CANVAS, a sensory neuronopathy to look for in ataxia.

Sensory neuronopathies name the degeneration of peripheral sensory neurons in dorsal root ganglia. Among the genetic causes, CANVAS could be the most frequent. CANVAS is a clinical entity associating cerebellar ataxia, sensory neuronopathy and vestibular areflexia due to biallelic expansions in RFC1. This study reports the 18 individuals with sensory neuronopathy tested for RFC1 expansion in our center. The clinical picture showed that chronic cough was a frequent sign beginning before the onset of other symptoms. CANVAS is an underestimated cause of late-onset sensory and cerebellar ataxia that needs to be tested for widely now that the molecular cause is known.

Has the introduction of high-flow nasal cannula modified the clinical characteristics and outcomes of infants with bronchiolitis admitted to pediatric intensive care units? A retrospective study.

BACKGROUND: This study aimed to assess how the emergence of high-flow nasal cannula (HFNC) has modified the demographic and clinical characteristics as well as outcomes of infants with bronchiolitis admitted to a pediatric intensive care unit (PICU). METHODS: This was a single-center retrospective study including infants aged 1 day to 6 months with bronchiolitis requiring HFNC, noninvasive ventilation (NIV), or invasive ventilation on admission. RESULTS: A total of 252 infants (mean age 53±36 days) were included in the study. The use of HFNC increased from 18 (21.4%) during 2013-2014 to 53 infants (55.2%) during 2015-2016. The length of stay in the PICU decreased over time from 4.7±2.9 to 3.5±2.7 days (P<0.01) but the hospital length of stay remained similar (P=0.17). On admission, patients supported by HFNC as the first-line therapy were older. The PICU length of stay was similar according to the type of respiratory support (P=0.16), but the hospital length of stay was longer for patients supported by HFNC (P=0.01). CONCLUSION: The distribution of respiratory support has significantly changed over time for patients with bronchiolitis and HFNC is increasingly used. The demographic and clinical characteristics of the have not changed over time. However, the PICU length of stay decreased significantly.

Prospective study of the additional benefit of plexus magnetic resonance imaging in the diagnosis of chronic inflammatory demyelinating polyneuropathy.

BACKGROUND AND PURPOSE: Hypertrophy/signal hyperintensity and/or gadolinium enhancement of plexus structures on magnetic resonance imaging (MRI) are observed in two-thirds of cases of typical chronic inflammatory demyelinating polyneuropathy (CIDP). The objective of our study was to determine the additional benefit of plexus MRI in patients referred to tertiary centers with baseline clinical and electrophysiological characteristics suggestive of typical or atypical CIDP. METHODS: A total of 28 consecutive patients with initial suspicion of CIDP were recruited in nine centers and followed for 2 years. Plexus MRI data from the initial assessment were reviewed centrally. Physicians blinded to the plexus MRI findings established the final diagnosis (CIDP or neuropathy of another cause). The proportion of patients with abnormal MRI was analyzed in each group. RESULTS: Chronic inflammatory demyelinating polyneuropathy was confirmed in 14 patients (50%), as were sensorimotor CIDP (n = 6), chronic immune sensory polyradiculoneuropathy (n = 2), motor CIDP (n = 1) and multifocal acquired demyelinating sensory and motor neuropathy (n = 5). A total of 37 plexus MRIs were performed (17 brachial, 19 lumbosacral and 8 in both localizations). MRI was abnormal in 5/37 patients (14%), all of whom were subsequently diagnosed with CIDP [5/14(36%)], after an atypical baseline presentation. With plexus MRI results masked, non-invasive procedures confirmed the diagnosis of CIDP in all but one patient [1/14 (7%)]. Knowledge of the abnormal MRI findings in the latter could have prevented nerve biopsy being performed. CONCLUSION: Systematic plexus MRI in patients with initially suspected CIDP provides little additional benefit in confirming the diagnosis of CIDP.

Hypertonic sodium lactate reverses brain oxygenation and metabolism dysfunction after traumatic brain injury.

