Diversity in spatial scope of contrast adaptation among mouse retinal ganglion cells

PubMed Central

Khani, Mohammad Hossein

2017-01-01

Retinal ganglion cells adapt to changes in visual contrast by adjusting their response kinetics and sensitivity. While much work has focused on the time scales of these adaptation processes, less is known about the spatial scale of contrast adaptation. For example, do small, localized contrast changes affect a cell’s signal processing across its entire receptive field? Previous investigations have provided conflicting evidence, suggesting that contrast adaptation occurs either locally within subregions of a ganglion cell’s receptive field or globally over the receptive field in its entirety. Here, we investigated the spatial extent of contrast adaptation in ganglion cells of the isolated mouse retina through multielectrode-array recordings. We applied visual stimuli so that ganglion cell receptive fields contained regions where the average contrast level changed periodically as well as regions with constant average contrast level. This allowed us to analyze temporal stimulus integration and sensitivity separately for stimulus regions with and without contrast changes. We found that the spatial scope of contrast adaptation depends strongly on cell identity, with some ganglion cells displaying clear local adaptation, whereas others, in particular large transient ganglion cells, adapted globally to contrast changes. Thus, the spatial scope of contrast adaptation in mouse retinal ganglion cells appears to be cell-type specific. This could reflect differences in mechanisms of contrast adaptation and may contribute to the functional diversity of different ganglion cell types. NEW & NOTEWORTHY Understanding whether adaptation of a neuron in a sensory system can occur locally inside the receptive field or whether it always globally affects the entire receptive field is important for understanding how the neuron processes complex sensory stimuli. For mouse retinal ganglion cells, we here show that both local and global contrast adaptation exist and that this diversity

Agmatine protects retinal ganglion cells from hypoxia-induced apoptosis in transformed rat retinal ganglion cell line

PubMed Central

Hong, Samin; Lee, Jong Eun; Kim, Chan Yun; Seong, Gong Je

2007-01-01

Background Agmatine is an endogenous polyamine formed by the decarboxylation of L-arginine. We investigated the protective effects of agmatine against hypoxia-induced apoptosis of immortalized rat retinal ganglion cells (RGC-5). RGC-5 cells were cultured in a closed hypoxic chamber (5% O2) with or without agmatine. Cell viability was determined by lactate dehydrogenase (LDH) assay and apoptosis was examined by annexin V and caspase-3 assays. Expression and phosphorylation of mitogen-activated protein kinases (MAPKs; JNK, ERK p44/42, and p38) and nuclear factor-kappa B (NF-κB) were investigated by Western immunoblot analysis. The effects of agmatine were compared to those of brain-derived neurotrophic factor (BDNF), a well-known protective neurotrophin for retinal ganglion cells. Results After 48 hours of hypoxic culture, the LDH assay showed 52.3% cell loss, which was reduced to 25.6% and 30.1% when agmatine and BDNF were administered, respectively. This observed cell loss was due to apoptotic cell death, as established by annexin V and caspase-3 assays. Although total expression of MAPKs and NF-κB was not influenced by hypoxic injury, phosphorylation of these two proteins was increased. Agmatine reduced phosphorylation of JNK and NF-κB, while BDNF suppressed phosphorylation of ERK and p38. Conclusion Our results show that agmatine has neuroprotective effects against hypoxia-induced retinal ganglion cell damage in RGC-5 cells and that its effects may act through the JNK and NF-κB signaling pathways. Our data suggest that agmatine may lead to a novel therapeutic strategy to reduce retinal ganglion cell injury related to hypoxia. PMID:17908330

[The neurotrophic effect of endogenous NT-3 from adult cat spared dorsal root ganglion on ganglionic neurons].

PubMed

Zhang, Wei; Zhou, Xue; Wang, Ting-hua; Wang, Te-wei; Liu, Su; Chen, Si-xiu; Ou, Ke-qun

2004-01-01

To investigate the neurotrophic effect of endogenous NT-3 from adult cat dorsal root ganglion (DRG) on ganglionic neurons. Rhizotomy of bilateral L1, L3, L5 and L7 dorsal roots of cats was performed, leaving L2, L4 and L6 DRG as spared DRGs. The separate neurons of normal (control) DRG, spared DRG and anti-NT-3 antibody blocking DRG were cultured in vitro respectively. The number of survival neurons and the length of neurites were measured and used for comparison in the control, spared DRG, and block groups. There were survival neurons and cell clusters in every group. The number of survival neurons and cell clusters of spared DRG group were much larger than those of the control and block groups. The neurite length of neurons, the neurite number and the length of cell clusters of spared DRG group were much greater than those of control and block groups. Endogenous NT-3 from spared DRG may act on ganglionic neurons to maintain survival of neuron and stimulate growth of neurite.

Spiral Ganglion Stem Cells Can Be Propagated and Differentiated Into Neurons and Glia

PubMed Central

Zecha, Veronika; Wagenblast, Jens; Arnhold, Stefan; Edge, Albert S. B.; Stöver, Timo

2014-01-01

Abstract The spiral ganglion is an essential functional component of the peripheral auditory system. Most types of hearing loss are associated with spiral ganglion cell degeneration which is irreversible due to the inner ear's lack of regenerative capacity. Recent studies revealed the existence of stem cells in the postnatal spiral ganglion, which gives rise to the hope that these cells might be useful for regenerative inner ear therapies. Here, we provide an in-depth analysis of sphere-forming stem cells isolated from the spiral ganglion of postnatal mice. We show that spiral ganglion spheres have characteristics similar to neurospheres isolated from the brain. Importantly, spiral ganglion sphere cells maintain their major stem cell characteristics after repeated propagation, which enables the culture of spheres for an extended period of time. In this work, we also demonstrate that differentiated sphere-derived cell populations not only adopt the immunophenotype of mature spiral ganglion cells but also develop distinct ultrastructural features of neurons and glial cells. Thus, our work provides further evidence that self-renewing spiral ganglion stem cells might serve as a promising source for the regeneration of lost auditory neurons. PMID:24940560

Characterization of Ganglionic Acetylcholine Receptor Autoantibodies

PubMed Central

Vernino, Steven; Lindstrom, Jon; Hopkins, Steve; Wang, Zhengbei; Low, Phillip A.

2008-01-01

In myasthenia gravis (MG), autoantibodies bind to the α1 subunit and other subunits of the muscle nicotinic acetylcholine receptor (AChR). Autoimmune autonomic ganglionopathy (AAG) is an antibody-mediated neurological disorder caused by antibodies against neuronal AChRs in autonomic ganglia. Subunits of muscle and neuronal AChR are homologous. We examined the specificity of AChR antibodies in patients with MG and AAG. Ganglionic AChR autoantibodies found in AAG patients are specific for AChRs containing the α3 subunit. Muscle and ganglionic AChR antibody specificities are distinct. Antibody crossreactivity between AChRs with different α subunits is uncommon but can occur. PMID:18485491

Ganglionic adrenergic action modulates ovarian steroids and nitric oxide in prepubertal rat.

PubMed

Delgado, Silvia Marcela; Casais, Marilina; Sosa, Zulema; Rastrilla, Ana María

2006-08-01

Both peripheral innervation and nitric oxide (NO) participate in ovarian steroidogenesis. The purpose of this work was to analyse the ganglionic adrenergic influence on the ovarian release of steroids and NO and the possible steroids/NO relationship. The experiments were carried out in the ex vivo coeliac ganglion-superior ovarian nerve (SON)-ovary system of prepubertal rats. The coeliac ganglion-SON-ovary system was incubated in Krebs Ringer-bicarbonate buffer in presence of adrenergic agents in the ganglionic compartment. The accumulation of progesterone, androstenedione, oestradiol and NO in the ovarian incubation liquid was measured. Norepinephrine in coeliac ganglion inhibited the liberation of progesterone and increased androstenedione, oestradiol and NO in ovary. The addition of alpha and beta adrenergic antagonists also showed different responses in the liberation of the substances mentioned before, which, from a physiological point of view, reveals the presence of adrenergic receptors in coeliac ganglion. In relation to propranolol, it does not revert the effect of noradrenaline on the liberation of progesterone, which leads us to think that it might also have a "per se" effect on the ganglion, responsible for the ovarian response observed for progesterone. Finally, we can conclude that the ganglionic adrenergic action via SON participates on the regulation of the prepubertal ovary in one of two ways: either increasing the NO, a gaseous neurotransmitter with cytostatic characteristics, to favour the immature follicles to remain dormant or increasing the liberation of androstenedione and oestradiol, the steroids necessary for the beginning of the near first estral cycle.

Evidence that ganglion cells react to retinal detachment.

PubMed

Coblentz, Francie E; Radeke, Monte J; Lewis, Geoffrey P; Fisher, Steven K

2003-03-01

Growth associated protein 43 (GAP 43) is involved in synapse formation and it is expressed in the retina in a very specific pattern. Although GAP 43 is downregulated at the time of synapse formation, it can be re-expressed following injury such as axotomy or ischemia. Because of this we sought to characterize the expression of GAP 43 after retinal detachment (RD). Immunoblot, immunocytochemical and quantitative polymerase chain reaction (QPCR) techniques were used to assess the level of GAP 43 expression after experimental RD. GAP 43 was localized to three sublaminae of the inner plexiform layer of the normal retina. GAP 43 became upregulated in a subset of retinal ganglion cells following at least 7 days of RD. By immunoblot GAP 43 could be detected by 3 days. QPCR shows the upregulation of GAP 43 message by 6hr of detachment. To further characterize changes in ganglion cells, we used an antibody to neurofilament 70 and 200kDa (NF) proteins. Anti-NF labels horizontal cells, ganglion cell dendrites in the inner plexiform layer, and ganglion cell axons (fasicles) in the normal retina. Following detachment it is upregulated in horizontal cells and ganglion cells. When detached retina was double labelled with anti-GAP 43 and anti-NF, some cells were labelled with both markers, while others labelled with only one. We have previously shown that second order neurons respond to detachment; here we show that third order neurons are responding as well. Cellular remodelling of this type in response to detachment may explain the slow recovery of vision that often occurs after reattachment, or those changes that are often assumed to be permanent.

Retinal ganglion cell topography and spatial resolving power in penguins.

PubMed

Coimbra, João Paulo; Nolan, Paul M; Collin, Shaun P; Hart, Nathan S

2012-01-01

Penguins are a group of flightless seabirds that exhibit numerous morphological, behavioral and ecological adaptations to their amphibious lifestyle, but little is known about the topographic organization of neurons in their retinas. In this study, we used retinal wholemounts and stereological methods to estimate the total number and topographic distribution of retinal ganglion cells in addition to an anatomical estimate of spatial resolving power in two species of penguins: the little penguin, Eudyptula minor, and the king penguin, Aptenodytes patagonicus. The total number of ganglion cells per retina was approximately 1,200,000 in the little penguin and 1,110,000 in the king penguin. The topographic distribution of retinal ganglion cells in both species revealed the presence of a prominent horizontal visual streak with steeper gradients in the little penguin. The little penguin retinas showed ganglion cell density peaks of 21,867 cells/mm², affording spatial resolution in water of 17.07-17.46 cycles/degree (12.81-13.09 cycles/degree in air). In contrast, the king penguin showed a relatively lower peak density of ganglion cells of 14,222 cells/mm², but--due to its larger eye--slightly higher spatial resolution in water of 20.40 cycles/degree (15.30 cycles/degree in air). In addition, we mapped the distribution of giant ganglion cells in both penguin species using Nissl-stained wholemounts. In both species, topographic mapping of this cell type revealed the presence of an area gigantocellularis with a concentric organization of isodensity contours showing a peak in the far temporal retina of approximately 70 cells/mm² in the little penguin and 39 cells/mm² in the king penguin. Giant ganglion cell densities gradually fall towards the outermost isodensity contours revealing the presence of a vertically organized streak. In the little penguin, we confirmed our cytological characterization of giant ganglion cells using immunohistochemistry for microtubule

Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review.

PubMed

Ho, Kwo Wei David; Przkora, Rene; Kumar, Sanjeev

2017-12-28

Sphenopalatine ganglion is the largest collection of neurons in the calvarium outside of the brain. Over the past century, it has been a target for interventional treatment of head and facial pain due to its ease of access. Block, radiofrequency ablation, and neurostimulation have all been applied to treat a myriad of painful syndromes. Despite the routine use of these interventions, the literature supporting their use has not been systematically summarized. This systematic review aims to collect and summarize the level of evidence supporting the use of sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Medline, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were reviewed for studies on sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Studies included in this review were compiled and analyzed for their treated medical conditions, study design, outcomes and procedural details. Studies were graded using Oxford Center for Evidence-Based Medicine for level of evidence. Based on the level of evidence, grades of recommendations are provided for each intervention and its associated medical conditions. Eighty-three publications were included in this review, of which 60 were studies on sphenopalatine ganglion block, 15 were on radiofrequency ablation, and 8 were on neurostimulation. Of all the studies, 23 have evidence level above case series. Of the 23 studies, 19 were on sphenopalatine ganglion block, 1 study on radiofrequency ablation, and 3 studies on neurostimulation. The rest of the available literature was case reports and case series. The strongest evidence lies in using sphenopalatine ganglion block, radiofrequency ablation and neurostimulation for cluster headache. Sphenopalatine ganglion block also has evidence in treating trigeminal neuralgia, migraines, reducing the needs of analgesics after endoscopic sinus surgery and reducing pain associated with nasal packing

Structural basis of orientation sensitivity of cat retinal ganglion cells.

PubMed

Leventhal, A G; Schall, J D

1983-11-10

We investigated the structural basis of the physiological orientation sensitivity of retinal ganglion cells (Levick and Thibos, '82). The dendritic fields of 840 retinal ganglion cells labeled by injections of horseradish peroxidase into the dorsal lateral geniculate nucleus (LGNd) or optic tracts of normal cats. Siamese cats, and cat deprived of patterned visual experience from birth by monocular lid-suture (MD) were studied. Mathematical techniques designed to analyze direction were used to find the dendritic field orientation of each cell. Statistical techniques designed for angular data were used to determine the relationship between dendritic field orientation and angular position on the retina (polar angle). Our results indicate that 88% of retinal ganglion cells have oriented dendritic fields and that dendritic field orientation is related systematically to retinal position. In all regions of retina more that 0.5 mm from the area centralis the dendritic fields of retinal ganglion cells are oriented radially, i.e., like the spokes of a wheel having the area centralis at its hub. This relationship was present in all animals and cell types studied and was strongest for cells located close to the horizontal meridian (visual streak) of the retina. Retinal ganglion cells appear to be sensitive to stimulus orientation because they have oriented dendritic fields.

Morphology of retinal ganglion cells in the ferret (Mustela putorius furo).

PubMed

Isayama, Tomoki; O'Brien, Brendan J; Ugalde, Irma; Muller, Jay F; Frenz, Aaron; Aurora, Vikas; Tsiaras, William; Berson, David M

2009-12-01

The ferret is the premiere mammalian model of retinal and visual system development, but the spectrum and properties of its retinal ganglion cells are less well understood than in another member of the Carnivora, the domestic cat. Here, we have extensively surveyed the dendritic architecture of ferret ganglion cells and report that the classification scheme previously developed for cat ganglion cells can be applied with few modifications to the ferret retina. We confirm the presence of alpha and beta cells in ferret retina, which are very similar to those in cat retina. Both cell types exhibited an increase in dendritic field size with distance from the area centralis (eccentricity) and with distance from the visual streak. Both alpha and beta cell populations existed as two subtypes whose dendrites stratified mainly in sublamina a or b of the inner plexiform layer. Six additional morphological types of ganglion cells were identified: four monostratified cell types (delta, epsilon, zeta, and eta) and two bistratified types (theta and iota). These types closely resembled their counterparts in the cat in terms of form, relative field size, and stratification. Our data indicate that, among carnivore species, the retinal ganglion cells resemble one another closely and that the ferret is a useful model for studies of the ontogenetic differentiation of ganglion cell types.

Ganglion cyst of the temporomandibular joint.

PubMed

Heng-Kun, W; Yan-Ling, G; Wen-Feng, Z; Zhe, S; Ren-Xin, W; Xiao-Tao, Z

2014-02-01

Ganglion cyst of the temporomandibular joint is a rare disease, which may arise from myxoid degeneration of the collagenous tissue of the temporomandibular joint capsule, without epithelial or endothelial lining. We report a case of cystic lesion in a 40-year-old female patient. The patient had a left pre-auricular oval-shaped swelling without any articular symptoms. The pathological analysis after surgical removal allowed diagnosing the lesion as a ganglion cyst of the left temporomandibular joint. We made a literature review and noted that this condition was predominant in female patients. We recommend using MRI for diagnostic purposes and surgery as the best therapeutic alternative. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

An anatomic and morphometric study of C2 nerve root ganglion and its corresponding foramen.

PubMed

Bilge, Okan

2004-03-01

Exposing and measuring the dorsal root ganglion of the second cervical spinal nerve (C2 ganglion) and the second intervertebral space, which is present between posterior arch of atlas (APA) and lamina of axis (LA). This study aims to investigate the shape, size, and relation of the C2 ganglion with the adjacent structures that limits the corresponding intervertebral space and the alterations of relation between C2 ganglion and APA and between C2 ganglion and LA with the movements of the head bilaterally. In previous studies, the position and the heights of the C2 ganglion have been described. But the shape of the C2 ganglion and its relation to APA and LA by the movement of the head had not been considered previously. Upper cervical spines of 20 cadavers were dissected posteriorly. The muscles attaching to the atlas and axis were resected to ease the head movements. The heights of the C2 ganglion and space were measured in anatomic position and in hyperextension with opposite rotation position of the head. Originally in this study, plastic dough casts were used to obtain reliable outcomes. The shape of the ganglions was defined in three types: 70% were oval, 20% were spindle-like, and 10% were spherical. The height of the C2 ganglion was 4.97 +/- 0.92 mm on the right side and 4.6 +/- 0.84 mm on the left side. The height of the intervertebral space in anatomic position and in hyperextension with rotation to the opposite position of the head were, respectively, 9.74 +/- 1.77 mm and 7.48 +/- 1.44 mm on the right side and 9.64 +/- 1.47 mm and 7.12 +/- 0.96 mm on the left side. There was no bone contact or impact to the ganglion in each position of the head. The C2 ganglions are confident in their place between APA and LA. No bone contact to the C2 ganglion was detected in either normal limited or in forced head motions.

Changes in morphology of retinal ganglion cells with eccentricity in retinal degeneration.

PubMed

Anderson, E E; Greferath, U; Fletcher, E L

2016-05-01

Ganglion cells are the output neurons of the retina and are known to remodel during the subtle plasticity changes that occur following the death of photoreceptors in inherited retinal degeneration. We examine the influence of retinal eccentricity on anatomical remodelling and ganglion cell morphology well after photoreceptor loss. Rd1 mice that have a mutation in the β subunit of phosphodiesterase 6 were used as a model of retinal degeneration and gross remodelling events were examined by processing serial sections for immunocytochemistry. Retinal wholemounts from rd1-Thy1 and control Thy1 mice that contained a fluorescent protein labelling a subset of ganglion cells were processed for immunohistochemistry at 11 months of age. Ganglion cells were classified based on their soma size, dendritic field size and dendritic branching pattern and their dendritic fields were analysed for their length, area and quantity of branching points. Overall, more remodelling was found in the central compared with the peripheral retina. In addition, the size and complexity of A2, B1, C1 and D type ganglion cells located in the central region of the retina decreased. We propose that the changes in ganglion cell morphology are correlated with remodelling events in these regions and impact the function of retinal circuitry in the degenerated retina.

A Case Report of an Acromioclavicular Joint Ganglion Associated with a Rotator Cuff Tear.

PubMed

Tanaka, Suguru; Gotoh, Masafumi; Mitsui, Yasuhiro; Shirachi, Isao; Okawa, Takahiro; Higuchi, Fujio; Shiba, Naoto

2017-04-13

We report a case of subcutaneous ganglion adjacent to the acromioclavicular joint with massive rotator cuff tear [1-7]. An 81-year-old woman presented with a ganglion adjacent to the acromioclavicular joint that had first been identified 9 months earlier. The ganglion had recurred after having been aspirated by her local physician, so she was referred to our hospital. The puncture fluid was yellowish, clear and viscous. Magnetic resonance imaging identified a massive rotator cuff tear with multi- lobular cystic lesions continuous to the acromioclavicular joint, presenting the "geyser sign". During arthroscopy, distal clavicular resection and excision of the ganglion were performed together with joint debridement. At present, the ganglion has not recurred and the patient has returned to normal daily activity. In this case, the ganglion may have developed subsequent to the concomitant massive cuff tear, due to subcutaneous fluid flow through the damaged acromioclavicular joint.

Synaptic potentials recorded by the sucrosegap method from the rabbit superior cervical ganglion

PubMed Central

Kosterlitz, H. W.; Lees, G. M.; Wallis, D. I.

1970-01-01

1. Compound ganglionic potentials evoked by stimulation of the preganglionic nerves to the superior cervical ganglion of the rabbit were recorded by the sucrose-gap method. 2. When the distal part of the ganglion was bathed in flowing isotonic sucrose solution or sodium-deficient solutions, ganglionic action potentials were no longer evoked, only large synaptic potentials. 3. The compound synaptic potential, which remained unaltered for more than 1 h, originated in a population of cells at the interface between the Krebs and sucrose solutions. Hexamethonium reduced the size but did not alter the time course of the synaptic potential. 4. It is suggested that a higher concentration of sodium ions is required for the generation of ganglionic action potentials than for either conduction in the postganglionic axons or production of synaptic potentials. 5. When lithium replaced sodium in the solution bathing the distal part of the ganglion, the synaptic potential was greatly reduced in amplitude. Impulse propagation in the postganglionic axons was only slightly impaired when lithium replaced sodium in the solution bathing the axons. 6. A quantitative assessment of the potency of the ganglion-blocking drugs nicotine, pentolinium, hexamethonium and pempidine was made by measuring the depression of the synaptic potentials produced by bathing the distal part of the ganglion in flowing isotonic sucrose solution. The concentrations which produced a 50% depression were 8·1 μM nicotine, 26·5 μM pentolinium, 111 μM hexamethonium and 22·2 μM pempidine. PMID:5492898

Regenerating reptile retinas: a comparative approach to restoring retinal ganglion cell function.

PubMed

Williams, D L

2017-02-01

Transection or damage to the mammalian optic nerve generally results in loss of retinal ganglion cells by apoptosis. This cell death is seen less in fish or amphibians where retinal ganglion cell survival and axon regeneration leads to recovery of sight. Reptiles lie somewhere in the middle of this spectrum of nerve regeneration, and different species have been reported to have a significant variation in their retinal ganglion cell regenerative capacity. The ornate dragon lizard Ctenophoris ornatus exhibits a profound capacity for regeneration, whereas the Tenerife wall lizard Gallotia galloti has a more variable response to optic nerve damage. Some individuals regain visual activity such as the pupillomotor responses, whereas in others axons fail to regenerate sufficiently. Even in Ctenophoris, although the retinal ganglion cell axons regenerate adequately enough to synapse in the tectum, they do not make long-term topographic connections allowing recovery of complex visually motivated behaviour. The question then centres on where these intraspecies differences originate. Is it variation in the innate ability of retinal ganglion cells from different species to regenerate with functional validity? Or is it variances between different species in the substrate within which the nerves regenerate, the extracellular environment of the damaged nerve or the supporting cells surrounding the regenerating axons? Investigations of retinal ganglion cell regeneration between different species of lower vertebrates in vivo may shed light on these questions. Or perhaps more interesting are in vitro studies comparing axon regeneration of retinal ganglion cells from various species placed on differing substrates.

Dorsal raphe nucleus projecting retinal ganglion cells: Why Y cells?

PubMed Central

Pickard, Gary E.; So, Kwok-Fai; Pu, Mingliang

2015-01-01

Retinal ganglion Y (alpha) cells are found in retinas ranging from frogs to mice to primates. The highly conserved nature of the large, fast conducting retinal Y cell is a testament to its fundamental task, although precisely what this task is remained ill-defined. The recent discovery that Y-alpha retinal ganglion cells send axon collaterals to the serotonergic dorsal raphe nucleus (DRN) in addition to the lateral geniculate nucleus (LGN), medial interlaminar nucleus (MIN), pretectum and the superior colliculus (SC) has offered new insights into the important survival tasks performed by these cells with highly branched axons. We propose that in addition to its role in visual perception, the Y-alpha retinal ganglion cell provides concurrent signals via axon collaterals to the DRN, the major source of serotonergic afferents to the forebrain, to dramatically inhibit 5-HT activity during orientation or alerting/escape responses, which dis-facilitates ongoing tonic motor activity while dis-inhibiting sensory information processing throughout the visual system. The new data provide a fresh view of these evolutionarily old retinal ganglion cells. PMID:26363667

[Ganglions of the wrist: proposals for topographical systematization and natural history].

PubMed

Kuhlmann, J-N; Luboinski, J; Baux, S; Mimoun, M

2003-06-01

We looked for the anatomic origin and mechanism of constitution of the so-called "ganglions" of the wrist. Fifty-nine formations considered to be synovial ganglions were dissected and removed according to the same protocol by the same surgeon. Eleven were re-examined by a pathologist. All ganglions were extra-articular but had intra- and extra-capsular components. The extra-capsular part was the clinically palpable main cyst. The intra-capsular part was composed of the cystic stalk and its base of implantation. An intra-capsular stalk was present in 58 cases. The stalk was situated between the joint synovium and the capsula which it perforated at a weak point between two ligaments, forming a collar before expanding outwardly. Based on our findings, we propose a topographical systematization and natural history of ganglions of the wrist. The stalk's implantation base was always located on bone and found in the intermediate area of Colomniati and Soubbotine, which lies outside the articular cartilage between the synovium and the ligamentous capsula. This area is exposed to mechanical stress initiating histological degenerative lesions, particularly mucoid degeneration. At the radiocarpal joint, the stalk's base of implantation was located at the distal end of the lateral dorsal or volar edge of the lunate bone or at the corresponding part of the scaphoid. The collar of the proximal ganglions was situated between the dorsal radiocarpal and transverse scaphotriquetral ligament. The collar of distal dorsal ganglions was situated between the transverse scaphotriquetral and the trapezotriquetral ligament. The collar of the lateral ganglions was situated between the lateral collateral and the transverse ligament. The collar of the volar ganglions was situated between the stylocarpal ligament and the radiolunotriquetral ligament, or between the different stylocarpal ligaments. At the level of the scaphotrapezal joint, the stalk's base of implantation was located near the

Strychnine blocks transient but not sustained inhibition in mudpuppy retinal ganglion cells.

PubMed Central

Belgum, J H; Dvorak, D R; McReynolds, J S

1984-01-01

Transient and sustained inhibitory synaptic inputs to on-centre, off-centre, and on-off ganglion cells in the mudpuppy retina were studied using intracellular recording in the superfused eye-cup preparation. When chemical transmission was blocked with 4 mM-Co2+, application of either glycine or gamma-aminobutyric acid (GABA) caused a hyperpolarization and conductance increase in all ganglion cells. For both amino acids, the responses were dose dependent in the range 0.05-10 mM, with a half-maximal response at about 0.7 mM. Glycine and GABA sensitivities were very similar in all three types of ganglion cells. The response to applied glycine was selectively antagonized by 10(-5) M-strychnine and the response to applied GABA was selectively antagonized by 10(-5) M-picrotoxin. In all ganglion cells, 10(-5) M-strychnine eliminated the transient inhibitory events which occur at the onset and termination of a light stimulus. The block of transient inhibition was associated with a relative depolarization of membrane potential and decrease in conductance at these times. Strychnine had no effect on membrane potential or conductance in darkness or during sustained inhibitory responses to light. Picrotoxin (10(-5) M) did not block transient inhibitory events in any ganglion cells, but did affect other components of their responses. The results suggest that in all three classes of ganglion cells transient inhibition, but not sustained inhibition, may be mediated by glycine or a closely related substance. PMID:6481635

Quantifying Spiral Ganglion Neurite and Schwann Behavior on Micropatterned Polymer Substrates.

PubMed

Cheng, Elise L; Leigh, Braden; Guymon, C Allan; Hansen, Marlan R

2016-01-01

The first successful in vitro experiments on the cochlea were conducted in 1928 by Honor Fell (Fell, Arch Exp Zellforsch 7(1):69-81, 1928). Since then, techniques for culture of this tissue have been refined, and dissociated primary culture of the spiral ganglion has become a widely accepted in vitro model for studying nerve damage and regeneration in the cochlea. Additionally, patterned substrates have been developed that facilitate and direct neural outgrowth. A number of automated and semi-automated methods for quantifying this neurite outgrowth have been utilized in recent years (Zhang et al., J Neurosci Methods 160(1):149-162, 2007; Tapias et al., Neurobiol Dis 54:158-168, 2013). Here, we describe a method to study the effect of topographical cues on spiral ganglion neurite and Schwann cell alignment. We discuss our microfabrication process, characterization of pattern features, cell culture techniques for both spiral ganglion neurons and spiral ganglion Schwann cells. In addition, we describe protocols for reducing fibroblast count, immunocytochemistry, and methods for quantifying neurite and Schwann cell alignment.

The nervus terminalis ganglion in Anguilla rostrata: an immunocytochemical and HRP histochemical analysis.

PubMed

Grober, M S; Bass, A H; Burd, G; Marchaterre, M A; Segil, N; Scholz, K; Hodgson, T

1987-12-08

Immunocytochemistry and retrograde horseradish peroxidase (HRP) transport were used to study the ganglion of the nervus terminalis in the American eel, Anguilla rostrata. Luteinizing hormone releasing hormone (LHRH) like immunoreactivity was found in large, ganglion-like cells located ventromedially at the junction of the telencephalon and olfactory bulb and in fibers within the retina and olfactory epithelium. HRP transport from the retina demonstrated direct connections with both the ipsi- and contralateral populations of these ganglion-like cells. Given the well-documented role of both olfaction and vision during migratory and reproductive phases of the life cycle of eels, the robust nature of a nervus terminalis system in these fish may present a unique opportunity to study the behavioral correlates of structure-function organization in a discrete population of ganglion-like cells.

Protecting retinal ganglion cells.

PubMed

Khatib, T Z; Martin, K R

2017-02-01

Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials.

Clustering is a feature of the spiral ganglion in the basal turn.

PubMed

Gacek, Richard R

2012-01-01

To demonstrate the organization of the spiral ganglion in the mammalian species. Temporal bone (TB) specimens from man (n = 2), monkey (n = 2), lion (n = 2) and cat (n = 20) were stained, decalcified and dissected according to the Sudan black B method of Rasmussen. These TB specimens were examined under a Zeiss operating microscope and photographed with a Canon 100 camera interfaced with the microscope. Spiral ganglion cells occurred in clusters within Rosenthal's canal in all four species. The location of the clusters was marked by the interface between axon and dendritic bundles as well as groups of ganglion cells. In monkey and man the clusters were more separated than in lion and cat. These observations indicate that the spiral ganglion forms clusters of neurons within Rosenthal's canal at the basal cochlear turn in the mammals investigated here. The formation of clusters may be related to the principles of neurogenesis. Copyright © 2011 S. Karger AG, Basel.

Berberine exerts antioxidant effects via protection of spiral ganglion cells against cytomegalovirus-induced apoptosis.

PubMed

Zhuang, Wei; Li, Ting; Wang, Caiji; Shi, Xi; Li, Yalan; Zhang, Shili; Zhao, Zeqi; Dong, Hongyan; Qiao, Yuehua

2018-06-01

Cytomegalovirus (CMV) is the leading cause of sensorineural hearing loss (SNHL) in children because of its damage to the cochlea and spiral ganglion cells. Therefore, it has become a top priority to devise new methods to effectively protect spiral ganglion cells from damage. Berberine (BBR) has gained attention for its vast beneficial biological effects through immunomodulation, and its anti-inflammatory and anti-apoptosis properties. However, the effect of BBR on spiral ganglion cells and molecular mechanisms are still unclear. This study aims to investigate whether BBR has an anti-apoptosis effect in CMV-induced apoptosis in cultured spiral ganglion cells and explore the possible mechanism. In this study, TUNEL and MTT assays significantly demonstrated that low doses of BBR did not promote cell apoptosis and they also inhibited the CMV-induced cultured spiral ganglion cell apoptosis. Immunofluorescence and Western blot assays indicated that the anti-apoptosis effect of BBR was related to Nox3. Mitochondrial calcium and Western blot assays revealed that NMDAR1 mediated this anti-apoptosis effect. Our results demonstrated that BBR exerted an anti-apoptosis effect against CMV in cultured spiral ganglion cells, and the mechanism is related to NMDAR1/Nox3-mediated mitochondrial reactive oxygen species (ROS) generation. Copyright © 2018 Elsevier Inc. All rights reserved.

Retinal ganglion cell distribution and spatial resolving power in elasmobranchs.

PubMed

Lisney, Thomas J; Collin, Shaun P

2008-01-01

The total number, distribution and peak density of presumed retinal ganglion cells was assessed in 10 species of elasmobranch (nine species of shark and one species of batoid) using counts of Nissl-stained cells in retinal wholemounts. The species sampled include a number of active, predatory benthopelagic and pelagic sharks that are found in a variety of coastal and oceanic habitats and represent elasmobranch groups for which information of this nature is currently lacking. The topographic distribution of cells was heterogeneous in all species. Two benthic species, the shark Chiloscyllium punctatum and the batoid Taeniura lymma, have a dorsal or dorso-central horizontal streak of increased cell density, whereas the majority of the benthopelagic and pelagic sharks examined exhibit a more concentric pattern of increasing cell density, culminating in a central area centralis of higher cell density located close to the optic nerve head. The exception is the shark Alopias superciliosus, which possesses a ventral horizontal streak. Variation in retinal ganglion cell topography appears to be related to the visual demands of different habitats and lifestyles, as well as the positioning of the eyes in the head. The upper limits of spatial resolving power were calculated for all 10 species, using peak ganglion cell densities and estimates of focal length taken from cryo-sectioned eyes in combination with information from the literature. Spatial resolving power ranged from 2.02 to 10.56 cycles deg(-1), which is in accordance with previous studies. Species with a lower spatial resolving power tend to be benthic and/or coastal species that feed on benthic invertebrates and fishes. Active, benthopelagic and pelagic species from more oceanic habitats which feed on larger, more active prey, possess a higher resolving power. Additionally, ganglion cells in a juvenile of C. punctatum, were retrogradely-labeled from the optic nerve with biotinylated dextran amine (BDA). A comparison

[Met]- and [Leu]enkephalin-like immunoreactive cell bodies and nerve fibres in the coeliac ganglion of the cat.

PubMed

Julé, Y; Clerc, N; Niel, J P; Condamin, M

1986-06-01

The occurrence and distribution of methionine- and leucine-enkephalin-like immunoreactivity were investigated in the cat coeliac ganglion using either the indirect immunoperoxidase method or the peroxidase-antiperoxidase technique. Several antisera raised to methionine- and leucine-enkephalin were used. Their specificity was assessed by incubating sections of the coeliac ganglion with increasing dilutions of antisera and with antisera saturated with their respective antigen. The present study was performed both in untreated and in colchicine-treated cats. Immunoreactive methionine- and leucine-enkephalin-like cell bodies were only visualized in colchicine-treated cats. Two types of labeled cells were observed. The first type had a size similar to that of unlabeled principal ganglion cells. These labeled cells were numerous and scattered throughout the ganglion; they probably represented enkephalin-containing ganglion cells. The second type of immunoreactive cells were of a much smaller size. They were always gathered in small clusters of about 5-15 cells and were not numerous; they presumably represented enkephalin-containing small intensely fluorescent cells. Immunoreactive nerve fibres were mainly observed in untreated cats and accessorily in colchicine-treated cats. In untreated animals dense networks of methionine- and leucine-enkephalin-like immunoreactive fibres were found in the coeliac ganglion. These fibres had numerous varicosities which often closely surrounded unlabeled principal ganglion cells. In colchicine-treated cats some immunoreactive fibres surrounded labeled principal ganglion cell bodies. The present results establish for the first time the presence of enkephalin-like immunoreactive principal ganglion cells in a mammalian sympathetic prevertebral ganglion. The presence of enkephalin-containing principal ganglion cells, small intensely fluorescent cells and nerve terminals, supports an important role of enkephalins in the integrative synaptic

Protecting retinal ganglion cells

PubMed Central

Khatib, T Z; Martin, K R

2017-01-01

Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials. PMID:28085136

Features and functions of nonlinear spatial integration by retinal ganglion cells.

PubMed

Gollisch, Tim

2013-11-01

Ganglion cells in the vertebrate retina integrate visual information over their receptive fields. They do so by pooling presynaptic excitatory inputs from typically many bipolar cells, which themselves collect inputs from several photoreceptors. In addition, inhibitory interactions mediated by horizontal cells and amacrine cells modulate the structure of the receptive field. In many models, this spatial integration is assumed to occur in a linear fashion. Yet, it has long been known that spatial integration by retinal ganglion cells also incurs nonlinear phenomena. Moreover, several recent examples have shown that nonlinear spatial integration is tightly connected to specific visual functions performed by different types of retinal ganglion cells. This work discusses these advances in understanding the role of nonlinear spatial integration and reviews recent efforts to quantitatively study the nature and mechanisms underlying spatial nonlinearities. These new insights point towards a critical role of nonlinearities within ganglion cell receptive fields for capturing responses of the cells to natural and behaviorally relevant visual stimuli. In the long run, nonlinear phenomena of spatial integration may also prove important for implementing the actual neural code of retinal neurons when designing visual prostheses for the eye. Copyright © 2012 Elsevier Ltd. All rights reserved.

Spontaneous Discharge Patterns in Cochlear Spiral Ganglion Cells Prior to the Onset of Hearing in Cats

PubMed Central

Jones, Timothy A.; Leake, Patricia A.; Snyder, Russell L.; Stakhovskaya, Olga; Bonham, Ben

2008-01-01

Spontaneous neural activity has been recorded in the auditory nerve of cats as early as 2 days postnatal (P2 ), yet individual auditory neurons do not respond to ambient sound levels below 90–100 dB SPL until about P10. Significant refinement of the central projections from the spiral ganglion to the cochlear nucleus occurs during this neonatal period. This refinement may be dependent on peripheral spontaneous discharge activity. We recorded from single spiral ganglion cells in kittens aged P3 to P9. The spiral ganglion was accessed via the round window through the spiral lamina. A total of 112 ganglion cells were isolated for study in 9 animals. Spike rates in neonates were very low, ranging from 0.06 to 56 sp/s with a mean of 3.09 +/− 8.24 sp/s. Ganglion cells in neonatal kittens exhibited remarkable repetitive spontaneous bursting discharge patterns. The unusual patterns were evident in the large mean interval coefficient of variation (CVi = 2.9 +/−1.6) and burst index of 5.2 +/− 3.5 across ganglion cells. Spontaneous bursting patterns in these neonatal mammals were similar to those reported for cochlear ganglion cells of the embryonic chicken suggesting this may be a general phenomenon that is common across animal classes. Rhythmic spontaneous discharge of retinal ganglion cells has been shown to be important in the development of central retinotopic projections and normal binocular vision (Shatz, 1996, Proc Natl Acad Sci 93). Bursting rhythms in cochlear ganglion cells may play a similar role in the auditory system during pre-hearing periods. PMID:17686914

Cochlear implants and ex vivo BDNF gene therapy protect spiral ganglion neurons.

PubMed

Rejali, Darius; Lee, Valerie A; Abrashkin, Karen A; Humayun, Nousheen; Swiderski, Donald L; Raphael, Yehoash

2007-06-01

Spiral ganglion neurons often degenerate in the deaf ear, compromising the function of cochlear implants. Cochlear implant function can be improved by good preservation of the spiral ganglion neurons, which are the target of electrical stimulation by the implant. Brain derived neurotrophic factor (BDNF) has previously been shown to enhance spiral ganglion survival in experimentally deafened ears. Providing enhanced levels of BDNF in human ears may be accomplished by one of several different methods. The goal of these experiments was to test a modified design of the cochlear implant electrode that includes a coating of fibroblast cells transduced by a viral vector with a BDNF gene insert. To accomplish this type of ex vivo gene transfer, we transduced guinea pig fibroblasts with an adenovirus with a BDNF gene cassette insert, and determined that these cells secreted BDNF. We then attached BDNF-secreting cells to the cochlear implant electrode via an agarose gel, and implanted the electrode in the scala tympani. We determined that the BDNF expressing electrodes were able to preserve significantly more spiral ganglion neurons in the basal turns of the cochlea after 48 days of implantation when compared to control electrodes. This protective effect decreased in the higher cochlear turns. The data demonstrate the feasibility of combining cochlear implant therapy with ex vivo gene transfer for enhancing spiral ganglion neuron survival.

Intrinsically photosensitive retinal ganglion cells.

PubMed

Do, Michael Tri Hoang; Yau, King-Wai

2010-10-01

Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors.

TRPC1 is required for survival and proliferation of cochlear spiral ganglion stem/progenitor cells.

PubMed

Chen, Hsin-Chien; Wang, Chih-Hung; Shih, Cheng-Ping; Chueh, Sheau-Huei; Liu, Shu-Fan; Chen, Hang-Kang; Lin, Yi-Chun

2015-12-01

The present studies were designed to test the hypothesis that canonical transient receptor potential channel 1 (TRPC1) is required for the proliferation of cochlear spiral ganglion stem/progenitor cells (SPCs). TRPC1 were detected and evaluated in postnatal day 1 CBA/CaJ mice pups derived-cochlear spiral ganglion SPCs by reverse transcription-polymerase chain reaction, Western blot, immunocytochemistry, and calcium imaging. The cell viability and proliferation of the spiral ganglion SPCs following si-RNA mediated knockdown of TRPC1 or addition of TRPC channel blocker SKF9635 were compared to controls. In spiral ganglion SPCs, TRPC1 was found to be the most abundantly expressed TRPC subunit and shown to contribute to store-operated calcium entry. Silencing of TRPC1 or addition of TRPC channel blockers significantly decreased the rate of cell proliferation. The results suggest that TRPC1 might serve as an essential molecule in regulating the proliferation of spiral ganglion SPCs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A decay of gap junctions associated with ganglion cell differentiation during retinal regeneration of the adult newt.

PubMed

Oi, Hanako; Chiba, Chikafumi; Saito, Takehiko

2003-12-01

Changes in the gap junctional coupling and maturation of voltage-activated Na(+) currents during regeneration of newt retinas were examined by whole-cell patch-clamping in slice preparations. Progenitor cells in regenerating retinas did not exhibit Na(+) currents but showed prominent electrical and tracer couplings. Cells identified by LY-fills were typically slender. Na(+) currents were detected in premature ganglion cells with round somata in the 'intermediate-II' regenerating retina. No electrical and tracer couplings were observed between these cells. Mature ganglion cells did not exhibit electrical coupling, but showed tracer coupling. On average, the maximum Na(+) current amplitude recorded from premature ganglion cells was roughly 2.5-fold smaller than that of mature ganglion cells. In addition, the activation threshold of the Na(+) current was nearly 11 mV more positive than that of mature cells. We provide morphological and physiological evidence showing that loss of gap junctions between progenitor cells is associated with ganglion cell differentiation during retinal regeneration and that new gap junctions are recreated between mature ganglion cells. Also we provide evidence suggesting that the loss of gap junctions correlates with the appearance of voltage-activated Na(+) currents in ganglion cells.

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor.

PubMed

Mavlyutov, Timur A; Nickells, Robert W; Guo, Lian-Wang

2011-04-26

The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1(-/-)) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1(-/-) mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1(-/-), demonstrating a significant difference between the wild-type and the Sigmar1(-/-) in crush-induced ganglion cell loss. Our data indicated faster retinal ganglion cell death in Sigmar1(-/-) than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma.

Angioarchitecture of the coeliac sympathetic ganglion complex in the common tree shrew (Tupaia glis)

PubMed Central

PROMWIKORN, WARAPORN; THONGPILA, SAKPORN; PRADIDARCHEEP, WISUIT; MINGSAKUL, THAWORN; CHUNHABUNDIT, PANJIT; SOMANA, REON

1998-01-01

The angioarchitecture of the coeliac sympathetic ganglion complex (CGC) of the common tree shrew (Tupaia glis) was studied by the vascular corrosion cast technique in conjunction with scanning electron microscopy. The CGC of the tree shrew was found to be a highly vascularised organ. It normally received arterial blood supply from branches of the inferior phrenic, superior suprarenal and inferior suprarenal arteries and of the abdominal aorta. In some animals, its blood supply was also derived from branches of the middle suprarenal arteries, coeliac artery, superior mesenteric artery and lumbar arteries. These arteries penetrated the ganglion at variable points and in slightly different patterns. They gave off peripheral branches to form a subcapsular capillary plexus while their main trunks traversed deeply into the inner part before branching into the densely packed intraganglionic capillary networks. The capillaries merged to form venules before draining into collecting veins at the peripheral region of the ganglion complex. Finally, the veins coursed to the dorsal aspect of the ganglion to drain into the renal and inferior phrenic veins and the inferior vena cava. The capillaries on the coeliac ganglion complex do not possess fenestrations. PMID:9877296

Retinal ganglion cell projections to the hamster suprachiasmatic nucleus, intergeniculate leaflet, and visual midbrain: bifurcation and melanopsin immunoreactivity

NASA Technical Reports Server (NTRS)

Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio

2003-01-01

The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.

