Effect of standing frames used in real life on bone remodeling in non-walking children with cerebral palsy.

Children with severe cerebral palsy are prone to low bone mineral density. No clear recommendation exists for an optimal use of standing frame to enhance bone health in this context. Used in real life, this study suggests for the first time that standing practice improved bone mineralization by limiting bone resorption. INTRODUCTION: To compare the bone health of children with severe cerebral palsy who use a static standing frame in real life to that of children who do not. METHODS: A total of 24 children with severe cerebral palsy GMFCS IV & V were included in the study and were divided into two groups: 13 were using a passive standing frame and 11 were not. We performed a single center retrospective cross-sectional study comparing the two groups using dual X-ray absorptiometry data and tests on biological samples, including bone remodeling factors. RESULTS: Total body (less head) bone mineral content was significantly higher in children who used a standing frame for an average of 30 min/day. This was confirmed in the lumbar spine. Although the total body bone mineral density (less head and proximal femur) densitometric data were not significantly higher, a positive trend favored the use of a standing frame in the children. Bone resorptive factors (CTX) were higher in the non-standing-frame group, whereas there was no difference among osteoformation factors. No difference in fracture history was found. CONCLUSIONS: We show that non-ambulant children with cerebral palsy who use a static standing frame in real life have better bone health, with lower bone resorption, than children who do not. Further studies are needed to determine how standing practice could impact bone mineralization over time in real life and to explore more bone remodeling factors.

Hypoxia inducible factor (HIF)-2α accelerates disease progression in mouse models of leukemia and lymphoma but is not a poor prognosis factor in human AML.

Hypoxia-inducible factor (HIF)-1α accumulation promotes hematopoietic stem cells' quiescence and is necessary to maintain their self-renewal. However, the role of HIF-2α in hematopoietic cells is less clear. We investigated the role of HIF-2α in leukemia and lymphoma cells. HIF-2α expression was high in subsets of human and mouse leukemia and lymphoma cells, whereas it was low in normal bone marrow leukocytes. To investigate the role of HIF-2α, we transduced human HIF-2α cDNA in mouse syngeneic models of myeloid preleukemia and a transgenic model of B lymphoma. Ectopic expression of HIF-2α accelerated leukemia cell proliferation in vitro. Mice transplanted with cells transduced with HIF-2α died significantly faster of leukemia or B lymphoma than control mice transplanted with empty vector-transduced cells. Conversely, HIF-2α knockdown in human myeloid leukemia HL60 cells decreased proliferation in vitro and significantly prolonged animal survival following transplantation. In human acute myeloid leukemia (AML), HIF-2α mRNA was significantly elevated in several subsets such as the t(15;17), inv(16), complex karyotype and favorable cytogenetic groups. However, patients with high HIF-2α expression had a trend to higher disease-free survival in univariate analysis. The different effects of HIF-2α overexpression in mouse models of leukemia and human AML illustrates the complexity of this mutliclonal disease.

HIF-1α is required for hematopoietic stem cell mobilization and 4-prolyl hydroxylase inhibitors enhance mobilization by stabilizing HIF-1α.

Many patients with hematological neoplasms fail to mobilize sufficient numbers of hematopoietic stem cells (HSCs) in response to granulocyte colony-stimulating factor (G-CSF) precluding subsequent autologous HSC transplantation. Plerixafor, a specific antagonist of the chemokine receptor CXCR4, can rescue some but not all patients who failed to mobilize with G-CSF alone. These refractory poor mobilizers cannot currently benefit from autologous transplantation. To discover alternative targetable pathways to enhance HSC mobilization, we studied the role of hypoxia-inducible factor-1α (HIF-1α) and the effect of HIF-1α pharmacological stabilization on HSC mobilization in mice. We demonstrate in mice with HSC-specific conditional deletion of the Hif1a gene that the oxygen-labile transcription factor HIF-1α is essential for HSC mobilization in response to G-CSF and Plerixafor. Conversely, pharmacological stabilization of HIF-1α with the 4-prolyl hydroxylase inhibitor FG-4497 synergizes with G-CSF and Plerixafor increasing mobilization of reconstituting HSCs 20-fold compared with G-CSF plus Plerixafor, currently the most potent mobilizing combination used in the clinic.

