Developmental emergence of first- and higher-order thalamic neuron molecular identities.

The thalamus is organized into nuclei that have distinct input and output connectivities with the cortex. Whereas first-order (FO) nuclei - also called core nuclei - relay input from sensory organs on the body surface and project to primary cortical sensory areas, higher-order (HO) nuclei - matrix nuclei - instead receive their driver input from the cortex and project to secondary and associative areas within cortico-thalamo-cortical loops. Input-dependent processes have been shown to play a crucial role in the emergence of FO thalamic neuron identity from a ground-state HO neuron identity, yet how this identity emerges during development remains unknown.

Molecular programs guiding arealization of descending cortical pathways.

Layer 5 extratelencephalic (ET) neurons are present across neocortical areas and send axons to multiple subcortical targets. Two cardinal subtypes exist: (1) Slco2a1-expressing neurons (ET), which predominate in the motor cortex and project distally to the pons, medulla and spinal cord; and (2) Nprs1- or Hpgd-expressing neurons (ET), which predominate in the visual cortex and project more proximally to the pons and thalamus. An understanding of how area-specific ET and ET emerge during development is important because they are critical for fine motor skills and are susceptible to spinal cord injury and amyotrophic lateral sclerosis.

Cxcr4 and Ackr3 regulate allocation of caudal ganglionic eminence-derived interneurons to superficial cortical layers.

The function of the cerebral cortex depends on various types of interneurons (cortical interneurons [cINs]) and their appropriate allocation to the cortical layers. Caudal ganglionic eminence-derived cINs (cGE-cINs) are enriched in superficial layers. Developmental mechanisms directing cGE-cINs toward superficial layers remain poorly understood.

The microcephaly gene Donson is essential for progenitors of cortical glutamatergic and GABAergic neurons.

Biallelic mutations in DONSON, an essential gene encoding for a replication fork protection factor, were linked to skeletal abnormalities and microcephaly. To better understand DONSON function in corticogenesis, we characterized Donson expression and consequences of conditional Donson deletion in the mouse telencephalon. Donson was widely expressed in the proliferation and differentiation zones of the embryonic dorsal and ventral telencephalon, which was followed by a postnatal expression decrease.

ACKR3 Regulation of Neuronal Migration Requires ACKR3 Phosphorylation, but Not β-Arrestin.

Phosphorylation of heptahelical receptors is thought to regulate G protein signaling, receptor endocytosis, and non-canonical signaling via recruitment of β-arrestins. We investigated chemokine receptor functionality under phosphorylation-deficient and β-arrestin-deficient conditions by studying interneuron migration in the embryonic cortex. This process depends on CXCL12, CXCR4, G protein signaling and on the atypical CXCL12 receptor ACKR3.

A Translaminar Genetic Logic for the Circuit Identity of Intracortically Projecting Neurons.

Neurons of the neocortex are organized into six radial layers, which have appeared at different times during evolution, with the superficial layers representing a more recent acquisition. Input to the neocortex predominantly reaches superficial layers (SL, i.e.

CXCL12-mediated feedback from granule neurons regulates generation and positioning of new neurons in the dentate gyrus.

Adult hippocampal neurogenesis is implicated in learning and memory processing. It is tightly controlled at several levels including progenitor proliferation as well as migration, differentiation and integration of new neurons. Hippocampal progenitors and immature neurons reside in the subgranular zone (SGZ) and are equipped with the CXCL12-receptor CXCR4 which contributes to defining the SGZ as neurogenic niche.

Intermediate Progenitors Facilitate Intracortical Progression of Thalamocortical Axons and Interneurons through CXCL12 Chemokine Signaling.

Glutamatergic principal neurons, GABAergic interneurons and thalamocortical axons (TCAs) are essential elements of the cerebrocortical network. Principal neurons originate locally from radial glia and intermediate progenitors (IPCs), whereas interneurons and TCAs are of extrinsic origin. Little is known how the assembly of these elements is coordinated.

CXCR7 prevents excessive CXCL12-mediated downregulation of CXCR4 in migrating cortical interneurons.

The CXCL12/CXCR4 signaling pathway is involved in the development of numerous neuronal and non-neuronal structures. Recent work established that the atypical second CXCL12 receptor, CXCR7, is essential for the proper migration of interneuron precursors in the developing cerebral cortex. Two CXCR7-mediated functions were proposed in this process: direct modulation of β-arrestin-mediated signaling cascades and CXCL12 scavenging to regulate local chemokine availability and ensure responsiveness of the CXCL12/CXCR4 pathway in interneurons.

Reelin and CXCL12 regulate distinct migratory behaviors during the development of the dopaminergic system.

The proper functioning of the dopaminergic system requires the coordinated formation of projections extending from dopaminergic neurons in the substantia nigra (SN), ventral tegmental area (VTA) and retrorubral field to a wide array of forebrain targets including the striatum, nucleus accumbens and prefrontal cortex. The mechanisms controlling the assembly of these distinct dopaminergic cell clusters are not well understood. Here, we have investigated in detail the migratory behavior of dopaminergic neurons giving rise to either the SN or the medial VTA using genetic inducible fate mapping, ultramicroscopy, time-lapse imaging, slice culture and analysis of mouse mutants.