Thresholds for activation of rabbit retinal ganglion cells with an ultrafine, extracellular microelectrode.

PubMed

Jensen, Ralph J; Rizzo, Joseph F; Ziv, Ofer R; Grumet, Andrew; Wyatt, John

2003-08-01

To determine electrical thresholds required for extracellular activation of retinal ganglion cells as part of a project to develop an epiretinal prosthesis. Retinal ganglion cells were recorded extracellularly in retinas isolated from adult New Zealand White rabbits. Electrical current pulses of 100- micro s duration were delivered to the inner surface of the retina from a 5- micro m long electrode. In about half of the cells, the point of lowest threshold was found by searching with anodal current pulses; in the other cells, cathodal current pulses were used. Threshold measurements were obtained near the cell bodies of 20 ganglion cells and near the axons of 19 ganglion cells. Both cathodal and anodal stimuli evoked a neural response in the ganglion cells that consisted of a single action potential of near-constant latency that persisted when retinal synaptic transmission was blocked with cadmium chloride. For cell bodies, but not axons, thresholds for both cathodal and anodal stimulation were dependent on the search method used to find the point of lowest threshold. With search and stimulation of matching polarity, cathodal stimuli evoked a ganglion cell response at lower currents (approximately one seventh to one tenth axonal threshold) than did anodal stimuli for both cell bodies and axons. With cathodal search and stimulation, cell body median thresholds were somewhat lower (approximately one half) than the axonal median thresholds. With anodal search and stimulation, cell body median thresholds were approximately the same as axonal median thresholds. The results suggest that cathodal stimulation should produce lower thresholds, more localized stimulation, and somewhat better selectivity for cell bodies over axons than would anodal stimulation.

Muscarinic Acetylcholine Receptor Localization and Activation Effects on Ganglion Response Properties

PubMed Central

Renna, Jordan M.; Amthor, Franklin R.; Keyser, Kent T.

2010-01-01

Purpose. The activation and blockade of muscarinic acetylcholine receptors (mAChRs) affects retinal ganglion cell light responses and firing rates. This study was undertaken to identify the full complement of mAChRs expressed in the rabbit retina and to assess mAChR distribution and the functional effects of mAChR activation and blockade on retinal response properties. Methods. RT-PCR, Western blot analysis, and immunohistochemistry were used to identify the complement and distribution of mAChRs in the rabbit retina. Extracellular electrophysiology was used to determine the effects of the activation or blockade of mAChRs on ganglion cell response properties. Results. RT-PCR of whole neural retina resulted in the amplification of mRNA transcripts for the m1 to m5 mAChR subtypes. Western blot and immunohistochemical analyses confirmed that all five mAChR subtypes were expressed by subpopulations of bipolar, amacrine, and ganglion cells in the rabbit retina, including subsets of cells in cholinergic and glycinergic circuits. Nonspecific muscarinic activation and blockade resulted in the class-specific modulation of maintained ganglion cell firing rates and light responses. Conclusions. The expression of mAChR subtypes on subsets of bipolar, amacrine, and ganglion cells provides a substrate for both enhancement and suppression of retinal responses via activation by cholinergic agents. Thus, the muscarinic cholinergic system in the retina may contribute to the modulation of complex stimuli. Understanding the distribution and function of mAChRs in the retina has the potential to provide important insights into the visual changes that are caused by decreased ACh in the retinas of Alzheimer's patients and the potential visual effects of anticholinergic treatments for ocular diseases. PMID:20042645

Broad Thorny Ganglion Cells: A Candidate for Visual Pursuit Error Signaling in the Primate Retina

PubMed Central

Manookin, Michael B.; Neitz, Jay; Rieke, Fred

2015-01-01

Functional analyses exist only for a few of the morphologically described primate ganglion cell types, and their correlates in other mammalian species remain elusive. Here, we recorded light responses of broad thorny cells in the whole-mounted macaque retina. They showed ON-OFF-center light responses that were strongly suppressed by stimulation of the receptive field surround. Spike responses were delayed compared with parasol ganglion cells and other ON-OFF cells, including recursive bistratified ganglion cells and A1 amacrine cells. The receptive field structure was shaped by direct excitatory synaptic input and strong presynaptic and postsynaptic inhibition in both ON and OFF pathways. The cells responded strongly to dark or bright stimuli moving either in or out of the receptive field, independent of the direction of motion. However, they did not show a maintained spike response either to a uniform background or to a drifting plaid pattern. These properties could be ideally suited for guiding movements involved in visual pursuit. The functional characteristics reported here permit the first direct cross-species comparison of putative homologous ganglion cell types. Based on morphological similarities, broad thorny ganglion cells have been proposed to be homologs of rabbit local edge detector ganglion cells, but we now show that the two cells have quite distinct physiological properties. Thus, our data argue against broad thorny cells as the homologs of local edge detector cells. PMID:25834063

Paracoccygeal corkscrew approach to ganglion impar injections for tailbone pain.

PubMed

Foye, Patrick M; Patel, Shounuck I

2009-01-01

A new technique for performing nerve blocks of the ganglion impar (ganglion Walther) is presented. These injections have been reported to relieve coccydynia (tailbone pain), as well as other malignant and nonmalignant pelvic pain syndromes. A variety of techniques have been previously described for blocking this sympathetic nerve ganglion, which is located in the retrorectal space just anterior to the upper coccygeal segments. Prior techniques have included approaches through the anococcygeal ligament, through the sacrococcygeal joint, and through intracoccygeal joint spaces. This article presents a new, paracoccygeal approach whereby the needle is inserted alongside the coccyx and the needle is guided through three discrete steps with a rotating or corkscrew trajectory. Compared with some of the previously published techniques, this paracoccygeal corkscrew approach has multiple potential benefits, including ease of fluoroscopic guidance using the lateral view, ability to easily use a stylet for the spinal needle, and use of a shorter, thinner needle. While no single technique works best for all patients and each technique has potential advantages and disadvantages, this new technique adds to the available options.

Diagnostic ability of macular ganglion cell asymmetry for glaucoma.

PubMed

Hwang, Young Hoon; Ahn, Sang Il; Ko, Sung Ju

2015-11-01

Using spectral-domain optical coherence tomography (OCT), this study aims to investigate the glaucoma diagnostic ability of macular ganglion cell asymmetry analysis. A cross-sectional study was conducted. This study was performed to investigate glaucoma diagnostic ability of macular ganglion cell asymmetry analysis in eyes with various degrees of glaucoma. We enrolled 181 healthy eyes and 265 glaucomatous eyes. Glaucomatous eyes were subdivided into pre-perimetric, early, moderate and advanced-to-severe glaucoma based on visual field test results. For each eye, macular ganglion cell-inner plexiform layer (GCIPL) thickness was measured using OCT. Average GCIPL thickness, GCIPL thicknesses in superior and inferior hemispheres, absolute difference in GCIPL thickness between superior and inferior hemispheres and GCIPL asymmetry index calculated as the absolute value of log10 (inferior hemisphere thickness/superior hemisphere thickness) were analysed. Areas under the receiver operating characteristics curves (AUCs) of GCIPL parameter were calculated and compared. All of the GCIPL parameters showed good glaucoma diagnostic ability (AUCs ≥ 0.817, P < 0.01). AUCs of average, superior and inferior GCIPL thickness increased as the severity of glaucoma increased. GCIPL thickness difference and asymmetry index showed the highest AUCs in early and moderate glaucoma and lower AUCs in pre-perimetric and advanced-to-severe glaucoma. GCIPL thickness difference and asymmetry index showed better glaucoma diagnostic ability than other GCIPL parameters only in early stage of glaucoma (P < 0.05); in other stages, these parameters had similar to or worse glaucoma diagnostic ability than other GCIPL parameters. Macular ganglion cell asymmetry analysis showed good glaucoma diagnostic ability, especially in early-stage glaucoma. However, it has limited usefulness in other stages of glaucoma. © 2015 Royal Australian and New Zealand College of Ophthalmologists.

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor

PubMed Central

Mavlyutov, Timur A.; Nickells, Robert W.

2011-01-01

Purpose The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1−/−) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Methods Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1−/− mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Results Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1−/−, demonstrating a significant difference between the wild-type and the Sigmar1−/− in crush-induced ganglion cell loss. Conclusions Our data indicated faster retinal ganglion cell death in Sigmar1−/− than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma. PMID

Relationship between macular ganglion cell complex thickness and macular outer retinal thickness: a spectral-domain optical coherence tomography study.

PubMed

Kita, Yoshiyuki; Kita, Ritsuko; Takeyama, Asuka; Anraku, Ayako; Tomita, Goji; Goldberg, Ivan

2013-01-01

To assess the relationship between macular ganglion cell complex and macular outer retinal thicknesses. Case-control study. Forty-two normal eyes and 91 eyes with primary open-angle glaucoma were studied. Spectral-domain optical coherence tomography (RTVue-100) was used to measure the macular ganglion cell complex and macular outer retinal thickness. Ganglion cell complex to outer retinal thickness ratio was also calculated. The relationships between the ganglion cell complex and outer retinal thicknesses and between the ganglion cell complex to outer retinal thickness ratio and outer retinal thickness were evaluated. There was a positive correlation between ganglion cell complex and outer retinal thicknesses in the normal group and the glaucoma group (r = 0.53, P < 0.001 and r = 0.42, P < 0.001, respectively). In that respect, there was no correlation between ganglion cell complex to outer retinal thickness ratio and outer retinal thickness in the both groups (r = -0.07, P = 0.657, and r = 0.04, P = 0.677, respectively). The ganglion cell complex to outer retinal thickness ratio was 55.65% in the normal group, 45.07% in the glaucoma group. This difference was statistically significant. The ganglion cell complex thickness may be affected by outer retinal thickness, and there is individual variation in the outer retinal thickness. Therefore, when determining the ganglion cell complex, it seems necessary to consider the outer retinal thickness as well. We propose the ratio as a suitable parameter to account for individual variations in outer retinal thickness. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Digital Museum of Retinal Ganglion Cells with Dense Anatomy and Physiology.

PubMed

Bae, J Alexander; Mu, Shang; Kim, Jinseop S; Turner, Nicholas L; Tartavull, Ignacio; Kemnitz, Nico; Jordan, Chris S; Norton, Alex D; Silversmith, William M; Prentki, Rachel; Sorek, Marissa; David, Celia; Jones, Devon L; Bland, Doug; Sterling, Amy L R; Park, Jungman; Briggman, Kevin L; Seung, H Sebastian

2018-05-17

When 3D electron microscopy and calcium imaging are used to investigate the structure and function of neural circuits, the resulting datasets pose new challenges of visualization and interpretation. Here, we present a new kind of digital resource that encompasses almost 400 ganglion cells from a single patch of mouse retina. An online "museum" provides a 3D interactive view of each cell's anatomy, as well as graphs of its visual responses. The resource reveals two aspects of the retina's inner plexiform layer: an arbor segregation principle governing structure along the light axis and a density conservation principle governing structure in the tangential plane. Structure is related to visual function; ganglion cells with arbors near the layer of ganglion cell somas are more sustained in their visual responses on average. Our methods are potentially applicable to dense maps of neuronal anatomy and physiology in other parts of the nervous system. Copyright © 2018 Elsevier Inc. All rights reserved.

Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia

PubMed Central

Vit, Jean-Philippe; Ohara, Peter T; Sundberg, Christopher; Rubi, Blanca; Maechler, Pierre; Liu, Chunyan; Puntel, Mariana; Lowenstein, Pedro; Castro, Maria; Jasmin, Luc

2009-01-01

Background Our goal is to use gene therapy to alleviate pain by targeting glial cells. In an animal model of facial pain we tested the effect of transfecting the glutamic acid decarboxylase (GAD) gene into satellite glial cells (SGCs) of the trigeminal ganglion by using a serotype 5 adenovector with high tropisms for glial cells. We postulated that GABA produced from the expression of GAD would reduce pain behavior by acting on GABA receptors on neurons within the ganglion. Results Injection of adenoviral vectors (AdGAD65) directly into the trigeminal ganglion leads to sustained expression of the GAD65 isoform over the 4 weeks observation period. Immunohistochemical analysis showed that adenovirus-mediated GAD65 expression and GABA synthesis were mainly in SGCs. GABAA and GABAB receptors were both seen in sensory neurons, yet only GABAA receptors decorated the neuronal surface. GABA receptors were not found on SGCs. Six days after injection of AdGAD65 into the trigeminal ganglion, there was a statistically significant decrease of pain behavior in the orofacial formalin test, a model of inflammatory pain. Rats injected with control virus (AdGFP or AdLacZ) had no reduction in their pain behavior. AdGAD65-dependent analgesia was blocked by bicuculline, a selective GABAA receptor antagonist, but not by CGP46381, a selective GABAB receptor antagonist. Conclusion Transfection of glial cells in the trigeminal ganglion with the GAD gene blocks pain behavior by acting on GABAA receptors on neuronal perikarya. PMID:19656360

Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia.

PubMed

Vit, Jean-Philippe; Ohara, Peter T; Sundberg, Christopher; Rubi, Blanca; Maechler, Pierre; Liu, Chunyan; Puntel, Mariana; Lowenstein, Pedro; Castro, Maria; Jasmin, Luc

2009-08-05

Our goal is to use gene therapy to alleviate pain by targeting glial cells. In an animal model of facial pain we tested the effect of transfecting the glutamic acid decarboxylase (GAD) gene into satellite glial cells (SGCs) of the trigeminal ganglion by using a serotype 5 adenovector with high tropisms for glial cells. We postulated that GABA produced from the expression of GAD would reduce pain behavior by acting on GABA receptors on neurons within the ganglion. Injection of adenoviral vectors (AdGAD65) directly into the trigeminal ganglion leads to sustained expression of the GAD65 isoform over the 4 weeks observation period. Immunohistochemical analysis showed that adenovirus-mediated GAD65 expression and GABA synthesis were mainly in SGCs. GABAA and GABAB receptors were both seen in sensory neurons, yet only GABAA receptors decorated the neuronal surface. GABA receptors were not found on SGCs. Six days after injection of AdGAD65 into the trigeminal ganglion, there was a statistically significant decrease of pain behavior in the orofacial formalin test, a model of inflammatory pain. Rats injected with control virus (AdGFP or AdLacZ) had no reduction in their pain behavior. AdGAD65-dependent analgesia was blocked by bicuculline, a selective GABAA receptor antagonist, but not by CGP46381, a selective GABAB receptor antagonist. Transfection of glial cells in the trigeminal ganglion with the GAD gene blocks pain behavior by acting on GABAA receptors on neuronal perikarya.

Visual Field Defects and Retinal Ganglion Cell Losses in Human Glaucoma Patients

PubMed Central

Harwerth, Ronald S.; Quigley, Harry A.

2007-01-01

Objective The depth of visual field defects are correlated with retinal ganglion cell densities in experimental glaucoma. This study was to determine whether a similar structure-function relationship holds for human glaucoma. Methods The study was based on retinal ganglion cell densities and visual thresholds of patients with documented glaucoma (Kerrigan-Baumrind, et al.) The data were analyzed by a model that predicted ganglion cell densities from standard clinical perimetry, which were then compared to histologic cell counts. Results The model, without free parameters, produced accurate and relatively precise quantification of ganglion cell densities associated with visual field defects. For 437 sets of data, the unity correlation for predicted vs. measured cell densities had a coefficient of determination of 0.39. The mean absolute deviation of the predicted vs. measured values was 2.59 dB, the mean and SD of the distribution of residual errors of prediction was -0.26 ± 3.22 dB. Conclusions Visual field defects by standard clinical perimetry are proportional to neural losses caused by glaucoma. Clinical Relevance The evidence for quantitative structure-function relationships provides a scientific basis of interpreting glaucomatous neuropathy from visual thresholds and supports the application of standard perimetry to establish the stage of the disease. PMID:16769839

Expression of squid iridescence depends on environmental luminance and peripheral ganglion control.

PubMed

Gonzalez-Bellido, P T; Wardill, T J; Buresch, K C; Ulmer, K M; Hanlon, R T

2014-03-15

Squid display impressive changes in body coloration that are afforded by two types of dynamic skin elements: structural iridophores (which produce iridescence) and pigmented chromatophores. Both color elements are neurally controlled, but nothing is known about the iridescence circuit, or the environmental cues, that elicit iridescence expression. To tackle this knowledge gap, we performed denervation, electrical stimulation and behavioral experiments using the long-fin squid, Doryteuthis pealeii. We show that while the pigmentary and iridescence circuits originate in the brain, they are wired differently in the periphery: (1) the iridescence signals are routed through a peripheral center called the stellate ganglion and (2) the iridescence motor neurons likely originate within this ganglion (as revealed by nerve fluorescence dye fills). Cutting the inputs to the stellate ganglion that descend from the brain shifts highly reflective iridophores into a transparent state. Taken together, these findings suggest that although brain commands are necessary for expression of iridescence, integration with peripheral information in the stellate ganglion could modulate the final output. We also demonstrate that squid change their iridescence brightness in response to environmental luminance; such changes are robust but slow (minutes to hours). The squid's ability to alter its iridescence levels may improve camouflage under different lighting intensities.

Macroanatomical investigation of the aorticorenal ganglion in 1-day-old infant sheep.

PubMed

Klećkowska-Nawrot, J; Kaczyńska, K; Jakubowska, W

2009-06-01

The aorticorenal gland belongs to the paired splanchnic ganglion, which is the main component of the coeliac plexus. It lies near the renal artery and suprarenal gland. The research was conducted on 13 1-day-old infant sheep - eight males and five females. Based on the conducted studies, it was concluded that the aorticorenal ganglion is characterized by the variable location in relation to the abdominal aorta, renal artery, caudal vena cava and suprarenal gland (holotopy), the thoracic and lumbar segment of the vertebral column (skeletotopy) (between L(1) and L(3)) and also a different shape (elongated, round, triangular, oval) as well as variable length (the aorticorenal ganglion is longer on the left side of the body; 2.72 mm) and distance from the caudal end of the suprarenal gland (longer on the left side of the body; 8.34 mm). With regard to the sex of the animal, the ganglion is the longest on the left side in ewes (3.02 mm), while in rams it is the longest on the right side (2.68 mm). Regarding the division according to sex, the longest segment was observed on the right side in ewes (9.27 mm), and the shortest segment in rams was also on the right side (6.84 mm).

Processing of central and reflex vagal drives by rat cardiac ganglion neurones: an intracellular analysis

PubMed Central

McAllen, Robin M; Salo, Lauren M; Paton, Julian F R; Pickering, Anthony E

2011-01-01

Abstract Cardiac vagal tone is an important indicator of cardiovascular health, and its loss is an independent risk factor for arrhythmias and mortality. Several studies suggest that this loss of vagal tone can occur at the cardiac ganglion but the factors affecting ganglionic transmissionin vivoare poorly understood. We have employed a novel approach allowing intracellular recordings from functionally connected cardiac vagal ganglion cells in the working heart–brainstem preparation. The atria were stabilisedin situpreserving their central neural connections, and ganglion cells (n = 32) were impaled with sharp microelectrodes. Cardiac ganglion cells with vagal synaptic inputs (spontaneous, n = 10; or electrically evoked from the vagus, n = 3) were identified as principal neurones and showed tonic firing responses to current injected to their somata. Cells lacking vagal inputs (n = 19, presumed interneurones) were quiescent but showed phasic firing responses to depolarising current. In principal cells the ongoing action potentials and EPSPs exhibited respiratory modulation, with peak frequency in post-inspiration. Action potentials arose from unitary EPSPs and autocorrelation of those events showed that each ganglion cell received inputs from a single active preganglionic source. Peripheral chemoreceptor, arterial baroreceptor and diving response activation all evoked high frequency synaptic barrages in these cells, always from the same single preganglionic source. EPSP amplitudes showed frequency dependent depression, leading to more spike failures at shorter inter-event intervals. These findings indicate that rather than integrating convergent inputs, cardiac vagal postganglionic neurones gate preganglionic inputs, so regulating the proportion of central parasympathetic tone that is transmitted on to the heart. PMID:22005679

Recurrent Cubital Tunnel Syndrome Caused by Ganglion: A Report of Nine Cases.

PubMed

Komatsu, Masatoshi; Uchiyama, Shigeharu; Kimura, Takumi; Suenaga, Naoki; Hayashi, Masanori; Kato, Hiroyuki

2018-06-01

Cubital tunnel syndrome (CuTS) is generally treated successfully by surgery and recurrent cases are rare. This study retrospectively investigated the clinical characteristics of recurrent CuTS caused by ganglion. We evaluated nine patients who were surgically treated for recurrent CuTS caused by ganglion. Age distribution at recurrence ranged from 43 to 79 years. The initial surgery for CuTS had been performed using various methods. The asymptomatic period from initial surgery to recurrence ranged from 22 to 252 months. Clinical, diagnostic imaging, and operative findings during the second surgery were analyzed. All patients were treated by anterior subcutaneous ulnar nerve transposition with ganglion resection and later examined directly within a mean of 71 months after the second surgery. The interval from recurrence to consultation was shorter than two months for eight cases. Chief complaints included numbness with or without pain in the ring and little fingers in all patients and resting pain in the medial elbow in five patients. Elbow osteoarthritis was present in all cases. Although four of 10 ganglia were palpable, ultrasonography and magnetic resonance imaging could identify all ganglia preoperatively. The ulnar nerve typically had become entrapped by the ganglion posteriorly and by fascia, scar tissue, and/or muscle anteriorly. Chief complaints and ulnar nerve function were improved in all patients following revision surgery. The acute onset of numbness with or without intolerable pain in the ring and little fingers after a long-term remission period following initial surgery for CuTS in patients with elbow osteoarthritis appears to be the characteristic clinical profile of recurrent CuTS caused by ganglion. As ganglia are often not palpable, ultrasonography and magnetic resonance imaging are recommended for accurate diagnosis.

Approche de prise en charge du trouble du spectre de l’autisme

PubMed Central

Lee, Patrick F.; Thomas, Roger E.; Lee, Patricia A.

2015-01-01

Résumé Objectif Se pencher sur les critères diagnostiques du trouble du spectre de l’autisme (TSA) comme les définit le Manuel diagnostique et statistique des troubles mentaux, cinquième édition (DSM-V), et concevoir une approche de prise en charge du TSA à l’aide du cadre CanMEDS–Médecine familiale (CanMEDS-MF). Sources d’information Le DSM-V, publié par l’American Psychiatric Association en mai 2013, énonce de nouveaux critères diagnostiques du TSA. Le cadre CanMEDS-MF du Collège des médecins de famille du Canada fournit un plan d’orientation pour la prise en charge complexe du TSA. Nous avons utilisé des données recueillies par le Centers for Disease Control and Prevention afin de déterminer la prévalence du TSA, ainsi que la revue systématique et méta-analyse détaillée effectuée par le National Institute for Health and Care Excellence du R.-U. pour ses lignes directrices sur le TSA dans le but d’évaluer les données probantes issues de plus de 100 interventions. Message principal Selon les données du Centers for Disease Control and Prevention, la prévalence du TSA se chiffrait à 1 sur 88 en 2008 aux États-Unis. La classification du TSA dans la quatrième édition du DSM incluait l’autisme, le syndrome d’Asperger, le trouble envahissant du développement et le trouble désintégratif de l’enfance. La dernière révision du DSM-V réunit tous ces troubles sous la mention TSA, avec différents niveaux de sévérité. La prise en charge du TSA est complexe; elle exige les efforts d’une équipe multidisciplinaire ainsi que des soins continus. Les rôles CanMEDS-MF fournissent un cadre de prise en charge. Conclusion Les médecins de famille sont au cœur de l’équipe de soins multidisciplinaire pour le TSA, et le cadre CanMEDS-MF tient lieu de plan détaillé pour guider la prise en charge d’un enfant atteint de TSA et aider la famille de cet enfant.

Complex distribution patterns of voltage-gated calcium channel α-subunits in the spiral ganglion

PubMed Central

Chen, Wei Chun; Xue, Hui Zhong; Hsu, Yun (Lucy); Liu, Qing; Patel, Shail; Davis, Robin L.

2011-01-01

As with other elements of the peripheral auditory system, spiral ganglion neurons display specializations that vary as a function of location along the tonotopic axis. Previous work has shown that voltage-gated K+ channels and synaptic proteins show graded changes in their density that confers rapid responsiveness to neurons in the high frequency, basal region of the cochlea and slower, more maintained responsiveness to neurons in the low frequency, apical region of the cochlea. In order to understand how voltage-gated calcium channels (VGCCs) may contribute to these diverse phenotypes, we identified the VGCC α-subunits expressed in the ganglion, investigated aspects of Ca2+-dependent neuronal firing patterns, and mapped the intracellular and intercellular distributions of seven VGCC α-subunits in the spiral ganglion in vitro. Initial experiments with qRT-PCR showed that eight of the ten known VGCC α-subunits were expressed in the ganglion and electrophysiological analysis revealed firing patterns that were consistent with the presence of both LVA and HVA Ca2+ channels. Moreover, we were able to study seven of the α-subunits with immunocytochemistry, and we found that all were present in spiral ganglion neurons, and that three of them were neuron-specific (CaV1.3, CaV2.2, and CaV3.3). Further characterization of neuron-specific α-subunits showed that CaV1.3 and CaV3.3 were tonotopically-distributed, whereas CaV2.2 was uniformly distributed in apical and basal neurons. Multiple VGCC α-subunits were also immunolocalized to Schwann cells, having distinct intracellular localizations, and, significantly, appearing to distinguish putative compact0 (CaV2.3, CaV3.1) from loose (CaV1.2) myelin. Electrophysiological evaluation of spiral ganglion neurons in the presence of TEA revealed Ca2+ plateau potentials with slopes that varied proportionately with the cochlear region from which neurons were isolated. Because afterhyperpolarizations were minimal or absent under

Central Projections of Melanopsin-Expressing Retinal Ganglion Cells in the Mouse

PubMed Central

HATTAR, SAMER; KUMAR, MONICA; PARK, ALEXANDER; TONG, PATRICK; TUNG, JONATHAN; YAU, KING-WAI; BERSON, DAVID M.

2010-01-01

A rare type of ganglion cell in mammalian retina is directly photosensitive. These novel retinal photoreceptors express the photopigment melanopsin. They send axons directly to the suprachiasmatic nucleus (SCN), intergeniculate leaflet (IGL), and olivary pretectal nucleus (OPN), thereby contributing to photic synchronization of circadian rhythms and the pupillary light reflex. Here, we sought to characterize more fully the projections of these cells to the brain. By targeting tau-lacZ to the melanopsin gene locus in mice, ganglion cells that would normally express melanopsin were induced to express, instead, the marker enzyme β-galactosidase. Their axons were visualized by X-gal histochemistry or anti-β-galactosidase immunofluorescence. Established targets were confirmed, including the SCN, IGL, OPN, ventral division of the lateral geniculate nucleus (LGv), and preoptic area, but the overall projections were more widespread than previously recognized. Targets included the lateral nucleus, peri-supraoptic nucleus, and subparaventricular zone of the hypothalamus, medial amygdala, margin of the lateral habenula, posterior limitans nucleus, superior colliculus, and periaqueductal gray. There were also weak projections to the margins of the dorsal lateral geniculate nucleus. Co-staining with the cholera toxin B subunit to label all retinal afferents showed that melanopsin ganglion cells provide most of the retinal input to the SCN, IGL, and lateral habenula and much of that to the OPN, but that other ganglion cells do contribute at least some retinal input to these targets. Staining patterns after monocular enucleation revealed that the projections of these cells are overwhelmingly crossed except for the projection to the SCN, which is bilaterally symmetrical. PMID:16736474

Ganglion blocks as a treatment of pain: current perspectives

PubMed Central

Gunduz, Osman Hakan; Kenis-Coskun, Ozge

2017-01-01

The inputs from sympathetic ganglia have been known to be involved in the pathophysiology of various painful conditions such as complex regional pain syndrome, cancer pain of different origin, and coccygodynia. Sympathetic ganglia blocks are used to relieve patients who suffer from these conditions for over a century. Many numbers of local anesthetics such as bupivacaine or neurolytic agents such as alcohol can be chosen for a successful block. The agent is selected according to its duration of effect and the purpose of the injection. Most commonly used sympathetic blocks are stellate ganglion block, lumbar sympathetic block, celiac plexus block, superior hypogastric block, and ganglion Impar block. In this review, indications, methods, effectiveness, and complications of these blocks are discussed based on the data from the current literature. PMID:29276402

A Learning Model for L/M Specificity in Ganglion Cells

NASA Technical Reports Server (NTRS)

Ahumada, Albert J.

2016-01-01

An unsupervised learning model for developing LM specific wiring at the ganglion cell level would support the research indicating LM specific wiring at the ganglion cell level (Reid and Shapley, 2002). Removing the contributions to the surround from cells of the same cone type improves the signal-to-noise ratio of the chromatic signals. The unsupervised learning model used is Hebbian associative learning, which strengthens the surround input connections according to the correlation of the output with the input. Since the surround units of the same cone type as the center are redundant with the center, their weights end up disappearing. This process can be thought of as a general mechanism for eliminating unnecessary cells in the nervous system.

An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival

PubMed Central

Tang, Zhongshu; Zhang, Shuihua; Lee, Chunsik; Kumar, Anil; Arjunan, Pachiappan; Li, Yang; Zhang, Fan; Li, Xuri

2011-01-01

Injury to the optic nerve can lead to axonal degeneration, followed by a gradual death of retinal ganglion cells (RGCs), which results in irreversible vision loss. Examples of such diseases in human include traumatic optic neuropathy and optic nerve degeneration in glaucoma. It is characterized by typical changes in the optic nerve head, progressive optic nerve degeneration, and loss of retinal ganglion cells, if uncontrolled, leading to vision loss and blindness. The optic nerve crush (ONC) injury mouse model is an important experimental disease model for traumatic optic neuropathy, glaucoma, etc. In this model, the crush injury to the optic nerve leads to gradual retinal ganglion cells apoptosis. This disease model can be used to study the general processes and mechanisms of neuronal death and survival, which is essential for the development of therapeutic measures. In addition, pharmacological and molecular approaches can be used in this model to identify and test potential therapeutic reagents to treat different types of optic neuropathy. Here, we provide a step by step demonstration of (I) Baseline retrograde labeling of retinal ganglion cells (RGCs) at day 1, (II) Optic nerve crush injury at day 4, (III) Harvest the retinae and analyze RGC survival at day 11, and (IV) Representative result. PMID:21540827

Thalamic pain alleviated by stellate ganglion block: A case report.

PubMed

Liao, Chenlong; Yang, Min; Liu, Pengfei; Zhong, Wenxiang; Zhang, Wenchuan

2017-02-01

Thalamic pain is a distressing and treatment-resistant type of central post-stroke pain. Although stellate ganglion block is an established intervention used in pain management, its use in the treatment of thalamic pain has never been reported. A 66-year-old woman presented with a 3-year history of severe intermittent lancinating pain on the right side of the face and the right hand. The pain started from the ulnar side of the right forearm after a mild ischemic stroke in bilateral basal ganglia and left thalamus. Weeks later, the pain extended to the dorsum of the finger tips and the whole palmar surface, becoming more severe. Meanwhile, there was also pain with similar characteristics emerging on her right face, resembling atypical trigeminal neuralgia. Thalamic pain was diagnosed. After refusing the further invasive treatment, she was suggested to try stellate ganglion block. After a 3-day period of pain free (numerical rating scale: 0) postoperatively, she reported moderate to good pain relief with a numerical rating scale of about 3 to 4 lasting 1 month after the first injection. Pain as well as the quality of life was markedly improved with less dose of analgesic agents. Stellate ganglion block may be an optional treatment for thalamic pain.

Learning LM Specificity for Ganglion Cells

NASA Technical Reports Server (NTRS)

Ahumada, Albert J.

2015-01-01

Unsupervised learning models have been proposed based on experience (Ahumada and Mulligan, 1990;Wachtler, Doi, Lee and Sejnowski, 2007) that allow the cortex to develop units with LM specific color opponent receptive fields like the blob cells reported by Hubel and Wiesel on the basis of visual experience. These models used ganglion cells with LM indiscriminate wiring as inputs to the learning mechanism, which was presumed to occur at the cortical level.

Protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion.

PubMed

Zhai, S-Q; Guo, W; Hu, Y-Y; Yu, N; Chen, Q; Wang, J-Z; Fan, M; Yang, W-Y

2011-05-01

To explore the protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion. Recombinant adenovirus brain-derived neurotrophic factor vector, recombinant adenovirus LacZ and artificial perilymph were prepared. Guinea pigs with audiometric auditory brainstem response thresholds of more than 75 dB SPL, measured seven days after four hours of noise exposure at 135 dB SPL, were divided into three groups. Adenovirus brain-derived neurotrophic factor vector, adenovirus LacZ and perilymph were infused into the cochleae of the three groups, variously. Eight weeks later, the cochleae were stained immunohistochemically and the spiral ganglion cells counted. The auditory brainstem response threshold recorded before and seven days after noise exposure did not differ significantly between the three groups. However, eight weeks after cochlear perfusion, the group receiving brain-derived neurotrophic factor had a significantly decreased auditory brainstem response threshold and increased spiral ganglion cell count, compared with the adenovirus LacZ and perilymph groups. When administered via cochlear infusion following noise damage, brain-derived neurotrophic factor appears to improve the auditory threshold, and to have a protective effect on the spiral ganglion cells.

Ocular anatomy, ganglion cell distribution and retinal resolution of a killer whale (Orcinus orca).

PubMed

Mass, Alla M; Supin, Alexander Y; Abramov, Andrey V; Mukhametov, Lev M; Rozanova, Elena I

2013-01-01

Retinal topography, cell density and sizes of ganglion cells in the killer whale (Orcinus orca) were analyzed in retinal whole mounts stained with cresyl violet. A distinctive feature of the killer whale's retina is the large size of ganglion cells and low cell density compared to terrestrial mammals. The ganglion cell diameter ranged from 8 to 100 µm, with the majority of cells within a range of 20-40 µm. The topographic distribution of ganglion cells displayed two spots of high cell density located in the temporal and nasal quadrants, 20 mm from the optic disk. The high-density areas were connected by a horizontal belt-like area passing below the optic disk of the retina. Peak cell densities in these areas were evaluated. Mean peak cell densities were 334 and 288 cells/mm(2) in the temporal and nasal high-density areas, respectively. With a posterior nodal distance of 19.5 mm, these high-density data predict a retinal resolution of 9.6' (3.1 cycles/deg.) and 12.6' (2.4 cycles/deg.) in the temporal and nasal areas, respectively, in water. Copyright © 2012 S. Karger AG, Basel.

Lithium alters the morphology of neurites regenerating from cultured adult spiral ganglion neurons.

PubMed

Shah, S M; Patel, C H; Feng, A S; Kollmar, R

2013-10-01

The small-molecule drug lithium (as a monovalent ion) promotes neurite regeneration and functional recovery, is easy to administer, and is approved for human use to treat bipolar disorder. Lithium exerts its neuritogenic effect mainly by inhibiting glycogen synthase kinase 3, a constitutively-active serine/threonine kinase that is regulated by neurotrophin and "wingless-related MMTV integration site" (Wnt) signaling. In spiral ganglion neurons of the cochlea, the effects of lithium and the function of glycogen synthase kinase 3 have not been investigated. We, therefore, set out to test whether lithium modulates neuritogenesis from adult spiral ganglion neurons. Primary cultures of dissociated spiral ganglion neurons from adult mice were exposed to lithium at concentrations between 0 and 12.5 mM. The resulting neurite morphology and growth-cone appearance were measured in detail by using immunofluorescence microscopy and image analysis. We found that lithium altered the morphology of regenerating neurites and their growth cones in a differential, concentration-dependent fashion. Low concentrations of 0.5-2.5 mM (around the half-maximal inhibitory concentration for glycogen synthase kinase 3 and the recommended therapeutic serum concentration for bipolar disorder) enhanced neurite sprouting and branching. A high concentration of 12.5 mM, in contrast, slowed elongation. As the lithium concentration rose from low to high, the microtubules became increasingly disarranged and the growth cones more arborized. Our results demonstrate that lithium selectively stimulates phases of neuritogenesis that are driven by microtubule reorganization. In contrast, most other drugs that have previously been tested on spiral ganglion neurons are reported to inhibit neurite outgrowth or affect only elongation. Lithium sensitivity is a necessary, but not sufficient condition for the involvement of glycogen synthase kinase 3. Our results are, therefore, consistent with, but do not prove

Enkephalin modulation of neural transmission in the cat stellate ganglion: pharmacological actions of exogenous opiates.

PubMed

Prosdocimi, M; Finesso, M; Gorio, A

1986-11-01

Neural ganglionic transmission was studied in vivo in the cat, using closed chest anesthetized preparations. The right stellate ganglion and its branches were exposed retropleurally and prepared for electrical stimulation of pre- and postganglionic nerve fibers. The axillary artery was cannulated allowing direct administration of drugs in the arterial blood supplying the ganglion. Stimulation of postjunctional receptors could thus be obtained by local administration of selective agents. Local administration of nicotinic, muscarinic or histaminergic agents increased heart rate and blood pressure. Opiates were given either i.v. or locally through the axillary artery: we tested the effects of morphine, Leu-enkephalin (Leu-enk), Met-enkephalin (Met-enk), [D-ala2]-Met-enkephalinamide (DAME) and etorphine. When given locally, Leu-enk (from 10 micrograms), Met-enk (from 20 micrograms), DAME (from 5 micrograms) and etorphine (from 0.2 micrograms) inhibited tachycardia induced by preganglionic stimulation and reduced the amplitude of the compound action potential recorded from the postganglionic nerve. Morphine (10-200 micrograms) had no effect. On the other hand, tachycardia induced by postganglionic nerve stimulation was unaffected by opiates in the same experimental conditions. Intravenous administration of similar doses of opiates had no effect on ganglionic transmission. When tachycardia was induced by chemical stimulation of nicotinic (DMPP), muscarinic (McN-A-343-11) or histamine receptors in the stellate ganglia, opiates were still active in reducing the effect of these chemicals. These data provide evidence that exogenous opiates exert a depressing action on postsynaptic responses of sympathetic ganglia tested in vivo, although an additional action on presynaptic terminals is not excluded. As endogenous opiates are normally present in various sympathetic ganglia, including the stellate ganglion of the cat, it is possible that they play some modulatory role on

Neuroprotective Effect of Tauroursodeoxycholic Acid on N-Methyl-D-Aspartate-Induced Retinal Ganglion Cell Degeneration

PubMed Central

Fernández-Sánchez, Laura; Rondón, Netxibeth; Esquiva, Gema; Germain, Francisco; de la Villa, Pedro; Cuenca, Nicolás

2015-01-01

Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss. PMID:26379056

Visual pattern recognition based on spatio-temporal patterns of retinal ganglion cells’ activities

PubMed Central

Jing, Wei; Liu, Wen-Zhong; Gong, Xin-Wei; Gong, Hai-Qing

2010-01-01

Neural information is processed based on integrated activities of relevant neurons. Concerted population activity is one of the important ways for retinal ganglion cells to efficiently organize and process visual information. In the present study, the spike activities of bullfrog retinal ganglion cells in response to three different visual patterns (checker-board, vertical gratings and horizontal gratings) were recorded using multi-electrode arrays. A measurement of subsequence distribution discrepancy (MSDD) was applied to identify the spatio-temporal patterns of retinal ganglion cells’ activities in response to different stimulation patterns. The results show that the population activity patterns were different in response to different stimulation patterns, such difference in activity pattern was consistently detectable even when visual adaptation occurred during repeated experimental trials. Therefore, the stimulus pattern can be reliably discriminated according to the spatio-temporal pattern of the neuronal activities calculated using the MSDD algorithm. PMID:21886670

Etude de l'affaiblissement du comportement mecanique du pergelisol du au rechauffement climatique

NASA Astrophysics Data System (ADS)

Buteau, Sylvie

Le rechauffement climatique predit pour les prochaines decennies, aura des impacts majeurs sur le pergelisol qui sont tres peu documentes pour l'instant. La presente etude a pour but d'evaluer ces impacts sur les proprietes mecaniques du pergelisol et sa stabilite a long terme. Une nouvelle technique d'essai de penetration au cone a taux de deformation controle, a ete developpee pour caracteriser en place le pergelisol. Ces essais geotechniques et la mesure de differentes proprietes physiques ont ete effectues sur une butte de pergelisol au cours du printemps 2000. Le developpement et l'utilisation d'un modele geothermique 1D tenant compte de la thermodependance du comportement mecanique ont permis d'evaluer que les etendues de pergelisol chaud deviendraient instables a la suite d'un rechauffement de l'ordre de 5°C sur cent ans. En effet, la resistance mecanique du pergelisol diminuera alors rapidement jusqu'a 11,6 MPa, ce qui correspond a une perte relative de 98% de la resistance par rapport a un scenario sans rechauffement.

Ganglion cell distribution and retinal resolution in the Florida manatee, Trichechus manatus latirostris.

PubMed

Mass, Alla M; Ketten, Darlene R; Odell, Daniel K; Supin, Alexander Ya

2012-01-01

The topographic organization of retinal ganglion cells was examined in the Florida manatee (Trichechus manatus latirostris) to assess ganglion cell size and distribution and to estimate retinal resolution. The ganglion cell layer of the manatee's retina was comprised primarily of large neurons with broad intercellular spaces. Cell sizes varied from 10 to 60 μm in diameter (mean 24.3 μm). The retinal wholemounts from adult animals measured 446-501 mm(2) in area with total ganglion cell counts of 62,000-81,800 (mean 70,200). The cell density changed across the retina, with the maximum in the area below the optic disc and decreasing toward the retinal edges and in the immediate vicinity of the optic disc. The maximum cell density ranged from 235 to 337 cells per millimeter square in the adult retinae. Two wholemounts obtained from juvenile animals were 271 and 282 mm(2) in area with total cell numbers of 70,900 and 68,700, respectively (mean 69,800), that is, nearly equivalent to those of adults, but juvenile retinae consequently had maximum cell densities that were higher than those of adults: 478 and 491 cells per millimeter square. Calculations indicate a retinal resolution of ∼19' (1.6 cycles per degree) in both adult and juvenile retinae. Copyright © 2011 Wiley Periodicals, Inc.

Periosteal ganglion: a report of three new cases including MRI findings and a review of the literature.

PubMed

Okada, K; Unoki, E; Kubota, H; Abe, E; Taniwaki, M; Morita, M; Sato, K

1996-02-01

To clarify the clinicopathological features of periosteal ganglion. Three patients with periosteal ganglion were studied clinicopathologically. One patient was selected from the files of our institute and two from a consultation file. All three lesions were located over the medial aspect of the tibia. Plain radiographs showed cortical erosions of varying degrees and mild periosteal reaction of the medial side of the tibia. MR images demonstrated well-circumscribed lesions overlying the cortical bone of the tibia, shown as low-intensity areas on T1-weighted images. On T2-weighted images, lesions were homogeneous, lobulated, and showed a characteristic markedly increased signal intensity. These findings are helpful in making a diagnosis of periosteal ganglion. Each patient had an uneventful clinical course after an excision involving the wall of the ganglion, the adjoining periosteum, and the underlying sclerotic cortical bone.

Synaptic transmission in the superior cervical ganglion of the cat after reinnervation by vagus fibres

PubMed Central

Ceccarelli, B.; Clementi, F.; Mantegazza, P.

