[Risk of urolithiasis in patients with cystic fibrosis]. / Riesgo de urolitiasis en pacientes con fibrosis quística.

INTRODUCTION: It has been generally admitted that kidneys are not affected in Cystic fibrosis (CF) patients. Anyway, there are several studies demonstrating a higher prevalence of calcium oxalate nephrolithiasis prevalence in CF patients compared to normal population. The aim of our study was to evaluate renal disease regional prevalence in CF patients METHODS: Cross-sectional regional controlled study. Index group = 20 CF subjects 4- 30 years old controlled in a CF outpatient clinic in a tertiary hospital. Control group = 73 healthy subjects randomly selected among the 100 subjects who completed the follow-up visits of the RICARDIN study. Physical examination and renal function analysis were conducted in both groups. CF patients had their functional measurements repeated in a 20 month interval. Renal ultrasonography was performed only in CF patients. RESULTS: Height estimated creatinine clearance in CF patients were not statistically different from controls. Oxaluria (0.77 mg/kg/24 h, p = 0.001) and phosphate excretion (18.98 mg/kg/24 h, p = 0.04) were significantly higher while citrate (7.76 mg/kg/24 h, p = 0.04) and magnesium (1.60 mg/kg/24 h, p = 0.04) excretion were significantly lower in CF patients than normal population reference values. No signs of nephrolithiasis or nephrocalcinosis were found. CONCLUSIONS: CF patients showed a conserved renal function , without ecographic abnormalities. CF patients showed increased urinary elimination of phosphate and oxalate and lower citrate and magnesium elimination, findings that predispose these patients to suffer from urolithiasis in the future.

[High blood pressure due to aortic coarctation and renal artery stenosis in a teenager with type 1 neurofibromatosis]. / Hipertensión secundaria a coartación de aorta y estenosis de arteria renal en adolescente con neurofibromatosis tipo 1.

Hypertension affect about 1% of patients with neurofibromatosis type 1 (NF1). Major causes are concomitant pheocromocytoma in adults and renovascular hypertension in children. In most cases, NF1 is associated with renal artery stenosis, smooth cell proliferation and advential fibrosis. We describe a 16 year old girl with hypertension complicating NF1 secondary to severe coarctation of abdominal aorta and tight stenosis of right renal artery, a very uncommon case. She was first diagnosed when she was 3-years-old and managed with antihypertensive drugs (atenolol, hidralazine and nifedipine); she experienced progressive uncontrollable hypertension but no symptoms, thus she was admitted to repeat studies. Laboratory evaluation (including creatinine, serum electrolytes, urinalysis, urine catecholamines and creatinine clearance) was normal Percutaneous transfemoral magnetic resonance angiography disclosed severe coarctation of abdominal aorta, functional occlusion of superior mesenteric artery and tight stenosis of right renal artery with poststenotic dilatation. Patient underwent surgery with aorto-aortic by-pass and right kidney artery reimplantation. Periodical controls confirmed no hypertension, even four years after surgery and normal flow patterns in Doppler ultrasonography. Patients with NF1 must be screened for pheochromoctyoma and renovascular hypertension. If hypertension appears, careful management is mandatory, as periodical follow-up even after surgery, since the long-term recurrence rate of renovascular lesions is not well established.

[Hemolytic uremic syndrome by Streptococcus pneumoniae]. / Síndrome hemolítico urémico asociado a neumonía neumocócica.

Hemolytic uremic síndrome (HUS) is an acute disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure, usually,but not always, associated with the prodrome of diarrhea. A 2-year-6-month old boy with pneumonía caused by Streptococcus pneumoniae developed the third day after admission oliguric acute renal failure, anemia, and thrombocytopenia. The patient needed veno-venous hemodiafiltration/ hemofiltration during ten days. He received five packed red blood cell, and one platelet transfusions, and was treated with plasma infusions during six days. Renal function was normal at discharge. HUS caused by Streptococcus pneumoniae has more morbility and mortality that classic HUS, although they usually recovery renal function. In those cases of atypical HUS, different from others, blood transfusions that contains IgM should be avoided,because they can increase antigen-antibody reaction and cellular damage. The low incidence of HUS by Streptococcus pneumoniae and the systemic infectious component difficult the early diagnosis. Taking into account the different transfusion approach in these cases, it is necessary to be aware for diagnosing HUS by Streptococcus pneumoniae in all patients with systemic infection and sudden renal function deterioration.

Targeted reduction in expression of Trypanosoma cruzi surface glycoprotein gp90 increases parasite infectivity.

