ENHANCER of TRY and CPC 2 ( ETC2 ) reveals redundancy in the region-specific control of trichome development of Arabidopsis

>An evolutionarily conserved set of proteins consisting of MYB and bHLH transcription factors and a WD40 domain protein is known to act in concert to control various developmental processes including trichome and root hair development. Their function is difficult to assess because most of them belong to multigene families and appear to act in a redundant fashion. In this study we identified an enhancer of the two root hair and trichome patterning mutants triptychon ( try ) and caprice ( cpc ), enhancer of try and cpc2 ( etc2 ). The ETC2 gene shows high sequence similarity to the single-repeat MYB genes CPC and TRY. Overexpression results in the suppression of trichomes and overproduction of root hairs similarly as observed for TRY and CPC suggesting that ETC2 has similar biochemical properties. The etc2 single mutant shows an increase in trichome number on leaves and petiols. Double and triple mutant analysis indicates that the ETC2 gene acts redundant with TRY and CPC in trichome patterning.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43456/1/11103_2004_Article_DO00000893.pd

Derivation of High Purity Neuronal Progenitors from Human Embryonic Stem Cells

The availability of human neuronal progenitors (hNPs) in high purity would greatly facilitate neuronal drug discovery and developmental studies, as well as cell replacement strategies for neurodegenerative diseases and conditions, such as spinal cord injury, stroke, Parkinson's disease, Alzheimer's disease, and Huntington's disease. Here we describe for the first time a method for producing hNPs in large quantity and high purity from human embryonic stem cells (hESCs) in feeder-free conditions, without the use of exogenous noggin, sonic hedgehog or analogs, rendering the process clinically compliant. The resulting population displays characteristic neuronal-specific markers. When allowed to spontaneously differentiate into neuronal subtypes in vitro, cholinergic, serotonergic, dopaminergic and/or noradrenergic, and medium spiny striatal neurons were observed. When transplanted into the injured spinal cord the hNPs survived, integrated into host tissue, and matured into a variety of neuronal subtypes. Our method of deriving neuronal progenitors from hESCs renders the process amenable to therapeutic and commercial use

Human Neural Stem Cells Differentiate and Promote Locomotor Recovery in an Early Chronic Spinal coRd Injury NOD-scid Mouse Model

Traumatic spinal cord injury (SCI) results in partial or complete paralysis and is characterized by a loss of neurons and oligodendrocytes, axonal injury, and demyelination/dysmyelination of spared axons. Approximately 1,250,000 individuals have chronic SCI in the U.S.; therefore treatment in the chronic stages is highly clinically relevant. Human neural stem cells (hCNS-SCns) were prospectively isolated based on fluorescence-activated cell sorting for a CD133(+) and CD24(-/lo) population from fetal brain, grown as neurospheres, and lineage restricted to generate neurons, oligodendrocytes and astrocytes. hCNS-SCns have recently been transplanted sub-acutely following spinal cord injury and found to promote improved locomotor recovery. We tested the ability of hCNS-SCns transplanted 30 days post SCI to survive, differentiate, migrate, and promote improved locomotor recovery.hCNS-SCns were transplanted into immunodeficient NOD-scid mice 30 days post spinal cord contusion injury. hCNS-SCns transplanted mice demonstrated significantly improved locomotor recovery compared to vehicle controls using open field locomotor testing and CatWalk gait analysis. Transplanted hCNS-SCns exhibited long-term engraftment, migration, limited proliferation, and differentiation predominantly to oligodendrocytes and neurons. Astrocytic differentiation was rare and mice did not exhibit mechanical allodynia. Furthermore, differentiated hCNS-SCns integrated with the host as demonstrated by co-localization of human cytoplasm with discrete staining for the paranodal marker contactin-associated protein.The results suggest that hCNS-SCns are capable of surviving, differentiating, and promoting improved locomotor recovery when transplanted into an early chronic injury microenvironment. These data suggest that hCNS-SCns transplantation has efficacy in an early chronic SCI setting and thus expands the "window of opportunity" for intervention