1971-01-01

1. A vagus-sympathetic anastomosis was performed in the cat by connecting end to end the cranial trunk of the vagus to the cranial end of the cervical sympathetic trunk, both severed under the ganglia. 2. Forty to sixty days after the anastomosis, the ocular signs of sympathetic paralysis (such as myosis and prolapse of the nictitating membrane) which had developed shortly after the operation, had completely disappeared, thus suggesting the recovery of synaptic transmission in the ganglion. In case of plain preganglionic denervation after the same period the ocular signs of cervical sympathetic paralysis were still present. 3. Contraction of the nictitating membrane could be induced by electrical stimulation of both the vagus preanastomotic and the sympathetic postanastomotic—preganglionic trunks. Ganglionic blocking agents induced the blockade of the `new' ganglionic synaptic function, while nicotine and pilocarpine provoked a marked contraction of the nictitating membrane. 4. Electron microscopy showed that the preganglionic regeneration of vagus fibers resulted in the formation of new synapses, mainly of axodendritic type, identical to normal ganglionic synapses. Moreover, after cutting the preanastomotic trunk of the vagus, these new ganglionic presynaptic profiles degenerated, thus proving their vagal origin. 5. During restoration of the synaptic contacts readjustment of dendritic tips occurred. ImagesText-fig. 2Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13Fig. 16Fig. 17Fig. 14Fig. 15Fig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 7Fig. 8 PMID:4326851

Spatial resolution, contrast sensitivity, and sensitivity to defocus of chicken retinal ganglion cells in vitro.

PubMed

Diedrich, Erich; Schaeffel, Frank

2009-11-01

The chicken has been extensively studied as an animal model for myopia because its eye growth is tightly controlled by visual experience. It has been found that the retina controls the axial eye growth rates depending on the amount and the sign of defocus imposed in the projected image. Glucagonergic amacrine cells were discovered that appear to encode for the sign of imposed defocus. It is not clear whether the downstream neurons, the retinal ganglion cells, still have access to this information-and whether it ultimately reaches the brain. We have analyzed the spike rates of chicken retinal ganglion cells in vitro using a microelectrode array. For this purpose, we initially defined spatial resolution and contrast sensitivity in vitro. Two classes of chicken retinal ganglions were found, depending on the linearity of their responses with increasing contrast. Responses generally declined with increasing defocus of the visual stimulus. These responses were well predicted by the modulation transfer function for a diffraction-limited defocused optical system, the first Bessel function. Thus, the studied retinal ganglion cells did not distinguish between a loss of contrast at a given spatial frequency due to reduced contrast of the stimulus pattern or because the pattern was presented out of focus. Furthermore, there was no indication that the retinal ganglion cells responded differently to defocus of either sign, at least for the cells that were recorded in this study.

Distribution of TRPV1 and TRPV2 in the human stellate ganglion and spinal cord.

PubMed

Kokubun, Souichi; Sato, Tadasu; Ogawa, Chikara; Kudo, Kai; Goto, Koju; Fujii, Yuki; Shimizu, Yoshinaka; Ichikawa, Hiroyuki

2015-03-17

Immunohistochemistry for the transient receptor potential cation channel subfamily V member 1 (TRPV1) and 2 (TRPV2) was performed on the stellate ganglion and spinal cord in human cadavers. In the stellate ganglion, 25.3% and 16.2% of sympathetic neurons contained TRPV1- and TRPV2-immunoreactivity, respectively. The cell size analysis also demonstrated that proportion of TRPV1- or TRPV2-immunoreactive (-IR) neurons among large (>600 μm(2)) sympathetic neurons (TRPV1, 30.7%; TRPV2, 27.0%) was higher than among small (<600 μm(2)) sympathetic neurons (TRPV1, 22.0%; TRPV2, 13.6%). The present study also demonstrated that 10.0% of sympathetic neurons in the stellate ganglion had pericellular TRPV2-IR nerve fibers. Fourteen percent of large neurons and 7.8% of small neurons were surrounded by TRPV2-IR nerve fibers. TRPV2-immunoreactivity was also detected in about 40% of neuronal cell bodies with pericellular TRPV2-IR nerve fibers. In the lateral horn of the human thoracic spinal cord, TRPV2-immunoreactivity was expressed by some neurons and many varicose fibers surrounding TRPV2-immunonegative neurons. TRPV2-IR pericellular fibers in the stellate ganglion may originate from the lateral horn of the spinal cord. There appears to be TRPV1- or TRPV2-IR sympathetic pathway in the human stellate ganglion and spinal cord. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Molecular Responses of the Spiral Ganglion to Aminoglycosides

ERIC Educational Resources Information Center

Balaban, Carey D.

2005-01-01

Aminoglycosides are toxic to both the inner ear hair cells and the ganglion cells that give rise to the eighth cranial nerve. According to recent studies, these cells have a repertoire of molecular responses to aminoglycoside exposure that engages multiple neuroprotective mechanisms. The responses appear to involve regulation of ionic homeostasis,…

Gasserian Ganglion and Retrobulbar Nerve Block in the Treatment of Ophthalmic Postherpetic Neuralgia: A Case Report.

PubMed

Huang, Jie; Ni, Zhongge; Finch, Philip

2017-09-01

Varicella zoster virus reactivation can cause permanent histological changes in the central and peripheral nervous system. Neural inflammatory changes or damage to the dorsal root ganglia sensory nerve fibers during reactivation can lead to postherpetic neuralgia (PHN). For PHN of the first division of the fifth cranial nerve (ophthalmic division of the trigeminal ganglion), there is evidence of inflammatory change in the ganglion and adjacent ocular neural structures. First division trigeminal nerve PHN can prove to be difficult and sometimes even impossible to manage despite the use of a wide range of conservative measures, including anticonvulsant and antidepressant medication. Steroids have been shown to play an important role by suppressing neural inflammatory processes. We therefore chose the trigeminal ganglion as an interventional target for an 88-year-old woman with severe ophthalmic division PHN after she failed to respond to conservative treatment. Under fluoroscopic guidance, a trigeminal ganglion nerve block was performed with lidocaine combined with dexamethasone. A retrobulbar block with lidocaine and triamcinolone settled residual oculodynia. At 1-year follow-up, the patient remained pain free and did not require analgesic medication. To our knowledge, this is the first reported case of ophthalmic division PHN successfully treated with a combination of trigeminal ganglion and retrobulbar nerve block using a local anesthetic agent and steroid for central and peripheral neural inflammatory processes. © 2016 World Institute of Pain.

Therapeutic potential of stellate ganglion block in orofacial pain: a mini review.

PubMed

Jeon, Younghoon

2016-09-01

Orofacial pain is a common complaint of patients that causes distress and compromises the quality of life. It has many etiologies including trauma, interventional procedures, nerve injury, varicella-zoster (shingles), tumor, and vascular and idiopathic factors. It has been demonstrated that the sympathetic nervous system is usually involved in various orofacial pain disorders such as postherpetic neuralgia, complex regional pain syndromes, and atypical facial pain. The stellate sympathetic ganglion innervates the head, neck, and upper extremity. In this review article, the effect of stellate ganglion block and its mechanism of action in orofacial pain disorders are discussed.

The spiral ganglion: connecting the peripheral and central auditory systems

PubMed Central

Nayagam, Bryony A; Muniak, Michael A; Ryugo, David K

2011-01-01

In mammals, the initial bridge between the physical world of sound and perception of that sound is established by neurons of the spiral ganglion. The cell bodies of these neurons give rise to peripheral processes that contact acoustic receptors in the organ of Corti, and the central processes collect together to form the auditory nerve that projects into the brain. In order to better understand hearing at this initial stage, we need to know the following about spiral ganglion neurons: (1) their cell biology including cytoplasmic, cytoskeletal, and membrane properties, (2) their peripheral and central connections including synaptic structure; (3) the nature of their neural signaling; and (4) their capacity for plasticity and rehabilitation. In this report, we will update the progress on these topics and indicate important issues still awaiting resolution. PMID:21530629

The retina of the shovel-nosed ray, Rhinobatos batillum (Rhinobatidae): morphology and quantitative analysis of the ganglion, amacrine and bipolar cell populations.

PubMed

Collin, S P

1988-01-01

A light microscopy study of the retina of the shovel-nosed ray, Rhinobatos batillum (Rhinobatidae) has revealed a duplex retina with a rod to cone ratio between 4:1 and 6:1. The inner nuclear layer consists of three layers of large horizontal cells, tightly packed, stellate bipolar cells, and up to three substrata of amacrine cells. The collaterals of the many supporting Müller cells project from the inner to the outer limiting membrane and divide the retina into many subunits. The cells of the ganglion cell layer are distributed into two layers, although a large proportion of ganglion cells are also displaced into the inner plexiform and inner nuclear layers. Topographic analysis of the cells in the ganglion cell layer, inner plexiform and inner nuclear layers reveals a number of regional specializations or "areae centrales". Ganglion cells were retrogradely-labelled with cobalt-lysine from the optic nerve, and three sub-populations of neurons characterized on their soma size and position. Small (20-50 microns2), large (80-300 microns2) and giant (greater than 300 microns2) sub-populations of ganglion cells each revealed distinct retinal specializations with peak densities of 3 x 10(3), 1.25 x 10(3) and 1.57 x 10(3) cells per mm2, respectively. Topographical comparison between Nissl-stained and retrogradely-labelled ganglion cell populations have established that a maximum of 20% in the "area centralis", and 75% in unspecialized, peripheral regions of the retina are non-ganglion cells. Out of a total of 210,566 cells in the ganglion cell layer, 49% were found to be non-ganglion cells. Iso-density contour maps of amacrine and bipolar cell distributions also reveal some specializations. These cell concentrations lie in corresponding regions to areas of increased density in the large and giant ganglion cell populations, suggesting some functional association.

Effect of duration and severity of migraine on retinal nerve fiber layer, ganglion cell layer, and choroidal thickness.

PubMed

Abdellatif, Mona K; Fouad, Mohamed M

2018-03-01

To investigate the factors in migraine that have the highest significance on retinal and choroidal layers' thickness. Ninety patients with migraine and 40 age-matched healthy participants were enrolled in this observational, cross-sectional study. After full ophthalmological examination, spectral domain-optical coherence tomography was done for all patients measuring the thickness of ganglion cell layer and retinal nerve fiber layer. Enhanced depth imaging technique was used to measure the choroidal thickness. There was significant thinning in the superior and inferior ganglion cell layers, all retinal nerve fiber layer quadrants, and all choroidal quadrants (except for the central subfield) in migraineurs compared to controls. The duration of migraine was significantly correlated with ganglion cell layer, retinal nerve fiber layer, and all choroidal quadrants, while the severity of migraine was significantly correlated with ganglion cell layer and retinal nerve fiber layer only. Multiregression analysis showed that the duration of migraine is the most important determinant factor of the superior retinal nerve fiber layer quadrant (β = -0.375, p = 0.001) and in all the choroidal quadrants (β = -0.531, -0.692, -0.503, -0.461, -0.564, respectively, p  < 0.001), while severity is the most important determinant factor of inferior, nasal, and temporal retinal nerve fiber layer quadrants (β = -0.256, -0.335, -0.308; p  = 0.036, 0.005, 0.009, respectively) and the inferior ganglion cell layer hemisphere (β = -0.377 and p = 0.001). Ganglion cell layer, retinal nerve fiber layer, and choroidal thickness are significantly thinner in patients with migraine. The severity of migraine has more significant influence in the thinning of ganglion cell layer and retinal nerve fiber layer, while the duration of the disease affected the choroidal thickness more.

Clinical value of a self-designed training model for pinpointing and puncturing trigeminal ganglion.

PubMed

He, Yu-Quan; He, Shu; Shen, Yun-Xia; Qian, Cheng

2014-04-01

OBJECTIVES. A training model was designed for learners and young physicians to polish their skills in clinical practices of pinpointing and puncturing trigeminal ganglion. METHODS. A head model, on both cheeks of which the deep soft tissue was replaced by stuffed organosilicone and sponge while the superficial soft tissue, skin and the trigeminal ganglion were made of organic silicon rubber for an appearance of real human being, was made from a dried skull specimen and epoxy resin. Two physicians who had experiences in puncturing foramen ovale and trigeminal ganglion were selected to test the model, mainly for its appearance, X-ray permeability, handling of the puncture, and closure of the puncture sites. Four inexperienced physicians were selected afterwards to be trained combining Hartel's anterior facial approach with the new method of real-time observation on foramen ovale studied by us. RESULTS. Both appearance and texture of the model were extremely close to those of a real human. The fact that the skin, superficial soft tissue, deep muscles of the cheeks, and the trigeminal ganglion made of organic silicon rubber all had great elasticity resulted in quick closure and sealing of the puncture sites. The head model made of epoxy resin had similar X-ray permeability to a human skull specimen under fluoroscopy. The soft tissue was made of radiolucent material so that the training can be conducted with X-ray guidance. After repeated training, all the four young physicians were able to smoothly and successfully accomplish the puncture. CONCLUSION. This self-made model can substitute for cadaver specimen in training learners and young physicians on foramen ovale and trigeminal ganglion puncture. It is very helpful for fast learning and mastering this interventional operation skill, and the puncture accuracy can be improved significantly with our new method of real-time observation on foramen ovale.

A morphometric analysis of the superior cervical ganglion and its surrounding structures.

PubMed

Fazliogullari, Zeliha; Kilic, Cenk; Karabulut, Ahmet Kagan; Yazar, Fatih

2016-04-01

The aim of this cadaveric study was to detect the superior cervical ganglion (SCG) in a topographic manner according to vertebrae and to determine the relationship between the vertebrae, mandibular angle and longus colli muscle through morphometric analysis. The present study was performed on 40 SCG of 20 human cadavers (16 males, 4 females). The level of the SCG was determined based on the vertebrae. Ganglion length, width and thickness were detected. Distance to the adjacent vertebra, the mandibular angle and medial side of the longus colli muscle were measured. The results were evaluated statistically. The SCG existing in all cadavers was detected at the C2 vertebra level in 34 cadavers and at the C3 vertebra level in 6 cadavers. The average length, width and thickness of the SCG were 15.18 ± 1.12, 4.62 ± 0.25, and 1.83 ± 0.10 mm, respectively. No statistically significant difference was detected in terms of the distances between the ganglion and anterior tubercle of transverse processes of the vertebrae as well as the mandibular angle on either side. The distance between the SCG and the medial edge of the longus colli muscle was significantly greater on the left side in both men (p < 0.001) and women (p < 0.01). Recognition of morphometric characteristics of the SCG and detection of its location according to adjacent formations may serve as a guide for nerve blockage studies and help surgeons to preserve the ganglion in both anterior and anterolateral cervical approaches.

Changes in ganglion cell physiology during retinal degeneration influence excitability by prosthetic electrodes

NASA Astrophysics Data System (ADS)

Cho, Alice; Ratliff, Charles; Sampath, Alapakkam; Weiland, James

2016-04-01

Objective. Here we investigate ganglion cell physiology in healthy and degenerating retina to test its influence on threshold to electrical stimulation. Approach. Age-related Macular Degeneration and Retinitis Pigmentosa cause blindness via outer retinal degeneration. Inner retinal pathways that transmit visual information to the central brain remain intact, so direct electrical stimulation from prosthetic devices offers the possibility for visual restoration. Since inner retinal physiology changes during degeneration, we characterize physiological properties and responses to electrical stimulation in retinal ganglion cells (RGCs) of both wild type mice and the rd10 mouse model of retinal degeneration. Main results. Our aggregate results support previous observations that elevated thresholds characterize diseased retinas. However, a physiology-driven classification scheme reveals distinct sub-populations of ganglion cells with thresholds either normal or strongly elevated compared to wild-type. When these populations are combined, only a weakly elevated threshold with large variance is observed. The cells with normal threshold are more depolarized at rest and exhibit periodic oscillations. Significance. During degeneration, physiological changes in RGCs affect the threshold stimulation currents required to evoke action potentials.

Periosteal ganglion: a cause of cortical bone erosion.

PubMed

McCarthy, E F; Matz, S; Steiner, G C; Dorfman, H D

1983-01-01

Three cases of periosteal ganglia of long bones are presented. These lesions are produced by mucoid degeneration and cyst formation of the periosteum to produce external cortical erosion and reactive periosteal new bone. They are not associated with a soft tissue ganglion or an intraosseous lesion. They may radiologically mimic other periosteal lesions or soft tissue neoplasms which erode bone.

Epibatidine, an alkaloid from the poison frog Epipedobates tricolor, is a powerful ganglionic depolarizing agent.

PubMed

Fisher, M; Huangfu, D; Shen, T Y; Guyenet, P G

1994-08-01

Epibatidine, a newly discovered alkaloid from the skin of Dendrobatidae frogs, has structural similarities to nicotine. We examined the effects of epibatidine on cardiorespiratory function and ganglionic synaptic transmission. Superior cervical or splanchnic sympathetic nerve discharge (sSND) and phrenic nerve discharge (PND) were recorded along with arterial pressure (AP) in urethane-anesthetized, paralyzed and artificially ventilated rats. Epibatidine administered i.v. at low doses (0.5-2 micrograms/kg) produced a transient increase in AP and sSND, followed by a decrease and return to baseline; this low dose of epibatidine also produced a dose-dependent increase in PND. At high doses (cumulative dose of 8-16 micrograms/kg), epibatidine produced bradycardia, a profound depression in sSND and a transient elimination of PND. After i.v. administration of the ganglionic blocker chlorisondamine (5 mg/kg), AP was still increased by 1 microgram/kg epibatidine (+39 +/- 11 mm Hg). This pressor effect was not altered by pretreatment with the alpha-1 adrenergic antagonist phentolamine (+40 +/- 10 mm Hg); however, it was blocked by additional pretreatment with the vasopressin antagonist [beta-mercapto-beta,beta-cyclopentamethylenepropiony1, O-ET-Tyr2,Val4,Arg8]vasopressin (50 micrograms/kg i.v.; +2 +/- 0.4 mm Hg). Low doses of epibatidine (0.5-2 micrograms/kg) produced firing of postganglionic neurons in a decentralized ganglion preparation and potentiated synaptic transmission; at high doses (cumulative dose of 8-16 micrograms/kg), the alkaloid blocked ganglionic synaptic transmission. These results suggest that epibatidine is a potent agonist of ganglionic nicotinic receptors and that the alkaloid elicits cardiorespiratory effects similar to those of nicotine.

One-day high-fat diet induces inflammation in the nodose ganglion and hypothalamus of mice.

PubMed

Waise, T M Zaved; Toshinai, Koji; Naznin, Farhana; NamKoong, Cherl; Md Moin, Abu Saleh; Sakoda, Hideyuki; Nakazato, Masamitsu

2015-09-04

A high-fat diet (HFD) induces inflammation in systemic organs including the hypothalamus, resulting in obesity and diabetes. The vagus nerve connects the visceral organs and central nervous system, and the gastric-derived orexigenic peptide ghrelin transmits its starvation signals to the hypothalamus via the vagal afferent nerve. Here we investigated the inflammatory response in vagal afferent neurons and the hypothalamus in mice following one day of HFD feeding. This treatment increased the number of macrophages/microglia in the nodose ganglion and hypothalamus. Furthermore, one-day HFD induced expression of Toll-like receptor 4 in the goblet cells of the colon and upregulated mRNA expressions of the proinflammatory biomarkers Emr1, Iba1, Il6, and Tnfα in the nodose ganglion and hypothalamus. Both subcutaneous administration of ghrelin and celiac vagotomy reduced HFD-induced inflammation in these tissues. HFD intake triggered inflammatory responses in the gut, nodose ganglion, and subsequently in the hypothalamus within 24 h. These findings suggest that the vagal afferent nerve may transfer gut-derived inflammatory signals to the hypothalamus via the nodose ganglion, and that ghrelin may protect against HFD-induced inflammation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Ganglion Cell and Displaced Amacrine Cell Density Distribution in the Retina of the Howler Monkey (Alouatta caraya)

PubMed Central

Muniz, José Augusto Pereira Carneiro; de Athaide, Luana Modesto; Gomes, Bruno Duarte; Finlay, Barbara L.; Silveira, Luiz Carlos de Lima

2014-01-01

Unlike all other New World (platyrrine) monkeys, both male and female howler monkeys (Alouatta sp.) are obligatory trichromats. In all other platyrrines, only females can be trichromats, while males are always dichromats, as determined by multiple behavioral, electrophysiological, and genetic studies. In addition to obligatory trichromacy, Alouatta has an unusual fovea, with substantially higher peak cone density in the foveal pit than every other diurnal anthropoid monkey (both platyrrhines and catarrhines) and great ape yet examined, including humans. In addition to documenting the general organization of the retinal ganglion cell layer in Alouatta, the distribution of cones is compared to retinal ganglion cells, to explore possible relationships between their atypical trichromacy and foveal specialization. The number and distribution of retinal ganglion cells and displaced amacrine cells were determined in six flat-mounted retinas from five Alouatta caraya. Ganglion cell density peaked at 0.5 mm between the fovea and optic nerve head, reaching 40,700–45,200 cells/mm2. Displaced amacrine cell density distribution peaked between 0.5–1.75 mm from the fovea, reaching mean values between 2,050–3,100 cells/mm2. The mean number of ganglion cells was 1,133,000±79,000 cells and the mean number of displaced amacrine cells was 537,000±61,800 cells, in retinas of mean area 641±62 mm2. Ganglion cell and displaced amacrine cell density distribution in the Alouatta retina was consistent with that observed among several species of diurnal Anthropoidea, both platyrrhines and catarrhines. The principal alteration in the Alouatta retina appears not to be in the number of any retinal cell class, but rather a marked gradient in cone density within the fovea, which could potentially support high chromatic acuity in a restricted central region. PMID:25546077

Chronic cervical radiculopathic pain is associated with increased excitability and hyperpolarization-activated current ( Ih) in large-diameter dorsal root ganglion neurons.

PubMed

Liu, Da-Lu; Wang, Xu; Chu, Wen-Guang; Lu, Na; Han, Wen-Juan; Du, Yi-Kang; Hu, San-Jue; Bai, Zhan-Tao; Wu, Sheng-Xi; Xie, Rou-Gang; Luo, Ceng

2017-01-01

Cervical radiculopathic pain is a very common symptom that may occur with cervical spondylosis. Mechanical allodynia is often associated with cervical radiculopathic pain and is inadequately treated with current therapies. However, the precise mechanisms underlying cervical radiculopathic pain-associated mechanical allodynia have remained elusive. Compelling evidence from animal models suggests a role of large-diameter dorsal root ganglion neurons and plasticity of spinal circuitry attached with Aβ fibers in mediating neuropathic pain. Whether cervical radiculopathic pain condition induces plastic changes of large-diameter dorsal root ganglion neurons and what mechanisms underlie these changes are yet to be known. With combination of patch-clamp recording, immunohistochemical staining, as well as behavioral surveys, we demonstrated that upon chronic compression of C7/8 dorsal root ganglions, large-diameter cervical dorsal root ganglion neurons exhibited frequent spontaneous firing together with hyperexcitability. Quantitative analysis of hyperpolarization-activated cation current ( I h ) revealed that I h was greatly upregulated in large dorsal root ganglion neurons from cervical radiculopathic pain rats. This increased I h was supported by the enhanced expression of hyperpolarization-activated, cyclic nucleotide-modulated channels subunit 3 in large dorsal root ganglion neurons. Blockade of I h with selective antagonist, ZD7288 was able to eliminate the mechanical allodynia associated with cervical radiculopathic pain. This study sheds new light on the functional plasticity of a specific subset of large-diameter dorsal root ganglion neurons and reveals a novel mechanism that could underlie the mechanical allodynia associated with cervical radiculopathy.

Enkephalin-containing neurons in the inferior mesenteric ganglion projecting to the distal colon of cat: evidence from combined retrograde tracing by fluorescent microspheres and immunohistochemistry.

PubMed

Bagnol, D; Jule, Y; Kirchner, G; Cupo, A; Roman, C

1993-02-01

Retrograde tracing with rhodamine fluorescent microspheres combined with fluorescein immunolabelling of methionine-enkephalin showed the presence of enkephalin-like material in neurons of the inferior mesenteric ganglion (sympathetic prevertebral ganglion) projecting to the distal colon in cat. Two weeks after injecting the microspheres into the wall of the distal colon, the inferior mesenteric ganglion was dissected out and incubated for 24 hours in a colchicine-containing culture medium in order to facilitate the detection of enkephalins in the soma of ganglion neurons. It was observed that retrogradely labelled ganglion cells contained enkephalin-like immunoreactive material. These ganglion cells corresponded to enkephalin-like postganglionic neurons, the terminals of which were located inside the wall of the distal colon. These enkephalin-like neurons were numerous and scattered throughout the ganglion. Sometimes enkephalin-like immunoreactive fibers, probably originating from spinal preganglionic neurons, ran close to immunoreactive and non-immunoreactive retrogradely labelled ganglion cells. This suggests that enkephalin-like immunoreactive fibers may make synaptic connections with enkephalin-like and non-enkephalin-like postganglionic neurons projecting to the distal colon. The present study establishes for the first time the existence of an enkephalin-like postganglionic pathway to the digestive tract originating from a sympathetic prevertebral ganglion. This finding indicates that the enkephalinergic innervation of the cat digestive tract may have at least two possible sources: (i) the sympathetic prevertebral ganglia; and (ii) the enteric nervous ganglia.

Functional interdependence of neurons in a single canine intrinsic cardiac ganglionated plexus

PubMed Central

Thompson, G W; Collier, K; Ardell, J L; Kember, G; Armour, J A

2000-01-01

To determine the activity characteristics displayed by different subpopulations of neurons in a single intrinsic cardiac ganglionated plexus, the behaviour and co-ordination of activity generated by neurons in two loci of the right atrial ganglionated plexus (RAGP) were evaluated in 16 anaesthetized dogs during basal states as well as in response to increasing inputs from ventricular sensory neurites. These sub-populations of right atrial neurons received afferent inputs from sensory neurites in both ventricles that were responsive to local mechanical stimuli and the nitric oxide donor nitroprusside. Neurons in at least one RAGP locus were activated by epicardial application of veratridine, bradykinin, the β1-adrenoceptor agonist prenaterol or glutamate. Epicardial application of angiotensin II, the selective β2-adrenoceptor agonist terbutaline and selective α-adrenoceptor agonists elicited inconsistent neuronal responses. The activity generated by both populations of atrial neurons studied over 5 min periods during basal states displayed periodic coupled behaviour (cross-correlation coefficients of activities that reached, on average, 0·88 ± 0·03; range 0·71–1) for 15–30 s periods of time. These periods of coupled activity occurred every 30–50 s during basal states, as well as when neuronal activity was enhanced by chemical activation of their ventricular sensory inputs. These results indicate that neurons throughout one intrinsic cardiac ganglionated plexus receive inputs from mechano- and chemosensory neurites located in both ventricles. That such neurons respond to multiple chemical stimuli, including those liberated from adjacent adrenergic efferent nerve terminals, indicates the complexity of the integrative processing of information that occurs within the intrinsic cardiac nervous system. It is proposed that the interdependent activity displayed by populations of neurons in different regions of one intrinsic cardiac ganglionated plexus

Protective effect of oestradiol in the coeliac ganglion against ovarian apoptotic mechanism on dioestrus.

PubMed

Cynthia, Bronzi; Cristina, Daneri Becerra; Adriana, Vega Orozco; Belén, Delsouc María; María, Rastrilla Ana; Marilina, Casais; Zulema, Sosa

2013-05-01

The aims of this work were to investigate if oestradiol 10(-8)M in the incubation media of either the ovary alone (OV) or the ganglion compartment of an ex vivo coeliac ganglion-superior ovarian nerve-ovary system (a) modifies the release of ovarian progesterone (P4) and oestradiol (E2) on dioestrus II, and (b) modifies the ovarian gene expression of 3β-HSD and 20α-HSD enzymes and markers of apoptosis. The concentration of ovarian P4 release was measured in both experimental schemes, and ovarian P4 and E2 in the ex vivo system by RIA at different times. The expression of 3β-hydroxysteroid dehydrogenase, 20α-hydroxysteroid dehydrogenase and antiapoptotic bcl-2 and proapoptotic bax by RT-PCR were determined. E2 added in the coeliac ganglion caused an increase in the ovarian release of the P4, E2 and 3β-HSD, while in the ovary incubation alone it decreased P4 and 3β-HSD but increased and 20α-HSD and bax/bcl-2 ratio. It is concluded that through a direct effect on the ovary, E2 promotes luteal regression in DII rats, but the addition of E2 in the coeliac ganglion does not have the same effect. The peripheral nervous system, through the superior ovarian nerve, has a protective effect against the apoptotic mechanism on DII. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Effects on survival of shRNA mediated APE/Ref1 gene silencing in rat spiral ganglion cells in oxidative stress].

PubMed

Jiang, Zhendong; Zhong, Cheng; Li, Taijun; Xiang, Zhaolan; Zhang, Xueyuan

2014-02-01

To investigate the effects of reducing APE/Ref1 expression in the cultures of rat spiral ganglion cells with oxidative damage induced by H(2)O(2). Primary cultured rat spiral ganglion cells were infected with small interfering RNA to APE/Ref1 (Ape1siRNA) for 72 h, followed by treating with H(2)O(2) (0, 10, 25, 50, 100 and 300 µmol/L) for 1 h , and then cultured in normal medium for 24 h. Western blot were used to detect the level of APE/Ref1 protein and phosphorylation of histone protein H2AX in the infected cells. The caspase3 activation was tested by spectrophotometric method . The cell viability was determined by MTT and the apoptosis of spiral ganglion cells was determined by terminal-deoxynucleotidyl transferase mediated nick and labeling (TUNEL). Western blot showed that infection with Ape1siRNA resulted in APE/Ref1 reduced expression in the spiral ganglion cells. Exposing spiral ganglion cultures with reduced expression of APE/Ref1 to H(2)O(2) (50, 100, 300 µmol/L) for 1 h resulted in increasing in the phosphorylation of histone protein H2AX. The reduction in APE/Ref1 significantly reduced cell viability in cultures 24 h after 1 h expression to 50-300 µmol/L H(2)O(2). The apoptosis of cells and caspase 3 activity was detected significantly improved. The induced of APE/Ref1 results in significantly decrease in spiral ganglion cells viability in oxidative stress. The repairing function of APE/Ref1 is necessary for optimal levels of neuronal rat spiral ganglion cells survival.

Intracochlear electrical stimulation suppresses apoptotic signaling in rat spiral ganglion neurons after deafening in vivo.

PubMed

Kopelovich, Jonathan C; Cagaanan, Alain P; Miller, Charles A; Abbas, Paul J; Green, Steven H

2013-11-01

To establish the intracellular consequences of electrical stimulation to spiral ganglion neurons after deafferentation. Here we use a rat model to determine the effect of both low and high pulse rate acute electrical stimulation on activation of the proapoptotic transcription factor Jun in deafferented spiral ganglion neurons in vivo. Experimental animal study. Hearing research laboratories of the University of Iowa Departments of Biology and Otolaryngology. A single electrode was implanted through the round window of kanamycin-deafened rats at either postnatal day 32 (P32, n = 24) or P60 (n = 22) for 4 hours of stimulation (monopolar, biphasic pulses, amplitude twice electrically evoked auditory brainstem response [eABR] threshold) at either 100 or 5000 Hz. Jun phosphorylation was assayed by immunofluorescence to quantitatively assess the effect of electrical stimulation on proapoptotic signaling. Jun phosphorylation was reliably suppressed by 100 Hz stimuli in deafened cochleae of P32 but not P60 rats. This effect was not significant in the basal cochlear turns. Stimulation frequency may be consequential: 100 Hz was significantly more effective than was 5 kHz stimulation in suppressing phospho-Jun. Suppression of Jun phosphorylation occurs in deafferented spiral ganglion neurons after only 4 hours of electrical stimulation. This finding is consistent with the hypothesis that electrical stimulation can decrease spiral ganglion neuron death after deafferentation.

Biofunctionalized peptide-based hydrogels provide permissive scaffolds to attract neurite outgrowth from spiral ganglion neurons.

PubMed

Frick, Claudia; Müller, Marcus; Wank, Ute; Tropitzsch, Anke; Kramer, Benedikt; Senn, Pascal; Rask-Andersen, Helge; Wiesmüller, Karl-Heinz; Löwenheim, Hubert

2017-01-01

Cochlear implants (CI) allow for hearing rehabilitation in patients with sensorineural hearing loss or deafness. Restricted CI performance results from the spatial gap between spiral ganglion neurons and the CI, causing current spread that limits spatially restricted stimulation and impairs frequency resolution. This may be substantially improved by guiding peripheral processes of spiral ganglion neurons towards and onto the CI electrode contacts. An injectable, peptide-based hydrogel was developed which may provide a permissive scaffold to facilitate neurite growth towards the CI. To test hydrogel capacity to attract spiral ganglion neurites, neurite outgrowth was quantified in an in vitro model using a custom-designed hydrogel scaffold and PuraMatrix ® . Neurite attachment to native hydrogels is poor, but significantly improved by incorporation of brain-derived neurotrophic factor (BDNF), covalent coupling of the bioactive laminin epitope IKVAV and the incorporation a full length laminin to hydrogel scaffolds. Incorporation of full length laminin protein into a novel custom-designed biofunctionalized hydrogel (IKVAV-GGG-SIINFEKL) allows for neurite outgrowth into the hydrogel scaffold. The study demonstrates that peptide-based hydrogels can be specifically biofunctionalized to provide a permissive scaffold to attract neurite outgrowth from spiral ganglion neurons. Such biomaterials appear suitable to bridge the spatial gap between neurons and the CI. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel model for rapid induction of apoptosis in spiral ganglions of mice.

PubMed

Lee, Ji Eun; Nakagawa, Takayuki; Kim, Tae Soo; Iguchi, Fukuichiro; Endo, Tsuyoshi; Dong, Youyi; Yuki, Kazuo; Naito, Yasushi; Lee, Sang Heun; Ito, Juichi

2003-06-01

The survival of the spiral ganglion (SG) is a critical issue in preservation of hearing. Research on topics related to this issue requires a mouse experimental model because such a model has advantages including use of genetic information and knockout or "knockin" mice. Thus, the aim of the study was to establish a mouse model for induction of apoptosis of SG neurons with a definite time course. Laboratory study using experimental animals. C57BL/6 mice were used as experimental animals and were subjected to direct application of cisplatin into the inner ear. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and immunostaining for Neurofilament 200-kD (NF) and peripherin were used for analysis of SG degeneration. In addition, generation of peroxynitrite in affected spiral ganglions was examined by immunostaining for nitrotyrosine. Cellular location of activated caspase-9 and cytochrome-c in dying SG neurons were examined for analysis of cell death pathway. The TUNEL assay and immunohistochemical analysis for NF and peripherin indicated that type I neurons in spiral ganglions were deleted through the apoptotic pathway over time. Spiral ganglion neurons treated with cisplatin exhibited expression of nitrotyrosine, indicating induction of peroxynitrite by cisplatin. In dying SG neurons, expression of activated caspase-9 and translocation of cytochrome-c from mitochondria to cytoplasm were observed, indicating the mitochondrial pathway of apoptosis. The predictable fashion of induction of apoptosis in SG neurons over a well-defined time course in the model in the study will aid studies of the molecular mechanism of cell death and elucidation of a strategy for prevention of SG degeneration.

Immediate Nerve Transfer for Treatment of Peroneal Nerve Palsy Secondary to an Intraneural Ganglion: Case Report and Review.

PubMed

Ratanshi, Imran; Clark, Tod A; Giuffre, Jennifer L

2018-05-01

Intraneural ganglion cysts, which occur within the common peroneal nerve, are a rare cause of foot drop. The current standard of treatment for intraneural ganglion cysts involving the common peroneal nerve involves (1) cyst decompression and (2) ligation of the articular nerve branch to prevent recurrence. Nerve transfers are a time-dependent strategy for recovering ankle dorsiflexion in cases of high peroneal nerve palsy; however, this modality has not been performed for intraneural ganglion cysts involving the common peroneal nerve. We present a case of common peroneal nerve palsy secondary to an intraneural ganglion cyst occurring in a 74-year-old female. The patient presented with a 5-month history of pain in the right common peroneal nerve distribution and foot drop. The patient underwent simultaneous cyst decompression, articular nerve branch ligation, and nerve transfer of the motor branch to flexor hallucis longus to a motor branch of anterior tibialis muscle. At final follow-up, the patient demonstrated complete (M4+) return of ankle dorsiflexion, no pain, no evidence of recurrence and was able to bear weight without the need for orthotic support. Given the minimal donor site morbidity and recovery of ankle dorsiflexion, this report underscores the importance of considering early nerve transfers in cases of high peroneal neuropathy due to an intraneural ganglion cyst.

The morphology and classification of α ganglion cells in the rat retinae: a fractal analysis study.

PubMed

Jelinek, Herbert F; Ristanović, Dušan; Milošević, Nebojša T

2011-09-30

Rat retinal ganglion cells have been proposed to consist of a varying number of subtypes. Dendritic morphology is an essential aspect of classification and a necessary step toward understanding structure-function relationships of retinal ganglion cells. This study aimed at using a heuristic classification procedure in combination with the box-counting analysis to classify the alpha ganglion cells in the rat retinae based on the dendritic branching pattern and to investigate morphological changes with retinal eccentricity. The cells could be divided into two groups: cells with simple dendritic pattern (box dimension lower than 1.390) and cells with complex dendritic pattern (box dimension higher than 1.390) according to their dendritic branching pattern complexity. Both were further divided into two subtypes due to the stratification within the inner plexiform layer. In the present study we have shown that the alpha rat RCGs can be classified further by their dendritic branching complexity and thus extend those of previous reports that fractal analysis can be successfully used in neuronal classification, particularly that the fractal dimension represents a robust and sensitive tool for the classification of retinal ganglion cells. A hypothesis of possible functional significance of our classification scheme is also discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Denervation does not alter the number of neuronal bungarotoxin binding sites on autonomic neurons in the frog cardiac ganglion.

PubMed

Sargent, P B; Bryan, G K; Streichert, L C; Garrett, E N

1991-11-01

The binding of neuronal bungarotoxin (n-BuTX; also known as bungarotoxin 3.1, kappa-bungarotoxin, and toxin F) was analyzed in normal and denervated parasympathetic cardiac ganglia of the frog Rana pipiens, n-BuTX blocks both EPSPs and ACh potentials at 5-20 nM, as determined by intracellular recording techniques. Scatchard analysis on homogenates indicates that cardiac ganglia have two classes of binding sites for 125I-n-BuTX: a high-affinity site with an apparent dissociation constant (Kd,app) of 1.7 nM and a Bmax (number of binding sites) of 3.8 fmol/ganglion and a low-affinity site with a Kd,app of 12 microM and a Bmax of 14 pmol/ganglion. alpha-Bungarotoxin does not appear to interfere with the binding of 125I-n-BuTX to either site. The high-affinity binding site is likely to be the functional nicotinic ACh receptor (AChR), given the similarity between its affinity for 125I-n-BuTX and the concentration of n-BuTX required to block AChR function. Light microscopic autoradiographic analysis of 125I-n-BuTX binding to the ganglion cell surface reveals that toxin binding is concentrated at synaptic sites, which were identified using a synaptic vesicle-specific antibody. Scatchard analysis of autoradiographic data reveals that 125I-n-BuTX binding to the neuronal surface is saturable and has a Kd,app similar to that of the high-affinity binding site characterized in homogenates. Surface binding of 125I-n-BuTX is blocked by nicotine, carbachol, and d-tubocurarine (IC50 less than 20 microM), but not by atropine (IC50 greater than 10 mM). Denervation of the heart increases the ACh sensitivity of cardiac ganglion cells but has no effect upon the number of high-affinity binding sites for 125I-n-BuTX in tissue homogenates. Moreover, autoradiographic analysis indicates that denervation does not alter the number of 125I-n-BuTX binding sites on the ganglion cell surface. n-BuTX is as effective in reducing ganglion cell responses to ACh in denervated ganglia as it is in

Nitrergic nerves derived from the pterygopalatine ganglion innervate arteries irrigating the cerebrum but not the cerebellum and brain stem in monkeys.

PubMed

Ayajiki, Kazuhide; Kobuchi, Shuhei; Tawa, Masashi; Okamura, Tomio

2012-01-01

The functional roles of the nitrergic nerves innervating the monkey cerebral artery were evaluated in a tension-response study examining isolated arteries in vitro and cerebral angiography in vivo. Nicotine produced relaxation of arteries by stimulation of nerve terminals innervating isolated monkey arteries irrigating the cerebrum, cerebellum and brain stem. Relaxation of arteries induced by nicotine was abolished by treatment with N(G)-nitro-L-arginine, a nitric oxide synthase inhibitor, and was restored by addition of L-arginine. Cerebral angiography showed that electrical stimulation of the unilateral greater petrosal nerve, which connects to the pterygopalatine ganglion via the parasympathetic ganglion synapse, produced vasodilatation of the anterior, middle and posterior cerebral arteries in the stimulated side. However, stimulation failed to produce vasodilatation of the superior and anterior-inferior cerebellar arteries and the basilar artery in anesthetized monkeys. Therefore, nitrergic nerves derived from the pterygopalatine ganglion appear to regulate cerebral vasomotor function. In contrast, circulation in the cerebellum and brain stem might be regulated by nitrergic nerves originating not from the pterygopalatine ganglion, but rather from an unknown ganglion (or ganglia).

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation.

PubMed

Dawes, P M; Vizi, E S

1973-06-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation.2. In the presence of physostigmine, the resting release of acetylcholine was 0.13 +/- 0.01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3.1 +/- 0.4 (pmol/g)/volley in 4 experiments (means +/- S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0.3 Hz.3. Tetrodotoxin, 0.8 muM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5 degrees C reduced to below detectable levels both the resting release and that produced by nerve stimulation.4. The resting release of acetylcholine was increased by a potassium-rich (49.4 mM K(+)) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li(+)).5. (-)-Noradrenaline bitartrate, 3 muM, and (+/-)-adrenaline bitartrate, 1.5 muM, reduced by 70% the output of acetylcholine induced by stimulation at 0.3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine.6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release.

Effects of cholinergic drugs on receptive field properties of rabbit retinal ganglion cells

PubMed Central

Ariel, M.; Daw, N. W.

1982-01-01

1. Retinal ganglion cells were recorded extracellularly from the rabbit's eye in situ to study the effects of cholinergic drugs on receptive field properties. Physostigmine, an acetylcholinesterase inhibitor, and nicotine increased the spontaneous activity of nearly all retinal ganglion cell types. The effectiveness of physostigmine was roughly correlated with the neurone's inherent level of spontaneous activity. Brisk cells, having high rates of spontaneous firing, showed large increases in their maintained discharge, whereas sluggish cells, with few or no spontaneous spikes, showed small and sometimes transient increases in spontaneous activity during physostigmine. 2. The sensitivity of ganglion cells to spots of optimal size and position did not change substantially during the infusion of physostigmine. However, the responsiveness to light (number of spikes per stimulus above the spontaneous level) increased. This effect occurred with sluggish and more complex cells, rarely with brisk cells. 3. Another effect of physostigmine on sluggish and more complex cells was to make these cells `on—off'. The additional response to the inappropriate change in contrast had a long latency and lacked an initial transient burst. 4. Complex receptive field properties such as orientation sensitivity, radial grating inhibition, speed tuning and size specificity were also examined. These inhibitory properties were still present during infusion of physostigmine and, in most cases, the trigger feature of each cell type remained. 5. These results are consistent with pharmacological results on ACh release from the retina. There appear to be two types of release of ACh, having their most powerful influences on separate classes of cells. One release (transient), occurs at light onset and offset and acts primarily on sluggish and more complex ganglion cells; the other release (tonic) is not light-modulated and acts primarily on brisk cells. A wiring diagram for the ACh cells is

Distinguishing ischaemic optic neuropathy from optic neuritis by ganglion cell analysis.