BACKGROUND: The mechanisms by which hypertonic sodium lactate (HSL) solution act in injured brain are unclear. We investigated the effects of HSL on brain metabolism, oxygenation, and perfusion in a rodent model of diffuse traumatic brain injury (TBI). METHODS: Thirty minutes after trauma, anaesthetised adult rats were randomly assigned to receive a 3 h infusion of either a saline solution (TBI-saline group) or HSL (TBI-HSL group). The sham-saline and sham-HSL groups received no insult. Three series of experiments were conducted up to 4 h after TBI (or equivalent) to investigate: 1) brain oedema using diffusion-weighted magnetic resonance imaging and brain metabolism using localized 1H-magnetic resonance spectroscopy (n = 10 rats per group). The respiratory control ratio was then determined using oxygraphic analysis of extracted mitochondria, 2) brain oxygenation and perfusion using quantitative blood-oxygenation-level-dependent magnetic resonance approach (n = 10 rats per group), and 3) mitochondrial ultrastructural changes (n = 1 rat per group). RESULTS: Compared with the TBI-saline group, the TBI-HSL and the sham-operated groups had reduced brain oedema. Concomitantly, the TBI-HSL group had lower intracellular lactate/creatine ratio [0.049 (0.047-0.098) vs 0.097 (0.079-0.157); P < 0.05], higher mitochondrial respiratory control ratio, higher tissue oxygen saturation [77% (71-79) vs 66% (55-73); P < 0.05], and reduced mitochondrial cristae thickness in astrocytes [27.5 (22.5-38.4) nm vs 38.4 (31.0-47.5) nm; P < 0.01] compared with the TBI-saline group. Serum sodium and lactate concentrations and serum osmolality were higher in the TBI-HSL than in the TBI-saline group. CONCLUSIONS: These findings indicate that the hypertonic sodium lactate solution can reverse brain oxygenation and metabolism dysfunction after traumatic brain injury through vasodilatory, mitochondrial, and anti-oedema effects.

[Small fiber neuropathy]. / La neuropathie des petites fibres.

Small fiber neuropathy (SFN) is still unknown. Characterised by neuropathic pain, it typically begins by burning feet, but could take many other expression. SFN affects the thinly myelinated Aδ and unmyelinated C-fibers, by an inherited or acquired mechanism, which could lead to paresthesia, thermoalgic disorder or autonomic dysfunction. Recent studies suggest the preponderant role of ion channels such as Nav1.7. Furthermore, erythromelalgia or burning mouth syndrome are now recognized as real SFN. Various aetiologies of SFN are described. It could be isolated or associated with diabetes, impaired glucose metabolism, vitamin deficiency, alcohol, auto-immune disease, sarcoidosis etc. Several mutations have recently been identified, like Nav1.7 channel leading to channelopathies. Diagnostic management is based primarily on clinical examination and demonstration of small fiber dysfunction. Laser evoked potentials, Sudoscan®, cutaneous biopsy are the main test, but had a difficult access. Treatment is based on multidisciplinary management, combining symptomatic treatment, psychological management and treatment of an associated etiology.

[Acute epiglottitis due to Haemophilus influenzae b: A severe consequence of increased skepticism about vaccination]. / Épiglottite aiguë à Haemophilus influenzae b : conséquence grave du scepticisme vaccinal.

Acute epiglottis is a life-threatening disease in relation with the occurrence of an acute upper airway obstruction. Its incidence has fallen dramatically since the widespread introduction of Haemophilus influenzae type b (Hib) conjugate vaccine. We report the case of a 26-month-old child who was not fully immunized and presented acute upper airway respiratory distress with fever. The symptoms quickly evolved to a respiratory arrest condition with bradycardia, revealing epiglottitis due to Hib. Despite high immunization coverage with great efficacy and occurrence of herd immunity, this entity still exists because of the French population's skepticism of the routine vaccination schedule.

Mitochondrial fusion/fission dynamics in neurodegeneration and neuronal plasticity.

