Glucocorticoids exert direct toxicity on microvasculature: analysis of cell death mechanisms.

Glucocorticoids (GCs) are routinely administered systemically or injected into the eye when treating numerous ocular diseases; however, their toxicity on the retinal microvasculature has not been previously investigated. In this article, the effects of hydrocortisone (Hydro), dexamethasone, dexamethasone-phosphate and triamcinolone acetonide (TA) were evaluated in vitro on human skin microcirculation cells and, bovine endothelial retinal cells, ex-vivo, on flat mounted rat retinas. The degree of GCs induced endothelial cell death varied according to the endothelial cell type and GCs chemical properties. GCs toxicity was higher in skin microvascular endothelial cells and for hydrophobic GC formulations. The mechanism of cell death differed between GCs, Hydro and TA activated the leukocyte elastase inhibitor/L-DNase II pathways but did not activate caspases. The mechanisms of cell death observed in cell cultures were similar to those observed in rat retinal explants. Taken together these results indicate that particular attention should be paid to the potential vascular side effects when administrating GCs clinically and in particular when developing sustained-release intraocular devices

Optimal calibration of TELEMAC-2D models based on a data assimilation algorithm

Water Qualit

Iron oxide doped boron nitride nanotubes: structural and magnetic properties

A first-principles formalism is employed to investigate the interaction of iron oxide (FeO) with a boron nitride (BN) nanotube. The stable structure of the FeO-nanotube has Fe atoms binding N atoms, with bond length of roughly $\sim$2.1 \AA, and binding between O and B atoms, with bond length of 1.55 \AA. In case of small FeO concentrations, the total magnetic moment is (4$\mu_{Bohr}$) times the number of Fe atoms in the unit cell and it is energetically favorable to FeO units to aggregate rather than randomly bind to the tube. As a larger FeO concentration case, we study a BN nanotube fully covered by a single layer of FeO. We found that such a structure has square FeO lattice with Fe-O bond length of 2.11 \AA, similar to that of FeO bulk, and total magnetic moment of 3.94$\mu_{Bohr}$ per Fe atom. Consistently with experimental results, the FeO covered nanotube is a semi-half-metal which can become a half-metal if a small change in the Fermi level is induced. Such a structure may be important in the spintronics context.Comment: 10 pages, 3 figure

Assessment of metal trace elements in the echinoderm Paracentrotus lividus from the North-Eastern coast of Algeria

The echinoderm sea urchin Paracentrotus lividus Lamarck, 1816 (Echinodermata, Echinoidea) is a good species to be used in environmental and toxicology research, in particular as a heavy metal bio-indicator. Our study’s objective is to evaluate the amounts of Zn, Pb, Fe, and Cu in sea urchin specimens collected from the coast of Skikda (Northeast Algeria) in order to validate the fact that sea urchins are good indicators of metal pollution and can be used effectively for environmental biomonitoring. To realize our objectives, three sampling sites were chosen based on suspected forms and sources of contamination. The main physicochemical parameters of the seawater were measured to determine their quality. 15 specimens of urchins in each station were obtained from exposed rocky surfaces and transported to the laboratory. Before dissection, the biometric parameters and the total wet weight were determined. The soft organs (gut and gonads) of individuals were separated and utilized to evaluate the levels of heavy metals. The condition index and metal indices were also determined. Our study confirmed that P. lividus may be considered a valuable bioindicator of heavy metal contamination in marine ecosystems. The results show that the amounts of heavy metals differed significantly between stations. Samples taken from the Larbi Ben M’hidi station showed greater amounts of Pb, Zn, and Cu. These amounts are above the recommended limits for fish and aquatic animals. Also, the heavy metals found in sea urchins vary depending on the physicochemical parameters, trace metals in the seawater, and the individual biometric parameters. These higher concentrations of metals in seawater and in P. lividus individuals at the Larbi Ben M’hidi station are largely caused by the construction of a massive oil industry complex and terminal with several refineries and petrochemical units near this station, as well as by a considerable amount of domestic wastewater. Finally, to avoid this metallic pollution risk, it is necessary that permanent controls be imposed as soon as possible. Urban and industrial wastes must be treated before being released, in the hope of reducing future metal concentrations

On the use of an appropriate TdT-mediated dUTP-biotin nick end labeling assay to identify apoptotic cells.