PubMed

Erlich-Malona, Natalie; Mendoza-Santiesteban, Carlos E; Hedges, Thomas R; Patel, Nimesh; Monaco, Caitlin; Cole, Emily

2016-12-01

To determine whether a pattern of altitudinal ganglion cell loss, as detected and measured by optical coherence tomography (OCT), can be used to distinguish non-arteritic ischaemic optic neuropathy (NAION) from optic neuritis (ON) during the acute phase, and whether the rate or severity of ganglion cell loss differs between the two diseases. We performed a retrospective, case-control study of 44 patients (50 eyes) with ON or NAION and 44 age-matched controls. Non-arteritic ischaemic optic neuropathy and ON patients had OCT at presentation and four consecutive follow-up visits. Controls had OCT at one point in time. The ganglion cell complex (GCC) was evaluated in the macula, and the retinal nerve fibre layer (RNFL) was evaluated in the peripapillary region. Ganglion cell complex thickness, RNFL thickness and GCC mean superior and inferior hemispheric difference were compared between NAION and ON patients at each time-point using unpaired t-tests and between disease and control subjects at first measurement using paired t-tests. Mean time from onset of symptoms to initial presentation was 10.7 ± 6.6 days in NAION and 11.7 ± 8.6 days in ON (p = 0.67). There was a significantly greater vertical hemispheric difference in GCC thickness in NAION patients than ON patients at all time-points (5.5-10.7 μm versus 3.1-3.6 μm, p = 0.01-0.049). Mean GCC thickness was significantly decreased at less than 2 weeks after onset in NAION compared to age-matched controls (72.1 μm versus 82.1 μm, p < 0.001), as well as in ON compared to age-matched controls (74.3 μm versus 84.5 μm, p < 0.001). Progression and severity of GCC and RNFL loss did not differ significantly between NAION and ON. A quantitative comparison of mean superior and inferior hemispheric GCC thickness with OCT may be used to distinguish NAION from ON. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Reactive oxygen species alters the electrophysiological properties and raises [Ca2+]i in intracardiac ganglion neurons

PubMed Central

Dyavanapalli, Jhansi; Rimmer, Katrina

2010-01-01

We have investigated the effects of the reactive oxygen species (ROS) donors hydrogen peroxide (H2O2) and tert-butyl hydroperoxide (t-BHP) on the intrinsic electrophysiological characteristics: ganglionic transmission and resting [Ca2+]i in neonate and adult rat intracardiac ganglion (ICG) neurons. Intracellular recordings were made using sharp microelectrodes filled with either 0.5 M KCl or Oregon Green 488 BAPTA-1, allowing recording of electrical properties and measurement of [Ca2+]i. H2O2 and t-BHP both hyperpolarized the resting membrane potential and reduced membrane resistance. In adult ICG neurons, the hyperpolarizing action of H2O2 was reversed fully by Ba2+ and partially by tetraethylammonium, muscarine, and linopirdine. H2O2 and t-BHP reduced the action potential afterhyperpolarization (AHP) amplitude but had no impact on either overshoot or AHP duration. ROS donors evoked an increase in discharge adaptation to long depolarizing current pulses. H2O2 blocked ganglionic transmission in most ICG neurons but did not alter nicotine-evoked depolarizations. By contrast, t-BHP had no significant action on ganglionic transmission. H2O2 and t-BHP increased resting intracellular Ca2+ levels to 1.6 ( ± 0.6, n = 11, P < 0.01) and 1.6 ( ± 0.3, n = 8, P < 0.001), respectively, of control value (1.0, ∼60 nM). The ROS scavenger catalase prevented the actions of H2O2, and this protection extended beyond the period of application. Superoxide dismutase partially shielded against the action of H2O2, but this was limited to the period of application. These data demonstrate that ROS decreases the excitability and ganglionic transmission of ICG neurons, attenuating parasympathetic control of the heart. PMID:20445155

Ganglion Cell Loss and Age-Related Visual Loss: A Cortical Pooling Analysis

PubMed Central

SCHMIDT, LAURA A.; LY-SCHROEDER, EMILY; SWANSON, WILLIAM H.

2006-01-01

Purpose To evaluate the ability of the cortical pooling model to predict the effects of random, mild ganglion cell loss, we compared the predictions of the model with the age-related loss and variability in achromatic and chromatic contrast sensitivity. Methods The relative sensitivity to small (0.5°) and large (3.0°) stimuli was compared in older (mean = 67 years, n = 27) and younger (mean = 23 years, n = 32) adults. Contrast sensitivity for modulations along the luminance, equiluminant L-cone, and equiluminant S-cone axes was assessed at the fovea and at four peripheral locations (12°). Results When the stimuli were large, threshold measurements obtained from all participants were reliable and well within the range of modulations along the chromatic axes that could be produced by the phosphors of the CRT. For the large stimuli, neither long- nor short-term variability increased as a function of age. Increasing the size of the stimulus did not decrease the magnitude of the age-related losses when the stimulus was chromatic, and visual losses observed with large chromatic stimuli were not different from those obtained with small achromatic stimuli. Moreover, chromatic contrast sensitivity assessments identified significant visual losses in four individuals who were not identified by achromatic contrast sensitivity assessments and only missed identifying one individual with significant losses in achromatic contrast sensitivity. Conclusions The declines in achromatic and chromatic sensitivity as a function of age (0.4 – 0.7 dB per decade) were similar to those obtained in previous studies of achromatic and chromatic perimetry and are consistent with the loss of retinal ganglion cells reported in histologic studies. The results of this study are consistent with the predictions the cortical pooling model makes for both variability and contrast sensitivity. These findings emphasize that selective visual impairments do not necessarily reflect preferential damage to

Spatial segregation of adaptation and predictive sensitization in retinal ganglion cells

PubMed Central

Kastner, David B.; Baccus, Stephen A.

2014-01-01

Sensory systems change their sensitivity based upon recent stimuli to adjust their response range to the range of inputs, and to predict future sensory input. Here we report the presence of retinal ganglion cells that have antagonistic plasticity, showing central adaptation and peripheral sensitization. Ganglion cell responses were captured by a spatiotemporal model with independently adapting excitatory and inhibitory subunits, and sensitization requires GABAergic inhibition. Using a simple theory of signal detection we show that the sensitizing surround conforms to an optimal inference model that continually updates the prior signal probability. This indicates that small receptive field regions have dual functionality—to adapt to the local range of signals, but sensitize based upon the probability of the presence of that signal. Within this framework, we show that sensitization predicts the location of a nearby object, revealing prediction as a new functional role for adapting inhibition in the nervous system. PMID:23932000

Four alpha ganglion cell types in mouse retina: Function, structure, and molecular signatures

PubMed Central

Sanes, Joshua R.

2017-01-01

The retina communicates with the brain using ≥30 parallel channels, each carried by axons of distinct types of retinal ganglion cells. In every mammalian retina one finds so-called "alpha" ganglion cells (αRGCs), identified by their large cell bodies, stout axons, wide and mono-stratified dendritic fields, and high levels of neurofilament protein. In the mouse, three αRGC types have been described based on responses to light steps: On-sustained, Off-sustained, and Off-transient. Here we employed a transgenic mouse line that labels αRGCs in the live retina, allowing systematic targeted recordings. We characterize the three known types and identify a fourth, with On-transient responses. All four αRGC types share basic aspects of visual signaling, including a large receptive field center, a weak antagonistic surround, and absence of any direction selectivity. They also share a distinctive waveform of the action potential, faster than that of other RGC types. Morphologically, they differ in the level of dendritic stratification within the IPL, which accounts for their response properties. Molecularly, each type has a distinct signature. A comparison across mammals suggests a common theme, in which four large-bodied ganglion cell types split the visual signal into four channels arranged symmetrically with respect to polarity and kinetics. PMID:28753612

Strychnine, but not PMBA, inhibits neuronal nicotinic acetylcholine receptors expressed by rabbit retinal ganglion cells.

PubMed

Renna, J M; Strang, C E; Amthor, F R; Keyser, K T

2007-01-01

Strychnine is considered a selective competitive antagonist of glycine gated Cl- channels (Saitoh et al., 1994) and studies have used strychnine at low micromolar concentrations to study the role of glycine in rabbit retina (Linn, 1998; Protti et al., 2005). However, other studies have shown that strychnine, in the concentrations commonly used, is also a potent competitive antagonist of alpha7 nicotinic acetylcholine receptors (nAChRs; Matsubayashi et al., 1998). We tested the effects of low micromolar concentrations of strychnine and 3-[2'-phosphonomethyl[1,1'-biphenyl]-3-yl] alanine (PMBA), a specific glycine receptor blocker (Saitoh et al., 1994; Hosie et al., 1999) on the activation of both alpha7 nAChRs on retinal ganglion cells and on ganglion cell responses to a light flash. Extracellular recordings were obtained from ganglion cells in an isolated retina/choroid preparation and 500 microM choline was used as an alpha7 agonist (Alkondon et al., 1997). We recorded from brisk sustained and brisk transient OFF cells, many of which have been previously shown to have alpha7 receptors (Strang et al., 2005). Further, we tested the effect of strychnine, PMBA and alpha-bungarotoxin on the binding of tetramethylrhodamine alpha-bungarotoxin in the inner plexiform layer. Our data indicates that strychnine, at doses as low as 1.0 microM, can inhibit the alpha7 nAChR-mediated response to choline, but PMBA at concentrations as high as 0.4 microM does not. Binding studies show strychnine and alpha-bungarotoxin inhibit binding of labeled alpha-bungarotoxin in the IPL. Thus, the effects of strychnine application may be to inhibit glycine receptors expressed by ganglion cell or to inhibit amacrine cell alpha7 nAChRs, both of which would result in an increase in the ganglion cell responses. Further research will be required to disentangle the effects of strychnine previously believed to be caused by a single mechanism of glycine receptor inhibition.

The du Bois sign.

PubMed

Voelpel, James H; Muehlberger, Thomas

2011-03-01

According to the current literature, the term "du Bois sign" characterizes the condition of a shortened fifth finger as a symptom of congenital syphilis, Down syndrome, dyscrania, and encephalic malformation. Modern medical dictionaries and text books attribute the eponym to the French gynecologist Paul Dubois (1795-1871). Yet, a literature analysis revealed incorrect references to the person and unclear definitions of the term. Our findings showed that the origin of the term is based on observations made by the Swiss dermatologist Charles du Bois (1874-1947) in connection with congenital syphilis. In addition, a further eponymical fifth finger sign is closely associated with the du Bois sign. In conclusion, the du Bois sign has only limited diagnostic value and is frequently occurring in the normal healthy population.

Nervus terminalis ganglion of the bonnethead shark (Sphyrna tiburo): evidence for cholinergic and catecholaminergic influence on two cell types distinguished by peptide immunocytochemistry.

PubMed

White, J; Meredith, M

1995-01-16

The nervus terminalis is a ganglionated vertebrate cranial nerve of unknown function that connects the brain and the peripheral nasal structures. To investigate its function, we have studied nervus terminalis ganglion morphology and physiology in the bonnethead shark (Sphyrna tiburo), where the nerve is particularly prominent. Immunocytochemistry for gonadotropin-releasing hormone (GnRH) and Leu-Pro-Leu-Arg-Phe-NH2 (LPLRFamide) revealed two distinct populations of cells. Both were acetylcholinesterase positive, but LPLR-Famide-immunoreactive cells consistently stained more darkly for acetylcholinesterase activity. Tyrosine hydroxylase immunocytochemistry revealed fibers and terminal-like puncta in the ganglion, primarily in areas containing GnRH-immunoreactive cells. Consistent with the anatomy, in vitro electrophysiological recordings provided evidence for cholinergic and catecholaminergic actions. In extracellular recordings, acetylcholine had a variable effect on baseline ganglion cell activity, whereas norepinephrine consistently reduced activity. Electrical stimulation of the nerve trunks suppressed ganglion activity, as did impulses from the brain in vivo. During electrical suppression, acetylcholine consistently increased activity, and norepinephrine decreased activity. Muscarinic and, to a lesser extent, alpha-adrenergic antagonists both increased activity during the electrical suppression, suggesting involvement of both systems. Intracellular recordings revealed two types of ganglion cells that were distinguishable pharmacologically and physiologically. Some cells were hyperpolarized by cholinergic agonists and unaffected by norepinephrine; these cells did not depolarize with peripheral nerve trunk stimulation. Another group of cells did depolarize with peripheral trunk stimulation; a representative of this group was depolarized by carbachol and hyperpolarized by norepinephrine. These and other data suggest that the bonnethead nervus terminalis ganglion

Effect of Tissue Heterogeneity on the Transmembrane Potential of Type-1 Spiral Ganglion Neurons: A Simulation Study.

PubMed

Sriperumbudur, Kiran Kumar; Pau, Hans Wilhelm; van Rienen, Ursula

2018-03-01

Electric stimulation of the auditory nerve by cochlear implants has been a successful clinical intervention to treat the sensory neural deafness. In this pathological condition of the cochlea, type-1 spiral ganglion neurons in Rosenthal's canal play a vital role in the action potential initiation. Various morphological studies of the human temporal bones suggest that the spiral ganglion neurons are surrounded by heterogeneous structures formed by a variety of cells and tissues. However, the existing simulation models have not considered the tissue heterogeneity in the Rosenthal's canal while studying the electric field interaction with spiral ganglion neurons. Unlike the existing models, we have implemented the tissue heterogeneity in the Rosenthal's canal using a computationally inexpensive image based method in a two-dimensional finite element model. Our simulation results suggest that the spatial heterogeneity of surrounding tissues influences the electric field distribution in the Rosenthal's canal, and thereby alters the transmembrane potential of the spiral ganglion neurons. In addition to the academic interest, these results are especially useful to understand how the latest tissue regeneration methods such as gene therapy and drug-induced resprouting of peripheral axons, which probably modify the density of the tissues in the Rosenthal's canal, affect the cochlear implant functionality.

The Effect of Transcutaneous Electrical Nerve Stimulation of Sympathetic Ganglions and Acupuncture Points on Distal Blood Flow.

PubMed

Kamali, Fahimeh; Mirkhani, Hossein; Nematollahi, Ahmadreza; Heidari, Saeed; Moosavi, Elahesadat; Mohamadi, Marzieh

2017-04-01

Transcutaneous electrical nerve stimulation (TENS) is a widely-practiced method to increase blood flow in clinical practice. The best location for stimulation to achieve optimal blood flow has not yet been determined. We compared the effect of TENS application at sympathetic ganglions and acupuncture points on blood flow in the foot of healthy individuals. Seventy-five healthy individuals were randomly assigned to three groups. The first group received cutaneous electrical stimulation at the thoracolumbar sympathetic ganglions. The second group received stimulation at acupuncture points. The third group received stimulation in the mid-calf area as a control group. Blood flow was recorded at time zero as baseline and every 3 minutes after baseline during stimulation, with a laser Doppler flow-meter. Individuals who received sympathetic ganglion stimulation showed significantly greater blood flow than those receiving acupuncture point stimulation or those in the control group (p<0.001). Data analysis revealed that blood flow at different times during stimulation increased significantly from time zero in each group. Therefore, the application of low-frequency TENS at the thoracolumbar sympathetic ganglions was more effective in increasing peripheral blood circulation than stimulation at acupuncture points. Copyright © 2017 Medical Association of Pharmacopuncture Institute. Published by Elsevier B.V. All rights reserved.

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation

PubMed Central

Dawes, P. M.; Vizi, E. S.

1973-01-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation. 2. In the presence of physostigmine, the resting release of acetylcholine was 0·13 ± 0·01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3·1 ± 0·4 (pmol/g)/volley in 4 experiments (means ± S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0·3 Hz. 3. Tetrodotoxin, 0·8 μM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5° C reduced to below detectable levels both the resting release and that produced by nerve stimulation. 4. The resting release of acetylcholine was increased by a potassium-rich (49·4 mM K+) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li+). 5. (-)-Noradrenaline bitartrate, 3 μM, and (±)-adrenaline bitartrate, 1·5 μM, reduced by 70% the output of acetylcholine induced by stimulation at 0·3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine. 6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release. PMID:4733726

Vesicular glutamate transporters, VGluT1 and VGluT2, in the trigeminal ganglion neurons of the rat, with special reference to coexpression.

PubMed

Li, Jin-Lian; Xiong, Kang-Hui; Dong, Yu-Lin; Fujiyama, Fumino; Kaneko, Takeshi; Mizuno, Noboru

2003-08-18

Vesicular glutamate transporters are responsible for glutamate transport into synaptic vesicles. In the present study, we examined immunohistochemically the expression of vesicular glutamate transporters, VGluT1 and VGluT2, in trigeminal ganglion neurons of the rat. Immunohistochemistry for VGluT1 and VGluT2 indicated that more than 80% of trigeminal ganglion neurons express VGluT1 and/or VGluT2 in their cell bodies. It also indicated that large and small trigeminal ganglion neurons express VGluT2 more frequently than VGluT1. Dual immunofluorescence histochemistry for VGluT1 and VGluT2 indicated that trigeminal ganglion neurons express VGluT2 more frequently than VGluT1 and that more than 80% of VGluT-expressing trigeminal ganglion neurons express VGluT1 and VGluT2. Many axon terminals in the superficial layers of the medullary dorsal horn also showed VGluT1 and VGluT2 immunoreactivities. Some of these axon terminals were confirmed to form the central core of the synaptic glomerulus. These results indicated that VGluT1 and VGluT2 are coexpressed in the cell bodies and axon terminals in most trigeminal ganglion neurons. Copyright 2003 Wiley-Liss, Inc.

Retinal ganglion cells in diabetes

PubMed Central

Kern, Timothy S; Barber, Alistair J

2008-01-01

Diabetic retinopathy has long been recognized as a vascular disease that develops in most patients, and it was believed that the visual dysfunction that develops in some diabetics was due to the vascular lesions used to characterize the disease. It is becoming increasingly clear that neuronal cells of the retina also are affected by diabetes, resulting in dysfunction and even degeneration of some neuronal cells. Retinal ganglion cells (RGCs) are the best studied of the retinal neurons with respect to the effect of diabetes. Although investigations are providing new information about RGCs in diabetes, including therapies to inhibit the neurodegeneration, critical information about the function, anatomy and response properties of these cells is yet needed to understand the relationship between RGC changes and visual dysfunction in diabetes. PMID:18565995

Progranulin deficiency causes the retinal ganglion cell loss during development.

PubMed

Kuse, Yoshiki; Tsuruma, Kazuhiro; Mizoguchi, Takahiro; Shimazawa, Masamitsu; Hara, Hideaki

2017-05-10

Astrocytes are glial cells that support and protect neurons in the central nervous systems including the retina. Retinal ganglion cells (RGCs) are in contact with the astrocytes and our earlier findings showed the reduction of the number of cells in the ganglion cell layer in adult progranulin deficient mice. In the present study, we focused on the time of activation of the astrocytes and the alterations in the number of RGCs in the retina and optic nerve in progranulin deficient mice. Our findings showed that the number of Brn3a-positive cells was reduced and the expression of glial fibrillary acidic protein (GFAP) was increased in progranulin deficient mice. The progranulin deficient mice had a high expression of GFAP on postnatal day 9 (P9) but not on postnatal day 1. These mice also had a decrease in the number of the Brn3a-positive cells on P9. Taken together, these findings indicate that the absence of progranulin can affect the survival of RGCs subsequent the activation of astrocytes during retinal development.

Spontaneous cell death in the semilunar ganglion during fetal and postnatal life in the ox, sheep, goat and guinea pig.

PubMed

Bortolami, R; Lucchi, M L; Callegari, E; De Pasquale, V; Lalatta Costerbosa, G

1979-07-15

A massive cell loss occurs in the semilunar ganglion. It is the result of either a casting-off of the semilunar ganglion cells into the cavernous sinus or a transformation of several cells into polyhedral cells with an epithelial-like organization, a process which immediately precedes their further degeneration.

Eliminating Glutamatergic Input onto Horizontal Cells Changes the Dynamic Range and Receptive Field Organization of Mouse Retinal Ganglion Cells.

PubMed

Ströh, Sebastian; Puller, Christian; Swirski, Sebastian; Hölzel, Maj-Britt; van der Linde, Lea I S; Segelken, Jasmin; Schultz, Konrad; Block, Christoph; Monyer, Hannah; Willecke, Klaus; Weiler, Reto; Greschner, Martin; Janssen-Bienhold, Ulrike; Dedek, Karin

2018-02-21

In the mammalian retina, horizontal cells receive glutamatergic inputs from many rod and cone photoreceptors and return feedback signals to them, thereby changing photoreceptor glutamate release in a light-dependent manner. Horizontal cells also provide feedforward signals to bipolar cells. It is unclear, however, how horizontal cell signals also affect the temporal, spatial, and contrast tuning in retinal output neurons, the ganglion cells. To study this, we generated a genetically modified mouse line in which we eliminated the light dependency of feedback by deleting glutamate receptors from mouse horizontal cells. This genetic modification allowed us to investigate the impact of horizontal cells on ganglion cell signaling independent of the actual mode of feedback in the outer retina and without pharmacological manipulation of signal transmission. In control and genetically modified mice (both sexes), we recorded the light responses of transient OFF-α retinal ganglion cells in the intact retina. Excitatory postsynaptic currents (EPSCs) were reduced and the cells were tuned to lower temporal frequencies and higher contrasts, presumably because photoreceptor output was attenuated. Moreover, receptive fields of recorded cells showed a significantly altered surround structure. Our data thus suggest that horizontal cells are responsible for adjusting the dynamic range of retinal ganglion cells and, together with amacrine cells, contribute to the center/surround organization of ganglion cell receptive fields in the mouse. SIGNIFICANCE STATEMENT Horizontal cells represent a major neuronal class in the mammalian retina and provide lateral feedback and feedforward signals to photoreceptors and bipolar cells, respectively. The mode of signal transmission remains controversial and, moreover, the contribution of horizontal cells to visual processing is still elusive. To address the question of how horizontal cells affect retinal output signals, we recorded the light

Diagnostic accuracy of ganglion cell complex substructures in different stages of primary open-angle glaucoma.

PubMed

Elbendary, Amal M; Abd El-Latef, Mohamed Hafez; Elsorogy, Hisham I; Enaam, Kamal M

2017-08-01

To evaluate diagnostic accuracy of substructure of ganglion cell complex versus peripapillary nerve fiber layer (NFL) thickness using spectral domain optical coherence tomography (SD-OCT) in different stages of glaucoma. Thirty eyes were normal, 120 were glaucomatous. Glaucomatous eyes were classified into: early glaucoma (46), moderate glaucoma (48), and severe glaucoma (26). Perimetry and SD-OCT were done. Peripapillary NFL thickness, ganglion cell layer (GCL), macular NFL thickness, combined GCL and macular ganglion cell complex (GCC), were recorded. Area under receiver operating characteristic curves (AUCs) was used to verify performance of different OCT parameters. Peripapillary NFL, GCL, and GCC thickness values were significantly different in all stages of glaucoma. All comparisons were significantly different; normal versus early, early versus moderate and moderate versus severe. The best parameters that distinguished normal from early stage were: peripapillary NFL (AUC: 0.90), GCC (AUC: 0.75), early from moderate stage were: peripapillary NFL thickness (AUC: 0.85), GCL (0.81),GCC (0.81), moderate from severe stage were: GCC (AUC:0.95), macular NFL (AUC:0.91), GCL (AUC:0.89), and peripapillary NFL (AUC:0.88). Peripapllary NFL and GCC thinning showed paradoxical course. The most diagnosed parameter in early glaucoma was peripapillary NFL and in severe glaucoma was GCC. In severe glaucoma, macular NFL showed higher diagnostic power than GCL and peripapillary NFL. Ganglion cell complex mapping may provide good alternative to optic disc imaging in advanced glaucoma with poor fixation. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Outcomes of Open Dorsal Wrist Ganglion Excision in Active-Duty Military Personnel.

PubMed

Balazs, George C; Donohue, Michael A; Drake, Matthew L; Ipsen, Derek; Nanos, George P; Tintle, Scott M

2015-09-01

To examine the most common presenting complaints of active-duty service members with isolated dorsal wrist ganglions and to determine the rate of return to unrestricted duty after open excision. Surgical records at 2 military facilities were screened to identify male and female active duty service members undergoing isolated open excision of dorsal wrist ganglions from January 1, 2006 to January 1, 2014. Electronic medical records and service disability databases were searched to identify the most common presenting symptoms and to determine whether patients returned to unrestricted active duty after surgery. Postoperative outcomes examined were pain persisting greater than 4 weeks after surgery, stiffness requiring formal occupational therapy treatment, surgical wound complications, and recurrence. A total of 125 active duty military personnel (Army, 54; Navy, 43; and Marine Corps, 28) met criteria for inclusion. Mean follow-up was 45 months. Fifteen percent (8 of 54) of the Army personnel were given permanent waivers from performing push-ups owing to persistent pain and stiffness. Pain persisting greater than 4 weeks after surgery was an independent predictor of eventual need for a permanent push-up waiver. The overall recurrence incidence was 9%. No demographic or perioperative factors were associated with recurrence. Patients whose occupation or activities require forceful wrist extension should be counseled on the considerable risk of residual pain and functional limitations that may occur after open dorsal wrist ganglion excision. Therapeutic IV. Published by Elsevier Inc.

Functional expression of ionotropic glutamate receptors in the rabbit retinal ganglion cells.

PubMed

Chen, Yin-Peng; Chiao, Chuan-Chin

2012-01-03

It has been known that retinal ganglion cells (RGCs) with distinct morphologies have different physiological properties. It was hypothesized that different functions of RGCs may in part result from various expressions of N-methyl-d-aspartate (NMDA), α-amino-3-hydroxyl-5-methyl-isoxazole-4-propinoic acid (AMPA), and kainic acid (KA) receptors on their dendrites. In the present study, we aimed to characterize the functional expression of AMPA and NMDA receptors of morphologically identified RGCs in the wholemount rabbit retina. The agmatine (AGB) activation assay was used to reveal functional expression of ionotropic glutamate receptors after the RGCs were targeted by injecting Neurobiotin. To examine the excitability of these glutamate receptors in an agonist specific manner, the lower concentrations of AMPA (2 μM) and NMDA (100 μM) were chosen to examine G7 (ON-OFF direction selective ganglion cells) and G11 (alpha ganglion cells) types of RGCs. We found that less than 40% of G7 type RGCs had salient AGB activation when incubated with 2 μM AMPA or 100 μM NMDA. The G11 type RGCs also showed similar activation frequencies, except that all of the OFF subtype examined had no AGB permeation under the same AMPA concentration. These results suggest that RGCs with large somata (G7 and G11 types) may express various heterogeneous functional ionotropic glutamate receptors, thus in part rendering their functional diversity. Copyright © 2011 Elsevier B.V. All rights reserved.

Nanosecond laser pulse stimulation of spiral ganglion neurons and model cells.

PubMed

Rettenmaier, Alexander; Lenarz, Thomas; Reuter, Günter

2014-04-01

Optical stimulation of the inner ear has recently attracted attention, suggesting a higher frequency resolution compared to electrical cochlear implants due to its high spatial stimulation selectivity. Although the feasibility of the effect is shown in multiple in vivo experiments, the stimulation mechanism remains open to discussion. Here we investigate in single-cell measurements the reaction of spiral ganglion neurons and model cells to irradiation with a nanosecond-pulsed laser beam over a broad wavelength range from 420 nm up to 1950 nm using the patch clamp technique. Cell reactions were wavelength- and pulse-energy-dependent but too small to elicit action potentials in the investigated spiral ganglion neurons. As the applied radiant exposure was much higher than the reported threshold for in vivo experiments in the same laser regime, we conclude that in a stimulation paradigm with nanosecond-pulses, direct neuronal stimulation is not the main cause of optical cochlea stimulation.

"Cirque du Freak."

ERIC Educational Resources Information Center

Rivett, Miriam

2002-01-01

Considers the marketing strategies that underpin the success of the "Cirque du Freak" series. Describes how "Cirque du Freak" is an account of events in the life of schoolboy Darren Shan. Notes that it is another reworking of the vampire narrative, a sub-genre of horror writing that has proved highly popular with both adult and…

Suivi après le traitement du cancer du sein

PubMed Central

Sisler, Jeffrey; Chaput, Geneviève; Sussman, Jonathan; Ozokwelu, Emmanuel

2016-01-01

Résumé Objectif Offrir aux médecins de famille un résumé des recommandations fondées sur les données probantes pour guider les soins aux survivantes traitées pour le cancer du sein. Qualité des données Une recherche documentaire a été effectuée dans MEDLINE entre 2000 et 2016 à l’aide des mots-clés anglais suivants : breast cancer, survivorship, follow-up care, aftercare, guidelines et survivorship care plans, en se concentrant sur la revue des lignes directrices publiées récemment par les organismes nationaux de cancérologie. Les données étaient de niveaux I à III. Message principal Les soins aux survivantes comportent 4 facettes : surveillance et dépistage, prise en charge des effets à long terme, promotion de la santé et coordination des soins. La surveillance des récidives ne se traduit que par une mammographie annuelle, et le dépistage d’autres cancers doit suivre les lignes directrices basées sur la population. La prise en charge des effets à long terme du cancer et de son traitement aborde des problèmes courants tels la douleur, la fatigue, le lymphœdème, la détresse et les effets indésirables des médicaments, de même que les préoccupations à long terme comme la santé du cœur et des os. La promotion de la santé met en relief les bienfaits de l’activité chez les survivantes du cancer, avec l’accent mis sur l’activité physique. Les soins aux survivantes sont de meilleure qualité lorsque divers services et professionnels de la santé participent aux soins, et le médecin de famille joue un rôle important dans la coordination des soins. Conclusion Les médecins de famille sont de plus en plus souvent les principaux fournisseurs de soins de suivi après le traitement du cancer du sein. Le cancer du sein doit être considéré comme une affection médicale chronique, même chez les femmes en rémission, et les patientes profitent de la même approche que celle utilisée pour les autres affections chroniques en

Sciatica and claudication caused by ganglion cyst.

PubMed

Yang, Guang; Wen, Xiaoyu; Gong, Yubao; Yang, Chen

2013-12-15

Case report. We report a rare case that a ganglion cyst compressed the sciatic nerve and caused sciatica and claudication in a 51-year-old male. Sciatica and claudication commonly occurs in spinal stenosis. To our knowledge, only 4 cases have been reported on sciatica resulting from posterior ganglion cyst of hip. A 51-year-old male had a 2-month history of radiating pain on his right leg. He could only walk 20 to 30 m before stopping and standing to rest for 1 to 3 minutes. Interestingly, he was able to walk longer distances (about 200 m) when walking slowly in small steps, without any rest. He had been treated as a case of lumbar disc herniation, but conservative treatment was ineffective. On buttock examination, a round, hard, and fixative mass was palpated at the exit of the sciatic nerve. MR imaging of hip revealed a multilocular cystic mass located on the posterior aspect of the superior gemellus and obturator internus, compressing the sciatic nerve. On operation, we found that the cyst extended to the superior gemellus and the obturator internus, positioned right at the outlet of the sciatic nerve. At 18 months of follow-up, the patient continued to be symptom free. He returned to comprehensive physical activity with no limitations. For an extraspinal source, a direct compression on the sciatic nerve also resulted in sciatica and claudication. A meticulous physical examination is very important for the differential diagnosis of extraspinal sciatica from spinal sciatica.

Drug discovery for hearing loss: Phenotypic screening of chemical compounds on primary cultures of the spiral ganglion.

PubMed

Whitlon, Donna S

2017-06-01

In the United States there are, at present, no drugs that are specifically FDA approved to treat hearing loss. Although several clinical trials are ongoing, including one testing D-methionine that is supported by the US Army, none of these trials directly address the effect of noise exposure on cochlear spiral ganglion neurons. We recently published the first report of a systematic chemical compound screen using primary, mammalian spiral ganglion cultures in which we were able to detect a compound and others in its class that increased neurite elongation, a critical step in restoring cochlear synapses after noise induced hearing loss. Here we discuss the issues, both pro and con, that influenced the development of our approach. These considerations may be useful for future compound screens that target the same or other attributes of cochlear spiral ganglion neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

Morphological relationship between the superior cervical ganglion and cervical nerves in Japanese cadaver donors.

PubMed

Mitsuoka, Kazuyuki; Kikutani, Takeshi; Sato, Iwao

2017-02-01

There are various communications between the superior cervical ganglion (SCG) and the vagus and glossopharyngeal nerves. However, little information exists concerning the origin of these sympathetic ganglion branches at the superior, middle, and inferior regions of the human SCG. The aim of this study was to describe the human SCG in a morphometric manner with the communication with cranial and cervical nerves and supply. This study characterized 72 SCG samples from 54 elderly Japanese human cadavers (30 males, 24 females; 65-100 years old). The SCG size (length, width, and thickness) and location were measured from the jugular foramen. We also defined the communication branches of the SCG to the vagus, glossopharyngeal, cervical, and accessory nerves at three regions (superior, middle, and inferior regions) of the SCG. Finally, we examined the arrangement and origin of the branch communications in detail and confirmed our observations, using histological sections of the SCG. The SCG in all cadaver donors was detected at the C2 and C3 vertebra levels. The number of SCG branches supplied the communicating branches, such as the carotid branch, communicating branch of the vagus nerve, and glossopharyngeal nerve, were frequently detected in the superior region of the SCG (χ 2  = 587.72, df = 26, p  <   .001). The number of ganglion cells with a large number of neurons per unit area (1 mm 2 ) was most often found in the middle region with shrunken neurons of the SCG compared with other regions. The communication branches of the SCG are mainly connected to the vagus and glossopharyngeal nerves. Characterizing these branches can provide useful data for head and neck ganglion block and surgical treatments.

[Sphenopalatine ganglion pulsed radiofrequency treatment in patients suffering from chronic face and head pain].

PubMed

Akbas, Mert; Gunduz, Emel; Sanli, Suat; Yegin, Arif

2016-01-01

There are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. Infrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25-0.5ms pulse width was applied for sensory stimulation at frequencies from 50Hz to 1V. Paraesthesias were exposed at the roof of the nose at 0.5-0.7V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120s at a temperature of 42°C. Pain relief could not be achieved in 23% of the patients (unacceptable), whereas pain was completely relieved in 35% of the patients (excellent) and mild to moderate pain relief could be achieved in 42% of the patients (good) through sphenopalatine ganglion-pulsed radiofrequency treatment. Pulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Sphenopalatine ganglion pulsed radiofrequency treatment in patients suffering from chronic face and head pain.

PubMed

Akbas, Mert; Gunduz, Emel; Sanli, Suat; Yegin, Arif

2016-01-01

There are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. Infrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25-0.5 ms pulse width was applied for sensory stimulation at frequencies from 50 Hz to 1 V. Paraesthesias were exposed at the roof of the nose at 0.5-0.7 V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2 Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120 s at a temperature of 42°C. Pain relief could not be achieved in 23% of the patients (unacceptable), whereas pain was completely relieved in 35% of the patients (excellent) and mild to moderate pain relief could be achieved in 42% of the patients (good) through sphenopalatine ganglion-pulsed radiofrequency treatment. Pulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

The release of acetylcholine from post-ganglionic cell bodies in response to depolarization.

PubMed Central

Johnson, D A; Pilar, G

1980-01-01

1. Acetylcholine (Ach) release from parasympathetic ganglia cell somata was investigated in denervated avian ciliary ganglia. Three days after the input to the ganglion (the oculomotor nerve) was sectioned, all presynaptic nerve terminals had degenerated. 2. Denervated ganglia were shown to contain endogenous ACh and to be capable of synthesizing [3H]ACh from [3H]choline added to the incubation medium. 3. In response to depolarization induced by incubation in 50 mM-[K+]o, denervated ganglia released [3H]ACh into bath effluents in amounts approximately 15% of the non-denervated contralateral control. This release was shown to be Ca2+ dependent in both intact and denervated ganglia. 4. Antidromic electrical stimulation of ciliary nerves also elicited [3H]ACh release. Nicotine (1 microgram/microliter.) depolarized denervated ciliary ganglion cells and evoked release of the transmitter and this release was antagonized by curare. 5. It is concluded that the ganglionic cell bodies sysnthesized ACh and released the transmitter in response to K+ depolarization, antidromic stimulation and cholinergic agonists, despite the lack of morphological specializations usually associated with stimulus-induced release of neurotransmitter. The evidence suggests the existence of a mechanism of transmitter release which is Ca2+ dependent, probably from a cytoplasmic pool and therefore distinct from the usual vesicular release at the nerve terminal. Images Plate 1 Plate 2 PMID:6247485

Ouabain-Induced Apoptosis in Cochlear Hair Cells and Spiral Ganglion Neurons In Vitro

PubMed Central

Fu, Yong; Ding, Dalian; Jiang, Haiyan; Salvi, Richard

2013-01-01

Ouabain is a common tool to explore the pathophysiological changes in adult mammalian cochlea in vivo. In prior studies, locally administering ouabain via round window membrane demonstrated that the ototoxic effects of ouabain in vivo varied among mammalian species. Little is known about the ototoxic effects in vitro. Thus, we prepared cochlear organotypic cultures from postnatal day-3 rats and treated these cultures with ouabain at 50, 500, and 1000 μM for different time to elucidate the ototoxic effects of ouabain in vitro and to provide insights that could explain the comparative ototoxic effects of ouabain in vivo. Degeneration of cochlear hair cells and spiral ganglion neurons was evaluated by hair-cell staining and neurofilament labeling, respectively. Annexin V staining was used to detect apoptotic cells. A quantitative RT-PCR apoptosis-focused gene array determined changes in apoptosis-related genes. The results showed that ouabain-induced damage in vitro was dose and time dependent. 500 μM ouabain and 1000 μM ouabain were destructively traumatic to both spiral ganglion neurons and cochlear hair cells in an apoptotic signal-dependent pathway. The major apoptotic pathways in ouabain-induced spiral ganglion neuron apoptosis culminated in the stimulation of the p53 pathway and triggering of apoptosis by a network of proapoptotic signaling pathways. PMID:24228256

Prévalence du portage asymptomatique du plasmodium chez les donneurs bénévoles de sang à Kisangani, République Démocratique du Congo

PubMed Central

Bassandja, Jacques Ossinga; Agasa, Salomon Batina; Likwela, Joris Losimba

2014-01-01

Introduction Le paludisme transfusionnel est une réalité en Afrique Sub-saharienne, en raison des transfusions sanguines répétées, peu ou non contrôlées et où les donneurs sont en majorité potentiellement porteurs d'hématozoaires. L'objectif de cette étude était de déterminer la prévalence du portage asymptomatique du plasmodium chez les donneurs bénévoles de sang à Kisangani. Méthodes Une étude transversale a été menée au Centre Provincial de Transfusion Sanguine à Kisangani du 1er Décembre 2012 au 31 Mars 2013 et a concerné 480 donneurs bénévoles de sang. Résultats La prévalence du portage asymptomatique du plasmodium chez les donneurs bénévoles de sang était de 28,3%. Plasmodium falciparum était l'espèce la plus répandue (96,3%). Près de la moitié des donneurs avait une parasitémie supérieure à 2000 parasites/µl. Les facteurs qui étaient significativement associés à la parasitémie étaient le jeune âge, le 1er don, et la non utilisation de la moustiquaire imprégnée d'insecticide à longue durée (MILD). Conclusion Les résultats de cette étude montrent que la prévalence du portage asymptomatique du plasmodium chez les donneurs bénévoles de sang était élevée, constituant ainsi un risque important de transmission du parasite aux receveurs souvent en mauvais état général. Cependant, l'utilisation de la MILD et la fidélisation des donneurs bénévoles semblent constituer des moyens utiles de réduction du risque de portage asymptomatique du Plasmodium. Une sensibilisation et éventuellement des distributions ciblées de MILD aux donneurs, en particuliers les plus jeunes, pourraient réduire considérablement le portage du Plasmodium parmi les donneurs de sang et ainsi réduire le risque de paludisme transfusionnel. PMID:25328616

[Ropivacaine use in transnasal sphenopalatine ganglion block for post dural puncture headache in obstetric patients - case series].

PubMed

Furtado, Inês; Lima, Isabel Flor de; Pedro, Sérgio

2018-02-02

Sphenopalatine ganglion block is widely accepted in chronic pain; however it has been underestimated in post dural puncture headache treatment. The ganglion block does not restore normal cerebrospinal fluid dynamics but effectively reduces symptoms associated with resultant hypotension. When correctly applied it may avoid performance of epidural blood patch. The transnasal approach is a simple and minimally invasive technique. In the cases presented, we attempted to perform and report the ganglion block effectiveness and duration, using ropivacaine. We present four obstetrics patients with post dural puncture headache, after epidural or combined techniques, with Tuohy needle 18G that underwent a safe and successful Sphenopalatine ganglion block. We performed the block 24-48h after dural puncture, with 4mL of ropivacaine 0.75% in each nostril. In three cases pain recurred within 12-48h, although less intense. In one patient a second block was performed with complete relief and without further recurrence. In the other two patients a blood patch was performed without success. All patients were asymptomatic within 7 days. The average duration of analgesic effect of the block remains poorly defined. In the cases reported, blocking with ropivacaine was a simple, safe and effective technique, with immediate and sustained pain relief for at least 12-24h. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Electrical Interaction of Paired Ganglion Cells in the Leech

PubMed Central

Eckert, Roger

1963-01-01

The two paired giant ganglion cells (PGC's) found in each ganglion of the leech central nervous system fire synchronously in response to certain sensory input. Polarizing current passed into either of these cells is seen to displace the membrane potentials of both cells, the voltage attenuation between the two somata ranging from 2 to 5 times. This attenuation factor remains unchanged when the direction of the polarizing current is reversed, and remains about the same when the other cell of the pair is directly polarized. When one of the PGC's is partially depolarized with outward current, a repetitive train of impulses is generated. Each spike is followed by a spike in the other cell. Occasionally, a small subspike potential is seen in place of a follower spike. This potential appears to differ in shape and time course from synaptic potentials elicited by afferent input to these cells, and appears rather to be an electrotonic potential derived from the prejunctional impulse in the stimulated PGC. It is proposed that transmission between these cells is electrical, being accomplished by a flow of local circuit current across a non-rectifying junction or connection to the spike-initiating region of the other PGC. PMID:19873553

The trophic effect of ouabain on retinal ganglion cells is mediated by IL-1β and TNF-α

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salles von-Held-Ventura, Juliana; Mázala-de-Oliveira, Thalita; Cândida da Rocha Oliveira, Amanda

Ouabain is a steroid hormone that binds to the enzyme Na{sup +}, K{sup +} – ATPase and stimulates different intracellular pathways controlling growth, proliferation and cell survival. IL-1β and TNF-α are pleiotropic molecules, conventionally regarded as pro-inflammatory cytokines with well-known effects in the immune system. In addition, IL-1β and TNF-α also play important roles in the nervous system including neuroprotective effects. Previous data from our group showed that ouabain treatment is able to induce an increase in retinal ganglion cell survival kept in mixed retinal cell cultures. The aim of this work was to investigate if IL-1β and TNF-α couldmore » be mediating the trophic effect of ouabain on retinal ganglion cells. Our results show that the trophic effect of ouabain on retinal ganglion cell was inhibited by either anti-IL-1β or anti-TNF-α antibodies. In agreement, IL-1β or TNF-α increased the retinal ganglion cells survival in a dose-dependent manner. Accordingly, ouabain treatment induces a temporal release of TNF-α and IL-1β from retinal cell cultures. Interestingly, TNF-α and IL-1β regulate each other intracellular levels. Our results suggest that ouabain treatment triggers the activation of TNF-α and IL-1β signaling pathways leading to an increase in retinal ganglion cell survival. - Highlights: • Pro-inflammatory cytokines regulates the ouabain effect on RGC survival. • Ouabain treatment modulates the intracellular levels of TNF-α and IL-1β. • Ouabain induces the release of TNF-α and IL-1β in retinal cell cultures.« less

Satellite glial cells in the trigeminal ganglion as a determinant of orofacial neuropathic pain

PubMed Central

VIT, JEAN-PHILIPPE; JASMIN, LUC; BHARGAVA, ADITI; OHARA, PETER T.

2008-01-01

Satellite glial cells (SGCs) tightly envelop the perikarya of primary sensory neurons in peripheral ganglion and are identified by their morphology and the presence of proteins not found in ganglion neurons. These SGC-unique proteins include the inwardly rectifying K+ channel Kir4.1, the connexin-43 (Cx43) subunit of gap junctions, the purinergic receptor P2Y4 and soluble guanylate cyclase. We also present evidence that the small-conductance Ca2+-activated K+ channel SK3 is present only in SGCs and that SGCs divide following nerve injury. All the above proteins are involved, either directly or indirectly, in potassium ion (K+) buffering and, thus, can influence the level of neuronal excitability, which, in turn, has been associated with neuropathic pain conditions. We used in vivo RNA interference to reduce the expression of Cx43 (present only in SGCs) in the rat trigeminal ganglion and show that this results in the development of spontaneous pain behavior. The pain behavior is present only when Cx43 is reduced and returns to normal when Cx43 concentrations are restored. This finding shows that perturbation of a single SGC-specific protein is sufficient to induce pain responses and demonstrates the importance of PNS glial cell activity in the pathophysiology of neuropathic pain. PMID:18568096

Localization of laminin B1 mRNA in retinal ganglion cells by in situ hybridization

PubMed Central

1990-01-01

In the nervous system, neuronal migration and axonal growth are dependent on specific interactions with extracellular matrix proteins. During development of the vertebrate retina, ganglion cell axons extend along the internal limiting (basement) membrane and form the optic nerve. Laminin, a major component of basement membranes, is known to be present in the internal limiting membrane, and might be involved in the growth of ganglion cell axons. The identity of the cells that produce retinal laminin, however, has not been established. In the present study, we have used in situ hybridization to localize the sites of laminin B1 mRNA synthesis in the developing mouse retina. Our results show that there are at least two principal sites of laminin B1 mRNA synthesis: (a) the hyaloid vessels and the lens during the period of major axonal outgrowth, and (b) the retinal ganglion cells at later development stages. Muller (glial) cells, the major class of nonneuronal cells in the retina, do not appear to express laminin B1 mRNA either during development or in the adult retina. In Northern blots, we found a single transcript of approximately 6-kb size that encodes the laminin B1 chain in the retina. Moreover, laminin B1 mRNA level was four- to fivefold higher in the postnatal retina compared to that in the adult. Our results show that in addition to nonneuronal cells, retinal ganglion cells also synthesize laminin. The function of laminin in postnatal retinas, however, remains to be elucidated. Nevertheless, our findings raise the possibility that neurons in other parts of the nervous system might also synthesize extracellular matrix proteins. PMID:2351694

Frequency-Dependent Activation of Glucose Utilization in the Superior Cervical Ganglion by Electrical Stimulation of Cervical Sympathetic Trunk

NASA Astrophysics Data System (ADS)

Yarowsky, Paul; Kadekaro, Massako; Sokoloff, Louis

1983-07-01

Electrical stimulation of the distal stump of the transected cervical sympathetic trunk produces a frequency-dependent activation of glucose utilization, measured by the deoxy[14C]glucose method, in the superior cervical ganglion of the urethane-anesthetized rat. The frequency dependence falls between 0-15 Hz; at 20 Hz the activation of glucose utilization is no greater than at 15 Hz. Deafferentation of the superior cervical ganglion by transection of the cervical sympathetic trunk does not diminish the rate of glucose utilization in the ganglion in the urethane-anesthetized rat. These results indicate that the rate of energy metabolism in an innervated neural structure is, at least in part, regulated by the impulse frequency of the electrical input to the structure, and this regulation may be an essential component of the mechanism of the coupling of metabolic activity to functional activity in the nervous system.