Cloning and characterization of the BgxA gene from <i>Erwinia chrysanthemi</i> D1 which encodes a β-glucosidase/xylosidase enzyme

International audienc

Corrective distal radius osteotomy: including bilateral differences in 3-D planning

After a fracture of the distal radius, the bone segments may heal in a suboptimal position. This condition may lead to a reduced hand function, pain and finally osteoarthritis, sometimes requiring corrective surgery. Recent studies report computer-assisted 3-D planning techniques in which the mirrored contralateral unaffected radius serves as reference for planning the position of the distal radius before corrective osteotomy surgery. Bilateral asymmetry, however, may introduce length errors into this type of preoperative planning that can be compensated for by taking into account the concomitant ulnae asymmetry. This article investigates a method for planning a correction osteotomy of the distal radius, while compensating for bilateral length differences using a linear regression model that describes the relationship between radii and ulnae asymmetry. The method is evaluated quantitatively using CT scans of 20 healthy individuals, and qualitatively using CT scans of patients suffering from a malunion of the distal radius. The improved planning method reduces absolute length deviations by a factor of two and markedly reduces positioning variation, from 2.9 ± 2.1 to 1.5 ± 0.6 mm. We expect the method to be of great value for future 3-D planning of a corrective distal radius osteotom

Patient-tailored plate for bone fixation and accurate 3D positioning in corrective osteotomy

A bone fracture may lead to malunion of bone segments, which gives discomfort to the patient and may lead to chronic pain, reduced function and finally to early osteoarthritis. Corrective osteotomy is a treatment option to realign the bone segments. In this procedure, the surgeon tries to improve alignment by cutting the bone at, or near, the fracture location and fixates the bone segments in an improved position, using a plate and screws. Three-dimensional positioning is very complex and difficult to plan, perform and evaluate using standard 2D fluoroscopy imaging. This study introduces a new technique that uses preoperative 3D imaging to plan positioning and design a patient-tailored fixation plate that only fits in one way and realigns the bone segments as planned. The method is evaluated using artificial bones and renders realignment highly accurate and very reproducible (d(err) < 1.2 ± 0.8 mm and φ(err) < 1.8° ± 2.1°). Application of a patient-tailored plate is expected to be of great value for future corrective osteotomy surgerie

Positioning evaluation of corrective osteotomy for the malunited radius: 3-D CT versus 2-D radiographs

The authors retrospectively investigated the postoperative position of the distal radius after a corrective osteotomy using 2-dimensional (2-D) and 3-dimensional (3-D) imaging techniques to determine whether malposition correlates with clinical outcome. Twenty-five patients who underwent a corrective osteotomy were available for follow-up. The residual positioning errors of the distal end were determined retrospectively using standard 2-D radiographs and 3-D computed tomography evaluations based on a scan of both forearms, with the contralateral healthy radius serving as reference. For 3-D analysis, use of an anatomical coordinate system for each reference bone allowed the authors to express the residual malalignment parameters in displacements (Δx, Δy, Δz) and rotations (Δφx, Δφy, Δφz) for aligning the affected bone in a standardized way with the corresponding reference bone. The authors investigated possible correlations between malalignment parameters and clinical outcome using patients' questionnaires. Two-dimensional radiographic evaluation showed a radial inclination of 24.9°±6.8°, a palmar tilt of 4.5°±8.6°, and an ulnar variance of 0.8±1.7 mm. With 3-D analysis, residual displacements were 2.6±3 (Δx), 2.4±3 (Δy), and -2.2±4 (Δz) mm. Residual rotations were -6.2°±10° (Δφx), 0.3°±7° (Δφy), and -5.1°±10° (Δφz). The large standard deviation is indicative of persistent malalignment in individual cases. Statistically significant correlations were found between 3-D rotational deficits and clinical outcome but not between 2-D evaluation parameters. Considerable residual malalignments and statistically significant correlations between malalignment parameters and clinical outcome confirm the need for better positioning technique