Embryonic enzyme patterns: characterization of the single lactate dehydrogenase isozyme in preimplanted mouse ova.

A single lactate dehydrogenase isozyme has been observed in mouse eggs from unfertilized eggs to blastocyst stage. As characterized by electrophoresis, substrate inhibition, and subunit dissociation-recombination experiments, it is identical to mouse lactate dehydrogenase 1.

Percutaneous needle biopsy preceding preoperative chemotherapy in the management of massive renal tumors in children.

While the National Wilms' Tumor Study (NWTS) Group in the United States puts an emphasis on accurate staging and histology before any therapy is given for Wilms' tumor, the International Society of Pediatric Oncology (SIOP) in Europe focuses on preoperative therapy and safer surgery. Our current approach combines the benefits of both policies in the management of massive renal tumors in children. In seven consecutive patients we first obtained a percutaneous posterior needle biopsy to obtain adequate tissue for histology, and proceeded with preoperative chemotherapy with vincristine and dactinomycin until tumor shrinkage was sufficient. Tumor removals were feasible and uneventful. At the time of operation, two tumors were found to be totally or almost totally necrotic. In the others, which still included viable tumor, the histology corresponded well to the needle biopsy findings. One case with unfavorable histology and one with rhabdoid sarcoma would have been missed and given suboptimal therapy without the primary needle biopsy. As possible biopsy-related complications, subcapsular intratumoral bleeding was recognized in two patients. We conclude that percutaneous posterior needle biopsy is safe and yields definite, detailed histology in massive renal tumors in children. Preoperative chemotherapy facilitates surgery in these patients.

Spectrum of COL4A5 mutations in Finnish Alport syndrome patients.

Alport syndrome (AS) is a hereditary kidney disorder, mainly caused by mutations in the X-chromosomal gene (COL4A5) encoding the type IV collagen a5 chain. In this study, detection of COL4A5 mutations was performed in 17 Finnish Alport syndrome families. Regions around the 51 previously known exons, as well as the two recently characterized exons 41A and 41B in COL4A5, were PCR-amplified from the patient DNA. Direct sequencing of the amplified products was performed and mutations were found in 12 families. None of the mutations involved exons 41A or 41B. Three of the mutations were potential splicing mutations, two of which were studied at the mRNA level. Seven of the mutations were single base substitutions, and two were deletions. In five families, no mutations were found.

Nephronophthisis in Finland: epidemiology and comparison of genetically classified subgroups.

Nephronophthisis--medullary cystic kidney disease is a progressive chronic tubulointerstitial nephritis leading to terminal renal failure. About two thirds of the patients with familial juvenile nephronophthisis, an autosomal recessive disease, have a homozygous deletion at the gene locus on 2q13. Through a nationwide search, 59 patients were ascertained in Finland. The incidence was 1:61,800 live births when calculated over a 20-year period. Of the patients, 17 came from four families showing dominant inheritance and 37 patients from 28 apparently recessive families when classified by family history, clinical features or presence of a deletion on 2q13. Two were considered as new dominant mutations; three sporadic patients could not be classified. The most significant difference between the patients with deletions, patients without deletions but having recessive family history, and patients belonging to families with dominant inheritance was the age at first symptoms, at the start of dialysis and at transplantation. These facts will be of help in determining the mode of inheritance of a sporadic patient without a deletion.

Trimethoprim pharmacokinetics in children with renal insufficiency.

We studied the pharmacokinetics of trimethoprim in 14 children (two neonates) with renal insufficiency. They were 1 week to 16.4 years old and had glomerular filtration rates (GFR) between 10.8 to 72.3 ml/min/1.73 m2. The half-life (t1/2) of trimethoprim was inversely related to the GFR. The relation followed a power curve (correlation of t1/2 with GFR: r = -0.86; P less than 0.001). The slower elimination rate was mainly the result of lowered renal clearance of trimethoprim. The volume of distribution (Varea) was, in most patients, in the upper normal range for children. In some of the patients, chiefly infants with severe renal insufficiency, the Varea was larger than normal. In some individuals the pharmacokinetics of trimethoprim deviated from that to be expected from the GRF. We recommend reduced daily doses of trimethoprim if the GFR is less than 30 ml/min/1.73 m2. The reduction should be proportional to the reduction in GFR and primarily take the form of a prolonged dose interval.

Infections and other maternal factors as risk indicators for congenital malformations: a case-control study with paired serum samples.