Pyruvate carboxylase deficiency: An underestimated cause of lactic acidosis.

Pyruvate carboxylase (PC) is a biotin-containing mitochondrial enzyme that catalyzes the conversion of pyruvate to oxaloacetate, thereby being involved in gluconeogenesis and in energy production through replenishment of the tricarboxylic acid (TCA) cycle with oxaloacetate. PC deficiency is a very rare metabolic disorder. We report on a new patient affected by the moderate form (the American type A). Diagnosis was nearly fortuitous, resulting from the revision of an initial diagnosis of mitochondrial complex IV (C IV) defect. The patient presented with severe lactic acidosis and pronounced ketonuria, associated with lethargy at age 23 months. Intellectual disability was noted at this time. Amino acids in plasma and organic acids in urine did not show patterns of interest for the diagnostic work-up. In skin fibroblasts PC showed no detectable activity whereas biotinidase activity was normal. We had previously reported another patient with the severe form of PC deficiency and we show that she also had secondary C IV deficiency in fibroblasts. Different anaplerotic treatments in vivo and in vitro were tested using fibroblasts of both patients with 2 different types of PC deficiency, type A (patient 1) and type B (patient 2). Neither clinical nor biological effects in vivo and in vitro were observed using citrate, aspartate, oxoglutarate and bezafibrate. In conclusion, this case report suggests that the moderate form of PC deficiency may be underdiagnosed and illustrates the challenges raised by energetic disorders in terms of diagnostic work-up and therapeutical strategy even in a moderate form.

Acute psychosis in propionic acidemia: 2 case reports.

Propionic acidemia is an inborn deficiency of propionyl-coenzyme A (CoA) carboxylase activity, which leads to mitochondrial accumulation of propionyl-CoA and its by-products. Neurologic complications are frequent, but only a few cases presenting with psychiatric symptoms have been reported so far. We report 2 cases of children with chronic psychiatric symptoms who presented with an acute psychotic episode as teenagers. Both patients had hallucinations, panic and grossly disorganized behavior, for several weeks to several months. They had signs of moderate metabolic decompensation at the beginning of the episode, although the psychiatric symptoms lasted longer than the metabolic imbalance. We propose that these episodes were at least partially imputable to propionic acidemia. Such episodes require psychiatric examination and antipsychotic treatment, which may have to be adapted in case of cardiomyopathy or long QT syndrome.

Renal transplantation in 4 patients with methylmalonic aciduria: a cell therapy for metabolic disease.

INTRODUCTION: Patients with methylmalonic acidemia (MMA) may develop many complications despite medical treatment, in particular, severe central nervous system damage and chronic kidney disease (CKD). A kidney transplant may partially correct the metabolic dysfunctions. Liver, kidney and combined liver-kidney transplantations have been advocated but no guidelines are available to identify the most suitable organ to transplant. PATIENTS AND METHODS: Four patients with MMA (mut° phenotype) received a kidney graft because of repeated metabolic decompensations, with progression to CKD in 3 patients (end-stage kidney disease in two patients and CKD stage III in one patient with an estimated glomerular filtration rate [eGFR] of 40ml/min/1.73m(2)) but normal renal function in one (eGFR of 93ml/min/1.73m(2)) before transplantation. RESULTS: The medium age at transplantation was 7.9y (5-10.2) and the median follow-up was 2.8years (1.8-4.6). Renal transplantation improved the relevant metabolic parameters in 4/4 patients and renal function in the patients with CKD. Plasma and urinary MMA levels immediately decreased and remained normal or subnormal (mean values of plasma MMA before transplantation 1530µmol/L versus 240µmol/L after transplantation, and mean values of urine MMA before transplantation 4700mmol/mol creatinine versus 2300mmol/mol creatinine after transplantation). No further acute metabolic decompensation was observed and protein-intake was increased from 0.60 to 0.83g/Kg/day. One patient transplanted at age 9.7years developed a hepatoblastoma at age 11years with subsequent neurological complications and eventually died. The three other patients are alive. Two of them remained neurologically stable. The 3rd patient who displayed choreoathetosis transiently improved his neurological condition immediately after transplantation and then remained stable. CONCLUSION: Kidney transplantation represents an interesting alternative therapeutic option in methylmalonic aciduria, for renal complications but also as a "cellular therapy" that may significantly reduce metabolic decompensations and hospitalizations. However, further neurological impairment remains possible.

