Mutational analysis of CLC-5, cofilin and CLC-4 in patients with Dent's disease.

BACKGROUND/AIMS: Dent's disease is caused by mutations in the chloride/proton antiporter, CLC-5, or oculo-cerebro-renal-syndrome-of-Lowe (OCRL1) genes. METHODS: Eighteen probands with Dent's disease were investigated for mutations in CLC-5 and two of its interacting proteins, CLC-4 and cofilin. Wild-type and mutant CLC-5s were assessed in kidney cells. Urinary calcium excretion following an oral calcium challenge was studied in one family. RESULTS: Seven different CLC-5 mutations consisting of two nonsense mutations (Arg347Stop and Arg718Stop), two missense mutations (Ser244Leu and Arg516Trp), one intron 3 donor splice site mutation, one deletion-insertion (nt930delTCinsA) and an in-frame deletion (523delVal) were identified in 8 patients. In the remaining 10 patients, DNA sequence abnormalities were not detected in the coding regions of CLC-4 or cofilin, and were independently excluded for OCRL1. Patients with CLC-5 mutations were phenotypically similar to those without. The donor splice site CLC-5 mutation resulted in exon 3 skipping. Electrophysiology demonstrated that the 523delVal CLC-5 mutation abolished CLC-5-mediated chloride conductance. Sixty percent of women with the CLC-5 deletion-insertion had nephrolithiasis, although calcium excretion before and after oral calcium challenge was similar to that in unaffected females. CONCLUSIONS: Three novel CLC-5 mutations were identified, and mutations in OCRL1, CLC-4 and cofilin excluded in causing Dent's disease in this patient cohort.

Collapsing glomerulopathy in Galloway-Mowat syndrome: a case report and review of the literature.

The Galloway-Mowat syndrome (GMS) (MIM251300) is described as an autosomal recessive disorder, the gene of which has not yet been identified. We report the case of a boy presenting with an early nephrotic syndrome, microcephaly, seizures, and psychomotor retardation. He died at 3 years and 11 months in a context of end-stage renal function consistent with a GMS. He was the second child of a non-consanguineous marriage. There was no family history of nephrotic syndrome or end-stage renal failure, but his mother had a moderate mental retardation complicated by seizures. He presented dysmorphologic features, including micrognathia and large and floppy ears. Renal biopsy showed a focal segmental glomerulosclerosis with a collapsing glomerulopathy and abundant visceral epithelial cell proliferation. The majority of the glomeruli were sclerotic. We report the first case of GMS associated with a collapsing glomerulopathy.

The unfinished journey with modafinil and discovery of a novel population of modafinil-immunoreactive neurons.

Modafinil, a wake-promoting compound now used worldwide in sleep medicine, was initially regarded as a sedative compound because mice were so quiet with respect to locomotion after receiving it that this behavioral state was qualified as sedation. In the early 1980's when modafinil was first assessed by polysomnography in a cat in our laboratory, surprisingly, the cat spent the whole night awake without even one minute of sleep! This initial observation resulted subsequently in a series of basic and clinical studies in order to define the pharmacological profile of modafinil and its mode of action and, notably, to identify the brain targets by which modafinil acts to promote wakefulness. These studies were undertaken using pharmacologic approach coupled with the Cerveau isolé (brain transection) preparation, c-fos labelling and knockout mouse models. It was also in this context that we have developed a purified polyclonal antibody against modafinil. We expected that using immunohistochemistry with this antibody would allow us to localize the brain distribution of modafinil dosing. Surprisingly, we found discrete modafinil immunoreactive neuronal populations in several brain areas of modafinil-naive cats, rodents and humans. The most numerous and intensely labeled modafinil-immunoreactive neurons characterized by granular staining were found in the basal forebrain. They shared the regional location with cholinergic and aspartate-containing neurons but did not colocalize with them. In summary, we here present a newly identified neuronal population located in the basal forebrain that has never previously been published and suggests that these modafinil-immunoreactive neurons might be involved in forebrain functions such as sleep-wake control and cognition. This paper briefly reviews our journey with modafinil research and presents new unpublished experimental data.

Neonatal acute renal failure secondary to maternal exposure to telmisartan, angiotensin II receptor antagonist.

Fetal and neonatal toxic effects of angiotensin II receptor antagonists have been described in animals and humans. Five cases of fetal or neonatal deaths have been reported following maternal use of sartans for hypertension. We report a case of neonatal transient renal failure following telmisartan therapy during pregnancy. This class of antihypertensive drugs should be avoided during pregnancy and breastfeeding.

Low-density lipoprotein apheresis in children with familial hypercholesterolemia: follow-up to 21 years.

