 37.0% after the 5th year. Renal biopsy was performed because of the symptoms of glomerular disease in 47 cases at an average time of 12 months following the appearance of proteinuria. Proteinuria appeared after a 2-5, 5-10, 10-15 and more than 15 years follow-up period in 16, 23, 6, and 2 patients respectively; 14 of them had Alport's nephropathy. The percentage of more serious azotaemia was 1.7 (creatinine clearance: 10-50 ml/min per 1.73 m2) and 0.3 (creatinine clearance: less than 10 ml/min per 1.73 m2). Mortality was 0.58%. Most of the patients who developed severe azotaemia had persistent microscopic haematuria at the beginning. The prevalence of hypertension was only 1.2%. The time of its appearance was above 5 years in 2 and below 5 years in 2 cases. All these patients had chronic glomerulonephritis. The haematuria was associated with hypercalciuria in 19.9%. In 14.3% of the overall group of patients urolithiasis developed 2-15 years after onset. All of these had hypercalciuria.(ABSTRACT TRUNCATED AT 250 WORDS)

[Long-term follow up of chronic recurrent isolated hematuria]

A retrospective multicentre study of 341 children with persistent/recurrent, isolated haematuria is described. The haematuria was isolated for at least half a year in the beginning of observation. 47.8% of the patients became symptom-free. In 18.4% the haematuria remained isolated, in 13.8% it was combined with greater than 250 mg/day proteinuria greater than 2 years later. The occurrence of associated proteinuria was 8.6% between the 3rd to fifth years, and 37.0% after the 5th years. 14 cases had Alport's nephropathy. The percentage of more serious azotaemia was 1.7 (Ccreat: 10-50 ml/min/1.73 m2) and 0.3 (Ccreat: less than 10 ml/min/1.73 m2). Mortality was 0.58%, rate of hypertension 1.2%. Most of the patients who developed severe azotaemia, had persistent microscopic haematuria in the beginning. The haematuria was associated with hypercalciuria in 19.9%. In 14.3% of the overall group of patients urolithiasis developed 2-15 years after onset. All of them had hypercalciuria. Our findings suggest that symptoms of isolated haematuria may last for a long-term period and need systematic control. When proteinuria and/or hypertension associates to haematuria a worse prognosis can be expected.

The effects of plasma from IgA nephropathy patients on vascular prostacyclin and platelet cyclic AMP production

The effects of plasma from 10 IgA nephropathy patients and from ten controls were studied on vascular prostacyclin (PGI2) production, the cyclic AMP (cAMP) level and the aggregation of normal platelets. The ability of the plasma to support PGI2-like activity (PSA) was significantly lower in the group of patients (18.0 +/- 13.3%) than in the controls (52.6 +/- 12.9%). The concentration of 6-keto-PGF1 alpha in the supernatant of the vascular tissue was also lower following incubation with patient plasma than with control plasma (p less than 0.001). The reduced PGI2 released by the patient plasma led to a significantly lower platelet cAMP than that following the control plasma (p less than 0.01). There was a significantly positive correlation between the 6-keto-PGF1 alpha and the plasma PSA, and also between both the plasma PSA and 6-keto-PGF1 alpha concentrations and the platelet cAMP level. These findings suggest that a vascular PGI2 defect may cause a reduced cAMP production and an uninhibited aggregation of platelets, which might play a role in the pathogenesis of IgA nephropathy.

Plasma factors influencing PGI2-like activity in patients with IgA nephropathy and Henoch-Schönlein purpura

Plasma factors influencing vascular PGI2-like activity (PSA) were studied in 45 patients with IgA nephropathy, 18 with Henoch-Schönlein purpura, including 8 children with nephrotic syndrome, and 41 controls. The results were compared with the levels of plasma high-density lipoprotein (HDL), low-density lipoprotein (LDL) and fatty acid components of plasma phospholipids. The plasma of 38 of 45 patients with IgA nephropathy and 14 with Henoch-Schönlein purpura showed a diminished ability or no ability to support PSA. Twenty-three patients with IgA nephropathy and 10 with Henoch-Schönlein purpura exhibited an inhibitory activity against PGI2 production. The plasma HDL level was lower, while the LDL level and the LDL/HDL ratio were significantly higher in IgA nephropathy and Henoch-Schönlein purpura cases than in the controls. A high LDL/HDL ratio was associated with a low plasma PSA. The levels of arachidonic acid and its precursor were not lower in the plasma of patients than in the controls. The decreased PGI2 synthesis may play an important role in the pathogenesis of IgA nephropathy and Henoch-Schönlein purpura, but it can not be explained by reduced PG precursors. LDL may have an inhibitory, and HDL a protective effect on PGI2 synthesis.