A novel astrovirus associated with encephalitis and ganglionitis in domestic sheep.

PubMed

Pfaff, F; Schlottau, K; Scholes, S; Courtenay, A; Hoffmann, B; Höper, D; Beer, M

2017-06-01

In June 2013, a 4-year-old Welsh Mountain ewe and in March 2014 a 10-day-old lamb of the same breed and the same flock presented progressive neurological signs including depressed sensorium, tremor, and unusual behaviour. Neuropathological examination of the brain and spinal cord detected non-suppurative polioencephalomyelitis and dorsal root ganglionitis, characteristic of a neurotropic viral agent in both sheep. Metagenomic analysis of different tissue samples from both animals identified a novel Ovine Astrovirus (OvAstV). The presence of viral genome in the central nervous system was confirmed by RT-qPCR. Although the cases presented nine months apart, the identified OvAstV shared nearly identical sequences, differing in only three nucleotide positions across the complete genome. Phylogenetic analysis revealed a close relation of OvAstV to neurotropic bovine astroviruses and an enteric OvAstV. In conclusion, these are the first reported cases of astrovirus infection in domestic sheep that were associated with encephalitis and ganglionitis. © 2017 Blackwell Verlag GmbH.

Sphenopalatine (nasal) ganglion: remote effects including "psychosomatic" symptoms, rage reaction, pain, and spasm.

PubMed

Ruskin, A P

1979-08-01

Many articles implicate the nasal ganglion in the production of remote symptoms and discuss treatment. Symptoms are primarily spastic, involving both visceral and voluntary muscles including muscle spasm in the neck, shoulder, and low back; asthma, hypertension, intestinal spasm; diarrhea, angina pectoris, uterine spasm; intractable hiccup, and many others. All these symptoms appear to have 2 common denominators. They are mediated by the autonomic nervous system and at least in some instances can be "psychosomatic." The sphenopalatine ganglion (SPG) is a major autonomic ganglion located superficially in the pterygopalatine fossa, with major afferent distribution to the entire nasopharynx and important connections with the trigeminal nerve, facial nerve, internal carotid artery plexus of the sympathetic nervous system and, as shown in the rat, direct connection with the anterior pituitary gland. This paper presents arguments supporting the following hypotheses: 1. The SPG probably has a crucial role in lower animals in declenching the reflex responses known collectively as the rage reaction. 2. The SPG is a major point of entry to the autonomic system exposed to pathologic influences and readily accessible for therapeutic influences and readily accessible for therapeutic intervention. 3. A wide variety of symptoms are produced or maintained by alteration in autonomic system tonus and some of these may be affected by intervention on the SPG. 4. The possible relationship of some symptoms and "psychosomatic" conditions to the autonomic nervous system and the rage reaction must be considered.20

Command and Control (C2) Agility (Agilite du commandement et du controle (C2))

DTIC Science & Technology

2014-10-01

de la rigueur et de l’emploi des méthodes de mesure et d’amélioration de l’agilité du C2. Le spectre des missions... Control and Intelligence (C2I) Section DRDC Valcartier 2459 de la Bravoure Road Québec (Québec) G3J 1X5 CANADA Email: Micheline.Belanger@drdc...Agilité du commandement et du contrôle (C2) (STO-TR-SAS-085) Synthèse L’agilité est la capacité à effectuer avec succès, s’occuper de

The effects of ropivacaine hydrochloride on the expression of CaMK II mRNA in the dorsal root ganglion neurons.

PubMed

Wen, Xianjie; Lai, Xiaohong; Li, Xiaohong; Zhang, Tao; Liang, Hua

2016-12-01

In this study, we identified the subtype of Calcium/calmodulin-dependent protein kinase II (CaMK II) mRNA in dorsal root ganglion neurons and observed the effects of ropivacaine hydrochloride in different concentration and different exposure time on the mRNA expression. Dorsal root ganglion neurons were isolated from the SD rats and cultured in vitro. The mRNA of the CaMK II subtype in dorsal root ganglion neurons were detected by real-time PCR. As well as, the dorsal root ganglion neurons were treated with ropivacaine hydrochloride in different concentration (1mM,2mM, 3mM and 4mM) for the same exposure time of 4h, or different exposure time (0h,2h,3h,4h and 6h) at the same concentration(3mM). The changes of the mRNA expression of the CaMK II subtype were observed with real-time PCR. All subtype mRNA of the CaMK II, CaMK II α , CaMK II β , CaMK II δ , CaMK II γ , can be detected in dorsal root ganglion neurons. With the increased of the concentration and exposure time of the ropivacaine hydrochloride, all the subtype mRNA expression increased. Ropivacaine hydrochloride up-regulate the CaMK II β , CaMK II δ , CaMK II g mRNA expression with the concentration and exposure time increasing. The nerve blocking or the neurotoxicity of the ropivacaine hydrochloride maybe involved with CaMK II. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Enkephalins in the inferior mesenteric ganglion of the cat and in the area of the lower digestive tract innervated by this ganglion: quantification by radio-immunoassay and characterization by high pressure liquid chromatography.

PubMed

Cupo, A; Niel, J P; Miolan, J P; Jule, Y; Jarry, T

1988-01-01

Met-enkephalin, Leu-enkephalin and Met-enkephalin-Arg-Gly-Leu were quantified and characterized in the cat inferior mesenteric ganglion and in the area of the lower digestive tract innervated by this ganglion, including the proximal colon, distal colon and internal anal sphincter. In the structures studied, the concentrations of enkephalins expressed as femtomole/mg of wet tissue ranged from 66 to 160 with Met-enkephalin, from 15 to 45 with Leu-enkephalin and from 2 to 12 for Met-enkephalin-arg-gly-leu. In the lower digestive tract, the Met- and Leu-enkephalin content decreased from the proximal colon to the internal anal sphincter. The Met-enkephalin versus Leu-enkephalin ratio of the structures investigated were as follows: inferior mesenteric ganglion 3.2, proximal colon 4.4, distal colon 5, internal and sphincter 4.5. In individual samples of all the structures assayed the results of high pressure liquid chromatography (HPLC) analysis pointed to the presence of authentic Met- and Leu-enkephalin. HPLC analysis could not be carried out on Met-enkephalin-Arg-Gly-Leu due to the very low concentrations of this peptide in all the structures assayed. Our results, combined with those of previous immunohistochemical and physiological studies, support the idea that enkephalins are involved in the nervous control of the motility of the lower digestive tract.

Effects of alpha-lipoic acid on retinal ganglion cells, retinal thicknesses, and VEGF production in an experimental model of diabetes.

PubMed

Kan, Emrah; Alici, Ömer; Kan, Elif Kılıç; Ayar, Ahmet

2017-12-01

The purpose of the present study was to investigate the effect of alpha-lipoic acid (ALA) on the thicknesses of various retinal layers and on the numbers of retinal ganglion cells and vascular endothelial growth factor levels in experimental diabetic mouse retinas. Twenty-one male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). One week after the induction of diabetes, the mice were divided randomly into three groups: control group (non-diabetic mice treated with alpha-lipoic acid, n = 7), diabetic group (diabetic mice without treatment, n = 7), and alpha-lipoic acid treatment group (diabetic mice with alpha-lipoic acid treatment, n = 7). At the end of the 8th week, the thicknesses of the inner nuclear layer (INL), outer nuclear layer (ONL), and full-length retina were measured; also retinal ganglion cells and VEGF expressions were counted on the histological sections of the mouse retinas and compared with each other. The thicknesses of the full-length retina, ONL, and INL were significantly reduced in the diabetic group compared to the control and ALA treatment groups (p = 0.001), whereas the thicknesses of these layers did not show a significant difference between ALA treatment and control groups. The number of ganglion cells in the diabetic group was significantly lower than those in the control and ALA treatment groups (p = 0.001). The VEGF expression was significantly higher in the diabetic group and mostly observed in the ganglion cell and inner nuclear layers compared to the control and ALA treatment groups (p = 0.001). Therefore, the number of ganglion cells and VEGF levels did not show significant differences between the ALA treatment and control groups (p = 0.7). Our results show that alpha-lipoic acid treatment may have an impact on reducing VEGF levels, protecting ganglion cells, and preserving the thicknesses of the inner and outer layers in diabetic mouse retinas.

Slit/Robo Signaling Mediates Spatial Positioning of Spiral Ganglion Neurons during Development of Cochlear Innervation

PubMed Central

Wang, Sheng-zhi; Ibrahim, Leena A.; Kim, Young J.; Gibson, Daniel A.; Leung, Haiwen C.; Yuan, Wei; Zhang, Ke K.; Tao, Huizhong W.

2013-01-01

During the development of periphery auditory circuits, spiral ganglion neurons (SGNs) extend their neurites to innervate cochlear hair cells (HCs) with their soma aggregated into a cluster spatially segregated from the cochlear sensory epithelium. The molecular mechanisms underlying this spatial patterning remain unclear. In this study, in situ hybridization in the mouse cochlea suggests that Slit2 and its receptor, Robo1/2, exhibit apparently complementary expression patterns in the spiral ganglion and its nearby region, the spiral limbus. In Slit2 and Robo1/2 mutants, the spatial restriction of SGNs was disrupted. Mispositioned SGNs were found to scatter in the space between the cochlear epithelium and the main body of spiral ganglion, and the neurites of mispositioned SGNs were misrouted and failed to innervate HCs. Furthermore, in Robo1/2 mutants, SGNs were displaced toward the cochlear epithelium as an entirety. Examination of different embryonic stages in the mutants revealed that the mispositioning of SGNs was due to a progressive displacement to ectopic locations after their initial normal settlement at an earlier stage. Our results suggest that Slit/Robo signaling imposes a restriction force on SGNs to ensure their precise positioning for correct SGN-HC innervations. PMID:23884932

Élimination du bore du silicium par plasma inductif sous champ électrique

NASA Astrophysics Data System (ADS)

Combes, R.; Morvan, D.; Picard, G.; Amouroux, J.

1993-05-01

We analyzed purification mechanisms of silicon by inductive plasma with a fluoride slag. The aim is to study boron elimination from doped electronic grade silicon in function of the nature of the slag to obtain a photovoltaic grade silicon. The steady began with the calculation and the comparison of the stability diagram of boron compounds in presence of CaF2, BaF2 and MgF2. This study led us to conclude that BaF2 is the better slag for silicon purification. This has been confirmed by experience. In a second time, we made purifications under electric bias to enhance slag efficiency. We noticed that BaF2 is more sensitive to electric bias than other slags. Nous avons analysé le mécanisme de purification du silicium sous plasma inductif en présence d'un laitier fluoré. L'objectif principal est d'étudier l'élimination du bore du silicium électronique dopé en fonction de la nature du fluorure pour obtenir un silicium de qualité photovoltaïque. L'étude a commencé par l'établissement et la comparaison de diagrammes des composés du bore en présence de CaF2, de MgF2 et de BaF2. Nous avons déduit de cette première étude que BaF2 est le meilleur laitier pour la purification du silicium. Ceci a été corroboré par l'expérience. Nous avons ensuite opéré en présence d'un champ électrique dans le but d'améliorer encore l'efficacité des laitiers. Nous avons constaté que BaF2 est plus sensible au champ électrique que les deux autres laitiers utilisés.

Consequences experimentales des effets des fluctuations du vide sur la fluorescence parametrique et la generation du second harmonique en milieu confine

NASA Astrophysics Data System (ADS)

Robichaud, Luc

Les fluctuations du vide, qui consistent en l'apparition momentanee de particules, ce qui est permit par le principe d'incertitude de Heisenberg, joue un role primordial dans les processus photoniques, en particulier les processus non-lineaires. Par la manipulation de ces fluctuations du vide a l'aide de confinement optique, on retrouve deux phenomenes particuliers : l'intensification de la fluorescence parametrique (Walker, 2008) et l'inhibition de la generation du second harmonique (Collette, 2013). Dans ce travail, on presente les resultats dans le cas classique ; c'est-a-dire sans fluctuations du vide et confinement. Par la suite, on presente les effets des fluctuations du vide et du confinement, ce qui mene aux deux effets mentionnes. Dans le cas de la fluorescence parametrique, le bruit quantique sur le champ interne et externe est calcule, le role du desaccord de phase dans le modele est expose et une generalisation tridimensionnelle est etudiee afin de generaliser la conception du modele d'un cas unidimensionnel a un cas tridimensionnel planaire. Dans le cas de la generation du second harmonique, les difficultes d'un modele purement tridimensionnel sont exposees et ensuite le cas limite planaire est etudie.

Developmental changes in expression of GABAA receptor-channels in rat intrinsic cardiac ganglion neurones

PubMed Central

Fischer, Harald; Harper, Alexander A; Anderson, Colin R; Adams, David J

2005-01-01

The effects of γ-aminobutyric acid (GABA) on the electrophysiological properties of intracardiac neurones were investigated in the intracardiac ganglion plexus in situ and in dissociated neurones from neonatal, juvenile and adult rat hearts. Focal application of GABA evoked a depolarizing, excitatory response in both intact and dissociated intracardiac ganglion neurones. Under voltage clamp, both GABA and muscimol elicited inward currents at −60 mV in a concentration-dependent manner. The fast, desensitizing currents were mimicked by the GABAA receptor agonists muscimol and taurine, and inhibited by the GABAA receptor antagonists, bicuculline and picrotoxin. The GABAA0 antagonist (1,2,5,6-tetrahydropyridin-4-yl)methyl phosphonic acid (TPMPA), had no effect on GABA-induced currents, suggesting that GABAA receptor-channels mediate the response. The GABA-evoked current amplitude recorded from dissociated neurones was age dependent whereby the peak current density measured at −100 mV was ∼ 20 times higher for intracardiac neurones obtained from neonatal rats (P2–5) compared with adult rats (P45–49). The decrease in GABA sensitivity occurred during the first two postnatal weeks and coincides with maturation of the sympathetic innervation of the rat heart. Immunohistochemical staining using antibodies against GABA demonstrate the presence of GABA in the intracardiac ganglion plexus of the neonatal rat heart. Taken together, these results suggest that GABA and taurine may act as modulators of neurotransmission and cardiac function in the developing mammalian intrinsic cardiac nervous system. PMID:15731187

Expression and function of system N glutamine transporters (SN1/SN2 or SNAT3/SNAT5) in retinal ganglion cells.

PubMed

Umapathy, Nagavedi S; Dun, Ying; Martin, Pamela M; Duplantier, Jennifer N; Roon, Penny; Prasad, Puttur; Smith, Sylvia B; Ganapathy, Vadivel

2008-11-01

Glutamine transport is essential for the glutamate-glutamine cycle, which occurs between neurons and glia. System N, consisting of SN1 (SNAT3) and SN2 (SNAT5), is the principal mediator of glutamine transport in retinal Müller cells. Mediators of glutamine transport in retinal ganglion cells were investigated. The relative contributions of various transport systems for glutamine uptake (systems N, A, L, y+L, ASCT, and ATB(0,+)) were examined in RGC-5 cells based on differential features of the individual transport systems. mRNA for the genes encoding members of these transport systems were analyzed by RT-PCR. Based on these data, SN1 and SN2 were analyzed in mouse retina, RGC-5 cells, and primary mouse ganglion cells (GCs) by in situ hybridization (ISH), immunofluorescence (IF), and Western blotting. Three transport systems--N, A, and L--participated in glutamine uptake in RGC-5 cells. System N was the principal contributor; systems A and L contributed considerably less. ISH and IF revealed SN1 and SN2 expression in the ganglion, inner nuclear, and photoreceptor cell layers. SN1 and SN2 colocalized with the ganglion cell marker Thy 1.2 and with the Müller cell marker vimentin, confirming their presence in both retinal cell types. SN1 and SN2 proteins were detected in primary mouse GCs. These findings suggest that in addition to its role in glutamine uptake in retinal glial cells, system N contributes significantly to glutamine uptake in ganglion cells and, hence, contributes to the retinal glutamate-glutamine cycle.

Association Between Regular Cannabis Use and Ganglion Cell Dysfunction.

PubMed

Schwitzer, Thomas; Schwan, Raymund; Albuisson, Eliane; Giersch, Anne; Lalanne, Laurence; Angioi-Duprez, Karine; Laprevote, Vincent

2017-01-01

Because cannabis use is a major public health concern and cannabis is known to act on central neurotransmission, studying the retinal ganglion cells in individuals who regularly use cannabis is of interest. To determine whether the regular use of cannabis could alter the function of retinal ganglion cells in humans. For this case-control study, individuals who regularly use cannabis, as well as healthy controls, were recruited, and data were collected from February 11 to October 28, 2014. Retinal function was used as a direct marker of brain neurotransmission abnormalities in complex mental phenomena. Amplitude and implicit time of the N95 wave on results of pattern electroretinography. Twenty-eight of the 52 participants were regular cannabis users (24 men and 4 women; median age, 22 years [95% CI, 21-24 years]), and the remaining 24 were controls (20 men and 4 women; median age, 24 years [95% CI, 23-27 years]). There was no difference between groups in terms of age (P = .13) or sex (P = .81). After adjustment for the number of years of education and alcohol use, there was a significant increase for cannabis users of the N95 implicit time on results of pattern electroretinography (median, 98.6 milliseconds [95% CI, 93.4-99.5]) compared with controls (median, 88.4 milliseconds [95% CI, 85.0-91.1]), with 8.4 milliseconds as the median of the differences (95% CI, 4.9-11.5; P < .001, Wald logistic regression). A receiver operating characteristic curve analysis (area under the curve, 0.84 [95% CI, 0.73-0.95]; P < .001) revealed, for a cutoff value of 91.13 milliseconds, a sensitivity of 78.6% (95% CI, 60.5%-89.8%) and a specificity of 75.0% (95% CI, 55.1%-88.0%) for correctly classifying both cannabis users and controls in their corresponding group. The positive predictive value was 78.6% (95% CI, 60.5%-89.8%), and the negative predictive value was 75.0% (95% CI, 55.1%-88.0%). Our results demonstrate a delay in transmission of action potentials by the

Delayed rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells

PubMed Central

Weick, Michael; Demb, Jonathan B.

2011-01-01

SUMMARY Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5–10 mV) also suppressed firing during subsequent depolarization. This suppression was sensitive selectively to blockers of delayed-rectifier K channels (KDR). Somatic membrane patches showed TEA-sensitive KDR currents with activation near −25 mV and removal of inactivation at voltages negative to Vrest. Brief periods of hyperpolarization apparently remove KDR inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. PMID:21745646

Atypical fibrosarcomas derived from cutaneous ganglion cell-like cells in 2 domestic Djungarian hamsters (Phodopus sungorus).

PubMed

Kondo, Hirotaka; Onuma, Mamoru; Shibuya, Hisashi; Sato, Tsuneo; Abbott, Jeffrey R

2011-07-01

Androgen-dependent atypical fibromas are benign tumors derived from ganglion-cell-like cells that are particular to Djungarian hamsters (Phodopus sungorus). Masses excised from 2 hamsters were composed of pleomorphic ganglion cell-like cells supported by small to moderate amounts of collagenous matrix. Intracytoplasmic fibrils were present in silver-stained sections, and immunohistochemistry showed that the cells expressed vimentin, androgen receptor, and, in one case, estrogen receptor α. In contrast to previously reported atypical fibromas, these tumors had features of anaplasia and were locally invasive. We diagnosed the tumors as atypical fibrosarcomas and consider them an unusual malignant counterpart of atypical fibroma. Copyright 2011 by the American Association for Laboratory Animal Science

Adult Human Nasal Mesenchymal-Like Stem Cells Restore Cochlear Spiral Ganglion Neurons After Experimental Lesion

PubMed Central

Bas, Esperanza; Van De Water, Thomas R.; Lumbreras, Vicente; Rajguru, Suhrud; Goss, Garrett; Hare, Joshua M.

2014-01-01

A loss of sensory hair cells or spiral ganglion neurons from the inner ear causes deafness, affecting millions of people. Currently, there is no effective therapy to repair the inner ear sensory structures in humans. Cochlear implantation can restore input, but only if auditory neurons remain intact. Efforts to develop stem cell-based treatments for deafness have demonstrated progress, most notably utilizing embryonic-derived cells. In an effort to bypass limitations of embryonic or induced pluripotent stem cells that may impede the translation to clinical applications, we sought to utilize an alternative cell source. Here, we show that adult human mesenchymal-like stem cells (MSCs) obtained from nasal tissue can repair spiral ganglion loss in experimentally lesioned cochlear cultures from neonatal rats. Stem cells engraft into gentamicin-lesioned organotypic cultures and orchestrate the restoration of the spiral ganglion neuronal population, involving both direct neuronal differentiation and secondary effects on endogenous cells. As a physiologic assay, nasal MSC-derived cells engrafted into lesioned spiral ganglia demonstrate responses to infrared laser stimulus that are consistent with those typical of excitable cells. The addition of a pharmacologic activator of the canonical Wnt/β-catenin pathway concurrent with stem cell treatment promoted robust neuronal differentiation. The availability of an effective adult autologous cell source for inner ear tissue repair should contribute to efforts to translate cell-based strategies to the clinic. PMID:24172073

GDF15 is elevated in mice following retinal ganglion cell death and in glaucoma patients

PubMed Central

Ban, Norimitsu; Siegfried, Carla J.; Lin, Jonathan B.; Shui, Ying-Bo; Sein, Julia; Pita-Thomas, Wolfgang; Sene, Abdoulaye; Santeford, Andrea; Gordon, Mae; Lamb, Rachel; Dong, Zhenyu; Kelly, Shannon C.; Cavalli, Valeria; Yoshino, Jun

2017-01-01

Glaucoma is the second leading cause of blindness worldwide. Physicians often use surrogate endpoints to monitor the progression of glaucomatous neurodegeneration. These approaches are limited in their ability to quantify disease severity and progression due to inherent subjectivity, unreliability, and limitations of normative databases. Therefore, there is a critical need to identify specific molecular markers that predict or measure glaucomatous neurodegeneration. Here, we demonstrate that growth differentiation factor 15 (GDF15) is associated with retinal ganglion cell death. Gdf15 expression in the retina is specifically increased after acute injury to retinal ganglion cell axons and in a murine chronic glaucoma model. We also demonstrate that the ganglion cell layer may be one of the sources of secreted GDF15 and that GDF15 diffuses to and can be detected in aqueous humor (AH). In validating these findings in human patients with glaucoma, we find not only that GDF15 is increased in AH of patients with primary open angle glaucoma (POAG), but also that elevated GDF15 levels are significantly associated with worse functional outcomes in glaucoma patients, as measured by visual field testing. Thus, GDF15 maybe a reliable metric of glaucomatous neurodegeneration, although further prospective validation studies will be necessary to determine if GDF15 can be used in clinical practice. PMID:28469085

Expression of zinc transporter ZnT7 in mouse superior cervical ganglion

USDA-ARS?s Scientific Manuscript database

The superior cervical ganglion (SCG) neurons contain a considerable amount of zinc ions, but little is known about zinc homeostasis in the SCG. It is known that zinc transporter 7 (ZnT7, Slc30a7), a member of the Slc30 ZnT family, is involved in mobilizing zinc ions from the cytoplasm into the Golgi...

Calcium channels in solitary retinal ganglion cells from post-natal rat.

PubMed Central

Karschin, A; Lipton, S A

1989-01-01

1. Calcium currents from identified, post-natal retinal ganglion cell neurones from rat were studied with whole-cell and single-channel patch-clamp techniques. Na+ and K+ currents were suppressed with pharmacological agents, allowing isolation of current carried by either 10 mM-Ca2+ or Ba2- during whole-cell recordings. For cell-attached patch recordings, the recording pipette contained 96-110 mM-BaCl2 while the bath solution consisted of isotonic potassium aspartate in order to zero the neuronal membrane potential. 2. A transient component, present in approximately one-third of the whole-cell recordings resembles closely the T-type calcium current observed previously in other tissues. This component activates at low voltages (-40 to -50 mV from holding potentials negative to -80 mV), inactivates with a time constant of 10-30 ms at 35 degrees C, and is carried equally well by Ba2+ or Ca2+. In single-channel recordings small (8 pS) channels are observed whose aggregate microscopic kinetics correspond well to the macroscopic current obtained during whole-cell measurements. 3. During whole-cell recordings, a more prolonged component activates in all retinal ganglion cells at -40 to -20 mV from a holding potential of -90 mV. This component is substantially larger when equimolar Ba2+ replaces Ca2+ as the charge carrier, and is sensitive to the dihydropyridine agonist Bay K8644 (5 microM) and antagonists nifedipine (1-10 microM) and nimodipine (1-10 microM). Thus, the dihydropyridine pharmacology of this prolonged component resembles that of the L-type calcium current found in dorsal root ganglion neurones and in heart cells. Also reminiscent of the L-current, the prolonged component in this preparation is less inactivated at depolarized holding potentials (-60 to -40 mV) than the transient component. In cell-attached recordings, large (20 pS) channels are observed with activation properties similar to those of the prolonged portion of the whole-cell current. 4. omega

Le role du phytoplancton de petite taille (<20 mum) dans les variations des proprietes optiques des eaux du Saint-Laurent

NASA Astrophysics Data System (ADS)

Mas, Sebastien

Les mesures satellitaires de couleur des oceans sont largement determinees par les proprietes optiques inherentes (IOPs) des eaux de surface. D'autre part, le phytoplancton de petite taille (<20 mum) est le plus souvent dominant dans les oceans, et peut donc etre une source importante de variation des IOPs dans les oceans. Dans ce contexte, le but principal de ce doctorat etait de definir l'impact du phytoplancton (<20 mum) sur les variations des proprietes optiques de l'Estuaire et du Golfe du Saint-Laurent (Canada). Afin d'atteindre cet objectif, il etait necessaire de determiner en milieu controle les facteurs de variabilite des proprietes optiques cellulaires et des IOPs du phytoplancton (<20 mum) des eaux du Saint-Laurent, et d'evaluer la contribution du phytoplancton (<20 mum) aux proprietes optiques totales des eaux du Saint-Laurent. Des experiences en laboratoire ont montre que les variations des proprietes optiques des cellules phytoplanctoniques soumises a un cycle jour-nuit, ainsi qu'a des changements concomitants d'intensite lumineuse, peuvent contribuer significativement a la variabilite des proprietes optiques observee en milieu naturel. D'autres experiences ont, quant a elles, mis en evidence que les variations des proprietes optiques des cellules phytoplanctoniques dues aux phases de croissance peuvent alterer les IOPs des oceans, particulierement pendant les periodes de floraison. De plus, la presence de bacteries et de particules detritiques peut egalement affecter la variabilite des IOPs totales, notamment la diffusion. Au printemps, dans l'Estuaire et le Golfe du Saint-Laurent, la contribution du phytoplancton <20 mum aux IOPs presentait des differences regionales evidentes pour les proprietes d'absorption et de diffusion. En plus de la variabilite spatiale, les proprietes optiques cellulaires presentaient des variations journalieres, et ce particulierement pour le picophytoplancton. Enfin, la plupart des differences observees dans les

Rupture simultanée du ligament croisé antérieur et du ligament patellaire: à propos d'un cas

PubMed Central

Achkoun, Abdessalam; Houjairi, Khalid; Quahtan, Omar; Hassoun, Jalal; Arssi, Mohamed; Rahmi, Mohamed; Garch, Abdelhak

2016-01-01

La rupture simultanée du tendon rotulien et du ligament croisé antérieur est une lésion relativement rare. Son diagnostic peut facilement manquer lors de l'examen initial. Les options de traitement incluent la réparation immédiate du tendon rotulien avec soit la reconstruction simultanée ou différée de ligament croisé antérieur. Nous rapportons le cas d'une rupture combinée du tendon rotulien et du ligament croisé antérieur chez un jeune footballeur de 22 ans. Une approche de traitement en deux temps a été effectuée avec un excellent résultat fonctionnel. PMID:27366288

La reconstruction du sourcil par greffon composite du cuir chevelu: une astuce pour faciliter la technique

PubMed Central

El Omari, Mounia; El Mazouz, Samir; Gharib, Noureddine; EL Abbassi, Abdallah

2015-01-01

Les sourcils jouent un rôle important dans l’équilibre esthétique du visage. Leur reconstruction ou ophriopoïése, après séquelle de brûlure fait partie intégrante du programme de réhabilitation de la face brûlée. Plusieurs techniques ont été décrites. Nous insistons ici sur l'intérêt d'une technique simple, à la portée de tous les chirurgiens, et dont la méthode et les résultats peuvent être améliorés par un dessin bien planifié des zones donneuse et receveuse: la greffe composite prélevée au niveau du cuir chevelu dessinée à l'aide d'un calque du sourcil controlatéral. PMID:26401195

Functional Pattern of Increasing Concentrations of Brain-Derived Neurotrophic Factor in Spiral Ganglion: Implications for Research on Cochlear Implants.

PubMed

Ramku, Emina; Ramku, Refik; Spanca, Dugagjin; Zhjeqi, Valbona

2017-04-15

As previously various studies have suggested application of brain-derived neurotrophic factor (BDNF) may be considered as a promising future therapy for hearing deficits, in particular for the improvement of cochlear neurone loss during cochlear implantation. The present study's aim was to establish the upper threshold of the concentration of BDNF in Naval Medical Research Institute (NMRI) mice spiral ganglion outgrowth. Spiral ganglion explants were prepared from post-natal day 4 (p4) (NMRI) mice of both sexes under the approval and guidelines of the regional council of Hearing Research Institute Tubingen. Spiral ganglion explants were cultured at postnatal days 4 in the presence of different concentrations of BDNF as described under methods. We chose an age of postnatal day (P4) and concentrations of BDNF 0; 6; 12.5; 25 and 50 ƞg/ml. Averaged neurite outgrowth is measured in 4 different cultures that were treated with different concentrations. Results show that with increasing concentrations of BDNF, the neurite density increases. The present finding show evidence that BDNF has a clear incremental effect on the number of neurites of spiral ganglia in the prehearing organ, but less on the neurite length. The upper threshold of exogenous BNDF concentration on spiral ganglion explant is 25 ƞg/ml. This means that concentration beyond this level has no further incremental impact. Therefore our suggestion for hydrogel concentration in NMRA mice in future research should be 25 ƞg/ml.

Comparative expression analysis of POU4F1, POU4F2 and ISL1 in developing mouse cochleovestibular ganglion neurons

PubMed Central

Deng, Min; Yang, Hua; Xie, Xiaoling; Liang, Guoqing; Gan, Lin

2014-01-01

POU-homeodomain and LIM-homeodomain transcription factors are expressed in developing projection neurons within retina, inner ear, dorsal root ganglion, and trigeminal ganglion, and play synergistic roles in their differentiation and survival. Here, using immunohistochemistry, we present a comparative analysis of the spatiotemporal expression pattern of POU4F1, POU4F2, and ISL1 during the development of cochleovestibular ganglion (CVG) neurons in mouse inner ear. At early stages, when otic neurons are first detected in the otic epithelium (OE) and migrate into periotic mesenchyme to form the CVG, POU4F1 and ISL1 are co-expressed in a majority of the delaminated CVG neurons, which are marked by NEUROD1 expression, but POU4F1 is absent in the otic epithelium. The onset of POU4F2 expression starts after that of POU4F1 and ISL1, and is observed in the NEUROD1-negative, post-mitotic CVG neurons. When the CVG neurons innervate the vestibular and cochlear sensory organs, the expression of POU4F1, POU4F2, and ISL1 continues in both vestibular and spiral ganglion cells. Later in development, POU4F1 expression becomes down-regulated in a majority of spiral ganglion (SG) neurons and more neurons express POU4F2 expression while ISL1 expression is maintained. The differential as well as overlapping expression of POU4F1, POU4F2, and ISL1 combined with previous studies suggests possible functional interaction and regulatory relationship of these transcription factors in the development of inner ear neurons. PMID:24709358

Expression and Function of System N Glutamine Transporters (SN1/SN2 or SNAT3/SNAT5) in Retinal Ganglion Cells

PubMed Central

Umapathy, Nagavedi S.; Dun, Ying; Martin, Pamela M.; Duplantier, Jennifer N.; Roon, Penny; Prasad, Puttur; Smith, Sylvia B.; Ganapathy, Vadivel

2008-01-01

Purpose Glutamine transport is essential for the glutamate-glutamine cycle, which occurs between neurons and glia. System N, consisting of SN1 (SNAT3) and SN2 (SNAT5), is the principal mediator of glutamine transport in retinal Müller cells. Mediators of glutamine transport in retinal ganglion cells were investigated. Methods The relative contributions of various transport systems for glutamine uptake (systems N, A, L, y+L, ASCT, and ATB0,+) were examined in RGC-5 cells based on differential features of the individual transport systems. mRNA for the genes encoding members of these transport systems were analyzed by RT-PCR. Based on these data, SN1 and SN2 were analyzed in mouse retina, RGC-5 cells, and primary mouse ganglion cells (GCs) by in situ hybridization (ISH), immunofluorescence (IF), and Western blotting. Results Three transport systems—N, A, and L—participated in glutamine uptake in RGC-5 cells. System N was the principal contributor; systems A and L contributed considerably less. ISH and IF revealed SN1 and SN2 expression in the ganglion, inner nuclear, and photoreceptor cell layers. SN1 and SN2 colocalized with the ganglion cell marker Thy 1.2 and with the Müller cell marker vimentin, confirming their presence in both retinal cell types. SN1 and SN2 proteins were detected in primary mouse GCs. Conclusions These findings suggest that in addition to its role in glutamine uptake in retinal glial cells, system N contributes significantly to glutamine uptake in ganglion cells and, hence, contributes to the retinal glutamate-glutamine cycle. PMID:18689705

The Three-Dimensional Culture System with Matrigel and Neurotrophic Factors Preserves the Structure and Function of Spiral Ganglion Neuron In Vitro.

PubMed

Sun, Gaoying; Liu, Wenwen; Fan, Zhaomin; Zhang, Daogong; Han, Yuechen; Xu, Lei; Qi, Jieyu; Zhang, Shasha; Gao, Bradley T; Bai, Xiaohui; Li, Jianfeng; Chai, Renjie; Wang, Haibo

2016-01-01

Whole organ culture of the spiral ganglion region is a resourceful model system facilitating manipulation and analysis of live sprial ganglion neurons (SGNs). Three-dimensional (3D) cultures have been demonstrated to have many biomedical applications, but the effect of 3D culture in maintaining the SGNs structure and function in explant culture remains uninvestigated. In this study, we used the matrigel to encapsulate the spiral ganglion region isolated from neonatal mice. First, we optimized the matrigel concentration for the 3D culture system and found the 3D culture system protected the SGNs against apoptosis, preserved the structure of spiral ganglion region, and promoted the sprouting and outgrowth of SGNs neurites. Next, we found the 3D culture system promoted growth cone growth as evidenced by a higher average number and a longer average length of filopodia and a larger growth cone area. 3D culture system also significantly elevated the synapse density of SGNs. Last, we found that the 3D culture system combined with neurotrophic factors had accumulated effects in promoting the neurites outgrowth compared with 3D culture or NFs treatment only groups. Together, we conclude that the 3D culture system preserves the structure and function of SGN in explant culture.

In vivo fluorescence imaging of primate retinal ganglion cells and retinal pigment epithelial cells

NASA Astrophysics Data System (ADS)

Gray, Daniel C.; Merigan, William; Wolfing, Jessica I.; Gee, Bernard P.; Porter, Jason; Dubra, Alfredo; Twietmeyer, Ted H.; Ahamd, Kamran; Tumbar, Remy; Reinholz, Fred; Williams, David R.

2006-08-01

The ability to resolve single cells noninvasively in the living retina has important applications for the study of normal retina, diseased retina, and the efficacy of therapies for retinal disease. We describe a new instrument for high-resolution, in vivo imaging of the mammalian retina that combines the benefits of confocal detection, adaptive optics, multispectral, and fluorescence imaging. The instrument is capable of imaging single ganglion cells and their axons through retrograde transport in ganglion cells of fluorescent dyes injected into the monkey lateral geniculate nucleus (LGN). In addition, we demonstrate a method involving simultaneous imaging in two spectral bands that allows the integration of very weak signals across many frames despite inter-frame movement of the eye. With this method, we are also able to resolve the smallest retinal capillaries in fluorescein angiography and the mosaic of retinal pigment epithelium (RPE) cells with lipofuscin autofluorescence.

Combined application of BDNF to the eye and brain enhances ganglion cell survival and function in the cat after optic nerve injury.

PubMed

Weber, Arthur J; Viswanáthan, Suresh; Ramanathan, Chidambaram; Harman, Christine D

2010-01-01

To determine whether application of BDNF to the eye and brain provides a greater level of neuroprotection after optic nerve injury than treatment of the eye alone. Retinal ganglion cell survival and pattern electroretinographic responses were compared in normal cat eyes and in eyes that received (1) a mild nerve crush and no treatment, (2) a single intravitreal injection of BDNF at the time of the nerve injury, or (3) intravitreal treatment combined with 1 to 2 weeks of continuous delivery of BDNF to the visual cortex, bilaterally. Relative to no treatment, administration of BDNF to the eye alone resulted in a significant increase in ganglion cell survival at both 1 and 2 weeks after nerve crush (1 week, 79% vs. 55%; 2 weeks, 60% vs. 31%). Combined treatment of the eye and visual cortex resulted in a modest additional increase (17%) in ganglion cell survival in the 1-week eyes, a further significant increase (55%) in the 2-week eyes, and ganglion cell survival levels for both that were comparable to normal (92%-93% survival). Pattern ERG responses for all the treated eyes were comparable to normal at 1 week after injury; however, at 2 weeks, only the responses of eyes receiving the combined BDNF treatment remained so. Although treatment of the eye alone with BDNF has a significant impact on ganglion cell survival after optic nerve injury, combined treatment of the eye and brain may represent an even more effective approach and should be considered in the development of future optic neuropathy-related neuroprotection strategies.

Organ of Corti explants direct tonotopically graded morphology of spiral ganglion neurons in vitro.

PubMed

Smith, Felicia L; Davis, Robin L

2016-08-01

The spiral ganglion is a compelling model system to examine how morphological form contributes to sensory function. While the ganglion is composed mainly of a single class of type I neurons that make simple one-to-one connections with inner hair cell sensory receptors, it has an elaborate overall morphological design. Specific features, such as soma size and axon outgrowth, are graded along the spiral contour of the cochlea. To begin to understand the interplay between different regulators of neuronal morphology, we cocultured neuron explants with peripheral target tissues removed from distinct cochlear locations. Interestingly, these "hair cell microisolates" were capable of both increasing and decreasing neuronal somata size, without adversely affecting survival. Moreover, axon characteristics elaborated de novo by the primary afferents in culture were systematically regulated by the sensory endorgan. Apparent peripheral nervous system (PNS)-like and central nervous system (CNS)-like axonal profiles were established in our cocultures allowing an analysis of putative PNS/CNS axon length ratios. As predicted from the in vivo organization, PNS-like axon bundles elaborated by apical cocultures were longer than their basal counterparts and this phenotype was methodically altered when neuron explants were cocultured with microisolates from disparate cochlear regions. Thus, location-dependent signals within the organ of Corti may set the "address" of neurons within the spiral ganglion, allowing them to elaborate the appropriate tonotopically associated morphological features in order to carry out their signaling function. J. Comp. Neurol. 524:2182-2207, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Macular ganglion cell imaging study: glaucoma diagnostic accuracy of spectral-domain optical coherence tomography.

PubMed

Jeoung, Jin Wook; Choi, Yun Jeong; Park, Ki Ho; Kim, Dong Myung

2013-07-01

We evaluated the diagnostic accuracy of macular ganglion cell-inner plexiform layer (GCIPL) measurements using a high-definition optical coherence tomography (Cirrus HD-OCT) ganglion cell analysis algorithm for detecting early and moderate-to-severe glaucoma. Totals of 119 normal subjects and 306 glaucoma patients (164 patients with early glaucoma and 142 with moderate-to-severe glaucoma) were enrolled from the Macular Ganglion Cell Imaging Study. Macular GCIPL, peripapillary retinal nerve fiber layer (RNFL) thickness, and optic nerve head (ONH) parameters were measured in each subject. Areas under the receiver operating characteristic curves (AUROCs) were calculated and compared. Based on the internal normative database, the sensitivity and specificity for detecting early and moderate-to-severe glaucoma were calculated. There was no statistically significant difference between the AUROCs for the best OCT parameters. For detecting early glaucoma, the sensitivity of the Cirrus GCIPL parameters ranged from 26.8% to 73.2% and that of the Cirrus RNFL parameters ranged from 6.1% to 61.6%. For the early glaucoma group, the best parameter from the GCIPL generally had a higher sensitivity than those of the RNFL and ONH parameters with comparable specificity (P < 0.05, McNemar's test). There were no significant differences between the AUROCs for Cirrus GCIPL, RNFL, and ONH parameters, indicating that these maps have similar diagnostic potentials for glaucoma. The minimum GCIPL showed better glaucoma diagnostic performance than the other parameters at comparable specificities. However, other GCIPL parameters showed performances comparable to those of the RNFL parameters.

Separability of stimulus parameter encoding by on-off directionally selective rabbit retinal ganglion cells

PubMed Central

Nowak, Przemyslaw; Dobbins, Allan C.; Gawne, Timothy J.; Grzywacz, Norberto M.

2011-01-01

The ganglion cell output of the retina constitutes a bottleneck in sensory processing in that ganglion cells must encode multiple stimulus parameters in their responses. Here we investigate encoding strategies of On-Off directionally selective retinal ganglion cells (On-Off DS RGCs) in rabbits, a class of cells dedicated to representing motion. The exquisite axial discrimination of these cells to preferred vs. null direction motion is well documented: it is invariant with respect to speed, contrast, spatial configuration, spatial frequency, and motion extent. However, these cells have broad direction tuning curves and their responses also vary as a function of other parameters such as speed and contrast. In this study, we examined whether the variation in responses across multiple stimulus parameters is systematic, that is the same for all cells, and separable, such that the response to a stimulus is a product of the effects of each stimulus parameter alone. We extracellularly recorded single On-Off DS RGCs in a superfused eyecup preparation while stimulating them with moving bars. We found that spike count responses of these cells scaled as independent functions of direction, speed, and luminance. Moreover, the speed and luminance functions were common across the whole sample of cells. Based on these findings, we developed a model that accurately predicted responses of On-Off DS RGCs as products of separable functions of direction, speed, and luminance (r = 0.98; P < 0.0001). Such a multiplicatively separable encoding strategy may simplify the decoding of these cells' outputs by the higher visual centers. PMID:21325684

Petrosal ganglion: a more complex role than originally imagined.