CXC chemokine receptor 7 (CXCR7) affects the migration of GnRH neurons by regulating CXCL12 availability.

Gonadotropin-releasing hormone (GnRH) neurons are neuroendocrine cells, located in the hypothalamus, that play an essential role in mammalian reproduction. These neurons originate in the nasal placode and migrate during embryonic development, in association with olfactory/vomeronasal nerves, first in the nose, then through the cribriform plate to enter the forebrain, before settling in the hypothalamus. One of the molecules required for their early migration in the nose is the chemokine CXCL12, which is expressed in the embryonic nasal mesenchyme in an increasing ventral to dorsal gradient, presumably guiding GnRH neurons toward the forebrain.

CXCR4 prevents dispersion of granule neuron precursors in the adult dentate gyrus.

Neurogenesis in the adult dentate gyrus (DG) generates new granule neurons that differentiate in the inner one-third of the granule cell layer (GCL). The migrating precursors of these neurons arise from neural stem cells (NSCs) in the subgranular zone (SGZ). Although it is established that pathological conditions, including epilepsy and stroke, cause dispersion of granule neuron precursors, little is known about the factors that regulate their normal placement.

Masticatory fatigue, fracture resistance, and marginal discrepancy of ceramic partial crowns with and without coverage of compromised cusps.

Purpose: To evaluate preparation designs of compromised cusps and whether or not they influence masticatory fatigue, fracture resistance, and marginal discrepancy of ceramic partial-coverage restorations (PCRs) luted on mandibular molars.

Materials And Methods: Sixty-four caries-free molars were equally divided into four groups. Control group NP received no preparation (NP).

Mechanical evaluation of a respiratory device.

This article aims to characterize the mechanical behaviour of the Flutter VRP1, a respiratory physiotherapy device designed to aid sputum clearance of the airways of patients. The device resembles a smoking pipe with a conical cavity containing a stainless steel sphere which floats up and down while the patient comes with a forced expiration through it. The sphere's oscillatory movement is function of the air flow rate and angular orientation of the device.

Use of real-time PCR with multiple targets to identify Pseudomonas aeruginosa and other nonfermenting gram-negative bacilli from patients with cystic fibrosis.

Pseudomonas aeruginosa and other gram-negative isolates from patients with cystic fibrosis (CF) may be difficult to identify because of their marked phenotypic diversity. We examined 200 gram-negative clinical isolates from CF respiratory tract specimens and compared identification by biochemical testing and real-time PCR with multiple different target sequences using a standardized combination of biochemical testing and molecular identification, including 16S rRNA partial sequencing and gyrB PCR and sequencing as a "gold standard." Of 50 isolates easily identified phenotypically as P.

Extrapulmonary Legionella micdadei infection in a previously healthy child.

A previously healthy 9-year-old girl presented with a 1-week history of left neck mass and low grade fever. Surgical drainage specimens from the mass were bacterial culture-negative. Legionella micdadei infection was diagnosed by a two step PCR-nucleic acid sequencing method and supported by organism-specific serology.

Bordetella pertussis PCR: simultaneous targeting of signature sequences.

The absence of analytical controls for polymerase chain reaction (PCR)-based diagnostic tests for Bordetella pertussis limits their clinical utility. In this study, multiplex PCR simultaneously targeted two specific Bordetella pertussis sequences, the chromosomal repeated insertion sequence IS481 (IS) and the pertussis toxin promoter region (PT). A multi-target hybridization-EIA (Hyb-EIA) method in a 96-well microtiter-plate format was used to detect amplicons.

Hemolytic activity of Fusobacterium necrophorum culture supernatants due to presence of phospholipase A and lysophospholipase.

Culture supernatants of Fusobacterium necrophorum demonstrated hemolytic activity. The hemolysin(s), which was partially purified by ammonium sulfate precipitation, was temperature-dependent and heat labile. The spectrum of hemolytic activity against various erythrocytes included rabbit, human, and dog erythrocytes.

Immunization of mice against Fusobacterium necrophorum infection by perenteral or oral administration of vaccine.

Immunization of mice against Fusobacterium necrophorum infection was attempted by using 3 vaccination procedures: (1) intraperitoneal (IP) injection of F necrophorum cells in saline solution, (2) IP injection of cells with added aluminum hydroxide adjuvant, and (3) feeding of a powdered mouse diet containing lyophilized cells. One or 2 weekly IP injections of the bacteria cells (in saline solution) for 3, 6, or 12 weeks resulted in protection of 48.7% to 64.

Fusobacterium necrophorum infection in mice as a model for the study of liver abscess formation and induction of immunity.

A mouse model is described in which intraperitoneal injection of Fusobacterium necrophorum results in chronic liver abscesses. Viable bacterial counts from mouse lung, liver, and spleen were obtained after whole organ homogenization. From 2 h to 5 days postchallenge, liver was found to contain more bacteria than lung on a per gram basis.