An obstetric population of 48,000 individuals was prospectively followed up for evidence of possible teratogenic factors that might be associated with congenital malformations. Serum samples from 274 mothers of defective children and from paired controls were collected during early pregnancy and approximately one month after delivery and tested for antibodies against ten different viruses, Mycoplasma pneumoniae, and Toxoplasma. These data were supplemented with clinical information on infections, other diseases, drug intake, and other potentially teratogenic factors during pregnancy. Mothers of defective children had more seroconversions (fourfold or greater increase in titer) than the controls, 123 vs. 86. This difference was mainly due to an increase in herpes simplex viruses 1 and 2, cytomegalovirus, varicella-zoster virus, and Toxoplasma titers. In addition, the number of reported diseases during the pregnancy, the intake of drugs (especially analgesics and hormones), and the number of earlier abortions were greater in the mothers of the defective children than in the controls.

Predictive factors associated with significant urinary tract abnormalities in infants with pyelonephritis.

BACKGROUND: Major urinary tract abnormalities are detected in 20 to 40% of infants with acute pyelonephritis (APN). Early detection of structural defects is essential for protecting the kidneys from reinfection and subsequent scarring. The purpose of this study was to investigate whether any factors present during the acute phase of infection could predict the presence of existing significant urinary tract abnormalities in infants. METHODS: A prospective study of 180 infants, aged 1 to 24 months, with APN was conducted. Blood and urine samples were collected. Renal ultrasound (US) was performed within 0 to 6 days from admission. Final diagnosis of the urinary tract anatomy was elucidated using the results of two or more radiologic imaging studies. RESULTS: Risk factors for the presence of significant urinary tract abnormalities in infants were pathogens other than Escherichia coli in urine [relative risk (RR) 3.4, 95% confidence interval (CI) 2.2 to 5.3; P = 0.001], positive blood culture (RR 2.3, 95% CI 1.3 to 4.0; P = 0.039), young age (1 to 6 months) (RR 2.2, 95% CI 1.3 to 3.9; P = 0.004), lack of papG adhesin genes of E. coli in urine (RR 2.1, 95% CI 1.2 to 3.9; P = 0.016) and abnormal renal US (RR 2.0, 95% CI 1.2 to 3.4; P = 0.008). CONCLUSIONS: Infants 1 to 6 months of age with APN caused by bacteria other than E. coli or by papG-negative E. coli strain, positive blood culture and abnormal renal US carry an increased risk for significant urinary tract abnormalities and need enforced follow-up.

Alphacalcidol oral pulses are effective in secondary hyperparathyroidism prior to dialysis.

Secondary hyperparathyroidism in chronic renal failure (CRF) is due to the increased activity of parathyroid gland. The negative feedback control exerted by the vitamin D metabolite 1,25 (OH)2 D3 is lacking due to the deficiency of this metabolite in CRF. We have studied whether alphacalcidol given orally as thrice weekly evening pulses lowers parathyroid hormone (PTH) levels of children with CRF. Alphacalcidol 0.5-3.0 micrograms was given thrice weekly orally to a total of 22 children (mean age 5.6 years) with CRF; the dosis was adjusted according to PTH, ionized calcium and phosphate concentration. Serum PTH decreased significantly from a pretreatment level of 393 +/- 81 to 122 +/- 34 ng/l after 12 months, and stabilized at this level. Mean vitamin D metabolite concentrations were within normal range. 1,25 dihydroxyvitamin D did not increase during therapy while PTH decreased. The estimated creatinine clearance remained nearly the same (20 +/- 3 and 21 +/- 6 ml/min/ 1.73 m2). Growth remained low normal and bone mineral density did not decrease. Oral alphacalcidol pulse therapy for hyperparathyroidism in uremic children seemed to be easy and effective. The response is even better in inhibiting potential autonomous parathyroid hyperplasia if this treatment was started early. We conclude that feedback regulation of PTH with oral alphacalcidol pulse therapy is efficient in the treatment of hyperparathyroidism in children with CRF prior to dialysis.

Outcome of Henoch-Schoenlein nephritis with nephrotic-range proteinuria.

