Deposition chamber technology as building blocks for a standardized brain-on-chip framework.

The in vitro modeling of human brain connectomes is key to exploring the structure-function relationship of the central nervous system. Elucidating this intricate relationship will allow better studying of the pathological mechanisms of neurodegeneration and hence result in improved drug screenings for complex neurological disorders, such as Alzheimer's and Parkinson diseases. However, currently used in vitro modeling technologies lack the potential to mimic physiologically relevant neural structures. Herein, we present an innovative microfluidic design that overcomes one of the current limitations of in vitro brain models: their inability to recapitulate the heterogeneity of brain regions in terms of cellular density and number. This device allows the controlled and uniform deposition of any cellular population within unique plating chambers of variable size and shape. Through the fine tuning of the hydrodynamic resistance and cell deposition rate, the number of neurons seeded in each plating chamber can be tailored from a thousand up to a million. By applying our design to so-called neurofluidic devices, we offer novel neuro-engineered microfluidic platforms that can be strategically used as organ-on-a-chip platforms for neuroscience research. These advances provide essential enhancements to in vitro platforms in the quest to provide structural architectures that support models for investigating human neurodegenerative diseases.

Rapid mask prototyping for microfluidics.

With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks.

[Metabolic abnormalities in obese French children]. / Prévalence des anomalies métaboliques chez l'enfant obèse.

PURPOSE: The aim of this retrospective study was to describe the prevalence of metabolic abnormalities among obese children. PATIENTS AND METHODS: Two hundred and forty-four obese children were referred in our center between 2003 and 2007. The frequency of metabolic syndrome (MS) was assessed with the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria. Insulin resistance was defined as a Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) greater than the 75th percentile. RESULTS: Around 95.9% of the children had abdominal obesity, 38.1% had systolic hypertension, 19.3% diastolic hypertension, 12.3% hypertriglyceridemia, and 4.1% hypoHDLemia. Insulin resistance was present in 69.6% of children; 11.5% of children met the criteria for MS. Both the Z-score of the body mass index and the prevalence of metabolic abnormalities were higher in the group of the youngest children. CONCLUSION: The prevalence of metabolic abnormalities is high among overweight children, particularly in the youngest children. However, the management of obesity but not metabolic-specific intervention remains the priority.

[Diagnosis of a Friedreich's ataxia: contribution of electrophysical explorations]. / Diagnostic d'ataxie de Friedreich: apport des explorations neurophysiologiques.

UNLABELLED: The monitoring of scoliosis treatment can lead to discover its cause. CASE REPORT: A 16-year-old patient was allowed in Center of Functional Rehabilitation for intensive orthopaedic treatment of a severe scoliosis. Electrophysiological explorations carried out within the framework of the monitoring of this treatment detected an axonal neuropathy with sensitive prevalence, whose association with clinical signs made it possible to diagnose Friedreich's disease, then confirmed by molecular biology. CONCLUSION: Electrophysiological examination is useful in a Rehabilitation Center within the framework of the monitoring of the treatment proposed, more especially as it can make it possible to direct a diagnosis.

[Electrophysical surveillance in limb lengthening in 25 children and adolescents]. / Intérêt de la surveillance électrophysiologique des allongements de membre par fixateur externe: à propos de 25 enfants et adolescents.

OBJECTIVE: To evaluate neurological tolerance during limb lengthening in children and adolescents. MATERIAL AND METHODS: Retrospective study of 25 children and adolescents [15 girls, 10 boys; mean age 11.3 years, range 5-18 years] undergoing limb lengthening. Limbs involved were the femur [11 cases], tibia [10 cases], radius [3 cases] and humerus [1 case], and lengthening was 1 mm/day, adjusted depending on clinically and electrophysically observed alterations during weekly surveillance. RESULTS: Lengthening in 8 cases was accompanied by electrophysiological deterioration and in 1 by clinical alteration without electrophysiological anomaly. Eight of 25 lengthenings had to be slowed and 1 discontinued. DISCUSSION: This work confirms poor neurological tolerance with limb lengthening. It shows the interest of clinical and electrophysiological monitoring in preventing severe neurological accidents with such lengthening.