Apoptosis is an essential cellular mechanism involved in many processes such as embryogenesis, metamorphosis, and tissue homeostasis. DNA fragmentation is one of the key markers of this form of cell death. DNA fragmentation is executed by endogenous endonucleases such as caspase-activated DNase (CAD) in caspase-dependent apoptosis. The TUNEL (TdT-mediated dUTP-biotin nick end labeling) technique is the most widely used method to identify apoptotic cells in a tissue or culture and to assess drug toxicity. It is based on the detection of 3'-OH termini that are labeled with dUTP by the terminal deoxynucleotidyl transferase. Although the test is very reliable and sensitive in caspase-dependent apoptosis, it is completely useless when cell death is mediated by pathways involving DNA degradation that generates 3'-P ends as in the LEI/L-DNase II pathway. Here, we propose a modification in the TUNEL protocol consisting of a dephosphorylation step prior to the TUNEL labeling. This allows the detection of both types of DNA breaks induced during apoptosis caspase-dependent and independent pathways, avoiding underestimating the cell death induced by the treatment of interest

Trisomie 21 et prise en charge orthodontique

Les signes cliniques liés à la trisomie 21 mettent en évidence un retard cognitif associé à des modifications morphologiques de la sphère cervico-bucco-faciale, des bases osseuses mais aussi de la denture. Les troubles fonctionnels associés compliquent le tableau clinique qui s'aggrave au cours de la croissance de l'enfant entraînant une dysmorphose importante. L'enfant porteur de trisomie 21 est, par conséquent, un patient orthodontique, du fait de sa dysmorphose primaire. Nous proposons une réflexion sur la prise en charge orthodontique du patient porteur de trisomie 21 en envisageant les possibilités thérapeutiques et leurs limites en fonction des différents facteurs généraux et locaux liés à l'aberration chromosomique

Effect of a nonuniform distribution of voids on the plastic response of voided materials: a computational and statistical analysis

This study investigates the overall and local response of porous media composed of a perfectly plastic matrix weakened by stress-free voids. Attention is focused on the specific role played by porosity fluctuations inside a representative volume element. To this end, numerical simulations using the Fast Fourier Transform (FFT) are performed on different classes of microstructure corresponding to different spatial distributions of voids. Three types of microstructures are investigated: random microstructures with no void clustering, microstructures with a connected cluster of voids and microstructures with disconnected void clusters. These numerical simulations show that the porosity fluctuations can have a strong effect on the overall yield surface of porous materials. Random microstructures without clusters and microstructures with a connected cluster are the hardest and the softest configurations, respectively, whereas microstructures with disconnected clusters lead to intermediate responses. At a more local scale, the salient feature of the fields is the tendency for the strain fields to concentrate in specific bands. Finally, an image analysis tool is proposed for the statistical characterization of the porosity distribution. It relies on the distribution of the ‘distance function’, the width of which increases when clusters are present. An additional connectedness analysis allows us to discriminate between clustered microstructures

Patients with complicated Pott's disease: Management in a rehabilitation department and functional prognosis

AbstractObjectiveThe objective is to study the rehabilitation management and to assess autonomy in daily life activities as well as walking recovery in patients with complicated Pott's disease.Patients and methodsRetrospective study in nine patients over a period of 8 years extending from 2000 to 2008, collated in the Department of Physical Medicine and Functional Rehabilitation, CHU Sahloul, Sousse, Tunisia.ResultsThe mean age of our patients was 43.8 years; sex ratio was 5/4. The spine involvement of tuberculosis was dorsal in seven cases, dorso-lumbar in one patient, and multiple (cervical, dorsal and lumbar) in one case. All patients were paraplegic with a neurological involvement of the bladder. They had prior antituberculosis chemotherapy for at least 8 months. Decompression surgery was performed in six cases. Two female patients presented disorders of spinal posture during treatment requiring surgical revision with osteosynthesis. All patients received additional rehabilitation care. Following a mean duration of hospitalisation in the Rehabilitation department of 47 days with twice-daily sessions of tailored physiotherapy, three patients remained in complete paraplegia, autonomous in wheel-chair and with vesical and sphincter incontinence. The measure of functional independence (MFI) was at admission/discharge 71/92.ConclusionRehabilitation takes an important place in the medico-surgical management in Pott's disease, to limite or compensate the disabilities and handicap related to this pathology