PubMed

Retamal, Mauricio A; Reyes, Edison P; Alcayaga, Julio

2014-01-01

The petrosal ganglion (PG) is a peripheral sensory ganglion, composed of pseudomonopolar sensory neurons that innervate the posterior third of the tongue and the carotid sinus and body. According to their electrical properties PG neurons can be ascribed to one of two categories: (i) neurons with action potentials presenting an inflection (hump) on its repolarizing phase and (ii) neurons with fast and brisk action potentials. Although there is some correlation between the electrophysiological properties and the sensory modality of the neurons in some species, no general pattern can be easily recognized. On the other hand, petrosal neurons projecting to the carotid body are activated by several transmitters, with acetylcholine and ATP being the most conspicuous in most species. Petrosal neurons are completely surrounded by a multi-cellular sheet of glial (satellite) cells that prevents the formation of chemical or electrical synapses between neurons. Thus, PG neurons are regarded as mere wires that communicate the periphery (i.e., carotid body) and the central nervous system. However, it has been shown that in other sensory ganglia satellite glial cells and their neighboring neurons can interact, partly by the release of chemical neuro-glio transmitters. This intercellular communication can potentially modulate the excitatory status of sensory neurons and thus the afferent discharge. In this mini review, we will briefly summarize the general properties of PG neurons and the current knowledge about the glial-neuron communication in sensory neurons and how this phenomenon could be important in the chemical sensory processing generated in the carotid body.

Mise à jour sur le nouveau vaccin 9-valent pour la prévention du virus du papillome humain

PubMed Central

Yang, David Yi; Bracken, Keyna

2016-01-01

Résumé Objectif Informer les médecins de famille quant à l’efficacité, à l’innocuité, aux effets sur la santé publique et à la rentabilité du vaccin 9-valent contre le virus du papillome humain (VPH). Qualité des données Des articles pertinents publiés dans PubMed jusqu’en mai 2015 ont été examinés et analysés. La plupart des données citées sont de niveau I (essais randomisés et contrôlés et méta-analyses) ou de niveau II (études transversales, cas-témoins et épidémiologiques). Des rapports et recommandations du gouvernement sont aussi cités en référence. Message principal Le vaccin 9-valent contre le VPH, qui offre une protection contre les types 6, 11, 16, 18, 31, 33, 45, 52 et 58 du VPH, est sûr et efficace et réduira encore plus l’incidence des infections à VPH, de même que les cas de cancer lié au VPH. Il peut également protéger indirectement les personnes non immunisées par l’entremise du phénomène d’immunité collective. Un programme d’immunisation efficace peut prévenir la plupart des cancers du col de l’utérus. Les analyses montrent que la rentabilité du vaccin 9-valent chez les femmes est comparable à celle du vaccin quadrivalent original contre le VPH (qui protège contre les types 6, 11, 16 et 18 du VPH) en usage à l’heure actuelle. Toutefois, il faut investiguer plus en profondeur l’utilité d’immuniser les garçons avec le vaccin 9-valent contre le VPH. Conclusion en plus d’être sûr, le vaccin 9-valent protège mieux contre le VPH que le vaccin quadrivalent. Une analyse coûtefficacité en favorise l’emploi, du moins chez les adolescentes. Ainsi, les médecins devraient recommander le vaccin 9-valent à leurs patients plutôt que le vaccin quadrivalent contre le VPH.

Connaissances des médecins généralistes de Mohammedia (Maroc) concernant le dépistage du cancer du sein

PubMed Central

Zine, Karima; Nani, Samira; Lahmadi, Imad Ait; Maaroufi, Abderrahmane

2016-01-01

Introduction Le cancer du sein représente un problème de santé publique majeur au Maroc. C'est le premier cancer chez la femme. L'objectif de ce travail était d'évaluer les connaissances des médecins généralistes (MG) en matière de dépistage du cancer du sein dans la préfecture de Mohammedia Maroc. Méthodes Nous avons mené une étude transversale, descriptive, exhaustive incluant les 97 MG exerçant dans les établissements de soins de santé de base du secteur public et privé de la province de Mohammedia. Résultats Le taux de participation était de 87%. L'âge moyen des MG était de 49,6 ± 8,1. Quatre-vingt pour cent (n=55) des MG ont donné une incidence incorrecte, 77,6% (n=85) ont reconnu l'existence d'un plan national de prévention et de contrôle du cancer (PNPCC) au Maroc, et 67,1 des MG ont rapporté l'existence d'un registre du cancer au Maroc. Le secteur d'activité était associé significativement avec les connaissances des MG sur le PNPCC et sur l'existence d'un guide de détection précoce du cancer du sein avec respectivement (p=0,003 et p=0,001). Une association significative entre l'ancienneté et l'existence d'un guide de détection précoce du cancer du sein et d'un registre du cancer du sein a été retrouvée avec (respectivement p=0,005 et p=0.002). Conclusion À la lumière de ces résultats il faudra renforcer les connaissances et les pratiques des MG par la promotion de la formation initiale et continue sur le dépistage. PMID:27800098

Suprascapular Nerve Entrapment Caused by Protrusion of an Intraosseous Ganglion of the Glenoid into the Spinoglenoid Notch: A Rare Cause of Posterior Shoulder Pain

PubMed Central

Terabayashi, Nobuo; Nishimoto, Yutaka; Akiyama, Haruhiko

2017-01-01

We describe a case of suprascapular nerve entrapment caused by protrusion of an intraosseous ganglion of the glenoid into the spinoglenoid notch. A 47-year-old man with left shoulder pain developed an intraosseous cyst in the left glenoid, which came into contact with the suprascapular nerve. The area at which the patient experienced spontaneous shoulder pain was innervated by the suprascapular nerve, and 1% xylocaine injection into the spinoglenoid notch under ultrasonographic guidance relieved the pain. Therefore, we concluded that the protrusion of an intraosseous cyst of the glenoid into the spinoglenoid notch was a cause of the pain, and performed curettage. Consequently, the shoulder pain was resolved promptly without suprascapular nerve complications, and the cyst was histologically diagnosed as an intraosseous ganglion. This case demonstrated that the intraosseous ganglion of the glenoid was a benign lesion but could be a cause of suprascapular nerve entrapment syndrome. Curettage is a useful treatment option for a ganglion inside bone and very close to the suprascapular nerve. PMID:28620557

Unmasking of spiral ganglion neuron firing dynamics by membrane potential and neurotrophin-3.

PubMed

Crozier, Robert A; Davis, Robin L

2014-07-16

Type I spiral ganglion neurons have a unique role relative to other sensory afferents because, as a single population, they must convey the richness, complexity, and precision of auditory information as they shape signals transmitted to the brain. To understand better the sophistication of spiral ganglion response properties, we compared somatic whole-cell current-clamp recordings from basal and apical neurons obtained during the first 2 postnatal weeks from CBA/CaJ mice. We found that during this developmental time period neuron response properties changed from uniformly excitable to differentially plastic. Low-frequency, apical and high-frequency basal neurons at postnatal day 1 (P1)-P3 were predominantly slowly accommodating (SA), firing at low thresholds with little alteration in accommodation response mode induced by changes in resting membrane potential (RMP) or added neurotrophin-3 (NT-3). In contrast, P10-P14 apical and basal neurons were predominately rapidly accommodating (RA), had higher firing thresholds, and responded to elevation of RMP and added NT-3 by transitioning to the SA category without affecting the instantaneous firing rate. Therefore, older neurons appeared to be uniformly less excitable under baseline conditions yet displayed a previously unrecognized capacity to change response modes dynamically within a remarkably stable accommodation framework. Because the soma is interposed in the signal conduction pathway, these specializations can potentially lead to shaping and filtering of the transmitted signal. These results suggest that spiral ganglion neurons possess electrophysiological mechanisms that enable them to adapt their response properties to the characteristics of incoming stimuli and thus have the capacity to encode a wide spectrum of auditory information. Copyright © 2014 the authors 0270-6474/14/349688-15$15.00/0.

Tumor necrosis factor-α stimulation of calcitonin gene-related peptide expression and secretion from rat trigeminal ganglion neurons

PubMed Central

Bowen, Elizabeth J.; Schmidt, Thomas W.; Firm, Christina S.; Russo, Andrew F.; Durham, Paul L.

2006-01-01

Expression of the neuropeptide calcitonin gene-related peptide (CGRP) in trigeminal ganglion is implicated in neurovascular headaches and temporomandibular joint disorders. Elevation of cytokines contributes to the pathology of these diseases. However, a connection between cytokines and CGRP gene expression in trigeminal ganglion nerves has not been established. We have focused on the effects of the cytokine tumor necrosis factorα (TNFα). TNFR1 receptors were found on the majority of CGRP-containing rat trigeminal ganglion neurons. Treatment of cultures with TNFα stimulated CGRP secretion. In addition, the intracellular signaling intermediate from the TNFR1 receptor, ceramide, caused a similar increase in CGRP release. TNFα caused a coordinate increase in CGRP promoter activity. TNFα treatment activated the transcription factor NF-κB, as well as the Jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinase pathways. The importance of TNFα induction of MAP kinase pathways was demonstrated by inhibiting MAP kinases with pharmacological reagents and gene transfer with an adenoviral vector encoding MAP kinase phosphatase-1 (MKP-1). We propose that selective and regulated inhibition of MAP kinases in trigeminal neurons may be therapeutically beneficial for inflammatory disorders involving elevated CGRP levels. PMID:16277606

Ganglion cyst arising from the composite occipito-atlanto-axial joint cavity in a cat.

PubMed

Aikawa, T; Sadahiro, S; Nishimura, M; Miyazaki, Y; Shibata, M

2014-01-01

A four-year-old, female spayed Domestic Longhaired cat was referred for evaluation with a two month history of initial inability to jump progressing to ambulatory tetraparesis. Magnetic resonance imaging studies demonstrated a cystic lesion arising from the composite occipito-atlanto-axial joint cavity and extending to the region of the occipital bone and the axis. The lesion surrounded the spinal canal, causing moderate dorsal spinal cord compression at the atlanto-occipital joint. A dynamic myelographic study demonstrated attenuation of the dorsal contrast column at the atlanto-occipital joint when the cervical spine was positioned in extension. Partial excision of the cyst capsule by a ventral approach resulted in long-term (64 months) resolution of clinical signs. Histological evaluation was consistent with a ganglion cyst. An intra-spinal ganglion cyst arising from the composite occipito-atlanto-axial joint cavity may be considered as an uncommon differential diagnosis for cats with cervical myelopathy.

Effects of nifedipine and captopril on vascular capacitance of ganglion-blocked anesthetized dogs.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1990-03-01

The hemodynamic effects of nifedipine and captopril at doses producing similar reductions in arterial pressure were studied in pentobarbital-anesthetized ventilated dogs after splenectomy during ganglion blockade with hexamethonium. Mean circulatory filling pressure (Pmcf) was determined during transient circulatory arrest induced by acetylcholine at baseline circulating blood volumes and after increases of 5 and 10 mL/kg. Central blood volumes (pulmonary artery to aortic root) were determined from transit times, and separately determined cardiac outputs (right atrium to pulmonary artery) were estimated by thermodilution. Nifedipine (n = 5) increased Pmcf at all circulating blood volumes and reduced total vascular capacitance without a change in total vascular compliance. Central blood volume, right atrial pressure, and cardiac output were increased with induced increases in circulating blood volume. In contrast, captopril (n = 5) did not alter total vascular capacitance, central blood volume, right atrial pressure, or cardiac output at baseline or with increased circulating volume. Thus, at doses producing similar reductions in arterial pressure, nifedipine but not captopril increased venous return and cardiac output in ganglion-blocked dogs.

Delayed-rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells.

PubMed

Weick, Michael; Demb, Jonathan B

2011-07-14

Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5-10 mV) also suppressed firing during subsequent depolarization. This suppression was selectively sensitive to blockers of delayed-rectifier K channels (K(DR)). In somatic membrane patches, we observed tetraethylammonium-sensitive K(DR) currents that activated near -25 mV. Recovery from inactivation occurred at potentials hyperpolarized to V(rest). Brief periods of hyperpolarization apparently remove K(DR) inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. Copyright © 2011 Elsevier Inc. All rights reserved.

Cirque du Monde en tant qu’intervention en santé

PubMed Central

Fournier, Cynthia; Drouin, Mélodie-Anne; Marcoux, Jérémie; Garel, Patricia; Bochud, Emmanuel; Théberge, Julie; Aubertin, Patrice; Favreau, Gil; Fleet, Richard

2014-01-01

Résumé Objectif Présenter le programme Cirque du Monde du Cirque du Soleil et son potentiel en tant qu’intervention en soins de santé de première ligne pour les médecins de famille. Sources des données Une revue de la littérature menée dans les bases de données PubMed, Cochrane Library, PsycINFO, La Presse, Eureka, Google Scholar et Érudit à l’aide des mots-clés circus, social circus, Cirque du Monde et Cirque du Soleil. Une initiative à Montréal nommée Espace Transition qui s’inspire directement de Cirque du Monde. Communication personnelle avec le conseiller principal en formation en cirque social du Cirque du Soleil. Sélection d’études Les 50 premiers articles ou sites Internet répertoriés pour chaque mot-clé dans chacune des bases de données ciblées ont été révisés sur la base des titres et des résumés, s’il s’agissait d’un article, ou sur la base du titre et du contenu de la page, s’il s’agissait d’une page Internet. Ensuite, les articles et les sites Internet qui étudiaient un aspect du cirque social ou qui présentaient une intervention impliquant le cirque étaient retenus pour une révision. Aucune contrainte d’année de publication n’a été appliquée étant donné qu’on cherchait une littérature générale sur le cirque social. Synthèse Aucun article n’a été trouvé sur le cirque social en tant qu’intervention en santé. Nous avons trouvé une étude sur l’utilisation du cirque en tant qu’intervention en milieu scolaire. Cette étude a démontré une augmentation de l’estime personnelle des enfants grâce à l’intervention. Nous avons trouvé une étude sur l’utilisation du cirque en tant qu’intervention sur une réserve amérindienne. Cette étude présente des résultats qualitatifs non spécifiques au programme du cirque social. Les autres articles répertoriés n’étaient que des descriptions du cirque social. Un site web concernant l’utilisation du cirque social pour

The Gastric Ganglion of Octopus vulgaris: Preliminary Characterization of Gene- and Putative Neurochemical-Complexity, and the Effect of Aggregata octopiana Digestive Tract Infection on Gene Expression

PubMed Central

Baldascino, Elena; Di Cristina, Giulia; Tedesco, Perla; Hobbs, Carl; Shaw, Tanya J.; Ponte, Giovanna; Andrews, Paul L. R.

2017-01-01

The gastric ganglion is the largest visceral ganglion in cephalopods. It is connected to the brain and is implicated in regulation of digestive tract functions. Here we have investigated the neurochemical complexity (through in silico gene expression analysis and immunohistochemistry) of the gastric ganglion in Octopus vulgaris and tested whether the expression of a selected number of genes was influenced by the magnitude of digestive tract parasitic infection by Aggregata octopiana. Novel evidence was obtained for putative peptide and non-peptide neurotransmitters in the gastric ganglion: cephalotocin, corticotrophin releasing factor, FMRFamide, gamma amino butyric acid, 5-hydroxytryptamine, molluscan insulin-related peptide 3, peptide PRQFV-amide, and tachykinin–related peptide. Receptors for cholecystokininA and cholecystokininB, and orexin2 were also identified in this context for the first time. We report evidence for acetylcholine, dopamine, noradrenaline, octopamine, small cardioactive peptide related peptide, and receptors for cephalotocin and octopressin, confirming previous publications. The effects of Aggregata observed here extend those previously described by showing effects on the gastric ganglion; in animals with a higher level of infection, genes implicated in inflammation (NFκB, fascin, serpinB10 and the toll-like 3 receptor) increased their relative expression, but TNF-α gene expression was lower as was expression of other genes implicated in oxidative stress (i.e., superoxide dismutase, peroxiredoxin 6, and glutathione peroxidase). Elevated Aggregata levels in the octopuses corresponded to an increase in the expression of the cholecystokininA receptor and the small cardioactive peptide-related peptide. In contrast, we observed decreased relative expression of cephalotocin, dopamine β-hydroxylase, peptide PRQFV-amide, and tachykinin-related peptide genes. A discussion is provided on (i) potential roles of the various molecules in food intake

KYNA analogue SZR72 modifies CFA-induced dural inflammation- regarding expression of pERK1/2 and IL-1β in the rat trigeminal ganglion.

PubMed

Lukács, M; Warfvinge, K; Kruse, L S; Tajti, J; Fülöp, F; Toldi, J; Vécsei, L; Edvinsson, L

2016-12-01

Neurogenic inflammation has for decades been considered an important part of migraine pathophysiology. In the present study, we asked the question if administration of a novel kynurenic acid analogue (SZR72), precursor of an excitotoxin antagonist and anti-inflammatory substance, can modify the neurogenic inflammatory response in the trigeminal ganglion. Inflammation in the trigeminal ganglion was induced by local dural application of Complete Freunds Adjuvant (CFA). Levels of phosphorylated MAP kinase pERK1/2 and IL-1β expression in V1 region of the trigeminal ganglion were investigated using immunohistochemistry and Western blot. Pretreatment with one dose of SZR72 abolished the CFA-induced pERK1/2 and IL-1β activation in the trigeminal ganglion. No significant change was noted in case of repeated treatment with SZR72 as compared to a single dose. This is the first study that demonstrates that one dose of KYNA analog before application of CFA can give anti-inflammatory response in a model of trigeminal activation, opening a new line for further investigations regarding possible effects of KYNA derivates.

Participation des médecins généralistes de la province de Benimellal (Maroc) dans le dépistage du cancer du col

PubMed Central

Nani, Samira; Benallal, Mohamed; Hassoune, Samira; Kissi, Dounia; Maaroufi, Abderrahmane

2013-01-01

Introduction Au Maroc, chaque année il y aurait environ 2000 nouveaux cas de cancer du col et les 2/3 des cas sont pris en charge à un stade très avancé. Nous avons mené une étude transversale, exhaustive incluant les 71 médecins généralistes exerçant dans les établissements de soins de santé de base du secteur public et privé de la province de Benimellal. Le but était d’évaluer leurs connaissances et leur participation au dépistage du cancer du col. Méthodes Nous avons mené une étude transversale, exhaustive incluant les 71 médecins généralistes exerçant dans les établissements de soins de santé de base du secteur public et privé de la province de Benimellal. Le but était d’évaluer leurs connaissances et leur participation au dépistage du cancer du col. Résultats Le niveau de connaissance était relativement modeste, 22 médecins généraliste avaient répondu à la question sur l'incidence du cancer du col au Maroc, Parmi eux (81,8%) avaient donné une réponse incorrecte. L'Herpes Papilloma virus comme facteur de risque du cancer du col a été identifié par seulement 21% des médecins généralistes. La participation au dépistage était également défaillante, 92,8% n'avaient jamais pratiqué le FCV chez leurs patientes à cause principalement du manque de formation (95,5%). Conclusion Les résultats montrent la nécessité d'améliorer les connaissances théoriques et pratique des médecins généralistes concernant le dépistage du cancer du col. PMID:23785557

Séroprévalence et facteurs associés à l’acceptation du Conseil et Dépistage Volontaire du VIH chez l’enfant à Lubumbashi, République Démocratique du Congo

PubMed Central

Ngwej, Dieudonné Tshikwej; Mukuku, Olivier; Malonga, Françoise Kaj; Luboya, Oscar Numbi; Kakoma, Jean-Baptiste Sakatolo; Wembonyama, Stanis Okitotsho

2017-01-01

Résumé Introduction Malgré le dépistage du VIH proposé lors de la naissance ou au cours des consultations préscolaires, la proportion des enfants qui croissent ou décèdent sous statut sérologique au VIH inconnu est importante en République Démocratique du Congo (RDC). L’objectif de cette étude était de déterminer la séroprévalence au cours d’un dépistage volontaire et d’identifier les facteurs associés à l’acceptation du conseil et dépistage du VIH (CDV) en dehors de la maladie ou de toute exposition au VIH dans une population pédiatrique à Lubumbashi, RDC. Méthodes Il s’agissait d’une étude prospective transversale à visée analytique menée du 1er août 2006 au 31 septembre 2007. Elle avait été réalisée dans 4 centres communautaires de CDV répartis dans 4 zones de santé de la ville de Lubumbashi en RDC (Lubumbashi, Ruashi, Kampemba et de Kenya). L’étude avait consisté à faire le dépistage volontaire du VIH chez les enfants de moins de 15 ans. Les caractéristiques sociodémographiques et les paramètres relatifs au conseil et dépistage volontaire ont été étudiés. Les analyses statistiques descriptives usuelles et une régression logistique ont été réalisées. Résultats Sur 463 enfants dépistés du VIH, 41 (8,9%; IC 95%: 6,5%-11,9%) ont été testés positifs. L’acceptation du conseil et dépistage volontaire du VIH en dehors de la maladie ou de l’exposition au VIH était significativement plus élevée lorsque l’enfant était âgé de plus de 2 ans (Odds ratio ajusté (ORa) = 3,6 [IC 95%: 1,1-12,2]), lorsque le statut sérologique du VIH des parents était négatif ou inconnu (ORa = 27,4 [IC 95%: 9,4-80,0]), lorsque l’un ou l’autre ou les deux parents biologiques étaient en vie (ORa = 24,9 [IC 95%: 2,4-250,8]) et lorsque la connaissance du lieu de dépistage était fait par des moyens autres que le professionnel de santé (ORa = 2,9 [IC 95%: 1,0-7,9]). Conclusion Notre étude montre une forte

L'Aventure du LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-06-11

Cette présentation s’adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l’engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro

PubMed Central

Leitmeyer, Katharina; Glutz, Andrea; Radojevic, Vesna; Setz, Cristian; Huerzeler, Nathan; Bumann, Helen; Bodmer, Daniel; Brand, Yves

2015-01-01

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation. PMID:25918725

Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro.

PubMed

Leitmeyer, Katharina; Glutz, Andrea; Radojevic, Vesna; Setz, Cristian; Huerzeler, Nathan; Bumann, Helen; Bodmer, Daniel; Brand, Yves

2015-01-01

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.

Non-destructive analysis of DU content in the NIF hohlraums

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gharibyan, Narek; Moody, Ken J.; Shaughnessy, Dawn A.

2015-12-16

The advantage of using depleted uranium (DU) hohlraums in high-yield deuterium-tritium (DT) shots at the National Ignition Facility (NIF) is addressed by Döppner, et al., in great detail [1]. This DU based hohlraum incorporates a thin layer of DU, ~7 μm thick, on the inner surface along with a thin layer of a gold coating, ~0.7 μm thick, while the outer layer is ~22 μm thick gold. A thickness measurement of the DU layer can be performed using an optical microscope where the total DU weight can be computed provided a uniform DU layer. However, the uniformity of the thicknessmore » is not constant throughout the hohlraum since CAD drawing calculations of the DU weight do not agree with the computed values from optical measurements [2]. Therefore, a non-destructive method for quantifying the DU content in hohlraums has been established by utilizing gamma-ray spectroscopy. The details of this method, along with results from several hohlraums, are presented in this report.« less

Tumor necrosis factor-alpha stimulation of calcitonin gene-related peptide expression and secretion from rat trigeminal ganglion neurons.

PubMed

Bowen, Elizabeth J; Schmidt, Thomas W; Firm, Christina S; Russo, Andrew F; Durham, Paul L

2006-01-01

Expression of the neuropeptide calcitonin gene-related peptide (CGRP) in trigeminal ganglion is implicated in neurovascular headaches and temporomandibular joint disorders. Elevation of cytokines contributes to the pathology of these diseases. However, a connection between cytokines and CGRP gene expression in trigeminal ganglion nerves has not been established. We have focused on the effects of the cytokine tumor necrosis factor-alpha (TNF-alpha). TNFR1 receptors were found on the majority of CGRP-containing rat trigeminal ganglion neurons. Treatment of cultures with TNF-alpha stimulated CGRP secretion. In addition, the intracellular signaling intermediate from the TNFR1 receptor, ceramide, caused a similar increase in CGRP release. TNF-alpha caused a coordinate increase in CGRP promoter activity. TNF-alpha treatment activated the transcription factor NF-kappaB, as well as the Jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinase pathways. The importance of TNF-alpha induction of MAP kinase pathways was demonstrated by inhibiting MAP kinases with pharmacological reagents and gene transfer with an adenoviral vector encoding MAP kinase phosphatase-1 (MKP-1). We propose that selective and regulated inhibition of MAP kinases in trigeminal neurons may be therapeutically beneficial for inflammatory disorders involving elevated CGRP levels.

Computerized tomography-guided sphenopalatine ganglion pulsed radiofrequency treatment in 16 patients with refractory cluster headaches: Twelve- to 30-month follow-up evaluations.

PubMed

Fang, Luo; Jingjing, Lu; Ying, Shen; Lan, Meng; Tao, Wang; Nan, Ji

2016-02-01

Sphenopalatine ganglion percutaneous radiofrequency thermocoagulation treatment can improve the symptoms of cluster headaches to some extent. However, as an ablation treatment, radiofrequency thermocoagulation treatment also has side effects. To preliminarily evaluate the efficacy and safety of a non-ablative computerized tomography-guided pulsed radiofrequency treatment of sphenopalatine ganglion in patients with refractory cluster headaches. We included and analysed 16 consecutive cluster headache patients who failed to respond to conservative therapy from the Pain Management Center at the Beijing Tiantan Hospital between April 2012 and September 2013 treated with pulsed radiofrequency treatment of sphenopalatine ganglion. Eleven of 13 episodic cluster headaches patients and one of three chronic cluster headaches patient were completely relieved of the headache within an average of 6.3 ± 6.0 days following the treatment. Two episodic cluster headache patients and two chronic cluster headache patients showed no pain relief following the treatment. The mean follow-up time was 17.0 ± 5.5 months. All patients enrolled in this study showed no treatment-related side effects or complications. Our data show that patients with refractory episodic cluster headaches were quickly, effectively and safely relieved from the cluster period after computerized tomography-guided pulsed radiofrequency treatment of sphenopalatine ganglion, suggesting that it may be a therapeutic option if conservative treatments fail. © International Headache Society 2015.

Portage vaginal du streptocoque du groupe B chez la femme enceinte au niveau de la région de Marrakech

PubMed Central

Bassir, Ahlam; Dhibou, Hanane; Farah, Majdi; Mohamed, Lharmis; Amal, Addebous; Nabila, Souraa; Abderahim, Aboulfalah; Asmouki, Hamid; Soummani, Abderraouf

2016-01-01

Introduction Le streptocoque du groupe B est le principal agent impliqué dans les infections materno-fœtales, les septicémies et les méningites du nouveau-né à terme. L'objectif est de déterminer le taux de portage maternel du streptocoque du groupe B (SGB) à terme. Méthodes Un prélèvement vaginal a été réalisé de manière prospective chez 275 parturientes lors de l'entrée en salle d'accouchement sur une période de 06 mois. Résultats Le taux de portage était de 20,2%. Le portage était variable en fonction de l’âge gestationnel, il constitue 57.5% entre 37 et 38 semaines d'aménorrhée. Aucun des facteurs de risque n'a était statistiquement prédictif du portage maternel du SGB. Conclusion Le dépistage doit être réalisé à partir de 37 semaines d'aménorrhée, et comme le portage est intermittent, un prélèvement négatif ne garantirait pas que le portage soit négatif à l'accouchement. PMID:27222693

Reliable, responsive pacemaking and pattern generation with minimal cell numbers: the crustacean cardiac ganglion.

PubMed

Cooke, Ian M

2002-04-01

Investigations of the electrophysiology of crustacean cardiac ganglia over the last half-century are reviewed for their contributions to elucidating the cellular mechanisms and interactions by which a small (as few as nine cells) neuronal network accomplishes extremely reliable, rhythmical, patterned activation of muscular activity-in this case, beating of the neurogenic heart. This ganglion is thus a model for pacemaking and central pattern generation. Favorable anatomy has permitted voltage- and space-clamp analyses of voltage-dependent ionic currents that endow each neuron with the intrinsic ability to respond with rhythmical, patterned impulse activity to nonpatterned stimulation. The crustacean soma and initial axon segment do not support impulse generation but integrate input from stretch-sensitive dendrites and electrotonic and chemically mediated synapses on axonal processes in neuropils. The soma and initial axon produce a depolarization-activated, calcium-mediated, sustained potential, the "driver potential," so-called because it drives a train of impulses at the "trigger zone" of the axon. Extreme reliability results from redundancy and the electrotonic coupling and synaptic interaction among all the neurons. Complex modulation by central nervous system inputs and by neurohormones to adjust heart pumping to physiological demands has long been demonstrated, but much remains to be learned about the cellular and molecular mechanisms of action. The continuing relevance of the crustacean cardiac ganglion as a relatively simple model for pacemaking and central pattern generation is confirmed by the rapidly widening documentation of intrinsic potentials such as plateau potentials in neurons of all major animal groups. The suite of ionic currents (a slowly inactivating calcium current and various potassium currents, with variations) observed for the crustacean cardiac ganglion have been implicated in or proven to underlie a majority of the intrinsic potentials

Prevention of Excitotoxicity in Primary Retinal Ganglion Cells by (+)-Pentazocine, a Sigma Receptor-1-Specific Ligand

PubMed Central

Dun, Ying; Thangaraju, Muthusamy; Prasad, Puttur; Ganapathy, Vadivel; Smith, Sylvia B.

2013-01-01

Purpose σRs are non-opioid, non-phencyclidine binding sites with robust neuroprotective properties. Previously, we induced death in the RGC-5 cell line using very high concentrations (1 mM) of the excitatory amino acids glutamate (Glu) and homocysteine (Hcy) and demonstrated that the σR1 ligand (+)-pentazocine ((+)-PTZ) could protect against cell death. The purpose of the present study was to establish a physiologically relevant paradigm for testing the neuroprotective effect of (+)-PTZ in retinal ganglion cells. Methods Primary ganglion cells (1°GCs) were isolated by immunopanning from retinas of 1-day-old mice, maintained in culture for 3 days and then exposed to 10, 20, 25 or 50 µM Glu or 10, 25, 50 or 100 µM Hcy for 6 or 18 h in the presence or absence of (+)-PTZ (0.5, 1, 3 µM). Cell viability was measured using the Live/Dead and ApopTag Fluorescein In Situ Assays. Expression of σR1 was assessed by immunocytochemistry, RT-PCR and western blotting. Morphological appearance of live ganglion cells and their processes was examined over time (0, 3, 6, 18 h) by differential interference contrast (DIC) microscopy following exposure to excitotoxins in the presence or absence of (+)-PTZ. Results 1°GCs showed robust σR1 expression. The cells are exquisitely sensitive to Glu or Hcy toxicity (6 h treatment with 25 or 50 µM Glu or 50 or 100 µM Hcy induced marked cell death). 1°GCs pre-treated 1 h with (+)-PTZ followed by 18 h co-treatment with 25 µM Glu and (+)-PTZ showed a marked decrease in cell death: (25 µM Glu alone: 50%; 25 µM Glu/0.5 µM (+)-PTZ: 38%; 25 µM Glu/1 µM (+)-PTZ: 20%; 25 µM Glu/3 µM (+)-PTZ: 18%). Similar results were obtained with Hcy. σR1 mRNA and protein levels did not change in the presence of the excitotoxins. DIC examination of cells exposed to excitotoxins revealed substantial disruption of neuronal processes; co-treatment with (+)-PTZ revealed marked preservation of these processes. The stereoselective effect of (+)-PTZ for �

Empirical Derivation of Correction Factors for Human Spiral Ganglion Cell Nucleus and Nucleolus Count Units.

PubMed

Robert, Mark E; Linthicum, Fred H

2016-01-01

Profile count method for estimating cell number in sectioned tissue applies a correction factor for double count (resulting from transection during sectioning) of count units selected to represent the cell. For human spiral ganglion cell counts, we attempted to address apparent confusion between published correction factors for nucleus and nucleolus count units that are identical despite the role of count unit diameter in a commonly used correction factor formula. We examined a portion of human cochlea to empirically derive correction factors for the 2 count units, using 3-dimensional reconstruction software to identify double counts. The Neurotology and House Histological Temporal Bone Laboratory at University of California at Los Angeles. Using a fully sectioned and stained human temporal bone, we identified and generated digital images of sections of the modiolar region of the lower first turn of cochlea, identified count units with a light microscope, labeled them on corresponding digital sections, and used 3-dimensional reconstruction software to identify double-counted count units. For 25 consecutive sections, we determined that double-count correction factors for nucleus count unit (0.91) and nucleolus count unit (0.92) matched the published factors. We discovered that nuclei and, therefore, spiral ganglion cells were undercounted by 6.3% when using nucleolus count units. We determined that correction factors for count units must include an element for undercounting spiral ganglion cells as well as the double-count element. We recommend a correction factor of 0.91 for the nucleus count unit and 0.98 for the nucleolus count unit when using 20-µm sections. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Modulation of release of [3H]acetylcholine in the major pelvic ganglion of the rat.

PubMed

Somogyi, G T; de Groat, W C

1993-06-01

Cholinergic modulation of [3H]acetylcholine release evoked by electrical stimulation was studied in the rat major pelvic ganglion, which was prelabeled with [3H]choline. Acetylcholine (ACh) release was independent of the frequency of stimulation; 0.3 Hz produced the same volley output as 10 Hz. Tetrodotoxin (1 microM) or omission of Ca2+ from the medium abolished ACh release. The M1 receptor agonist (4-hydroxy-2-butynyl)-1-trimethylammonium m-chlorocarbanilate chloride (McN-A 343, 50 microM) increased release (by 136%), whereas the M2 muscarinic agonist oxotremorine (1 microM) decreased ACh release (by 22%). The muscarinic antagonists, atropine (1 microM) or pirenzepine (M1 selective, 1 microM), did not change ACh release. However, pirenzepine (1 microM) blocked the facilitatory effect of McN-A 343, and atropine (1 microM) blocked the inhibitory effect of oxotremorine. The cholinesterase inhibitor physostigmine (1-5 microM), the nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP, 10 microM), and the nicotinic antagonist D-tubocurarine (50 microM) did not change ACh release. 4-Aminopyridine, a K+ channel blocker, significantly increased the release (by 146%). Seven days after decentralization of the major pelvic ganglion, the evoked release of ACh was abolished. It is concluded that release of ACh occurs from the preganglionic nerve terminals rather than from the cholinergic cell bodies and is not modulated by actions of endogenous ACh on either muscarinic or nicotinic autoreceptors. These data confirm and extend previous electrophysiological findings indicating that synapses in the major pelvic ganglion have primarily a relay function.

Muscarinic receptor-mediated excitation of rat intracardiac ganglion neurons.

PubMed

Hirayama, Michiko; Ogata, Masanori; Kawamata, Tomoyuki; Ishibashi, Hitoshi

2015-08-01

Modulation of the membrane excitability of rat parasympathetic intracardiac ganglion neurons by muscarinic receptors was studied using an amphotericin B-perforated patch-clamp recording configuration. Activation of muscarinic receptors by oxotremorine-M (OxoM) depolarized the membrane, accompanied by repetitive action potentials. OxoM evoked inward currents under voltage-clamp conditions at a holding potential of -60 mV. Removal of extracellular Ca(2+) markedly increased the OxoM-induced current (IOxoM). The inward IOxoM in the absence of extracellular Ca(2+) was fully inhibited by removal of extracellular Na(+), indicating the involvement of non-selective cation channels. The IOxoM was inhibited by organic cation channel antagonists including SKF-96365 and ML-204. The IOxoM was antagonized by muscarinic receptor antagonists with the following potency: 4-DAMP > pirenzepine = darifenacin > methoctramine. Muscarinic toxin 7 (MT-7), a highly selective inhibitor for M1 receptor, produced partial inhibition of the IOxoM. In the presence of MT-7, concentration-inhibition curve of the M3-preferring antagonist darifenacin was shifted to the left. These results suggest the contribution of M1 and M3 receptors to the OxoM response. The IOxoM was inhibited by U-73122, a phospholipase C inhibitor. The membrane-permeable IP3 receptor blocker xestospongin C also inhibited the IOxoM. Furthermore, pretreatment with thapsigargin and BAPTA-AM inhibited the IOxoM, while KN-62, a blocker of Ca(2+)/calmodulin-dependent protein kinase II, had no effect. These results suggest that the activation mechanism involves a PLC pathway, release of Ca(2+) from intracellular Ca(2+) stores and calmodulin. The cation channels activated by muscarinic receptors may play an important role in neuronal membrane depolarization in rat intracardiac ganglion neurons. Copyright © 2015 Elsevier Ltd. All rights reserved.

Long-term outcome and prognostic factors after C2 ganglion decompression in 68 consecutive patients with intractable occipital neuralgia.

PubMed

Choi, Kyu-Sun; Ko, Yong; Kim, Young-Soo; Yi, Hyeong-Joong

2015-01-01

Occipital neuralgia is a rare cause of severe headache characterized by paroxysmal shooting or stabbing pain in the distribution of the greater occipital or lesser occipital nerve. In cases of intractable occipital neuralgia, a definite cause has not been uncovered, so various types of treatment have been applied. The aim of this study is to evaluate the prognostic factors, safety, and long-term clinical efficacy of second cervical (C2) ganglion decompression for intractable occipital neuralgia. Retrospective analysis was performed in 68 patients with medically refractory occipital neuralgia who underwent C2 ganglion decompression. Factors based on patients' demography, pre- and postoperative headache severity/characteristics, medication use, and postoperative complications were investigated. Therapeutic success was defined as pain relief by at least 50 % without ongoing medication. The visual analog scale (VAS) score was significantly reduced between the preoperative and most recent follow-up period. One year later, excellent or good results were achieved in 57 patients (83.9 %), but poor in 11 patients (16.1 %). The long-term outcome after 5 years was only slightly less than the 1-year outcome; 47 of the 68 patients (69.1 %) obtained therapeutic success. Longer duration of headache (over 13 years; p = 0.029) and presence of retro-orbital/frontal radiation (p = 0.040) were significantly associated with poor prognosis. In the current study, C2 ganglion decompression provided durable, adequate pain relief with minimal complications in patients suffering from intractable occipital neuralgia. Due to the minimally invasive and nondestructive nature of this surgical procedure, C2 ganglion decompression is recommended as an initial surgical treatment option for intractable occipital neuralgia before attempting occipital nerve stimulation. However, further study is required to manage the pain recurrence associated with longstanding nerve injury.

Retinal ganglion cell dendritic fields in old-world monkeys are oriented radially.

PubMed

Schall, J D; Perry, V H; Leventhal, A G

1986-03-12

We analyzed the dendritic field morphology of 297 ganglion cells from peripheral regions of monkey retina. Most of the dendritic fields were elongated, and there was a significant tendency for the dendritic fields to be oriented radially, i.e., like the spokes of a wheel with the fovea at the hub. An overrepresentation of radial orientations in the peripheral retina of primates might explain why humans are best able to detect stimuli which are oriented radially using peripheral vision.

Cirque du Monde as a health intervention

PubMed Central

Fournier, Cynthia; Drouin, Mélodie-Anne; Marcoux, Jérémie; Garel, Patricia; Bochud, Emmanuel; Théberge, Julie; Aubertin, Patrice; Favreau, Gil; Fleet, Richard

2014-01-01

Abstract Objective To present Cirque du Soleil’s social circus program, Cirque du Monde, to explore its potential as a primary health care tool for family physicians. Data sources A review of the literature in PubMed, the Cochrane Library, PsycINFO, LaPresse, Eureka, Google Scholar, and Érudit using the key words circus, social circus, Cirque du Monde, and Cirque du Soleil; a Montreal-based initiative, Espace Transition, modeled on Cirque du Monde; and personal communication with Cirque du Soleil’s Social Circus Training Advisor. Study selection The first 50 articles or websites identified for each key word in each of the databases were examined on the basis of their titles and abstracts in the case of articles, and on the basis of their titles and page content in the case of websites. Articles and websites that explored an aspect of social circuses or that described an intervention that involved circuses were then retained for analysis. Because all literature on social circuses was searched, no criterion for year of publication was used. Synthesis No articles on the social circus as a health intervention were found. One study on the use of the circus as an intervention in schools was identified. It demonstrated an increase in self-esteem in the children who took part. One study on the use of the circus in a First Nations community was found; it contained nonspecific, qualitative findings. The other articles identified were merely descriptions of social circuses. One website was identified on the use of the social circus to help youth who had been treated in a hospital setting for major psychiatric disorders to re-enter the community. The team in the pediatric psychiatry department at Centre Hospitalier Universitaire Sainte-Justine, the children’s hospital in Montreal, Que, was contacted; they were leading this project, called Espace Transition. The unpublished preliminary findings of its pilot project demonstrate substantial improvements in overall patient

Inhibitory masking controls the threshold sensitivity of retinal ganglion cells

PubMed Central

Pan, Feng; Toychiev, Abduqodir; Zhang, Yi; Atlasz, Tamas; Ramakrishnan, Hariharasubramanian; Roy, Kaushambi; Völgyi, Béla; Akopian, Abram

2016-01-01

Key points Retinal ganglion cells (RGCs) in dark‐adapted retinas show a range of threshold sensitivities spanning ∼3 log units of illuminance.Here, we show that the different threshold sensitivities of RGCs reflect an inhibitory mechanism that masks inputs from certain rod pathways.The masking inhibition is subserved by GABAC receptors, probably on bipolar cell axon terminals.The GABAergic masking inhibition appears independent of dopaminergic circuitry that has been shown also to affect RGC sensitivity.The results indicate a novel mechanism whereby inhibition controls the sensitivity of different cohorts of RGCs. This can limit and thereby ensure that appropriate signals are carried centrally in scotopic conditions when sensitivity rather than acuity is crucial. Abstract The responses of rod photoreceptors, which subserve dim light vision, are carried through the retina by three independent pathways. These pathways carry signals with largely different sensitivities. Retinal ganglion cells (RGCs), the output neurons of the retina, show a wide range of sensitivities in the same dark‐adapted conditions, suggesting a divergence of the rod pathways. However, this organization is not supported by the known synaptic morphology of the retina. Here, we tested an alternative idea that the rod pathways converge onto single RGCs, but inhibitory circuits selectively mask signals so that one pathway predominates. Indeed, we found that application of GABA receptor blockers increased the sensitivity of most RGCs by unmasking rod signals, which were suppressed. Our results indicate that inhibition controls the threshold responses of RGCs under dim ambient light. This mechanism can ensure that appropriate signals cross the bottleneck of the optic nerve in changing stimulus conditions. PMID:27350405

Myelin-induced inhibition in a spiral ganglion organ culture - Approaching a natural environment in vitro.

PubMed

Kramer, Benedikt; Tropitzsch, Anke; Müller, Marcus; Löwenheim, Hubert

2017-08-15

The performance of a cochlear implant depends on the defined interaction between afferent neurons of the spiral ganglion and the inserted electrode. Neurite outgrowth can be induced by neurotrophins such as brain-derived neurotrophic factor (BDNF) via tropomyosin kinase receptor B (TrkB). However, neurotrophin signaling through the p75 neurotrophin receptor (p75) inhibits neurite outgrowth in the presence of myelin. Organotypic cultures derived from postnatal (P3-5) mice were used to study myelin-induced inhibition in the cochlear spiral ganglion. Neurite outgrowth was analyzed and quantified utilizing an adapted Sholl analysis. Stimulation of neurite outgrowth was quantified after application of BDNF, the selective TrkB agonist 7,8-dihydroxyflavone (7,8-DHF) and a selective inhibitor of the Rho-associated kinase (Y27632), which inhibits the p75 pathway. Myelin-induced inhibition was assessed by application of myelin-associated glycoprotein (MAG-Fc) to stimulate the inhibitory p75 pathway. Inhibition of neurite outgrowth was achieved by the selective TrkB inhibitor K252a. Stimulation of neurite outgrowth was observed after treatment with BDNF, 7,8 DHF and a combination of BDNF and Y27632. The 7,8-DHF-induced growth effects could be inhibited by K252a. Furthermore, inhibition of neurite outgrowth was observed after supplementation with MAG-Fc. Myelin-induced inhibition could be overcome by 7,8-DHF and the combination of BDNF and Y27632. In this study, myelin-induced inhibition of neurite outgrowth was established in a spiral ganglion model. We reveal that 7,8-DHF is a viable novel compound for the stimulation of neurite outgrowth in a myelin-induced inhibitory environment. The combination of TrkB stimulation and ROCK inhibition can be used to overcome myelin inhibition. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Caspases in retinal ganglion cell death and axon regeneration

PubMed Central

Thomas, Chloe N; Berry, Martin; Logan, Ann; Blanch, Richard J; Ahmed, Zubair

2017-01-01

Retinal ganglion cells (RGC) are terminally differentiated CNS neurons that possess limited endogenous regenerative capacity after injury and thus RGC death causes permanent visual loss. RGC die by caspase-dependent mechanisms, including apoptosis, during development, after ocular injury and in progressive degenerative diseases of the eye and optic nerve, such as glaucoma, anterior ischemic optic neuropathy, diabetic retinopathy and multiple sclerosis. Inhibition of caspases through genetic or pharmacological approaches can arrest the apoptotic cascade and protect a proportion of RGC. Novel findings have also highlighted a pyroptotic role of inflammatory caspases in RGC death. In this review, we discuss the molecular signalling mechanisms of apoptotic and inflammatory caspase responses in RGC specifically, their involvement in RGC degeneration and explore their potential as therapeutic targets. PMID:29675270

Polysensory response characteristics of dorsal root ganglion neurones that may serve sensory functions during myocardial ischaemia.