A previous study had shown that the expression of gp90, a stage-specific surface glycoprotein of Trypanosoma cruzi metacyclic trypomastigotes, is inversely correlated with the parasite's ability to invade mammalian cells. By using antisense oligonucleotides complementary to a region of the gp90 gene implicated in host cell adhesion, we investigated whether the selective inhibition of gp90 synthesis affected the capacity of metacyclic forms to enter target cells. Parasites were incubated for 24 h with 20 microM PS1, a phosphorothioate oligonucleotide based on a sequence of the gp90 coding strand; PS2, the antisense counterpart of PS1; or PO2, the unmodified version of PS2 containing phosphodiester linkages, and the expression of surface molecules was analyzed by flow cytometry and immunoblotting using specific monoclonal antibodies. PS2 but not PS1 or PO2 inhibited the expression of gp90. Inhibition by PS2 was dose dependent. Northern blot analysis revealed that steady-state gp90 mRNA levels were diminished in PS2-treated parasites compared to untreated controls. Treatment with PS2 did not affect the expression of other metacyclic stage surface glycoproteins involved in parasite-host cell interaction, such as gp82 and the mucin-like gp35/50. Expression of gp90 was also inhibited by other phosphorothioate oligonucleotides targeted to the gp90 gene (PS4, PS5, PS6, and PS7) but not by PS3, with the same base composition as PS2 but a mismatched sequence. Parasites treated with PS2, PS4, or PS5 entered HeLa cells in significantly higher numbers than untreated controls, whereas the invasive capacity of PS1- and PS3-treated parasites was unchanged, confirming the inverse association between infectivity and gp90 expression.

Idiopathic hypercalciuria in children: pathophysiologic considerations of renal and absorptive subtypes.

Sixteen children with idiopathic hypercalciuria and seven control children were observed. Patients were classified into two groups by means of an orally administered calcium loading test. Individuals with renal hypercalciuria (five children) had a high fasting urinary calcium/creatinine concentration ratio (0.27 +/- 0.05), a mild increase of this value after calcium administration (0.29 +/- 0.07, P less than 0.05), and elevated mean serum parathyroid hormone (PTH) concentrations (0.95 +/- 1.14 ng/ml). Patients with absorptive hypercalciuria (11 children) had fasting urinary calcium/creatinine concentration ratio of 0.11 +/- 0.04, a large increase of this index after calcium loading (0.25 +/- 0.06, P less than 0.0005), and normal levels of serum PTH (0.29 +/- 0.10 ng/ml). Next, we examined the effects of two different calcium intakes on urinary calcium excretion, serum calcium, PTH, and 1,25-dihydroxyvitamin D3 concentrations. In patients with absorptive hypercalciuria, the increased calcium intake resulted in significant increments of calciuria (P less than 0.0005), mild elevation of serum calcium concentration (P less than 0.05), and reduction of serum 1,25-dihydroxyvitamin D3 concentrations (P less than 0.005). By contrast, these values were not modified in children with renal hypercalciuria. Serum PTH did not change within each group. After dietary calcium supplementation, serum ratios of 1,25-dihydroxyvitamin D3 to calcium, phosphate, and PTH concentrations decreased significantly only in the group of children with absorptive hypercalciuria. Our data support the contention that 1,25-dihydroxyvitamin D3 metabolism is different in the two groups of patients with hypercalciuria.

Effect of a low sodium diet on urinary elimination of cystine in cystinuric children.

Restriction of sodium intake has been shown to decrease urinary elimination of cystine in adult subjects with cystinuria. This simple therapeutic recommendation may be particularly useful in pediatric patients whose compliance with high fluid ingestion and repeated doses of alkali is usually poor. We studied the effect of sodium intake in 5 cystinuric children (3 males) aged 5.9-9.3 years. Urinary excretion of cystine (means +/- SD) was determined at the end of two sequential 1-week periods in which sodium content of diet was modified. Reduction of sodium intake brought about significant decreases in natriuresis (6.0 +/- 2.1 vs. 1.5 +/- 0.5 mEq/kg/day, p < 0.03) and urine cystine concentration (328.0 +/- 190.7 vs. 14.1 +/- 7.4 mg/l, p < 0.02) while urine volume output remained unchanged (58.0 +/- 36.0 vs. 70.3 +/- 33.0 ml/kg/day). These findings confirm that elimination of cystine is highly influenced by sodium intake in cystinuric children and suggest that a low sodium diet may play a key-role in the treatment of pediatric patients with cystinuria.

Renal cell carcinoma in childhood.