The Use of Green Fluorescent Protein-Tagged Recombinant Viruses to Test Lettuce mosaic virus Resistance in Lettuce.

ABSTRACT Seed certification and the use of cultivars containing one of two, probably allelic, recessive genes, mo1(1) and mo1(2), are the principal control methods for Lettuce mosaic virus (LMV) in lettuce. Although for a few LMV isolates, mo1(2) confers resistance with most isolates, the genes mo1(1) or mo1(2) confer a tolerance, and virus accumulation is readily detected in mo1-carrying plants. This phenotype complicates evaluation of the resistance status, in particular for mo1(1), for which there are no viral strains against which a true resistance is expressed. Two green fluorescent protein (GFP)-tagged viruses were constructed, derived from a non-resistance breaking isolate (LMV-0) and from a resistance-breaking isolate (LMV-E). An evaluation of 101 cultivars of known status was carried out with these recombinant viruses. Using the LMV-0-derived recombinant, identification of mo1-carrying cultivars was simple because, contrary to its wild-type parent, systemic movement of LMV-0-GFP was abolished in resistant plants. This assay detected four cases of misidentification of resistance status. In all these cases, further tests confirmed that the prior resistance status information was incorrect, so that a 100% correlation was observed between LMV-0-GFP behavior and the mo1 resistance status. Similarly, the LMV-E-derived recombinant allowed the identification of mo1(2) lettuce lines because its systemic movement was restricted in mo1(2) lines but not in susceptible or in mo1(1) lines. The tagged viruses were able to systemically invade another host, pea, irrespective of its resistance status against another member of the genus Potyvirus, Pea seed-borne mosaic virus. The use of these recombinant viruses could therefore greatly facilitate LMV resistance evaluation and speed up lettuce breeding programs.

A Lactuca universal hybridizer, and its use in creation of fertile interspecific somatic hybrids.

A Lactuca sativa cv. Ardente line heterozygous for a gene encoding resistance to kanamycin, a positive and dominant trait, was crossed with cv. Girelle, which is heterozygous for a recessive albinism marker. The resulting seeds yielded 25% albino seedlings, of which 50% were also resistant to kanamycin. Such plantlets (KR, a) grown in vitro were used for preparation of universal hybridizer protoplasts, since green buds that can develop on kanamycin containing-medium should result from fusion with any wild-type protoplast. To test the practicability of this selection scheme, we fused L. sativa KR, a protoplasts with protoplasts derived from various wild Lactuca as well as various other related species. Protoplast-derived cell colonies were selected for resistance to kanamycin at the regeneration stage. Green buds were regenerated after fusion with protoplasts of L. tatarica and of L. perennis. So far, 9 interspecific hybrid plants have been characterized morphologically. In addition, random amplified polymorphic DNA (RAPD) analysis with selected primers confirmed that these plants are indeed interspecific hybrids. Some plants are female-fertile and production of backcross progenies with L. sativa is in progress. Since many desirable traits such as resistances to viruses, bacteria and fungi (Bremia lactucae) have been characterized in wild Lactuca species, the use of somatic hybridization in breeding programmes now appears a practical possibility.

Rapid mapping of two genes for resistance to downy mildew from Lactuca serriola to existing clusters of resistance genes.

Two resistances to downy mildew derived from Lactuca serriola were characterized genetically and mapped using molecular markers. Classical genetic analysis suggested monogenic inheritance; however, the presence of multiple, tightly-linked genes in each case could not be eliminated. Therefore, they were designated resistance factors R17 and R18. Analysis with molecular markers known to be linked to clusters of resistance genes quickly revealed linkage of R18 to the major cluster of resistance genes and provided six linked markers, three RAPD (Random Amplified Polymorphic DNA) markers and three codominant SCAR (Sequence Characterized Amplified Region) markers. The mapping of R17 required the screening of arbitrary RAPD markers using bulked segregant analysis; this provided five linked markers, three of which segregated in the basic mapping population. This demonstrated loose linkage to a second cluster of resistance genes and provided additional linked markers. Two RAPD markers linked to R17 were converted into SCARs. The identification of reliable PCR-based markers flanking each gene will aid in selection and in combining these resistance genes with others.