Mitochondria are dynamic organelles that continually move, fuse and divide. The dynamic balance of fusion and fission of mitochondria determines their morphology and allows their immediate adaptation to energetic needs, keeps mitochondria in good health by restoring or removing damaged organelles or precipitates cells in apoptosis in cases of severe defects. Mitochondrial fusion and fission are essential in mammals and their disturbances are associated with several diseases. However, while mitochondrial fusion/fission dynamics, and the proteins that control these processes, are ubiquitous, associated diseases are primarily neurological disorders. Accordingly, inactivation of the main actors of mitochondrial fusion/fission dynamics is associated with defects in neuronal development, plasticity and functioning, both ex vivo and in vivo. Here, we present the central actors of mitochondrial fusion and fission and review the role of mitochondrial dynamics in neuronal physiology and pathophysiology. Particular emphasis is placed on the three main actors of these processes i.e. DRP1,MFN1-2, and OPA1 as well as on GDAP1, a protein of the mitochondrial outer membrane preferentially expressed in neurons. This article is part of a Special Issue entitled: Mitochondria & Brain.

[Pharyngeal-cervical-brachial syndrome: A rare form of Guillain-Barré syndrome with severe acute bulbar palsy]. / Le syndrome pharyngo-cervico-brachial: un tableau de syndrome de Guillain-Barré atypique avec paralysie bulbaire sévère.

The pharyngeal-cervical-brachial (PCB) variant of Guillain-Barré syndrome is rare in children. It is characterized by oropharyngeal, neck, and upper limb muscle involvement, without ataxia and disturbed consciousness. Although associated with anti-GT1a antibodies, there is no single clinical or serological marker of PCB syndrome. We report on two cases in a 14-year-old and a 15-year-old females. The first symptom was acute dysphonia followed by severe bulbar palsy with deglutition disorders, associated with involvement of other cranial nerves and arm and leg weakness. One of the girls had normal deep tendon reflexes. Both had normal cerebral imaging and normal cerebrospinal fluid. No sign of neuropathy was found on nerve conduction studies. The diagnosis of PCB syndrome was established based on the presence of antiganglioside antibodies. Both adolescents had IgG anti-GT1a antibodies. Anti-GQ1b and anti-GT1b antibodies were associated in the first case, anti-GM1 and anti-GD1a in the second case. Clinical improvement was fast after treatment with intravenous immunoglobulin therapy. Recovery was complete. Only a few cases of children and adolescents with PCB syndrome have been reported. The main differential diagnoses were excluded with brain MRI. The neurophysiological findings in PCB syndrome are axonal neuropathy rather than demyelinating neuropathy, which might be normal in the early stages of the disease. Positivity of anti-GT1a IgG antibodies is very helpful for the diagnosis of PCB syndrome. In atypical cases of bulbar palsy with other cranial nerve involvement and normal brain MRI, diagnosis of PCB syndrome should be considered. Recognizing the atypical cases of Guillain-Barré syndrome enables anticipatory monitoring for disease complications and identifies therapeutic options. The short- and long-term outcome of the PCB syndrome after intravenous immunoglobulin treatment seems favorable.

Effect of acute and chronic excesses of dietary nitrogen on blood neutrophil functions in cattle.

Excess dietary nitrogen (EDN) is commonly expected in dairy herds, but no data are available regarding its consequences on cattle immunity. In this study neutrophil functions were assessed during EDN in steers. In experiment 1, 4 one-month periods, 4 diets [16% crude protein (CP; DM basis), 20% CP based on soybean meal, 20% CP based on urea, and 24% CP based on urea and soybean meal], and 4 steers were included in a crossover design to determine the effects of a chronic excess. In experiment 2, the repercussions of an acute excess were assessed with 2 periods of 10 d, the same 4 steers, and 2 diets containing 14 and 20% CP. Sampling was done during the fourth week of each period in experiment 1, and on d 0, 1, 2, 3, 7, and 9 of each period in experiment 2. Individual blood biochemistry parameters were measured and neutrophil factors, such as counts, recovery after isolation, surface expression of CD11b and CD62L, phagocytosis, diapedesis, reactive oxygen species (ROS) production, and bacteria killing, were determined. Data were analyzed by general linear models of R, with period, diet or biochemical component, and animal as explanatory variables. The outcome variables were biochemical or immune variables. The variables diet, period, and animal were forced as fixed effects. Data collected over the entire period of experiment 2 were pooled. Several multiples linear regressions or ANOVA were performed and a Bonferroni correction was applied. In experiment 2 (acute EDN), neutrophil counts were negatively associated with nitrogen intake, conversely to CD62L expression. The observed relative neutropenia may be due to neutrophil margination because CD62L-expressing neutrophils are more likely to stick to endothelium. Interestingly, ROS production was changed by EDN: chronic EDN (experiment 1) was negatively associated with opsonized zymozan (OZ)-induced ROS production and acute EDN (experiment 2) with spontaneous ROS production. For chronic EDN, ROS production upon phorbol 12-myristate 13-acetate was not modified, in contrast to OZ stimulation. Decreased ROS production during chronic EDN probably involves the early events leading to ROS production, as OZ acts through membrane receptors and phorbol 12-myristate 13-acetate directly activates protein kinase C. This is the first study to provide evidence that the modifications of neutrophil functions produced by excess nitrogen depend on the intensity and duration of the excess. Further studies, including epidemiological studies during risk periods, are needed to resolve the issues linked to EDN.