Renal cell carcinoma is extremely infrequent in children. We report a case of renal cell carcinoma in a 13-year-old male. Presenting manifestations were loin pain, fever, and weight loss. A palpable abdominal mass was found. Imaging studies showed a solid mass into the right kidney. Nephrectomy was performed and pathological examination demonstrated characteristic findings of renal cell carcinoma. This report emphasizes that renal cell carcinoma should be included in the differential diagnosis of renal masses in children.

Renal amyloidosis complicating a recessive epidermolysis bullosa in childhood.

A case of recessive epidermolysis bullosa and secondary renal amyloidosis in a nine-year-old boy is reported. The first case observed in childhood. The clinical relationships of the two conditions are briefly discussed.

[The value of C-reactive protein in the diagnosis of acute pneumopathies in children]. / Valor de la proteína C reactiva en el diagnóstico de las neumopatías agudas de la infancia.

We have studied 164 children with pneumopathy, ranging from one month to 8 years old. They were classified in two groups according as clinical, biological and radiological criteria. Group I (probable bacterial etiology), 65 children; group II (presumable nonbacterial cause), 35 patients. An indeterminate pattern, 64 infants. The CRP was quantified by radial immunodiffusion method. In the group II, lowest CRP values (less than 30 micrograms/ml) were detected in 86% of the patients. In the group I, 88% of the cases offered values over 30 micrograms/ml. The CRP was a sensitive indicator of diagnosis of pneumopathies in children. High CRP values (greater than 30 micrograms/ml) are suggestive of a bacterial etiology, with statistical significance (p less than 0,001).

Unusual evolution of Wilms tumor in a patient with Wiedemann-Beckwith syndrome.

A very unusual case of Wilms tumor in a child with Wiedemann-Beckwith syndrome is presented. The patient had his first metastasis after a disease-free interval longer than three years. Later, he developed spinal epidural involvement. Both data emphasize the oncogenic potential of Wiedemann-Beckwith syndrome in children and support the contention that Wiedemann-Beckwith syndrome worsens the prognosis of Wilms tumor. Patients with Wilms tumor associated to Wiedemann-Beckwith syndrome should receive intensive therapy as well as close and prolonged follow-up in spite of apparent tumor remission.

[Schönlein-Henoch syndrome: review of a series of 142 cases]. / Síndrome de Schönlein-Henoch: revisión de una serie de 142 casos.

Clinical and laboratory findings in 142 children with Schönlein-Henoch syndrome are studied. The children were diagnosed during a ten-year period (1974-1984). Purpura, as more significant clinical finding, was observed in all patients, followed by articular signs (61.2%), abdominal complaints (57.7%), renal signs (30.2%) and testicular (4.2%). IgA, IgG, IgM, complement and cryoglobulin alterations, are remarkable factors to assume an immunologic origin for the syndrome.

[Nephropathy of the Schöenlein-Henoch syndrome: long-term prognosis in non-selected patients]. / Nefropatía del síndrome de Schönlein-Henoch: pronóstico a largo plazo en pacientes no seleccionados.

Nephritis plays a major role in long-term prognosis of Schönlein-Henoch syndrome. We have studied a group of 142 children with this syndrome; 43 (30.2%) showed clinical evidence of renal disease. Renal biopsy was obtained in 12 cases. A subgroup of 36 patients have been controlled during a much greater two years period. Thirty-five are asymptomatic and one with minor urinary anomalies. Thereafter in our experience the long-term prognosis (means = five years) of Schönlein-Henoch syndrome is excellent in unselected patients.

Predictors of final adult height after renal transplantation during childhood: a single-center study.

AIM: Assessment of final adult height and its predictive factors in children transplanted (RTx) and followed up in a single center. METHODS: A cohort of 32 patients (17 boys, 15 girls) who received RTx before the age of 15 years and had reached a final adult height was selected. Twenty patients received a single RTx, 9 patients received two RTx, and 3 patients received three RTx. Seven children were transplanted preemptively, while the remaining 25 children received peritoneal dialysis for relatively short periods of time. In 11 patients, recombinant human growth hormone (rhGH) was administered either before (n = 8) or after (n = 3) RTx. RESULTS: In 13 patiens (41%), the final height standard deviation score for chronological age (hSDS) was -2.3+/-0.5, below the 95% confidence limits for target height (group A), while in 19 patients (59%), it was -0.7+/-0.8, within the 95% confidence limits for target height (group B). The hSDS values at the start of dialysis and at the time of first RTx were significantly lower in group A than in group B. A higher hSDS at the start of dialysis and at the time of first RTx had a significant positive influence on the final height (FH), whereas a longer duration of dialysis had a significant negative effect on the FH. Administration of rhGH after RTx played an important role in the achievement of a normal FH in 3 girls. No differences were observed between group A and B with respect to age at start of dialysis, chronological or bone age at first RTx, number of rejection episodes, duration of the study period from last RTx to FH, glomerular filtration rate during this study period, or percentage of time on prednisone therapy. CONCLUSIONS: The FH is almost exclusively predetermined by the height achieved at the start of dialysis and at the time of first RTx. Therefore, to reach target adult height after RTx, the best strategy is to shorten the time of dialysis and to start rhGH administration at a young age and as early as possible during the course of chronic renal failure. Administration of rhGH after RTx is also highly effective, but, given its potential danger, still remains a matter of investigation.