Hematopoietic stem cell mobilizing agents G-CSF, cyclophosphamide or AMD3100 have distinct mechanisms of action on bone marrow HSC niches and bone formation.

The CXCR4 antagonist AMD3100 is progressively replacing cyclophosphamide (CYP) as adjuvant to granulocyte colony-stimulating factor (G-CSF) to mobilize hematopoietic stem cells (HSC) for autologous transplants in patients who failed prior mobilization with G-CSF alone. It has recently emerged that G-CSF mediates HSC mobilization and inhibits bone formation via specific bone marrow (BM) macrophages. We compared the effect of these three mobilizing agents on BM macrophages, bone formation, osteoblasts, HSC niches and HSC reconstitution potential. Both G-CSF and CYP suppressed niche-supportive macrophages and osteoblasts, and inhibited expression of endosteal cytokines resulting in major impairment of HSC reconstitution potential remaining in the mobilized BM. In sharp contrast, although AMD3100 was effective at mobilizing HSC, it did not suppress osteoblasts, endosteal cytokine expression or reconstitution potential of HSC remaining in the mobilized BM. In conclusion, although G-CSF, CYP and AMD3100 efficiently mobilize HSC into the blood, their effects on HSC niches and bone formation are distinct with both G-CSF and CYP targeting HSC niche function and bone formation, whereas AMD3100 directly targets HSC without altering niche function or bone formation.

Cognitive and neuroradiological improvement in three patients with attenuated MPS I treated by laronidase.

Stem cell transplantation is not appropriate first-line treatment for attenuated phenotypes of mucopolysaccharidosis type I (MPS I). In three patients with attenuated MPSA I treated by laronidase, Patients 2 and 3 displayed significant cognitive improvement within 2years; Patients 1 and 3 displayed improvement on MRI scans of the brain.

[Obsessive compulsive disorder (OCD)]. / Trouble obsessionnel-compulsif (TOC).

Obsessive compulsive disorder (OCD) is a frequent and disabling psychic illness. Along psychiatric history, several etiological models have been successively hypothesized to explain the obsessive compulsive symptoms from a psychological, behavioural or biological point of view. This review aims at presenting OCD etiological models as well as describing OCD clinical and therapeutic aspects.

Long-term outcome in methylmalonic aciduria: a series of 30 French patients.

OBJECTIVE: To better delineate the natural history of patients with methylmalonic aciduria (MMA). STUDY DESIGN: Thirty patients with vitamin-B12-unresponsive MMA (25 aged 1.5 to 22.0 years (y) at the end of the study and 5 who died during a metabolic crisis) were managed following standardized guidelines and studied retrospectively. The median follow-up was 8.3 y (range: 1.4-19.5). Patients were investigated with neuropsychological testing, brain MRIs, inulin clearances, biochemical and genetic studies. RESULTS: Fifteen patients had a neonatal onset. Thirteen patients (43%) had significant neurological impairment. Chronic renal disease (CRD) occurred in 14 patients (47%) with a median age of onset of 6.5 y (range 1.5-18.6). Renal function further deteriorated in 4 patients within a median period of 5.8 y (range 2-7.4). Of 25 patients investigated at the enzymatic level, 17 were classified mut(o), 3 mut- and 5 cblA. Mortality, number of acute decompensations (p=0.031), median MMA urinary excretion (p=0.006) and neurological impairment (p<0.0001) were higher in mut degrees patients compared to mut-/cblA patients. Concerning the CRD, no difference incidence was found although the onset of CRD occurred earlier in mut(o) patients and was more severe. CONCLUSIONS: Our study provides unique data concerning the progression of renal disease in MMA. Patients with mut(o) phenotype have a more severe phenotype and probably an earlier and more severe CRD than patients with mut-/cblA phenotype.