[Community-acquired Staphylococcus aureus necrotizing pneumonia secreting Panton-Valentine leukocidin in an infant]. / Un cas de pneumopathie nécrosante à Staphylococcus aureus sécréteur de toxine leucocidine de Panton Valentine chez un nourrisson.

Staphylococcus aureus (SA) necrotizing pneumonia secreting Panton-Valentine leukocidin (PVL) has a high mortality rate, approximately 50% according to recent data, mainly in children and young adults. Recently, 2 cases of the disease have been reported in newborn twins with a good outcome. We report a third case of community-acquired necrotizing pneumonia due to SA sensitive to methicillin (SASM) secreting Panton-Valentine leukocidin (PVL) in an infant, initially paucisymptomatic, in the context of familial furunculosis, with a fatal outcome. Cases of necrotizing pneumonia in this age group are emerging, and extensive information for clinicians is needed due to the high mortality rate of the disease.

[Sickle cell disease and invasive osteoarticular Salmonella infections]. / Drépanocytose et salmonelloses invasives ostéo-articulaires.

Non-typhi Salmonella are responsible for severe invasive infections in children with sickle cell disease, with osteoarticular locations that can affect short- and long-term outcomes. We describe the cases of 2 children with sickle cell disease who presented paucisymptomatic Salmonella osteoarticular infections on returning from North Africa. Progression was favorable in both cases after appropriate systemic antibiotic therapy, although one Salmonella was multidrug-resistant. Invasive salmonellosis remains rare in France, but, because of its severity, it should be suspected in any patient with sickle cell disease presenting fever, especially in the context of recent trips in Africa countries. Early clinical diagnosis is essential to start appropriate empirical treatment without waiting for bacteriological results.

Novel mutations in pyridoxine-dependent epilepsy.

PURPOSE: Pyridoxine-Dependent Epilepsy (PDE) is a rare autosomal recessive disease with neonatal seizures resistant to conventional anti-epileptic drugs. This metabolic disease has to be diagnosed early and treated to improve outcome. We report on two new mutations that open new prenatal prospects and suggest a new diagnostic procedure. CASE REPORT: We describe PDE in a neonate carrying two novel mutations in the ALDH7A1 gene: c.[852_856delCTTAG] + [1230C > A]; p.[(Phe410Leu)] + p.[(Leu285CysfsX26)]. This case also illustrates that diagnosis could have been made without any pyridoxine withdrawal, thanks to the measurement of biomarkers. The patient was successfully treated with pyridoxine supplementation and currently shows normal neurological development.

[Stiff-person syndrome and other neurological disorders associated with anti-GAD antibodies]. / Le syndrome de l'homme raide et autres maladies neurologiques associées aux anticorps anti-GAD.

Autoantibodies to glutamic acid decarboxylase (GAD), originally identified in the stiff-person syndrome, are also associated with rare cases of therapy-resistant epilepsy and sporadic cerebellar ataxia. The association of GAD antibodies with these three syndromes and other auto-immune diseases, particularly type 1 diabetes mellitus, argues for their auto-immune origin. Anti-GAD antibodies inhibit GABAergic circuits inducing a neuronal hyper-excitability that seems to be responsible for these three syndromes. However, an additional mechanism seems to be involved in the degenerative component of the cerebellar ataxia associated with anti-GAD antibodies. A more accurate diagnosis and the study of neuropathological cases are necessary to document the different mechanisms implicated in these neurological disorders.