Growth hormone metabolism in uremia.

The influence of chronic renal failure (CRF) on growth hormone (GH) and insulin-like growth factor I (IGF-I) metabolisms is not well understood. Clinical studies on GH secretion in CRF have yielded conflicting results. In vitro, pituitary GH secretion has been shown to be unimpaired in moderate uremia. CRF reduces binding of GH to liver as a result of decreased number of GH receptors. CRF induces elevation of serum GH concentrations and does not modify the circulating values of IGF-I. However, the somatomedin bioactivity of uremic serum is depressed, and unsaturated low-molecular-weight IGF-I-binding proteins have been suggested to act as inhibitory factors of IGF-I action. Circulating GH and IGF-I do not necessarily reflect the state of GH and IGF-I in tissues, and further investigations on the effect of CRF on GH and IGF-I metabolisms at the growth plate level are clearly required.

Renin, kallikrein and prostaglandin renal systems in normotensive boys with and without a family history of essential hypertension.

BACKGROUND: The role of the kidney in the development of essential hypertension is subject of debate. METHODS: We compared the renin, kallikrein and prostaglandin renal systems in two groups of normotensive boys, aged 7-16 years, with different degrees of risk for future hypertension: 27 had parents with essential hypertension and 12 had normotensive parents. Supine, standing and post-exercise plasma renin activity as well as levels of urinary kallikrein and prostaglandin E2 before and after exercise were measured. RESULTS: The ratio of post-exercise plasma renin activity (ng/ml/h) to 24 h urinary sodium excretion (mEq/kg/day) was lower in children with hypertensive parents (mean +/- SEM 1.86 +/- 0.24 compared with 3.62 +/- 0.94, P = 0.02). The boys with hypertensive parents had a lower ratio of urinary kallikrein to creatinine before (0.70 +/- 0.13 compared with 1.54 +/- 0.36, P = 0.01) and after exercise (0.80 +/- 0.13 compared with 1.35 +/- 0.23, P = 0.03). The ratio of urinary prostaglandin E2 to creatinine levels did not differ between the groups before or after exercise. CONCLUSION: The plasma renin activity response to exercise and urinary kallikrein excretion were decreased in boys at increased risk of future essential hypertension. These early abnormalities in the renin and kallikrein renal systems may be associated with the development of essential hypertension.

The syndrome of renal tubular acidosis and nerve deafness. Discordant manifestations in dizygotic twin brothers.

The syndrome of renal tubular acidosis (RTA) and nerve deafness is a distinct nosological entity that is inherited as an autosomal recessive trait. We studied a pair of dizygotic twin brothers both with nerve deafness but only one with RTA. Distal RTA was diagnosed in twin A because of inappropriately high urinary pH (6.9) and low net acid excretion (40.0 muEq/min per 1.73 m2) in the presence of hyperchloraemic metablic acidosis, and fractional bicarbonate excretion of 1.6% at a normal serum bicarbonate concentration. The urine minus blood PCO2 differences (U-B PCO2) during a neutral sodium phosphate load and in alkaline urine induced by bicarbonate supplementation were: 11 and 0 mm Hg, respectively. Twin A developed nephrocalcinosis and, after a 9.5-year follow-up period, was 5.3 cm taller than his brother. Twin B remained asymptomatic. Periodic determinations of blood pH and serum bicarbonate were normal and urine pH decreased to 4.6 in the face of ammonium chloride-induced metabolic acidosis. The U-B PCO2 assessed in alkaline urine was 33.5 mm Hg. Audiograms demonstrated bilateral nerve deafness in both brothers. The presence of deafness without RTA has not been previously reported in this syndrome. This report also shows that a primary distal acidification defect is responsible for the RTA observed in this syndrome.