Secondary creatine deficiency in ornithine delta-aminotransferase deficiency.

AIMS: Ornithine delta-aminotransferase (OAT) deficiency causes gyrate atrophy (GA) of the retina, as a consequence of high plasma ornithine concentrations. Because creatine synthesis requires the conversion of arginine and glycine into ornithine and guanidinoacetate, high ornithine concentration inhibits this reaction thus causing secondary creatine deficiency. The aim of this study was to evaluate the neuropsychological features and creatine metabolism in patients with GA. METHODS: The study involved 7 GA patients, aged from 11 to 27 years who underwent neuropsychological evaluation and cerebral proton magnetic resonance spectroscopy (MRS). RESULTS: Neurocognitive impairment was found in 5/7 patients, including mental retardation (3/7), school failure (1/7), major visuospatial dyspraxia (1/7), aggressive behavior (3/7) and epilepsy (2/7). Two patients had normal neuropsychological evaluation. Cerebral proton magnetic resonance spectroscopy revealed a profound creatine deficiency in all patients. MRS data were confirmed by decreased levels of creatine and/or guanidinoacetate in plasma and urine in all patients. CONCLUSIONS: In our group of patients with GA, we found a high prevalence of neurological impairment, not reported so far, and possibly related to secondary creatine deficiency and hyperornithinemia. We propose to treat mentally retarded GA patients with high doses of creatine, as it may normalize brain creatine levels and help to reduce ornithine levels.

Producing droplets in parallel microfluidic systems.

We study the dynamics of two microfluidic droplets emitters placed in parallel. We observe complex dynamical behavior, including synchronization, quasiperiodicity, and chaos. This dynamics has a considerable impact on the properties of the resulting emulsions: chaotic and quasi-periodic regimes give rise to polydispersed emulsions with poorly controllable characteristics, whereas synchronized regimes generate well-controlled monodispersed emulsions. We derive a dynamical model that reproduces the trends observed in the experiment.

Arnold tongues in a microfluidic drop emitter.

The Letter reports an experimental study of microfluidic droplets produced in T junctions and subjected to a local periodic forcing. Synchronized and quasiperiodic regimes--organized into Arnold tongues and devil staircases--are reported for the first time for a system dedicated to drop emission. The nature of the dynamical regime controls the droplet characteristics. These phenomena are mostly controlled by the characteristics of the forcing and the flow conditions.

Detection and quantification of 5-hydroxyoxindole in mammalian sera and tissues by high performance liquid chromatography with multi-electrode electrochemical detection.

OBJECTIVE: Since 5-hydroxyoxindole structurally related indole metabolites play different roles in some hepatic and neurologic disorders we found necessary to develop an assay to further investigate the physiologic relevance of this compound. METHODS: We have designed a convenient assay to determine 5-hydroxyoxindole in serum using solid phase extraction and a highly selective High Performance Liquid Chromatography system with multi-Electro Chemical Detection (HPLC-ECD). RESULTS: We have identified and quantified 5-hydroxyoxindole in various mammalian species. Its distribution in tissues showed that the molecule is also present in brain, liver, kidney and spleen, but not in skeletal muscle. CONCLUSIONS: 5-hydroxyoxindole is an endogenous tryptophan metabolite present in circulating blood and in some tissues at the nmol level, its determination using HPLC-ECD will be useful for elucidating the role of this molecule in normal and disease conditions.