Twenty-seven patients (14 girls, 13 boys) affected by familial hypercholesterolemia who had begun low-density lipoprotein (LDL) apheresis treatment before the age of 15 were studied. The median age at diagnosis was 4 years and the blood LDL cholesterol level was 704 +/- 163 mg/dL. Screening was performed for homozygous or double heterozygous mutations of the LDL cholesterol receptor gene and mutations were found in 24 of the patients. The mean age at the beginning of treatment was 8.5 years and the mean length of follow up was 12.6 years. The two main procedures used were direct adsorption of lipoproteins and dextran sulfate cellulose adsorption. Nine patients experienced anaphylactic reactions due to bradykinin and six had to have their treatment changed. The LDL cholesterol level before the session was lowered by 45 +/- 11% of the value at diagnosis. The LDL cholesterol reduction in a session was 72 +/- 10%. Tendinous xanthomas disappeared or diminished dramatically in 62% of the children. In 22 patients no cardiovascular event occurred during LDL apheresis treatment. Three had angina pectoris; two others had surgical management of aortic stenosis, but no clinical manifestations. Seven children had normal cardiovascular pictures while on treatment. Eleven had abnormalities of the aortic root or coronary arteries, which in six cases had appeared before treatment; the other five children did not undergo prior cardiac evaluation. In five children the abnormalities appeared during treatment. Based on these data, LDL-apheresis can be recommended for the treatment of homozygous familial hypercholesterolemia, even in young children, with good efficiency on biological parameters, cutaneous lesions and cardiovascular events.

Prospective, randomized trial comparing short and long intravenous antibiotic treatment of acute pyelonephritis in children: dimercaptosuccinic acid scintigraphic evaluation at 9 months.

OBJECTIVE: We report a prospective, randomized, multicenter trial that compared the effect of 3 vs 8 days of intravenous ceftriaxone treatment on the incidence of renal scarring at 6 to 9 months of follow-up in 383 children with a first episode of acute pyelonephritis. METHODS: After initial treatment with intravenous netilmicin and ceftriaxone, patients were randomly assigned to either 5 days of oral antibiotics (short intravenous treatment) or 5 days of intravenous ceftriaxone (long intravenous treatment). Inclusion criteria were age 3 months to 16 years and first acute pyelonephritis episode, defined by fever of >38.5 degrees C, C-reactive protein level of >20 mg/L, and bacteriuria at >10(5)/mL. All patients underwent 99m technetium-dimercaptosuccinic acid scintigraphy 6 to 9 months after inclusion. A total of 548 children were included, 48 of whom were secondarily excluded and 117 of whom were lost to follow-up or had incomplete data; therefore, 383 children were eligible, 205 of them in the short intravenous treatment group and 178 in the long intravenous treatment group. RESULTS: At inclusion, median age was 15 months, median duration of fever was 43 hours, and median C-reactive protein level was 122 mg/L. A total of 37% (143 of 383) of patients had a vesicoureteral reflux grades 1 to 3. Patient characteristics at inclusion were similar in both groups, except for a significantly higher proportion of girls in the short intravenous treatment group. The frequency of renal scars at scintigraphy was similar in both groups. Multivariate analysis demonstrated that renal scars were significantly associated with increased renal height at initial ultrasound and with the presence of grade 3 vesicoureteric reflux. CONCLUSIONS: The incidence of renal scars was similar in patients who received 3 days compared 8 days of intravenous ceftriaxone. Increased renal height at initial ultrasound examination and grade 3 vesicoureteric reflux were significant risk factors for renal scars.

Darbepoetin, effective treatment of anaemia in paediatric patients with chronic renal failure.

Darbepoetin alpha (DA) is a unique long-acting treatment for anaemia in patients with chronic renal failure (CRF). This study assessed the mean dose of DA to achieve and maintain haemoglobin (Hb) levels between 11 g/dl and 13 g/dl in CRF children aged 11 years to 18 years. This observational, prospective study was conducted in 39 patients treated with DA. Twenty-nine patients were switched from recombinant human erythropoietin (r-HuEPO), and ten patients were naive to r-HuEPO. Naive patients received initial doses of 0.45 microg/kg of DA. Switched patients received a dose adjusted to the prior dose of r-HuEPO (200 IU r-HuEPO:1 microg DA). Among the switched patients, 79.3% received dialysis. No naive patients underwent dialysis. Overall, 74% of patients showed increased Hb level, with a mean value of 11.6 +/- 1.6 g/dl, using a mean DA dose of 0.63 +/- 0.48 microg/kg per week, and 66.7% patients reached the target Hb level. Hb increased in naive patients from 9.5 (95% CI: 7.7, 11.4) to 11.7 (95% CI: 10.9, 12.6) g/dl and in switched patients from 11.1 (95% CI: 10.6, 11.5) to 11.5 (95% CI: 10.8, 12.2) g/dl). Higher doses of DA were needed in the "switched" than in the "naive" patients to maintain Hb levels over 11 g/dl, respectively 0.73 (95% CI: 0.54, 0.92) and 0.34 (95% CI: 0.16, 0.52) microg/kg per week. Our results indicate the doses of DA necessary to treat CRF patients aged 11 years to 18 years. DA was an effective treatment to stabilise CRF patients at extended dosing intervals.