PubMed

Huang, M H; Horackova, M; Negoescu, R M; Wolf, S; Armour, J A

1996-09-01

To determine the response characteristics of dorsal root ganglion neurones that may serve sensory functions during myocardial ischaemia. Extracellular recordings were made from 54 spontaneously active and 5 normally quiescent dorsal root ganglion neurones (T2-T5) in 22 anaesthetized open-chest dogs under control conditions and during epicardial mechanical or chemical stimulation and myocardial ischaemia. The activity of 78% of spontaneously active and all quiescent neurones with left ventricular sensory fields was modified by left ventricular ischaemia. Forty-six spontaneously active neurones (85%) were polysensory with respect to mechanical and chemical stimuli. The 5 quiescent neurones responded only to chemical stimuli. Spontaneously active neurones associated with left ventricular mechanosensory endings (37 neurones) generated four different activity patterns in response to similar mechanical stimuli (high or low pressure active, high-low pressure active, high-low pressure inactive). A fifth group generated activity which was not related to chamber dynamics. Adenosine, adenosine 5'-triphosphate, substance P and bradykinin modified 72, 61, 65 and 63% of the spontaneously active neurones, respectively. Maximum local mechanical or chemical stimuli enhanced activity to similar degrees, as did ischaemia. Each ischaemia-sensitive neurone displayed unique activity patterns in response to similar mechanical or chemical stimuli. Most myocardial ischemia-sensitive dorsal root ganglion neurones associated with epicardial neurites sense mechanical and multiple chemical stimuli, a small population sensing only mechanical or chemical stimuli. Activity patterns generated by these neurones depend on their primary sensory characteristics or those of other neurones that may converge on them, as well as the type and magnitude of the stimuli that impinge upon their sensory fields, both normally and during ischaemia.

Topographic specializations of catecholaminergic cells and ganglion cells and distribution of calcium binding proteins in the crepuscular rock cavy (Kerodon rupestris) retina.

PubMed

Oliveira, Francisco Gilberto; Nascimento-Júnior, Expedito Silva do; Cavalcante, Judney Cley; Guzen, Fausto Pierdoná; Cavalcante, Jeferson de Souza; Soares, Joacil Germano; Cavalcanti, José Rodolfo Lopes de Paiva; Freitas, Leandro Moura de; Costa, Miriam Stela Maris de Oliveira; Andrade-da-Costa, Belmira Lara da Silveira

2018-07-01

The rock cavy (Kerodon rupestris) is a crepuscular Hystricomorpha rodent that has been used in comparative analysis of retinal targets, but its retinal organization remains to be investigated. In order to better characterize its visual system, the present study analyzed neurochemical features related to the topographic organization of catecholaminergic cells and ganglion cells, as well the distribution of calcium-binding proteins in the outer and inner retina. Retinal sections and/or wholemounts were processed using tyrosine hydroxylase (TH), GABA, calbindin, parvalbumin and calretinin immunohistochemistry or Nissl staining. Two types of TH-immunoreactive (TH-IR) cells were found which differ in soma size, dendritic arborization, intensity of TH immunoreactivity and stratification pattern in the inner plexiform layer. The topographic distribution of all TH-IR cells defines a visual streak along the horizontal meridian in the superior retina. The ganglion cells are also distributed in a visual streak and the visual acuity estimated considering their peak density is 4.13 cycles/degree. A subset of TH-IR cells express GABA or calbindin. Calretinin is abundant in most of retinal layers and coexists with calbindin in horizontal cells. Parvalbumin is less abundant and expressed by presumed amacrine cells in the INL and some ganglion cells in the GCL. The topographic distribution of TH-IR cells and ganglion cells in the rock cavy retina indicate a suitable adaptation for using a broad extension of its inferior visual field in aspects that involve resolution, adjustment to ambient light intensity and movement detection without specialized eye movements. Copyright © 2017 Elsevier B.V. All rights reserved.

L'Aventure du LHC

ScienceCinema

None

2018-05-16

Cette présentation s’adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l’engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

Dedicated Caravan Sites for French Gens du Voyage

PubMed Central

2017-01-01

Abstract In France, gens du voyage (“people who travel” or “travellers”) is a term used by the government to categorize various itinerant populations, the majority of which are diverse Romani groups. People categorized as gens du voyage are legally required to reside in particular locations called “dedicated caravan sites.” Parliamentary debates about these dedicated caravan sites have clarified that one of the objectives of such sites is to help fulfill the gens du voyage’s right to health. However, there is a significant gap between the officially stated goals of such sites and the reality of life within them. This paper draws on research finding that the conditions in most dedicated caravan sites do not conform with the rights of gens du voyage to acceptable sanitary conditions and other underlying determinants of health. PMID:29302165

Adrenergic receptors inhibit TRPV1 activity in the dorsal root ganglion neurons of rats.

PubMed

Matsushita, Yumi; Manabe, Miki; Kitamura, Naoki; Shibuya, Izumi

2018-01-01

Transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor channel that responds to multiple types of stimuli, such as heat, acid, mechanical pressure and some vanilloids. Capsaicin is the most commonly used vanilloid to stimulate TRPV1. TRPV1 channels are expressed in dorsal root ganglion neurons that extend to Aδ- and C-fibers and have a role in the transduction of noxious inputs to the skin into the electrical signals of the sensory nerve. Although noradrenergic nervous systems, including the descending antinociceptive system and the sympathetic nervous system, are known to modulate pain sensation, the functional association between TRPV1 and noradrenaline in primary sensory neurons has rarely been examined. In the present study, we examined the effects of noradrenaline on capsaicin-evoked currents in cultured dorsal root ganglion neurons of the rat by the whole-cell voltage clamp method. Noradrenaline at concentrations higher than 0.1 pM significantly reduced the amplitudes of the inward capsaicin currents recorded at -60 mV holding potential. This inhibitory action was reversed by either yohimbine (an α2 antagonist, 10 nM) or propranolol (a β antagonist, 10 nM). The α2 agonists, clonidine (1 pM) and dexmedetomidine (1 pM) inhibited capsaicin currents, and yohimbine (1 nM) reversed the effects of clonidine. The inhibitory action of noradrenaline was not seen in the neurons pretreated with pertussis toxin (100 μg/ml for 24 h) and the neurons dialyzed intracellularly with guanosine 5'- [β-thio] diphosphate (GDPβS, 200 μM), the catalytic subunit of protein kinase A (250 U/ml) or okadaic acid (1 μM). These results suggest that noradrenaline directly acts on dorsal root ganglion neurons to inhibit the activity of TRPV1 depending on the activation of α2-adrenoceptors followed by the inhibition of the adenylate cyclase/cAMP/protein kinase A pathway.

The relationship between neurotrophic factors and CaMKII in the death and survival of retinal ganglion cells.

PubMed

Cooper, N G F; Laabich, A; Fan, W; Wang, X

2008-01-01

The scientific discourse relating to the causes and treatments for glaucoma are becoming reflective of the need to protect and preserve retinal neurons from degenerative changes, which result from the injurious environment associated with this disease. Knowledge, in particular, of the signal transduction pathways which affect death and survival of the retinal ganglion cells is critical to this discourse and to the development of a suitable neurotherapeutic strategy for this disease. The goal of this chapter is to review what is known of the chief suspects involved in initiating the cell death/survival pathways in these cells, and what still remains to be uncovered. The least controversial aspect of the subject relates to the potential role of neurotrophic factors in the protection of the retinal ganglion cells. On the other hand, the postulated triggers for signaling cell death in glaucoma remain controversial. Certainly, the restricted flow of neurotrophic factors has been cited as one possible trigger. However, the connections between glaucoma and other factors present in the retina, such as glutamate, long held to be a prospective culprit in retinal ganglion cell death are still being questioned. Whatever the outcome of this particular debate, it is clear that the downstream intersections between the cell death and survival pathways should provide important foci for future studies whose goal is to protect retinal neurons, situated as they are, in the stressful environment of a cell destroying disease. The evidence for CaMKII being one of these intersecting points is discussed.

High-wattage pulsed irradiation of linearly polarized near-infrared light to stellate ganglion area for burning mouth syndrome.

PubMed

Momota, Yukihiro; Kani, Koichi; Takano, Hideyuki; Matsumoto, Fumihiro; Aota, Keiko; Takegawa, Daisuke; Yamanoi, Tomoko; Kondo, Chika; Tomioka, Shigemasa; Azuma, Masayuki

2014-01-01

The purpose of this study was to apply high-wattage pulsed irradiation of linearly polarized near-infrared light to the stellate ganglion area for burning mouth syndrome (BMS) and to assess the efficacy of the stellate ganglion area irradiation (SGR) on BMS using differential time-/frequency-domain parameters (D parameters). Three patients with BMS received high-wattage pulsed SGR; the response to SGR was evaluated by visual analogue scale (VAS) representing the intensity of glossalgia and D parameters used in heart rate variability analysis. High-wattage pulsed SGR significantly decreased the mean value of VAS in all cases without any adverse event such as thermal injury. D parameters mostly correlated with clinical condition of BMS. High-wattage pulsed SGR was safe and effective for the treatment of BMS; D parameters are useful for assessing efficacy of SGR on BMS.

Recovery of cat retinal ganglion cell sensitivity following pigment bleaching.

PubMed Central

Bonds, A B; Enroth-Cugell, C

1979-01-01

1. The threshold illuminance for small spot stimulation of on-centre cat retinal ganglion cells was plotted vs. time after exposure to adapting light sufficiently strong to bleach significant amounts of rhodopsin. 2. When the entire receptive field of an X- or Y-type ganglion cell is bleached by at most 40%, recovery of the cell's rod-system proceeds in two phases: an early relatively fast one during which the response appears transient, and a late, slower one during which responses become more sustained. Log threshold during the later phase is well fit by an exponential in time (tau = 11.5-38 min). 3. After bleaches of 90% of the underlying pigment, threshold is cone-determined for as long as 40 min. Rod threshold continues to decrease for at least 85 min after the bleach. 4. The rate of recovery is slower after strong than after weak bleaches; 10 and 90% bleaches yield time constants for the later phase of 11.5 and 38 min, respectively. This contrasts with an approximate time constant of 11 min for rhodopsin regeneration following any bleach. 5. The relationship between the initial elevation of log rod threshold extrapolated from the fitted exponential curves and the initial amount of pigment bleached is monotonic, but nonlinear. 6. After a bleaching exposure, the maintained discharge is initially very regular. The firing rate first rises, then falls to the pre-bleach level, with more extended time courses of change in firing rate after stronger exposures. The discharge rate is restored before threshold has recovered fully. 7. The change in the response vs. log stimulus relationship after bleaching is described as a shift of the curve to the right, paired with a decrease in slope of the linear segment of the curve. PMID:521963

Charge-balanced biphasic electrical stimulation inhibits neurite extension of spiral ganglion neurons.

PubMed

Shen, Na; Liang, Qiong; Liu, Yuehong; Lai, Bin; Li, Wen; Wang, Zhengmin; Li, Shufeng

2016-06-15

Intracochlear application of exogenous or transgenic neurotrophins, such as neurotrophin-3 (NT-3) and brain derived neurotrophic factor (BDNF), could promote the resprouting of spiral ganglion neuron (SGN) neurites in deafened animals. These resprouting neurites might reduce the gap between cochlear implant electrodes and their targeting SGNs, allowing for an improvement of spatial resolution of electrical stimulation. This study is to investigate the impact of electrical stimulation employed in CI on the extension of resprouting SGN neurites. We established an in vitro model including the devices delivering charge-balanced biphasic electrical stimulation, and spiral ganglion (SG) dissociated culture treated with BDNF and NT-3. After electrical stimulation with varying durations and intensities, we quantified neurite lengths and Schwann cell densities in SG cultures. Stimulations that were greater than 50μA or longer than 8h significantly decreased SG neurite length. Schwann cell density under 100μA electrical stimulation for 48h was significantly lower compared to that in non-stimulated group. These electrical stimulation-induced decreases of neurite extension and Schwann cell density were attenuated by various types of voltage-dependent calcium channel (VDCC) blockers, or completely prevented by their combination, cadmium or calcium-free medium. Our study suggested that charge-balanced biphasic electrical stimulation inhibited the extension of resprouting SGN neurites and decreased Schwann cell density in vitro. Calcium influx through multiple types of VDCCs was involved in the electrical stimulation-induced inhibition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Soluble Adenylyl Cyclase Is Required for Retinal Ganglion Cell and Photoreceptor Differentiation

PubMed Central

Shaw, Peter X.; Fang, Jiahua; Sang, Alan; Wang, Yan; Kapiloff, Michael S.; Goldberg, Jeffrey L.

2016-01-01

Purpose We have previously demonstrated that soluble adenylyl cyclase (sAC) is necessary for retinal ganglion cell (RGC) survival and axon growth. Here, we further investigate the role of sAC in neuronal differentiation during retinal development. Methods Chx10 or Math5 promoter-driven Cre-Lox recombination were used to conditionally delete sAC from early and intermediate retinal progenitor cells during retinal development. We examined cell type–specific markers expressed by retinal cells to estimate their relative numbers and characterize retinal laminar morphology by immunofluorescence in adult and newborn mice. Results Retinal ganglion cell and amacrine cell markers were significantly lower in the retinas of adult Math5cre/sACfl/fl and Chx10cre/sACfl/fl mice than in those of wild-type controls. The effect on RGC development was detectable as early as postnatal day 1 and deleting sAC in either Math5- or Chx10-expressing retinal progenitor cells also reduced nerve fiber layer thickness into adulthood. The thickness of the photoreceptor layer was slightly but statistically significantly decreased in both the newborn Chx10cre/sACfl/fl and Math5cre/sACfl/fl mice, but this reduction and abnormal morphology persisted in the adults in only the Chx10cre/sACfl/fl mice. Conclusions sAC plays an important role in the early retinal development of RGCs as well as in the development of amacrine cells and to a lesser degree photoreceptors. PMID:27679853

Polymorphisme de l'apolipoprotéine E dans la population du nord du Maroc: fréquence et influence sur les paramètres lipidiques

PubMed Central

Benyahya, Fatiha; Barakat, Amina; Ghailani, Naima; Bennani, Mohcine

2013-01-01

Introduction L'objectif de ce travail est de déterminer les fréquences alléliques et génotypiques des sites polymorphes situés dans le gène de l'apolipoprotéine E (apo E) ainsi que leur impact sur les paramètres cliniques et lipidiques dans un échantillon de la population du nord du Maroc cliniquement diagnostiqué ADH. Méthodes Le génotype de l'apo E a été analysé par séquençage direct chez 46 patients cliniquement diagnostiqués ADH selon les critères standards. Résultats Les fréquences des allèles epsilon 3, epsilon 2 et epsilon 4 ont été respectivement 78.3%, 2.2% et 19.6%. La fréquence de l'allèle epsilon 4 est très élevée chez la population du nord du Maroc en comparaison avec les populations des autres régions marocaines. Elle est similaire à celle rapportée dans les pays de l'Europe du nord. Les taux du cholestérol total, du cholestérol LDL ainsi que la présence des xanthomes et les maladies cardiovasculaires ne différent pas entre les génotypes de l'apoE. En revanche, les résultats ont montré une influence de l'allèle epsilon4 sur le taux des triglycérides chez les sujets obèses. Conclusion Le génotype de l'apoE ne peut expliquer le phénotype clinique et biochimique présenté par des patients du Nord du Maroc cliniquement diagnostiqués ADH. PMID:24396563

Curcumin Attenuates Staurosporine-Mediated Death of Retinal Ganglion Cells

PubMed Central

Burugula, Balabharathi; Ganesh, Bhagyalaxmi S.

2011-01-01

Purpose. Staurosporine (SS) causes retinal ganglion cell (RGC) death in vivo, but the underlying mechanisms have been unclear. Since previous studies on RGC-5 cells indicated that SS induces cell death by elevating proteases, this study was undertaken to investigate whether SS induces RGC loss by elevating proteases in the retina, and curcumin prevents SS-mediated death of RGCs. Methods. Transformed mouse retinal ganglion-like cells (RGC-5) were treated with 2.0 μM SS and various doses of curcumin. Two optimal doses of SS (12.5 and 100 nM) and curcumin (2.5 and 10 μM) were injected into the vitreous of C57BL/6 mice. Matrix metalloproteinase (MMP)-9, tissue plasminogen activator (tPA), and urokinase plasminogen activator (uPA) activities were assessed by zymography assays. Viability of RGC-5 cells was assessed by MTT assays. RGC and amacrine cell loss in vivo was assessed by immunostaining with Brn3a and ChAT antibodies, respectively. Frozen retinal cross sections were immunostained for nuclear factor-κB (NF-κB). Results. Staurosporine induced uPA and tPA levels in RGC-5 cells, and MMP-9, uPA, and tPA levels in the retinas and promoted the death of RGC-5 cells in vitro and RGCs and amacrine cells in vivo. In contrast, curcumin attenuated RGC and amacrine cell loss, despite elevated levels of proteases. An NF-κB inhibitory peptide reversed curcumin-mediated protective effect on RGC-5 cells, but did not inhibit protease levels. Curcumin did not inhibit protease levels in vivo, but attenuated RGC and amacrine cell loss by restoring NF-κB expression. Conclusions. The results show that curcumin attenuates RGC and amacrine cell death despite elevated levels of proteases and raises the possibility that it may be used as a plausible adjuvant therapeutic agent to prevent the loss of these cells in retinal degenerative conditions. PMID:21498608

Mechanisms regulating plasminogen activators in transformed retinal ganglion cells

PubMed Central

Rock, Nathan; Chintala, Shravan K.

2008-01-01

Irreversible loss of retinal ganglion cells (RGCs) is a major clinical issue in glaucoma, but the mechanisms that lead to RGC death are currently unclear. We have previously reported that elevated levels of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) cause the death of RGCs in vivo and transformed retinal ganglion cells (RGC-5) in vitro. Yet, it is unclear how secreted proteases such as tPA and uPA directly cause RGCs' death. In this study, by employing RGC-5 cells, we report that tPA and uPA elicit their direct effect through the low-density lipoprotein-related receptor-1 (LRP-1). We also show that blockade of protease-LRP-1 interaction leads to a compete reduction in autocrine synthesis of tPA and uPA, and prevents protease-mediated death of RGC-5 cells. RGC-5 cells were cultured in serum-free medium and treated with 2.0 uM Staurosporine to induce their differentiation. Neurite outgrowth was observed by a phase contrast microscope and quantified by NeuroJ imaging software. Proteolytic activities of tPA and uPA were determined by zymography assays. Cell viability was determined by MTT assays. Compared to untreated RGC-5 cells, cells treated with Staurosporine differentiated, synthesized and secreted elevated levels of tPA and uPA, and underwent cell death. In contrast, when RGC-5 cells were treated with Staurosporine along with the receptor associated protein (RAP), proteolytic activities of both tPA and uPA were significantly reduced. Under these conditions, a significant number of RGC-5 cells survived and showed increased neurite outgrowth. These results indicate that LRP-1 regulates autocrine synthesis of tPA and uPA in RGC-5 cells and suggest that the use of RAP to antagonize the effect of proteases may be a way to prevent RGC death in glaucoma. PMID:18243176

Étude des déterminants individuels de l’adoption du dossier de santé électronique du Québec

PubMed Central

Mezni, H; M-P, Gagnon; Duplantie, J

2016-01-01

Résumé Objectif Selon des études précédentes, les dossiers de santé électroniques peuvent améliorer l’efficacité, la sécurité et la qualité de la prise en charge médicale. Cependant, les prestataires de soins restent réticents quant à son utilisation, ce qui limite son impact sur le système de santé. La présente étude avait pour objectif d’évaluer les perceptions des médecins face au dossier de santé du Québec. Méthodes À partir d’une revue de la littérature sur les facteurs influençant l’adoption des nouvelles technologies de l’information et des communications (NTIC) en général et de la cybersanté en particulier, nous avons élaboré un questionnaire semi-structuré. Au total, 12 médecins utilisateurs potentiels du dossier de santé du Québec (DSQ) ont complété et retourné le questionnaire. Par la suite, nous avons opéré une analyse thématique de contenu, suivie par une théorisation des concepts obtenus. Résultats L’intention d’adopter le DSQ est influencée positivement par l’utilité perçue, la facilité d’utilisation perçue, la démonstrabilité des résultats, la compatibilité du système avec la pratique et l’autoefficacité informatique perçue par les médecins. Inversement, la résistance au changement influence négativement l’adoption du DSQ par les médecins. Conclusion L’identification des déterminants de l’adoption du dossier de santé du Québec est cruciale pour les responsables du secteur de la santé au Québec. Il sera ainsi possible de saisir les attentes des utilisateurs potentiels et d’ajuster les stratégies d’implantation en vue de favoriser une meilleure intégration de cette technologie dans les pratiques médicales. PMID:27867453

Le kyste hydatique du cordon spermatique: une localisation exceptionnelle

PubMed Central

Hamdane, Mohamed Moncef; Bougrine, Fethi; Msakni, Issam; Dhaoui-Ghozzi, Amen; Bouziani, Ammar

2011-01-01

L’ hydatidose est une anthropo-zoonose due au développement chez l'homme de la forme larvaire du taenia Echinococcus granulosis. La plupart des kystes hydatiques se localisent dans le foie et les poumons. Le kyste hydatique du cordon spermatique est extrêmement rare avec seulement 4 cas rapportés dans la littérature. Les auteurs rapportent dans cet article un nouveau cas d'hydatidose du cordon spermatique. Il s'agissait d'un homme de 40 ans qui consultait pour des douleurs scrotales évoluant depuis huit mois. L'examen clinique a mis en évidence une tuméfaction mobile, inguino-scrotale, droite. L’échographie testiculaire a objectivé une hernie inguinale droite associée à deux kystes épididymaires bilatéraux. Le patient a été opéré pour cure de son hernie avec découverte en per-opératoire d'un kyste du cordon spermatique qui a été réséqué. L'examen anatomopathologique a conclu à une hydatidose du cordon spermatique. PMID:22384304

Acceptabilité du test VIH proposé aux nourrissons dans les services pédiatriques, en Côte d'Ivoire, Significations pour la couverture du diagnostic pédiatrique

PubMed Central

Oga, Maxime; Brou, Hermann; Dago-Akribi, Hortense; Coffie, Patrick; Amani-Bossé, Clarisse; Ékouévi, Didier; Yapo, Vincent; Menan, Hervé; Ndondoki, Camille; Timité-Konan, M.; Leroy, Valériane

2014-01-01

Résumé Problème: Le dépistage VIH chez les enfants a rarement été au centre des préoccupations des chercheurs. Quand le dépistage pédiatrique a retenu l'attention, cela a été pour éclairer seulement sur les performances diagnostiques en ignorant même que le test pédiatrique comme bien d'autres peut s'accepter ou se refuser. Cet article met au cœur de son analyse les raisons qui peuvent expliquer qu'on accepte ou qu'on refuse de faire dépister son enfant. Objectif: Etudier chez les parents, les mères, les facteurs explicatifs de l'acceptabilité du test VIH des nourrissons de moins de six mois. Méthodes: Entretien semi-directif à passages répétés avec les parents de nourrissons de moins de six mois dans les formations sanitaires pour la pesée/vaccination et les consultations pédiatriques avec proposition systématique d'un test VIH pour leur nourrisson. Résultats: Nous retenons que la réalisation effective du test pédiatrique du VIH chez le nourrisson repose sur trois éléments. Primo, le personnel de santé par son discours (qui dénote de ses connaissances et perceptions même sur l'infection) orienté vers les mères influence leur acceptation ou non du test. Secundo, la mère qui par ses connaissances et perceptions même sur le VIH, dont le statut particulier, l'impression de bien-être chez elle et son enfant influence toute réalisation du test pédiatrique VIH. Tertio, l'environnement conjugal de la mère, particulièrement caractérisé par les rapports au sein du couple, sur la facilité de parler du test VIH et sa réalisation chez les deux parents ou chez la mère seulement sont autant de facteurs qui influencent la réalisation effective du dépistage du VIH chez l'enfant. Le principe préventif du VIH, et le désir de faire tester l'enfant ne suffisent pas à eux seuls pour aboutir à sa réalisation effective, selon certaines mères confrontées au refus du conjoint. A l'opposé, les autres mères refusant la r

Beyond Darcy's law: The role of phase topology and ganglion dynamics for two-fluid flow

DOE PAGES

Armstrong, Ryan T.; McClure, James E.; Berrill, Mark A.; ...

2016-10-27

Relative permeability quantifies the ease at which immiscible phases flow through porous rock and is one of the most well known constitutive relationships for petroleum engineers. It however exhibits troubling dependencies on experimental conditions and is not a unique function of phase saturation as commonly accepted in industry practices. The problem lies in the multi-scale nature of the problem where underlying disequilibrium processes create anomalous macroscopic behavior. Here we show that relative permeability rate dependencies are explained by ganglion dynamic flow. We utilize fast X-ray micro-tomography and pore-scale simulations to identify unique flow regimes during the fractional flow of immisciblemore » phases and quantify the contribution of ganglion flux to the overall flux of non-wetting phase. We anticipate our approach to be the starting point for the development of sophisticated multi-scale flow models that directly link pore-scale parameters to macro-scale behavior. Such models will have a major impact on how we recover hydrocarbons from the subsurface, store sequestered CO 2 in geological formations, and remove non-aqueous environmental hazards from the vadose zone.« less

Effects of Icariside II on Corpus Cavernosum and Major Pelvic Ganglion Neuropathy in Streptozotocin-Induced Diabetic Rats

PubMed Central

Bai, Guang-Yi; Zhou, Feng; Hui, Yu; Xu, Yong-De; Lei, Hong-En; Pu, Jin-Xian; Xin, Zhong-Cheng

2014-01-01

Diabetic erectile dysfunction is associated with penile dorsal nerve bundle neuropathy in the corpus cavernosum and the mechanism is not well understood. We investigated the neuropathy changes in the corpus cavernosum of rats with streptozotocin-induced diabetes and the effects of Icariside II (ICA II) on improving neuropathy. Thirty-six 8-week-old Sprague-Dawley rats were randomly distributed into normal control group, diabetic group and ICA-II treated group. Diabetes was induced by a one-time intraperitoneal injection of streptozotocin (60 mg/kg). Three days later, the diabetic rats were randomly divided into 2 groups including a saline treated placebo group and an ICA II-treated group (5 mg/kg/day, by intragastric administration daily). Twelve weeks later, erectile function was measured by cavernous nerve electrostimulation with real time intracorporal pressure assessment. The penis was harvested for the histological examination (immunofluorescence and immunohistochemical staining) and transmission electron microscopy detecting. Diabetic animals exhibited a decreased density of dorsal nerve bundle in penis. The neurofilament of the dorsal nerve bundle was fragmented in the diabetic rats. There was a decreased expression of nNOS and NGF in the diabetic group. The ICA II group had higher density of dorsal nerve bundle, higher expression of NGF and nNOS in the penis. The pathological change of major pelvic nerve ganglion (including the microstructure by transmission electron microscope and the neurite outgrowth length of major pelvic nerve ganglion tissue cultured in vitro) was greatly attenuated in the ICA II-treated group (p < 0.01). ICA II treatment attenuates the diabetes-related impairment of corpus cavernosum and major pelvic ganglion neuropathy in rats with Streptozotocin-Induced Diabetes. PMID:25517034

Older age at diagnosis of Hirschsprung disease decreases risk of postoperative enterocolitis, but resection of additional ganglionated bowel does not.

PubMed

Haricharan, Ramanath N; Seo, Jeong-Meen; Kelly, David R; Mroczek-Musulman, Elizabeth C; Aprahamian, Charles J; Morgan, Traci L; Georgeson, Keith E; Harmon, Carroll M; Saito, Jacqueline M; Barnhart, Douglas C

2008-06-01

This study was conducted to determine the effect of age at diagnosis and length of ganglionated bowel resected on postoperative Hirschsprung-associated enterocolitis (HAEC). Children who underwent endorectal pull-through (ERPT) between January 1993 and December 2004 were retrospectively reviewed. t Test, analysis of variance, Kaplan-Meier, and Cox's proportional hazards analyses were performed. Fifty-two children with Hirschsprung disease (median age, 25 days; range, 2 days-16 years) were included. Nineteen (37%) had admissions for HAEC. Proportional hazards regression showed that HAEC admissions decreased by 30% with each doubling of age at diagnosis (P = .03) and increased 9-fold when postoperative stricture was present (P < .01), after controlling for type of ERPT, trisomy 21, transition zone level, and preoperative enterocolitis. Thirty-six children, with age at initial operation less than 6 months, were grouped based on length of ganglionated bowel excised (A [5 cm] and B [>5 cm]). No significant difference in the number of HAEC admissions during initial 2 years post-ERPT was seen between groups A (n = 18) and B (n = 18). The study had a power of 0.8 to detect a difference of 1 admission over 2 years. Children diagnosed with Hirschsprung disease at younger ages are at a greater risk for postoperative enterocolitis. Excising a longer margin of ganglionated bowel (>5 cm) does not seem to be beneficial in decreasing HAEC admissions.

The Sigma Receptor Ligand (+)-Pentazocine Prevents Apoptotic Retinal Ganglion Cell Death induced in vitro by Homocysteine and Glutamate

PubMed Central

Martin, Pamela Moore; Ola, Mohammad S.; Agarwal, Neeraj; Ganapathy, Vadivel; Smith, Sylvia B.

2013-01-01

Recent studies demonstrated that the excitotoxic amino acid homocysteine induces apoptotic death of retinal ganglion cells in vivo. In the present study, an in vitro rat retinal ganglion cell (RGC-5) culture system was used to analyze the toxicity of acute exposure to high levels of homocysteine, the mechanism of homocysteine-induced toxicity and the usefulness of σR1 ligands as neuroprotectants. When cultured RGC-5 cells were subjected to treatment with 1 mM D, L- homocysteine, a significant increase in cell death was detected by TUNEL analysis and analysis of activated caspase. When cells were treated with homocysteine- or glutamate in the presence of MK-801, an antagonist of the NMDA receptor, the cell death was inhibited significantly. In contrast, NBQX, an antagonist of the AMPA/Kainate receptor, and nifedipine, a calcium channel blocker, did not prevent the homocysteine- or glutamate-induced cell death. Semi-quantitative RT-PCR and immunocytochemical analysis demonstrated that RGC-5 cells exposed to homocysteine or glutamate express type 1 sigma receptor at levels similar to control cells. Treatment of RGC-5 cells with 3 µM or 10 µM concentrations of the σR1-specific ligand (+)-pentazocine inhibited significantly the apoptotic cell death induced by homocysteine or glutamate. The results suggest that homocysteine is toxic to ganglion cells in vitro, that the toxicity is mediated via NMDA receptor activation, and that the σR1-specific ligand (+)-pentazocine can block the RGC-5 cell death induced by homocysteine and glutamate. PMID:15046867

Retinal Astrocytes and GABAergic Wide-Field Amacrine Cells Express PDGFRα: Connection to Retinal Ganglion Cell Neuroprotection by PDGF-AA.

PubMed

Takahama, Shokichi; Adetunji, Modupe O; Zhao, Tantai; Chen, Shan; Li, Wei; Tomarev, Stanislav I

2017-09-01

Our previous experiments demonstrated that intravitreal injection of platelet-derived growth factor-AA (PDGF-AA) provides retinal ganglion cell (RGC) neuroprotection in a rodent model of glaucoma. Here we used PDGFRα-enhanced green fluorescent protein (EGFP) mice to identify retinal cells that may be essential for RGC protection by PDGF-AA. PDGFRα-EGFP mice expressing nuclear-targeted EGFP under the control of the PDGFRα promoter were used. Localization of PDGFRα in the neural retina was investigated by confocal imaging of EGFP fluorescence and immunofluorescent labeling with a panel of antibodies recognizing different retinal cell types. Primary cultures of mouse RGCs were produced by immunopanning. Neurobiotin injection of amacrine cells in a flat-mounted retina was used for the identification of EGFP-positive amacrine cells in the inner nuclear layer. In the mouse neural retina, PDGFRα was preferentially localized in the ganglion cell and inner nuclear layers. Immunostaining of the retina demonstrated that astrocytes in the ganglion cell layer and a subpopulation of amacrine cells in the inner nuclear layer express PDGFRα, whereas RGCs (in vivo or in vitro) did not. PDGFRα-positive amacrine cells are likely to be Type 45 gamma-aminobutyric acidergic (GABAergic) wide-field amacrine cells. These data indicate that the neuroprotective effect of PDGF-AA in a rodent model of glaucoma could be mediated by astrocytes and/or a subpopulation of amacrine cells. We suggest that after intravitreal injection of PDGF-AA, these cells secrete factors protecting RGCs.

Brain stem hypoplasia associated with Cri-du-Chat syndrome.

PubMed

Hong, Jin Ho; Lee, Ha Young; Lim, Myung Kwan; Kim, Mi Young; Kang, Young Hye; Lee, Kyung Hee; Cho, Soon Gu

2013-01-01

Cri-du-Chat syndrome, also called the 5p-syndrome, is a rare genetic abnormality, and only few cases have been reported on its brain MRI findings. We describe the magnetic resonance imaging findings of a 1-year-old girl with Cri-du-Chat syndrome who showed brain stem hypoplasia, particularly in the pons, with normal cerebellum and diffuse hypoplasia of the cerebral hemispheres. We suggest that Cri-du-Chat syndrome chould be suspected in children with brain stem hypoplasia, particularly for those with high-pitched cries.

Allogeneic Transplantation of Müller-Derived Retinal Ganglion Cells Improves Retinal Function in a Feline Model of Ganglion Cell Depletion

PubMed Central

Becker, Silke; Eastlake, Karen; Jayaram, Hari; Jones, Megan F.; Brown, Robert A.; McLellan, Gillian J.; Charteris, David G.; Khaw, Peng T.

2016-01-01

Human Müller glia with stem cell characteristics (hMGSCs) have been shown to improve retinal function upon transplantation into rat models of retinal ganglion cell (RGC) depletion. However, their translational potential may depend upon successful engraftment and improvement of retinal function in experimental models with anatomical and functional features resembling those of the human eye. We investigated the effect of allogeneic transplantation of feline Müller glia with the ability to differentiate into cells expressing RGC markers, following ablation of RGCs by N-methyl-d-aspartate (NMDA). Unlike previous observations in the rat, transplantation of hMGSC-derived RGCs into the feline vitreous formed aggregates and elicited a severe inflammatory response without improving visual function. In contrast, allogeneic transplantation of feline MGSC (fMGSC)-derived RGCs into the vitrectomized eye improved the scotopic threshold response (STR) of the electroretinogram (ERG). Despite causing functional improvement, the cells did not attach onto the retina and formed aggregates on peripheral vitreous remnants, suggesting that vitreous may constitute a barrier for cell attachment onto the retina. This was confirmed by observations that cellular scaffolds of compressed collagen and enriched preparations of fMGSC-derived RGCs facilitated cell attachment. Although cells did not migrate into the RGC layer or the optic nerve, they significantly improved the STR and the photopic negative response of the ERG, indicative of increased RGC function. These results suggest that MGSCs have a neuroprotective ability that promotes partial recovery of impaired RGC function and indicate that cell attachment onto the retina may be necessary for transplanted cells to confer neuroprotection to the retina. Significance Müller glia with stem cell characteristics are present in the adult human retina, but they do not have regenerative ability. These cells, however, have potential for

Reduced N-Type Ca2+ Channels in Atrioventricular Ganglion Neurons Are Involved in Ventricular Arrhythmogenesis.

PubMed

Zhang, Dongze; Tu, Huiyin; Cao, Liang; Zheng, Hong; Muelleman, Robert L; Wadman, Michael C; Li, Yu-Long

2018-01-15

Attenuated cardiac vagal activity is associated with ventricular arrhythmogenesis and related mortality in patients with chronic heart failure. Our recent study has shown that expression of N-type Ca 2+ channel α-subunits (Ca v 2.2-α) and N-type Ca 2+ currents are reduced in intracardiac ganglion neurons from rats with chronic heart failure. Rat intracardiac ganglia are divided into the atrioventricular ganglion (AVG) and sinoatrial ganglion. Ventricular myocardium receives projection of neuronal terminals only from the AVG. In this study we tested whether a decrease in N-type Ca 2+ channels in AVG neurons contributes to ventricular arrhythmogenesis. Lentiviral Ca v 2.2-α shRNA (2 μL, 2×10 7  pfu/mL) or scrambled shRNA was in vivo transfected into rat AVG neurons. Nontransfected sham rats served as controls. Using real-time single-cell polymerase chain reaction and reverse-phase protein array, we found that in vivo transfection of Ca v 2.2-α shRNA decreased expression of Ca v 2.2-α mRNA and protein in rat AVG neurons. Whole-cell patch-clamp data showed that Ca v 2.2-α shRNA reduced N-type Ca 2+ currents and cell excitability in AVG neurons. The data from telemetry electrocardiographic recording demonstrated that 83% (5 out of 6) of conscious rats with Ca v 2.2-α shRNA transfection had premature ventricular contractions ( P <0.05 versus 0% of nontransfected sham rats or scrambled shRNA-transfected rats). Additionally, an index of susceptibility to ventricular arrhythmias, inducibility of ventricular arrhythmias evoked by programmed electrical stimulation, was higher in rats with Ca v 2.2-α shRNA transfection compared with nontransfected sham rats and scrambled shRNA-transfected rats. A decrease in N-type Ca 2+ channels in AVG neurons attenuates vagal control of ventricular myocardium, thereby initiating ventricular arrhythmias. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Information non précise sur la taille du pénis en République Démocratique du Congo: à propos de 21 sources

PubMed Central

Mulenga, Philippe Cilundika; Kazadi, Alex Bukasa

2016-01-01

Introduction La taille du pénis constitue une préoccupation de beaucoup des gens actuellement et certains ne sont pas satisfaits de la dimension de leur pénis comme le montre l’étude de Tiggemann en 2008. Il existe relativement peu d'études sur le pénis en érection. Cela peut refléter les tabous culturels des chercheurs ou des médecins en interaction avec les hommes qui sont dans un état d’excitation sexuelle. Toutes fois, il est important pour les personnes qui annoncent des détails sur la taille du pénis d’annoncer d’abord les repères de la mesure du pénis puis ensuite donner les chiffres que proposent les chercheurs. Méthodes Notre enquête de type descriptif transversale s’est effectuée dans les deux grandes villes de la République Démocratique du Congo à savoir la ville de Kinshasa et la ville de Lubumbashi, pendant une période de deux ans soit de Mai 2014 à Mai 2016. Au total, 21 sources d’information ont constitué notre échantillon dont 8 à Kinshasa et 13 à Lubumbashi et nous avons trouvé cela suffisant car les sujets à caractère sexuel sont souvent rares chez nous. Les paramètres étudiés étaient: la nature de la source, la précision de la technique de la mesure, la présence de référence bibliographique, la longueur annoncée du pénis. Résultats La majorité des sources d’information sont faites des émissions de radio et de télévision (23,8%), ceci pourra s’expliquer par le fait que dans notre milieu il y a de plus en plus des chaines de radio et télévision et surtout dans les grandes villes. Concernant la précision de la technique de la mesure du pénis lors du partage du message sur la taille du pénis, l’étude nous montre que la majorité des sources d’information ne signale pas cela lorsqu’elles annoncent la taille du pénis au public soit 85,7%. Plusieurs sources ne déclarent pas les références bibliographiques (57,1%). Lorsqu’on regarde même les chiffres de la taille du p

Cholestéatome du méat acoustique externe

PubMed Central

Azeddine, Lachkar; Aabach, Ahmed; Chouai, Mohamed; Elayoubi, Fahd; Ghailan, Mohamed Rachid

2016-01-01

Le cholestéatome du méat acoustique externe se définit comme une accumulation de kératine en regard d’une érosion osseuse de nature ostéitique. C’est une entité otologique rare ou peut diagnostiquée. Le but de notre travail est d’illustrer sur la base d’un cas un cholestéatome du méat acoustique externe. Il s’agit d’un patient âgé de 65 ans diabétique et hypertendu sous traitement, présentant depuis 3 mois une otalgie droite intense, insomniante, avec hypoacousie, otorrhée purulente minime et paralysie faciale droite grade V. Le diagnostic évoqué était dans un premier temps celui d’otite externe maligne. Il a été mis sous traitement antibiotique sans amélioration. L’examen otologique a trouvé une lésion ulcéro-bourgeonnante de la paroi postérieure du méat acoustique externe droit, une biopsie systématique de la lésion a été pratiquée et a conclu à un cholestéatome. Le patient a bénéficié d’une tympanoplastie en technique ouverte. Le cholestéatome du méat acoustique externe est rare, la symptomatologie clinique n’est pas spécifique, le scanner des rocher est d’un grand apport pour le diagnostic positif montrant un cratère osseux du méat acoustique externe. Le traitement dépend de l’extension des lésions allant des simples soins locaux à une tympanoplastie en technique ouverte. Le cholestéatome du méat acoustique externe peut revêtir plusieurs aspects, et prêter confusion avec d’autres pathologies du méat acoustique externe. PMID:28154624

Cancer du sein au Maroc: profil phénotypique des tumeurs

PubMed Central

Khalil, Ahmadaye Ibrahim; Bendahhou, Karima; Mestaghanmi, Houriya; Saile, Rachid; Benider, Abdellatif

2016-01-01

Le cancer du sein est le plus fréquent chez la femme et figure parmi les principales causes de mortalité liées au cancer. La curabilité de ce type tumoral est en augmentation, grâce aux programmes de dépistage et aux progrès thérapeutiques, qui ont certes augmenté la survie des patients. Mais des défis restent à relever en rapport avec l’instabilité phénotypique des cellules cancéreuses. L’objectif de ce travail est d’étudier le profil phénotypique du cancer du sein chez les patients pris en charge au Centre Mohammed VI pour le traitement des Cancers, durant les années 2013-2014. Il s’agit d’une étude transversale sur deux années, incluant les cas du cancer du sein pris en charge au Centre. Le recueil des données était fait à partir des dossiers des patients et analysés par le logiciel Epi Info. 1277 patients ont été pris en charge au sein de notre centre. 99,5% des cas de sexe féminin, l’âge moyen était 50,20 ± 11,34 ans. Le type histologique le plus fréquent était le carcinome canalaire infiltrant (80,7% des cas). Le stade diagnostic était précoce (56,9%). Le phénotype moléculaire le plus fréquent était le luminal A (41,4% des cas). Le luminal B, le HER2 et les triples négatifs étaient dans respectivement 10,4%, 6,3%, 11,2% des cas. L’étude du phénotype tumoral des patients atteints du cancer du sein permet l’orientation du clinicien dans le choix du traitement, et des décideurs dans la planification de programmes de lutte contre cette pathologie. PMID:28292037

Identification d'une loi thermo-élasto-viscoplastique en vue de la modélisation du laminage à chaud du cuivre

NASA Astrophysics Data System (ADS)

Moureaux, P.; Moto Mpong, S.; Remy, M.; Bouffioux, C.; Lecomte-Beckers, J.; Habraken, A. M.

2002-12-01

la mise au point d'un modèle de simulation de la dernière passe du laminage à chaud du cuivre ne présente à priori pas de problème du point de vue numérique pour un code d'éléments finis non linéaire. La collecte d'informations précises tant sur le procédé industriel que sur le comportement du matériau est par contre une opération non triviale. Cet article présente les diverses méthodes expérimentales mises en œuvre pour caractériser le matériau : essais de compression à chaud, mesures d'analyse thermique différentielle, essais de dilatométrie et de diffusivité. Les méthodes permettant d'identifier les paramètres de la loi élasto-visco-plastique de type Norton-Hoff à partir des essais sont présentées et une analyse bibliographique investigue le problème de la détermination du module de Young à haute température. Tant les hypothèses supplémentaires relatives au procédé et nécessaires au modèle que les résultats finaux sont résumés.

Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.