PATIENTS AND METHODS: All children with Henoch-Schoenlein glomerulonephritis (HSP-GN) and nephrotic-range proteinuria (> 40 mg/h/m2), treated at 5 university hospitals and in 1 central hospital in Finland during in 1990-1997, were analyzed retrospectively. The mean age of these 19 patients (8 girls, 11 boys) at the time of diagnosis was 9.9 years (range 4.6-15.1 years). A renal biopsy had been performed in all cases, giving findings according to the classification used in the International Study of Kidney Diseases in Children (ISKDC) of grade II (4 patients), grade III (10), grade IV (4) and grade V (1). Six patients underwent a second biopsy. RESULTS: The yearly incidence of nephrotic-range HSP-GN in Finland was 2 per 1 million children under 15 years of age. After a mean follow-up of 4.6 years (range 9 months-9.1 years), 3 patients (15.7%) had no signs of nephritis, 11 (57.9%) had proteinuria < 1 g/day or microscopic hematuria, 2 (10.5%) had proteinuria > 1 g/day, and 3 (15.7%) had developed ESRD or uremia. 47% of the patients needed medication for proteinuria at the time of the latest follow-up. The first kidney biopsy did not predict the outcome of HSP-GN, since all the patients with the poorest outcome had only ISKDC II-III findings in their first biopsy. CONCLUSION: According to our series, the morbidity in cases of HSP-GN with nephrotic-range proteinuria is high and a close clinical follow-up is needed. The treatment of HSP-GN patients should be based on the clinical presentation rather than on the biopsy findings.

Arterial hypertension developing 10 years after radiotherapy for Wilms's tumour.

Three patients developed arterial hypertension more than 10 years after receiving irradiation for Wilm's tumour. Scattered radiation appeared to have caused changes in the remaining kidney which were not severe enough to inhibit compensatory hypertrophy but which produced a rise in blood pressure at a later date. Since arterial hypertension appears to be a delayed complication of radiotherapy which is easily detected and controlled and can occur at any age long-term surveillance after successful treatment of malignant tumours in childhood is necessary.

Interstitial nephritis of acute onset.

Interstitial nephritis was diagnosed at renal biopsy in 10 previously healthy children. All had identical clinical symptoms: anaemia, raised sedimentation rate, low glomerular filtration rate, protein and leucocytes in the urine, but no bacteria; nine also had glycosuria. Six of the children had a history of recent ingestion of drugs or a serologically proved infection, or both. One child later developed uveitis. After the acute phase all made at least partial recovery, but after a mean follow up of two years and eight months only four were without any signs of disease, three had equivocal findings, two definite renal disease, and one renal failure. Interstitial nephritis, therefore, seems to be a clinical entity often occurring without known cause or triggering factor, its prognosis is variable, and some patients may develop chronic renal failure.

A survey of 164 Finnish children and adolescents with hypertension.

A retrospective analysis was performed on 164 children and adolescents with persistent hypertension. Among the unselected 115 patients with hypertension seen within the last three years 47 (41%) exhibited renal disease, 37 (32%) coarctation of the aorta, 10 (9%) miscellaneous associated causes and 21 (18%) no associated cause (essential hypertension). A substantial number, 53/164, had a primary disease potentially curable by surgery, and in 37 patients the blood pressure was normalized postoperatively. The outcome depended mostly on the basic disease and the availability of chronic hemodialysis. 11/164 children have died, all because of terminal basic disease, and one with simultaneous hypertensive crisis. We thus recommend a thorough investigation in the case of a child with persistent hypertension.

Risk of relapse in steroid-sensitive nephrotic syndrome: effect of stage of post-prednisone adrenocortical suppression.

Glucocorticoid therapy has been effective in inducing remission in the majority of children with primary nephrotic syndrome. However, glucocorticoid-induced adrenocortical suppression is associated with early relapse, whereas normal adrenocortical function seems to delay the subsequent relapse. We analyzed 201 episodes of prednisone treatment in 47 children with steroid-sensitive nephrotic syndrome by the life-table method. The effect of partial cortisol substitution was studied as well. Adrenocortical function was determined by a two-hour ACTH test. A response of 50% to 100% of the minimum normal response was diagnosed as "moderate" suppression, and a response of less than 50% as "severe." Post-prednisone adrenocortical function was normal in 99 episodes (49%). Adrenocortical suppression occurred in 102 episodes; of these, 68 were considered moderate and 34 severe. Adrenocortical suppression increased both the initial relapse rate and the final risk of a relapse. Severe suppression was always associated with a relapse, the longest remission time being 0.5 year. In moderate suppression, several long, relapse-free intervals were observed, but the risk of relapse was still higher than in episodes with normal adrenocortical function. Cortisol substitution possibly decreased the risk of a relapse after severe adrenocortical suppression, but not after moderate suppression.