Targeted transgenesis at the HPRT locus: an efficient strategy to achieve tightly controlled in vivo conditional expression with the tet system.

The tet-inducible system has been widely used to achieve conditional gene expression in genetically modified mice. To alleviate the frequent difficulties associated with recovery of relevant transgenic founders, we tested whether a controlled strategy of transgenesis would support reliable cell-specific, doxycycline (Dox)-controlled transgene expression in vivo. Taking advantage of the potent hypoxanthine-aminopterin-thymidine selection strategy and an embryonic stem (ES) cell line supporting efficient germ-line transmission, we used hypoxanthine phosphoribosyltransferase (HPRT) targeting to insert a single copy tet-inducible construct designed to allow both glucocorticoid receptor (GR) and beta-galactosidase (beta-Gal) expression. Conditional, Dox-dependent GR and beta-Gal expression was evidenced in targeted ES cells. Breeding ES-derived single copy transgenic mice with mice bearing appropriate tet transactivators resulted in beta-Gal expression both qualitatively and quantitatively similar to that observed in mice with random integration of the same construct. Interestingly, GR expression in mice was dependent on transgene orientation in the HPRT locus while embryonic stem cell expression was not. Thus, a conditional construct inserted in single copy and in predetermined orientation at the HPRT locus demonstrated a Dox-dependent gene expression phenotype in adult mice suggesting that controlled insertion of tet-inducible constructs at the HPRT locus can provide an efficient alternative strategy to reproducibly generate animal models with tetracycline-induced transgene expression.

Characterization of rabbit ear skin as a skin model for in vitro transdermal permeation experiments: histology, lipid composition and permeability.

AIM: The aim of this work was to characterize rabbit ear skin in view of its use in transdermal permeation experiments. METHOD: The characterization included histological analysis of the tissue, qualitative and quantitative analysis of stratum corneum (SC) lipids, differential scanning calorimetry and permeation experiments (caffeine, nicotinamide, progesterone). As a reference, pig ear skin was used. RESULTS: The results obtained show that rabbit ear skin has a similar SC thickness compared to pig skin although the viable epidermis has a different structure. The lipid composition of rabbit SC was similar to pig SC but was characterized by a lower content of ceramides and a higher content of cholesterol esters and triglycerides. In terms of permeability, rabbit ear skin was 4-7 times less permeable to hydrophilic compounds, probably because of the higher lipophilicity of its SC. The permeability to progesterone was comparable between isolated pig epidermis and rabbit ear skin. CONCLUSION: Overall, the results obtained in this work support the usefulness of rabbit ear skin as barrier for skin penetration studies, for both lipophilic and hydrophilic permeants.

[Invasion of the pulmonary artery by an undifferentiated carcinoma]. / Obstruction tumorale de l'artère pulmonaire par un carcinome indifférencié

INTRODUCTION: The diagnosis of chronic obstruction of the pulmonary artery is difficult. We present the case of a woman with an invasive, undifferentiated carcinoma of the pulmonary artery. CASE REPORT: A 61 year old woman complained of increasing dyspnoea. This was evaluated by computed tomography which showed a defect in the main pulmonary artery. There was no clinical or radiological improvement following anticoagulant treatment for two months. A repeat CT scan showed a persisting intravascular defect and the diagnoses considered included post-embolic pulmonary arterial hypertension and angiosarcoma. A surgical biopsy was performed and pericardial and aortic tumour nodules were found during the operation. The pathological examination revealed undifferentiated carcinoma. Further investigations failed to reveal the primary site. CONCLUSION: Invasion of the pulmonary artery by angiosarcoma or other tumour is part of the differential diagnosis of chronic thromboembolic disease. The diagnosis rests on histology obtained by an intravascular or surgical procedure. Complete surgical excision may be possible in angiosarcoma but it was impossible in our patient. The patient died despite two courses of chemotherapy and targeted therapy with erlotinib.