The effect of E. coli infection on the prostaglandin synthesizing capacity of postobstructive rat kidney

The PGE2, PGI2, PGF2 alpha and TxA2 synthesizing activities were studied in an isolated microsomal fraction of rat kidney after temporary, unilateral ureter obstruction and E. coli infection. In the early phase of regeneration the synthesis of vasodilatory PGI2 was increased, whereas that of vasoconstrictory PGF2 alpha was decreased. An increased PGE2 synthesizing activity was observed when renal obstruction was associated with infection. The role of these changes in regenerating the haemodynamics and function of postobstructive kidney is discussed.

The role of renal prostaglandin E as a possible modulator of cyclic AMP production in nephrotic syndrome

Urinary prostaglandin E (PGE) and cyclic AMP (cAMP) excretions were studied by radioimmunoassay in children with nephrotic syndrome and in a control population. In cases with nephrotic syndrome there was a significant elevation in urinary PGE excretion and cAMP excretion was decreased. A positive correlation was found between urinary cAMP excretion and urinary osmolality (Uosm) and the ratio urine to plasma osmolality (Uosm/Posm); and a negative correlation between urinary cAMP excretion and urine volume. A negative correlation was observed between the values of PGE excretion and urinary cAMP. These data confirmed the role of PGE as a modulator of cAMP production, which was inhibited in the nephrotic syndrome.

Disturbances of prostacyclin metabolism in children with hemolytic-uremic syndrome and in first degree relatives

Plasma from 24 children with hemolytic uremic syndrome (HUS) (10 in acute, 14 in remission phase), 42 first degree relatives and 24 controls were studied for PGI2 supporting activity (PSA) from human umbilical arterial rings and the concentration of PGI2 metabolite (PGI2m). HUS patients in acute phase showed very low or absent level of plasma PSA, which remained depressed 3 months following presentation. Plasma from 2 out of 5 acute HUS patients showed inhibition against PGI2-like activity, and depressed preservation of PGI2 effect. The mean value of PGI2m in acute phase of HUS patients was elevated initially, but fell below control range by the day 14 and remained decreased at the end of 3rd month. Patients on long term remission showed a significantly lower concentration of plasma PGI2m. Eight of 14 HUS patients in remission and 18 of 42 family members had lower PSA levels than the controls. These studies confirmed a decreased PSA in HUS and suggest that persistently low PSA levels may reflect an inherited predisposition.

Typing of HLA antigens in a child population with nephrosis syndrome

Using the microlymphocytotoxicity test of Terasaki, HLA--A, B, Cw antigen typing was done for 37 antigens in 28 children with steroid-sensitive nephrosis and five children with steroid-resistant nephrosis. Evaluation was made by the chi 2 test as corrected by the method of Yeates. In steroid-sensitive nephrosis the frequency of HLA--B 8 antigen was 33.3% and in the resistant cases 40% as against 18.5% in the controls. The difference, however, was not significant, the B 12 and B 13 antigens were more frequent in both steroid-sensitive and resistant nephrosis, though not significantly.

Arteriolar lesions in human renal biopsy material with special regard to the ultrastructural changes in the basal lamina network of the vascular wall

The arteriolar changes in renal biopsy samples were studied by light and electron microscopy and immunohistologic observations. Arteriolar hyaline thickening was found to occur in virtually all renal diseases, regardless of whether these were accompanied by hypertension or not. Only amyloidosis and dense deposit glomerulonephritis were accompanied by specific ultrastructural arteriolar changes. The nonspecific "hyalin" was shown ultrastructurally to contain various components: accumulated basement membrane material, fine granular deposit (with filamentous or lipid details), and granulovesicular and threadlike membrane structures. Presumably the material constituting these structures originates partly from the blood and partly from elements of the vascular wall itself.

Indomethacin and gentamycin treatment in experimental kidney infection

Experiences in experimental renal infection of rats treated with gentamycin, indomethacin, and by the combination of both drugs are reported. Urine osmolality of animals treated with combined therapy normalized after the first dose of indomethacin; their antibody titers against the pathogenic bacteria, as compared to the controls, decreased significantly. When drugs were administered separately the above immunologic changes could not be observed. Indomethacin did not inhibit the antibacterial effect of gentamycin and, administered alone, it increased the renal concentration ability.

The effect of antidiuretic hormone, indomethacin and naproxen on prostaglandin synthesis of experimentally infected and healthy kidneys

The authors studied the effect of indomethacin and naproxen on the changes of renal prostaglandin E and F2 alpha concentration in experimental kidney infection, as well as the action of arginine-vasopressin in healthy rats. Naproxen proved to be an effective inhibitor of prostaglandin synthesis, as did indomethacin. In control animals an increased prostaglandin E and F2 alpha synthesis was observed caused by arginine vasopressin. It is supposed that ADH--depending on its concentration--has a metabolic modulator role in prostaglandin synthesis, which raises the possibility of a self-regulatory mechanism of water reabsorption.