Aspergillus fumigatus causes in vitro electrophysiological and morphological modifications in human nasal epithelial cells.

The role of the airway epithelium in the development of invasive aspergillosis in immunocompromised hosts has rarely been studied although patients at risk for this infection frequently have epithelial damage. We developed an in vitro model of primary culture of human nasal epithelial cells (HNEC) in air-liquid interface, which allows epithelial cell differentiation and mimics in vivo airway epithelium. We subsequently tested 7-day and 24-hour Aspergillus fumigatus filtrates on the apical side of HNEC to know whether A. fumigatus, the main species responsible for invasive aspergillosis, produces specific damage to the epithelial cells. The results were compared with those obtained with non-pathogenic filamentous fungi. Seven-day culture filtrates of A. fumigatus and Penicillium chrysogenum induced electrophysiological modifications whatever the fungus tested. In contrast, only 24-hour A. fumigatus filtrates induced a specific decrease in transepithelial resistance, hyperpolarization of the epithelium, and cytoplasmic vacuolization of HNEC compared with both A. niger and Penicillium chrysogenum. The inhibition of the A. fumigatus effects with amiloride suggests that the 24-hour fungal filtrate acts through sodium channels of HNEC. These early modifications of the epithelial cells could facilitate colonization of the airways by A. fumigatus. To know whether the molecules involved are specific to A. fumigatus or simply produced more rapidly than by other filamentous fungi warrants further investigation. In this perspective, the primary culture of HNEC represents a suitable model to study the interactions between airway epithelial cells and A. fumigatus.

New block-copolymer thermoassociating matrices for DNA sequencing: effect of molecular structure on rheology and resolution.

A new family of matrices for DNA sequencing by capillary electrophoresis is presented. These matrices combine easy injection with high sieving performances, due to thermal switching between a low and a high viscosity state through a modest increase in temperature (approximately 20 degrees C). They are constructed from a hydrophilic polymer backbone with grafted lower critical solution temperature (LCST) side chains. The comb-like LCST copolymers are characterized in terms of size of the polymer backbone, the size of LCST side chains and the grafting densities. The dependance of rheological behavior and electrophoretic performance of these copolymers is correlated with their microstructure. Without complete optimization, a resolution of order 0.5, corresponding to a very reasonable limit for read length with current base calling softwares, could be achieved for segments around 800 bases differing by 1 base in less than one hour in a commercial ABI 310 apparatus.

Neurologic outcomes of 90 neonates and infants with persistent hyperinsulinemic hypoglycemia.

OBJECTIVE: To evaluate the neurologic outcomes of neonates and infants suffering from persistent hyperinsulinemic hypoglycemia of infancy (PHHI). METHODS: The neurologic development of 90 PHHI patients was studied retrospectively. Sixty-three patients were treated surgically and 27 were treated medically. Fifty-four patients were neonates, of whom 8 were treated medically and 46 were operated on (19 for a focal adenomatous hyperplasia and 27 for diffuse hyperinsulinism). Thirty-six patients had infancy-onset hyperinsulinism, of whom 19 were treated medically and 17 underwent pancreatectomy (10 patients for a focal adenomatous hyperplasia and 7 for diffuse hyperinsulinism). RESULTS: Severe psychomotor retardation was found in 7 patients, 6 with neonatal-onset PHHI. Intermediate psychomotor disability existed in 12 patients; epilepsy existed in 16. Neonatal-onset was the main risk factor for severe retardation or epilepsy. Medically treated patients were less severely affected than those treated by surgery, and there was no difference between the diffuse and focal forms of hyperinsulinism. CONCLUSION: Neonatal hyperinsulinemic hypoglycemia is still a severe disease with an important risk to rapidly develop severe mental retardation and epilepsy.