PubMed

Lampert, E J; Andorra, M; Torres-Torres, R; Ortiz-Pérez, S; Llufriu, S; Sepúlveda, M; Sola, N; Saiz, A; Sánchez-Dalmau, B; Villoslada, P; Martínez-Lapiscina, Elena H

2015-11-01

Multiple Sclerosis (MS) results in color vision impairment regardless of optic neuritis (ON). The exact location of injury remains undefined. The objective of this study is to identify the region leading to dyschromatopsia in MS patients' NON-eyes. We evaluated Spearman correlations between color vision and measures of different regions in the afferent visual pathway in 106 MS patients. Regions with significant correlations were included in logistic regression models to assess their independent role in dyschromatopsia. We evaluated color vision with Hardy-Rand-Rittler plates and retinal damage using Optical Coherence Tomography. We ran SIENAX to measure Normalized Brain Parenchymal Volume (NBPV), FIRST for thalamus volume and Freesurfer for visual cortex areas. We found moderate, significant correlations between color vision and macular retinal nerve fiber layer (rho = 0.289, p = 0.003), ganglion cell complex (GCC = GCIP) (rho = 0.353, p < 0.001), thalamus (rho = 0.361, p < 0.001), and lesion volume within the optic radiations (rho = -0.230, p = 0.030). Only GCC thickness remained significant (p = 0.023) in the logistic regression model. In the final model including lesion load and NBPV as markers of diffuse neuroaxonal damage, GCC remained associated with dyschromatopsia [OR = 0.88 95 % CI (0.80-0.97) p = 0.016]. This association remained significant when we also added sex, age, and disease duration as covariates in the regression model. Dyschromatopsia in NON-eyes is due to damage of retinal ganglion cells (RGC) in MS. Color vision can serve as a marker of RGC damage in MS.

Developmental Profiling of Spiral Ganglion Neurons Reveals Insights into Auditory Circuit Assembly

PubMed Central

Lu, Cindy C.; Appler, Jessica M.; Houseman, E. Andres; Goodrich, Lisa V.

2011-01-01

The sense of hearing depends on the faithful transmission of sound information from the ear to the brain by spiral ganglion (SG) neurons. However, how SG neurons develop the connections and properties that underlie auditory processing is largely unknown. We catalogued gene expression in mouse SG neurons from embryonic day 12 (E12), when SG neurons first extend projections, up until postnatal day 15 (P15), after the onset of hearing. For comparison, we also analyzed the closely-related vestibular ganglion (VG). Gene ontology analysis confirmed enriched expression of genes associated with gene regulation and neurite outgrowth at early stages, with the SG and VG often expressing different members of the same gene family. At later stages, the neurons transcribe more genes related to mature function, and exhibit a dramatic increase in immune gene expression. Comparisons of the two populations revealed enhanced expression of TGFβ pathway components in SG neurons and established new markers that consistently distinguish auditory and vestibular neurons. Unexpectedly, we found that Gata3, a transcription factor commonly associated with auditory development, is also expressed in VG neurons at early stages. We therefore defined new cohorts of transcription factors and axon guidance molecules that are uniquely expressed in SG neurons and may drive auditory-specific aspects of their differentiation and wiring. We show that one of these molecules, the receptor guanylyl cyclase Npr2, is required for bifurcation of the SG central axon. Hence, our data set provides a useful resource for uncovering the molecular basis of specific auditory circuit assembly events. PMID:21795542

Electronic neuron within a ganglion of a leech (Hirudo medicinalis).

PubMed

Aliaga, J; Busca, N; Minces, V; Mindlin, G B; Pando, B; Salles, A; Sczcupak, L

2003-06-01

We report the construction of an electronic device that models and replaces a neuron in a midbody ganglion of the leech Hirudo medicinalis. In order to test the behavior of our device, we used a well-characterized synaptic interaction between the mechanosensory, sensitive to pressure, (P) cell and the anteropagoda (because of the action potential shape) (AP) neuron. We alternatively stimulated a P neuron and our device connected to the AP neuron, and studied the response of the latter. The number and timing of the AP spikes were the same when the electronic parameters were properly adjusted. Moreover, after changes in the depolarization of the AP cell, the responses under the stimulation of both the biological neuron and the electronic device vary in a similar manner.

Pulsed Radiofrequency to the Dorsal Root Ganglion in Acute Herpes Zoster and Postherpetic Neuralgia.

PubMed

Kim, Koohyun; Jo, Daehyun; Kim, EungDon

2017-03-01

Latent varicella zoster virus reactivates mainly in sensory ganglia such as the dorsal root ganglion (DRG) or trigeminal ganglion. The DRG contains many receptor channels and is an important region for pain signal transduction. Sustained abnormal electrical activity to the spinal cord via the DRG in acute herpes zoster can result in neuropathic conditions such as postherpetic neuralgia (PHN). Although the efficacy of pulsed radiofrequency (PRF) application to the DRG in various pain conditions has been previously reported, the application of PRF to the DRG in patients with herpes zoster has not yet been studied. The aim of the present study was to compare the clinical effects of PRF to the DRG in patients with herpes zoster to those of PRF to the DRG in patients with PHN. Retrospective comparative study. University hospital pain center in Korea. The medical records of 58 patients who underwent PRF to the DRG due to zoster related pain (herpes zoster or PHN) were retrospectively analyzed. Patients were divided into 2 groups according to the timing of PRF after zoster onset: an early PRF group (within 90 days) and a PHN PRF group (more than 90 days). The efficacy of PRF was assessed by a numeric rating scale (NRS) and by recording patient medication doses before PRF and at one week, 4 weeks, 8 weeks, and 12 weeks after PRF. Pain intensity was decreased after PRF in all participants. However, the degree of pain reduction was significantly higher in the early PRF group. Moreover, more patients discontinued their medication in the early PRF group, and the PRF success rate was also higher in the early PRF group. The relatively small sample size from a single center, short duration of review of medical records, and the retrospective nature of the study. PRF to the DRG is a useful treatment for treatment-resistant cases of herpes zoster and PHN. Particularly in herpes zoster patients with intractable pain, application of PRF to the DRG should be considered for pain control

The anti-nociceptive agent ralfinamide inhibits tetrodotoxin-resistant and tetrodotoxin-sensitive Na+ currents in dorsal root ganglion neurons.

PubMed

Stummann, Tina C; Salvati, Patricia; Fariello, Ruggero G; Faravelli, Laura

2005-03-14

Tetrodotoxin-resistant and tetrodotoxin-sensitive Na+ channels contribute to the abnormal spontaneous firing in dorsal root ganglion neurons associated with neuropathic pain. Effects of the anti-nociceptive agent ralfinamide on tetrodotoxin-resistant and tetrodotoxin-sensitive currents in rat dorsal root ganglion neurons were therefore investigated by patch clamp experiments. Ralfinamide inhibition was voltage-dependent showing highest potency towards inactivated channels. IC50 values for tonic block of half-maximal inactivated tetrodotoxin-resistant and tetrodotoxin-sensitive currents were 10 microM and 22 microM. Carbamazepine, an anticonvulsant used in the treatment of pain, showed significantly lower potency. Ralfinamide produced a hyperpolarising shift in the steady-state inactivation curves of both currents confirming the preferential interaction with inactivated channels. Additionally, ralfinamide use and frequency dependently inhibited both currents and significantly delayed repriming from inactivation. All effects were more pronounced for tetrodotoxin-resistant than tetrodotoxin-sensitive currents. The potency and mechanisms of actions of ralfinamide provide a hypothesis for the anti-nociceptive properties found in animal models.

Properties, use and health effects of depleted uranium (DU): a general overview.

PubMed

Bleise, A; Danesi, P R; Burkart, W

2003-01-01

Depleted uranium (DU), a waste product of uranium enrichment, has several civilian and military applications. It was used as armor-piercing ammunition in international military conflicts and was claimed to contribute to health problems, known as the Gulf War Syndrome and recently as the Balkan Syndrome. This led to renewed efforts to assess the environmental consequences and the health impact of the use of DU. The radiological and chemical properties of DU can be compared to those of natural uranium, which is ubiquitously present in soil at a typical concentration of 3 mg/kg. Natural uranium has the same chemotoxicity, but its radiotoxicity is 60% higher. Due to the low specific radioactivity and the dominance of alpha-radiation no acute risk is attributed to external exposure to DU. The major risk is DU dust, generated when DU ammunition hits hard targets. Depending on aerosol speciation, inhalation may lead to a protracted exposure of the lung and other organs. After deposition on the ground, resuspension can take place if the DU containing particle size is sufficiently small. However, transfer to drinking water or locally produced food has little potential to lead to significant exposures to DU. Since poor solubility of uranium compounds and lack of information on speciation precludes the use of radioecological models for exposure assessment, biomonitoring has to be used for assessing exposed persons. Urine, feces, hair and nails record recent exposures to DU. With the exception of crews of military vehicles having been hit by DU penetrators, no body burdens above the range of values for natural uranium have been found. Therefore, observable health effects are not expected and residual cancer risk estimates have to be based on theoretical considerations. They appear to be very minor for all post-conflict situations, i.e. a fraction of those expected from natural radiation.

Glaucoma Diagnostic Capability of Global and Regional Measurements of Isolated Ganglion Cell Layer and Inner Plexiform Layer.

PubMed

Chien, Jason L; Ghassibi, Mark P; Patthanathamrongkasem, Thipnapa; Abumasmah, Ramiz; Rosman, Michael S; Skaat, Alon; Tello, Celso; Liebmann, Jeffrey M; Ritch, Robert; Park, Sung Chul

2017-03-01

To compare glaucoma diagnostic capability of global/regional macular layer parameters in different-sized grids. Serial horizontal spectral-domain optical coherence tomography scans of macula were obtained. Automated macular grids with diameters of 3, 3.45, and 6 mm were used. For each grid, 10 parameters (total volume; average thicknesses in 9 regions) were obtained for 5 layers: macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), ganglion cell-inner plexiform layer (GCIPL; GCL+IPL), and ganglion cell complex (GCC; mRNFL+GCL+IPL). Sixty-nine normal eyes (69 subjects) and 87 glaucomatous eyes (87 patients) were included. For the total volume parameter, the area under the receiver operating characteristic curves (AUCs) in 6-mm grid were larger than the AUCs in 3- and 3.45-mm grids for GCL, GCC, GCIPL, and mRNFL (all P<0.020). For the average thickness parameters, the best AUC in 6-mm grid (T2 region for GCL, IPL, and GCIPL; I2 region for mRNFL and GCC) was greater than the best AUC in 3-mm grid for GCL, GCC, and mRNFL (P<0.045). The AUC of GCL volume (0.920) was similar to those of GCC (0.920) and GCIPL (0.909) volume. The AUC of GCL T2 region thickness (0.942) was similar to those of GCC I2 region (0.942) and GCIPL T2 region (0.934) thickness. Isolated macular GCL appears to be as good as GCC and GCIPL in glaucoma diagnosis, while IPL does not. Larger macular grids may be better at detecting glaucoma. Each layer has a characteristic region with the best glaucoma diagnostic capability.

Synaptic Proteins Are Tonotopically Graded in Postnatal and Adult Type I and Type II Spiral Ganglion Neurons

PubMed Central

Flores-Otero, Jacqueline; Davis, Robin L.

2011-01-01

Inherent in the design of the mammalian auditory system is the precision necessary to transduce complex sounds and transmit the resulting electrical signals to higher neural centers. Unique specializations in the organ of Corti are required to make this conversion, such that mechanical and electrical properties of hair cell receptors are tailored to their specific role in signal coding. Electrophysiological and immunocytochemical characterizations have shown that this principle also applies to neurons of the spiral ganglion, as evidenced by distinctly different firing features and synaptic protein distributions of neurons that innervate high- and low-frequency regions of the cochlea. However, understanding the fine structure of how these properties are distributed along the cochlear partition and within the type I and type II classes of spiral ganglion neurons is necessary to appreciate their functional significance fully. To address this issue, we assessed the localization of the postsynaptic AMPA receptor subunits GluR2 and GluR3 and the presynaptic protein synaptophysin by using immunocytochemical labeling in both postnatal and adult tissue. We report that these presynaptic and postsynaptic proteins are distributed oppositely in relation to the tonotopic map and that they are equally distributed in each neuronal class, thus having an overall gradation from one end of the cochlea to the other. For synaptophysin, an additional layer of heterogeneity was superimposed orthogonal to the tonotopic axis. The highest anti-synaptophysin antibody levels were observed within neurons located close to the scala tympani compared with those located close to the scala vestibuli. Furthermore, we noted that the protein distribution patterns observed in postnatal preparations were largely retained in adult tissue sections, indicating that these features characterize spiral ganglion neurons in the fully developed ear. PMID:21452215

Complete adult neurogenesis within a Wallerian degenerating nerve expressed as an ectopic ganglion.

PubMed

Nakano, Tomonori; Kurimoto, Shigeru; Kato, Shuichi; Asano, Kenichi; Hirata, Takuma; Kiyama, Hiroshi; Hirata, Hitoshi

2018-06-01

Neurogenesis in the adult peripheral nervous system remains to be demonstrated. We transplanted embryonic neural stem cells into a Wallerian degenerating nerve graft and observed development of a nodular structure consisting of neurons, glia, and Schwann cells. Histological analysis revealed a structure loosely resembling the spinal cord, including a synaptic network that formed along the neuron. Furthermore, the new axons reinnervated the paralysed muscle, forming both de novo and revived neuromuscular junctions. Reinnervation of the paralysed muscle resulted in significantly greater mean wet muscle weight and muscle fibre cross-sectional area on the cell transplantation side than on the surgical control side (body weight 0.071 ± 0.011% vs. 0.051 ± 0.007%, p = .006; area 355.6 ± 345.2 vs. 114.0 ± 132.0 μm 2 , p < .001). Electrophysiological experiments demonstrated a functional connection between the neurons and muscle; hence, we identified this nodule as an ectopic ganglion. Surprisingly, in green rat experiments, most of these glial cells, but none of the neurons, expressed enhanced green fluorescent protein, suggesting that the cells constituting the ectopic ganglion were derived from both transplanted stem cells and endogenous stem cells. Such adult neurogenesis in a peripheral nerve related to neural stem cell transplantation has not been reported previously, and these results form the basis for a novel regenerative medicine approach in paralysed muscle. Copyright © 2018 John Wiley & Sons, Ltd.

Macular retinal ganglion cell-inner plexiform layer thickness in patients on hydroxychloroquine therapy.

PubMed

Lee, Min Gyu; Kim, Sang Jin; Ham, Don-Il; Kang, Se Woong; Kee, Changwon; Lee, Jaejoon; Cha, Hoon-Suk; Koh, Eun-Mi

2014-11-25

We evaluated macular ganglion cell-inner plexiform layer (GC-IPL) thickness using spectral-domain optical coherence tomography (SD-OCT) in patients with chronic exposure to hydroxychloroquine (HCQ). This study included 130 subjects, who were divided into three groups: Group 1A, 55 patients with HCQ use ≥5 years; Group 1B, 46 patients with HCQ use <5 years; and Group 2, 29 normal controls. In all patients with exposure to HCQ, fundus examination, automated threshold perimetry, fundus autofluorescence photography, SD-OCT, and GC-IPL thickness measurement using the Cirrus HD-OCT ganglion cell analysis algorithm were performed. Average and minimum macular GC-IPL thickness were compared between subjects groups, and correlations between GC-IPL thickness and duration or total dose of HCQ use were analyzed. Among the 101 patients of Group 1, six patients who showed clinically evident HCQ retinopathy also showed markedly thin macular GC-IPL. In addition, weak but significant negative correlations were observed between the average and minimum GC-IPL thickness of Group 1 patients and cumulative dose of HCQ, even when analyzing without the six patients with HCQ retinopathy. However, when analyzing after exclusion of patients with high cumulative doses (>1000 g), significant correlations were not observed. This study revealed that macular GC-IPL thickness did not show definite correlations with HCQ use. However, some patients, especially with HCQ retinopathy or high cumulative doses, showed thin GC-IPL. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Sonic Hedgehog Has a Dual Effect on the Growth of Retinal Ganglion Axons Depending on Its Concentration

PubMed Central

Kolpak, Adrianne; Zhang, Jinhua; Bao, Zheng-Zheng

2006-01-01

The stereotypical projection of retinal ganglion cell (RGC) axons to the optic disc has served as a good model system for studying axon guidance. By both in vitro and in vivo experiments, we show that a secreted molecule, Sonic hedgehog (Shh), may play a critical role in the process. It is expressed in a dynamic pattern in the ganglion cell layer with a relatively higher expression in the center of the retina. Through gel culture and stripe assays, we show that Shh has a dual effect on RGC axonal growth, acting as a positive factor at low concentrations and a negative factor at high concentrations. Results from time-lapse video microscopic and stripe assay experiments further suggest that the effects of Shh on axons are not likely attributable to indirect transcriptional regulation by Shh. Overexpression of Shh protein or inhibition of Shh function inside the retina resulted in a complete loss of centrally directed projection of RGC axons, suggesting that precise regulation of Shh level inside the retina is critical for the projection of RGC axons to the optic disc. PMID:15800198

Rhythmic ganglion cell activity in bleached and blind adult mouse retinas.

PubMed

Menzler, Jacob; Channappa, Lakshmi; Zeck, Guenther

2014-01-01

In retinitis pigmentosa--a degenerative disease which often leads to incurable blindness--the loss of photoreceptors deprives the retina from a continuous excitatory input, the so-called dark current. In rodent models of this disease this deprivation leads to oscillatory electrical activity in the remaining circuitry, which is reflected in the rhythmic spiking of retinal ganglion cells (RGCs). It remained unclear, however, if the rhythmic RGC activity is attributed to circuit alterations occurring during photoreceptor degeneration or if rhythmic activity is an intrinsic property of healthy retinal circuitry which is masked by the photoreceptor's dark current. Here we tested these hypotheses by inducing and analysing oscillatory activity in adult healthy (C57/Bl6) and blind mouse retinas (rd10 and rd1). Rhythmic RGC activity in healthy retinas was detected upon partial photoreceptor bleaching using an extracellular high-density multi-transistor-array. The mean fundamental spiking frequency in bleached retinas was 4.3 Hz; close to the RGC rhythm detected in blind rd10 mouse retinas (6.5 Hz). Crosscorrelation analysis of neighbouring wild-type and rd10 RGCs (separation distance <200 µm) reveals synchrony among homologous RGC types and a constant phase shift (∼70 msec) among heterologous cell types (ON versus OFF). The rhythmic RGC spiking in these retinas is driven by a network of presynaptic neurons. The inhibition of glutamatergic ganglion cell input or the inhibition of gap junctional coupling abolished the rhythmic pattern. In rd10 and rd1 retinas the presynaptic network leads to local field potentials, whereas in bleached retinas additional pharmacological disinhibition is required to achieve detectable field potentials. Our results demonstrate that photoreceptor bleaching unmasks oscillatory activity in healthy retinas which shares many features with the functional phenotype detected in rd10 retinas. The quantitative physiological differences advance the

Non-steroidal Anti-inflammatory Drugs Attenuate Hyperalgesia and Block Upregulation of Trigeminal Ganglionic Sodium Channel 1.7 after Induction of Temporomandibular Joint Inflammation in Rats.

PubMed

Bi, Rui Yun; Ding, Yun; Gan, Ye Hua

2016-03-01

To investigate the association between the analgesic effect of non-steroidal antiinflammatory drugs (NSAIDs) and sodium channel 1.7 (Nav1.7) expression in the trigeminal ganglion (TG). Temporomandibular joint (TMJ) inflammation was induced by complete Freund's adjuvant (CFA) in female rats. Ibuprofen, diclofenac sodium and meloxicam were given intragastrically before induction of TMJ inflammation. Histopathological evaluation and scoring of TMJ inflammation was used to evaluate the level of inflammation. The head withdrawal threshold and food intake were measured to evaluate TMJ nociceptive responses. The mRNA and protein expression of trigeminal ganglionic Nav1.7 was examined using real-time polymerase chain reaction and western blot. Twenty-four hours after the injection of CFA into the TMJs, NSAIDs attenuated hyperalgesia of inflamed TMJ and simultaneously blocked inflammation-induced upregulation of Nav1.7 mRNA and protein expression in the TG. However, ibuprofen and diclofenac sodium slightly attenuated TMJ inflammation and meloxicam did not affect TMJ inflammation. Attenuation of hyperalgesia of inflamed TMJ by NSAIDs might be associated with their role in blocking upregulation of trigeminal ganglionic Nav1.7.

Bilirubin Modulates Acetylcholine Receptors In Rat Superior Cervical Ganglionic Neurons In a Bidirectional Manner

PubMed Central

Zhang, Chengmi; Wang, Zhenmeng; Dong, Jing; Pan, Ruirui; Qiu, Haibo; Zhang, Jinmin; Zhang, Peng; Zheng, Jijian; Yu, Weifeng

2014-01-01

Autonomic dysfunction as a partial contributing factor to cardiovascular instability in jaundiced patients is often associated with increased serum bilirubin levels. Whether increased serum bilirubin levels could directly inhibit sympathetic ganglion transmission by blocking neuronal nicotinic acetylcholine receptors (nAChRs) remains to be elucidated. Conventional patch-clamp recordings were used to study the effect of bilirubin on nAChRs currents from enzymatically dissociated rat superior cervical ganglia (SCG) neurons. The results showed that low concnetrations (0.5 and 2 μM) of bilirubin enhanced the peak ACh-evoked currents, while high concentrations (3 to 5.5 µM) of bilirubin suppressed the currents with an IC50 of 4 ± 0.5 μM. In addition, bilirubin decreased the extent of desensitization of nAChRs in a concentration-dependent manner. This inhibitory effect of bilirubin on nAChRs channel currents was non-competitive and voltage independent. Bilirubin partly improved the inhibitory effect of forskolin on ACh-induced currents without affecting the action of H-89. These data suggest that the dual effects of enhancement and suppression of bilirubin on nAChR function may be ascribed to the action mechanism of positive allosteric modulation and direct blockade. Thus, suppression of sympathetic ganglionic transmission through postganglionic nAChRs inhibition may partially contribute to the adverse cardiovascular effects in jaundiced patients. PMID:25503810

Spiral ganglion cell site of excitation I: comparison of scala tympani and intrameatal electrode responses.

PubMed

Cartee, Lianne A; Miller, Charles A; van den Honert, Chris

2006-05-01

To determine the site of excitation on the spiral ganglion cell in response to electrical stimulation similar to that from a cochlear implant, single-fiber responses to electrical stimuli delivered by an electrode positioned in the scala tympani were compared to responses from stimuli delivered by an electrode placed in the internal auditory meatus. The response to intrameatal stimulation provided a control set of data with a known excitation site, the central axon of the spiral ganglion cell. For both intrameatal and scala tympani stimuli, the responses to single-pulse, summation, and refractory stimulus protocols were recorded. The data demonstrated that summation pulses, as opposed to single pulses, are likely to give the most insightful measures for determination of the site of excitation. Single-fiber summation data for both scala tympani and intrameatally stimulated fibers were analyzed with a clustering algorithm. Combining cluster analysis and additional numerical modeling data, it was hypothesized that the scala tympani responses corresponded to central excitation, peripheral excitation adjacent to the cell body, and peripheral excitation at a site distant from the cell body. Fibers stimulated by an intrameatal electrode demonstrated the greatest range of jitter measurements indicating that greater fiber independence may be achieved with intrameatal stimulation.

Single cell RNA sequencing of stem cell-derived retinal ganglion cells.

PubMed

Daniszewski, Maciej; Senabouth, Anne; Nguyen, Quan H; Crombie, Duncan E; Lukowski, Samuel W; Kulkarni, Tejal; Sluch, Valentin M; Jabbari, Jafar S; Chamling, Xitiz; Zack, Donald J; Pébay, Alice; Powell, Joseph E; Hewitt, Alex W

2018-02-13

We used single cell sequencing technology to characterize the transcriptomes of 1,174 human embryonic stem cell-derived retinal ganglion cells (RGCs) at the single cell level. The human embryonic stem cell line BRN3B-mCherry (A81-H7), was differentiated to RGCs using a guided differentiation approach. Cells were harvested at day 36 and prepared for single cell RNA sequencing. Our data indicates the presence of three distinct subpopulations of cells, with various degrees of maturity. One cluster of 288 cells showed increased expression of genes involved in axon guidance together with semaphorin interactions, cell-extracellular matrix interactions and ECM proteoglycans, suggestive of a more mature RGC phenotype.

Threshold setting by the surround of cat retinal ganglion cells.

PubMed

Barlow, H B; Levick, W R

1976-08-01

1. The slope of curves relating the log increment threshold to log background luminance in cat retinal ganglion cells is affected by the area and duration of the test stimulus, as it is in human pyschophysical experiments. 2. Using large area, long duration stimuli the slopes average 0-82 and approach close to 1 (Weber's Law) in the steepest cases. Small stimuli gave an average of 0-53 for on-centre units using brief stimuli, and 0-56 for off-centre units, using long stimuli. Slopes under 0-5 (square root law) were not found over an extended range of luminances. 3. On individual units the slope was generally greater for larger and longer test stimulus, but no unit showed the full extent of change from slope of 0-5 to slope of 1. 4. The above differences hold for objective measures of quantum/spike ratio, as well as for thresholds either judged by ear or assessed by calculation. 5. The steeper slope of the curves for large area, long duration test stimuli compared with small, long duration stimuli, is associated with the increased effectiveness of antagonism from the surround at high backgrounds. This change may be less pronounced in off-centre units, one of which (probably transient Y-type) showed no difference of slope, and gave parallel area-threshold curves at widely separated background luminances, confirming the importance of differential surround effectiveness in changing the slope of the curves. 6. In on-centre units, the increased relative effectiveness of the surround is associated with the part of the raised background light that falls on the receptive field centre. 7. It is suggested that the variable surround functions as a zero-offset control that sets the threshold excitation required for generating impulses, and that this is separate from gain-setting adaptive mechanisms. This may be how ganglion cells maintain high incremental sensitivity in spite of a strong maintained excitatory drive that would otherwise cause compressive response non-linearities.

Le traumatisme du colon: l'expérience du CHU Hassan II de Fès

PubMed Central

Benjelloun, El Bachir; Hafid, Hasnai; Karim, Ibnmajdoub; Ousadden, Abdelmalek; Mazaz, Khalid; Taleb, Kahlid Ait

2012-01-01

Introduction Les traumatismes du colon sont associés à un risque majeur de complications septiques et de mortalité. Le but de notre étude est d’évaluer les circonstances, la prise en charge, le suivi et les facteurs pronostic de morbidité postopératoire des malades victimes d'un traumatisme colique. Méthodes Il s'agit d'une étude rétrospective sur une série de 49 patients opérés pour des plaies coliques aux services de chirurgie viscérale du CHU HASSAN II de Fès sur une période de 8 ans de juillet 2003 à juillet 2011. Résultats L’âge moyen de nos patients était de 25ans (16-70) avec une nette prédominance masculine (93.8%). Les plaies coliques secondaires à un traumatisme par arme blanche représentent 85% des cas (42 patients), suivi par les plaies iatrogènes au cours d'une coloscopie chez 6 patients (13%), puis les contusions abdominales chez 1 patient (2%). Les parties du cadre colique les plus touchées étaient le colon transverse chez 19 patients (38%) et le colon descendant chez 12 patients (24, 5%). Le colon sigmoïde était le segment le plus touché au cours d'une coloscopie4/6. Quarante-deux patients (85%) ont eu une suture primaire des plaies coliques, six patients (13%) une diversion fécale et un patient (2%) une résection-anastomose. Deux patients (4%) sont décédés suite à un choc septique. La morbidité globale était de 38,7% dominé essentiellement par l'infection de la paroi chez 14 patients et une péritonite post opératoire chez 3 patients. L'analyse univarié a montré une différence significatif en terme d'infection de la paroi entre le groupe colostomie versus suture simple (50% vs 20,9% p<0,05). L'atteinte du colon gauche et la réalisation d'une colostomie sont associés à un risque plus élevés de complications postopératoires. Conclusion La suture primaire peut être effectuée avec un faible taux de complications postopératoire chez la majorité des patients suite à un traumatisme du colon. PMID

PERCUTANEOUS BALLOON COMPRESSION OF GASSERIAN GANGLION FOR THE TREATMENT OF TRIGEMINAL NEURALGIA: AN EXPERIENCE FROM INDIA.

PubMed

Agarwal, Anurag; Dhama, Vipin; Manik, Yogesh K; Upadhyaya, M K; Singh, C S; Rastogi, V

2015-02-01

Trigeminal neuralgia (TN) is characterized by unilateral, lancinating, paroxysmal pain in the dermatomal distribution area of trigeminal nerve. Percutaneous balloon compression (PBC) of Gasserian ganglion is an effective, comparatively cheaper and simple therapeutic modality for treatment of TN. Compression secondary to PBC selectively injures the large myelinated A-alfa (afferent) fibers that mediate light touch and does not affect A-delta and C-fibres, which carry pain sensation. Balloon compression reduces the sensory neuronal input, thus turning off the trigger to the neuropathic trigeminal pain. In this current case series, we are sharing our experience with PBC of Gasserian Ganglion for the treatment of idiopathic TN in our patients at an academic university-based medical institution in India. During the period of August 2012 to October 2013, a total of twelve PBCs of Gasserian Ganglion were performed in eleven patients suffering from idiopathic TN. There were nine female patients and two male patients with the age range of 35-70 years (median age: 54 years). In all patients cannulation of foramen ovale was done successfully in the first attempt. In eight out of eleven (72.7%) patients ideal 'Pear-shaped' balloon visualization could be achieved. In the remaining three patients (27.3%), inflated balloon was 'Bullet-shaped'. In one patient final placement of Fogarty balloon was not satisfactory and it ruptured during inflation. This case was deferred for one week when it was completed successfully with 'Pear-shaped' balloon inflation. During the follow up period of 1-13 months, there have been no recurrences of TN. Eight out of eleven patients (72.7%) are completely off medicines (carbamazepine and baclofen) and other two patients are stable on very low doses of carbamazepine. All patients have reported marked improvement in quality of life. This case series shows that percutaneous balloon compression is a useful minimally invasive intervention for the

Annealing of (DU-10Mo)-Zr Co-Rolled Foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pacheco, Robin Montoya; Alexander, David John; Mccabe, Rodney James

2017-01-20

Producing uranium-10wt% molybdenum (DU-10Mo) foils to clad with Al first requires initial bonding of the DU-10Mo foil to zirconium (Zr) by hot rolling, followed by cold rolling to final thickness. Rolling often produces wavy (DU-10Mo)-Zr foils that should be flattened before further processing, as any distortions could affect the final alignment and bonding of the Al cladding to the Zr co-rolled surface layer; this bonding is achieved by a hot isostatic pressing (HIP) process. Distortions in the (DU-10Mo)-Zr foil may cause the fuel foil to press against the Al cladding and thus create thinner or thicker areas in the Almore » cladding layer during the HIP cycle. Post machining is difficult and risky at this stage in the process since there is a chance of hitting the DU-10Mo. Therefore, it is very important to establish a process to flatten and remove any waviness. This study was conducted to determine if a simple annealing treatment could flatten wavy foils. Using the same starting material (i.e. DU-10Mo coupons of the same thickness), five different levels of hot rolling and cold rolling, combined with five different annealing treatments, were performed to determine the effect of these processing variables on flatness, bonding of layers, annealing response, microstructure, and hardness. The same final thickness was reached in all cases. Micrographs, textures, and hardness measurements were obtained for the various processing combinations. Based on these results, it was concluded that annealing at 650°C or higher is an effective treatment to appreciably reduce foil waviness.« less

Endoscopic sphenopalatine ganglion blockade efficacy in pain control after endoscopic sinus surgery.

PubMed

Al-Qudah, Mohannad

2016-03-01

The objective of this study was to evaluate the efficacy of bilateral endoscopic injection of lidocaine with epinephrine in the sphenopalatine ganglion at the end of endoscopic sinus surgery (ESS) in controlling postoperative pain and rescue analgesic requirements. A prospective, double blinded, placebo-controlled clinical trial of 60 patients with chronic rhinosinusitis (CRS) undergoing general anesthesia for ESS was undertaken. Patients were randomized to receive injection of 2 mL of 2% lidocaine with epinephrine or 2 mL saline at the end of surgery. Postoperatively, patients were observed for 24 hours. Pain severity was reported immediately, 6 hours, and 24 hours after surgery using a 10-cm visual analog scale (VAS). The need of rescue analgesia was recorded and compared between the 2 groups. The 2 groups were matched in demographic and intraoperative details. Postoperative pain severity average was 3.4, 3.0, and 1.6 in the saline group compared to 1.6, 1.7, and 1.0 in the lidocaine group. These differences reached statically significant for the first 2 follow-up intervals. Also, there was significant difference in the whole-day postoperative average score between the 2 groups (2.6 vs 1.4). Twelve patients in the saline group required rescue analgesia compared to 5 in the lidocaine group. The average rescue analgesia dose was 27.5 mg of tramadol in the saline group vs 11.6 in the lidocaine group. These differences were statistically significant. No complications were reported in either group. Sphenopalatine ganglion injection of lidocaine at the end of surgery is safe, simple, noninvasive, and an effective method of short-term pain control after sinus surgery. © 2015 ARS-AAOA, LLC.

An alternative for cost-effective remediation of depleted uranium (DU) at certain environmental restoration sites.

PubMed

Miller, M; Galloway, B; VanDerpoel, G; Johnson, E; Copland, J; Salazar, M

2000-02-01

Numerous sites in the United States and around the world are contaminated with depleted uranium (DU) in various forms. A prevalent form is fragmented DU originating from various scientific tests involving high explosives and DU during weapon development programs, at firing practice ranges, or war theaters where DU was used in armor-piercing projectiles. The contamination at these sites is typically very heterogeneous, with discreet, visually identifiable DU fragments mixed with native soil. That is, the bulk-averaged DU activity is quite low, while specific DU fragments, which are distinct from the soil matrix, have much higher specific activity. DU is best known as a dark, black metal that is nearly twice as dense as lead, but DU in the environment readily weathers (oxidizes) to a distinctive bright yellow color that is readily visible. While the specific activity (amount of radioactivity per mass of soil) of DU is relatively low and presents only a minor radiological hazard, the fact that it is radioactive and visually identifiable makes it desirable to remove the DU "contamination" from the environment. The typical approach to conducting this DU remediation is to use radiation detection instruments to identify the contaminant and separate it from the adjacent soil, packaging it for disposal as radioactive waste. This process can be performed manually or by specialized, automated equipment. Alternatively, in certain situations a more cost-effective approach might be simple mechanical or gravimetric separation of the DU fragments from the host soil matrix. At SNL/NM, both the automated and simple mechanical approaches have recently been employed. This paper discusses the pros/cons of the two approaches.

W.E.B. DuBois and the Concepts of Race and Class.

ERIC Educational Resources Information Center

Green, Dan S.; Smith, Earl

1983-01-01

Summarizes and analyzes W.E.B. DuBois's publications on race and class, particularly as he observed the relationships between White and Black Americans from about 1890 to the 1960s. Contends that DuBois's work has been seriously underrated and cites William J. Wilson's work as corroborating and extending DuBois's theories. (CJM)

Sustainable growth, the DuPont way.

PubMed

Holliday, C

2001-09-01

Like many manufacturers, DuPont traditionally has grown by making more and more "stuff." And its business growth has been proportional to the amount of raw materials and energy used--as well as the resulting waste and emissions from operations. Over the years, though, DuPont became aware that cheap supplies of nonrenewable resources wouldn't be endlessly available and that the earth's ecosystems couldn't indefinitely absorb the waste and emissions of production and consumption. Chad Holliday, chairman and CEO of DuPont, believes strongly in the challenge of sustainable growth and makes the business case for it: By using creativity and scientific knowledge effectively, he says, companies can provide strong returns for shareholders and grow their businesses--while also meeting the human needs of societies around the world and reducing the environmental footprint of their operations and products. In fact, a focus on sustainability can help identify new products, markets, partnerships, and intellectual property and lead to substantial business growth. Holliday describes how DuPont developed a three-pronged strategy to translate the concept of sustainability into nuts-and-bolts business practices. Focusing on integrated science, knowledge intensity, and productivity improvement, the strategy was accompanied by a new way to measure progress quantitatively. Sustainable growth should be viewed not as a program for stepped-up environmental performance but as a comprehensive way of doing business, one that delivers tremendous economic value and opens up new opportunities. Ultimately, companies will find that they can generate substantial business value through sustainability while both enhancing the quality of life around the world and protecting the environment.

Visual Acuity and the Balance between Receptor Density and Ganglion Cell Receptive Field Overlap.

DTIC Science & Technology

1980-07-01

Physiol. 229:719-731. Cleland, B . G., Dubin, M. W. and Levick , W. R. (1971) Sustained and transient neurones in the cat’s retina and lateral...NOOOIQ.79C-0370 NLASSIFIED IA. EEEEEEEEEEinnuunuuuuuu ’mLuuuu~ 4,0 111 12. 11111IL25 1.4I 111111.6 MICROCOPY RESOLUTION TEST CHART LEVEt 9 70 b *tm...1970; Burke and Hayhow, 1968; Barlow and Levick , 1969). As far as they affect the ganglion cell, these sources of noise are equivalent so they have been

Response of cervicogenic headaches and occipital neuralgia to radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve.

PubMed

Hamer, John F; Purath, Traci A

2014-03-01

This article investigates the degree and duration of pain relief from cervicogenic headaches or occipital neuralgia following treatment with radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. It also addresses the procedure's complication rate and patient's willingness to repeat the procedure if severe symptoms recur. This is a single-center retrospective observational study of 40 patients with refractory cervicogenic headaches and or occipital neuralgia. Patients were all referred by a headache specialty clinic for evaluation for radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. After treatment, patients were followed for a minimum of 6 months to a year. Patient demographics and the results of radiofrequency ablation were recorded on the same day, after 3-4 days, and at 6 months to 1 year following treatment. Thirty-five percent of patients reported 100% pain relief and 70% reported 80% or greater pain relief. The mean duration of improvement is 22.35 weeks. Complication rate was 12-13%. 92.5% of patients reported they would undergo the procedure again if severe symptoms returned. Radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve can provide many months of greater than 50% pain relief in the vast majority of recipients with an expected length of symptom improvement of 5-6 months. © 2014 American Headache Society.

Changes in NGF and NT-3 protein species in the superior cervical ganglion following axotomy of postganglionic axons.

PubMed

Walker, Ryan G; Foster, Andrew; Randolph, Chris L; Isaacson, Lori G

2009-02-19

Mature sympathetic neurons in the superior cervical ganglion (SCG) are regulated by target-derived neurotrophins such as nerve growth factor (NGF) and neurotrophin-3 (NT-3). High molecular weight NGF species and mature NT-3 are the predominant NGF and NT-3 protein isoforms in the SCG, yet it is unknown whether the presence of these species is dependent on intact connection with the target tissues. In an attempt to determine the role of peripheral targets in regulating the neurotrophin species found in the SCG, we investigated the NGF and NT-3 protein species present in the SCG following axotomy (transection) or injury of the post-ganglionic axons. Following a 7 day axotomy, the 22-24 kDa NGF species and the mature 14 kDa NT-3 species in the SCG were significantly reduced by 99% and 66% respectively, suggesting that intact connection with the target is necessary for the expression of these protein species. As expected, tyrosine hydroxylase (TH) protein in the SCG was significantly reduced by 80% at 7 days following axotomy. In order to distinguish between the effects of injury and loss of target connectivity, the SCG was examined following compression injury to the post-ganglionic nerves. Following injury, no reduction in the 22-24 kDa NGF or 14 kDa mature NT-3 species was observed in the SCG. TH protein was slightly, yet significantly, decreased in the SCG following injury. The findings of this study suggest that the presence of the 22-24 kDa NGF and mature 14 kDa NT-3 species in the SCG is dependent on connection with peripheral targets and may influence, at least in part, TH protein expression in adult sympathetic neurons.

Synaptology of physiologically identified ganglion cells in the cat retina: a comparison of retinal X- and Y-cells.

PubMed

Weber, A J; Stanford, L R

1994-05-15

It has long been known that a number of functionally different types of ganglion cells exist in the cat retina, and that each responds differently to visual stimulation. To determine whether the characteristic response properties of different retinal ganglion cell types might reflect differences in the number and distribution of their bipolar and amacrine cell inputs, we compared the percentages and distributions of the synaptic inputs from bipolar and amacrine cells to the entire dendritic arbors of physiologically characterized retinal X- and Y-cells. Sixty-two percent of the synaptic input to the Y-cell was from amacrine cell terminals, while the X-cells received approximately equal amounts of input from amacrine and bipolar cells. We found no significant difference in the distributions of bipolar or amacrine cell inputs to X- and Y-cells, or ON-center and OFF-center cells, either as a function of dendritic branch order or distance from the origin of the dendritic arbor. While, on the basis of these data, we cannot exclude the possibility that the difference in the proportion of bipolar and amacrine cell input contributes to the functional differences between X- and Y-cells, the magnitude of this difference, and the similarity in the distributions of the input from the two afferent cell types, suggest that mechanisms other than a simple predominance of input from amacrine or bipolar cells underlie the differences in their response properties. More likely, perhaps, is that the specific response features of X- and Y-cells originate in differences in the visual responses of the bipolar and amacrine cells that provide their input, or in the complex synaptic arrangements found among amacrine and bipolar cell terminals and the dendrites of specific types of retinal ganglion cells.

Lack of early pattern stimulation prevents normal development of the alpha (Y) retinal ganglion cell population in the cat.

PubMed

Burnat, Kalina; Van Der Gucht, Estelle; Waleszczyk, Wioletta J; Kossut, Malgorzata; Arckens, Lutgarde

2012-08-01

Binocular deprivation of pattern vision (BD) early in life permanently impairs global motion perception. With the SMI-32 antibody against neurofilament protein (NFP) as a marker of the motion-sensitive Y-cell pathway (Van der Gucht et al. [2001] Cereb. Cortex 17:2805-2819), we analyzed the impact of early BD on the retinal circuitry in adult, perceptually characterized cats (Burnat et al. [2005] Neuroreport 16:751-754). In controls, large retinal ganglion cells exhibited a strong NFP signal in the soma and in the proximal parts of the dendritic arbors. The NFP-immunoreactive dendrites typically branched into sublamina a of the inner plexiform layer (IPL), i.e., the OFF inner plexiform sublamina. In the retina of adult BD cats, however, most of the NFP-immunoreactive ganglion cell dendrites branched throughout the entire IPL. The NFP-immunoreactive cell bodies were less regularly distributed, often appeared in pairs, and had a significantly larger diameter compared with NFP-expressing cells in control retinas. These remarkable differences in the immunoreactivity pattern were typically observed in temporal retina. In conclusion, we show that the anatomical organization typical of premature Y-type retinal ganglion cells persists into adulthood even if normal visual experience follows for years upon an initial 6-month period of BD. Binocular pattern deprivation possibly induces a lifelong OFF functional domination, normally apparent only during development, putting early high-quality vision forward as a premise for proper ON-OFF pathway segregation. These new observations for pattern-deprived animals provide an anatomical basis for the well-described motion perception deficits in congenital cataract patients. Copyright © 2012 Wiley Periodicals, Inc.

Lambeaux autofermants pour le traitement des brulures electriques du scalp par haut voltage

PubMed Central

Hafidi, J.; El Mazouz, S.; El Mejatti, H.; Fejjal, N.; Gharib, N.E.; Abbassi, A.; Belmahi, A.M.

2011-01-01

Summary Les brûlures électriques par haut voltage sont responsables de gros dégâts tissulaires en immédiat et dans les jours suivant l’accident du fait de la chaleur importante dégagée par effet joule et de la thrombose microvasculaire évolutive. Les pertes de substances du scalp secondaires à ces brûlures nécessitent une couverture par lambeaux vu la destruction du périoste et du calvarium en regard. De juin 1997 à juin 2008, 15 patients ont été traités pour des pertes de substance du scalp secondaires à des brûlures électriques par haut voltage de diamètre allant de 8 à 11 cm et siégeant dans la région tonsurale. Ces patients ont été opérés dans la première semaine suivant l’accident. Les pertes de substance du scalp de taille moyenne secondaires à ces brûlures peuvent être couvertes per primam de façon fiable par des lambeaux locaux axialisés et multiples. Nous relatons l’expérience du Service de Chirurgie Plastique du Centre Hospitalier Universitaire Ibn-Sina, Rabat, Maroc, dans la gestion et la prise en charge de ces brûlures. PMID:22262963

Survie au cancer du sein à Rabat (Maroc) 2005-2008

PubMed Central

Mechita, Nada Bennani; Tazi, Mohammed Adnane; Er-Raki, Abdelouahed; Mrabet, Mustapha; Saadi, Asma; Benjaafar, Noureddine; Razine, Rachid

2016-01-01

Introduction Le cancer du sein représente un problème de santé publique au Maroc. L’objectif de ce travail était d’estimer le taux de survie au cancer du sein chez les patientes habitant la ville de Rabat. Méthodes Etude pronostique réalisée chez les patientes diagnostiquées pour cancer du sein de 2005 à 2008, habitant la ville de Rabat et enregistrées au registre des cancers de Rabat. La date d’inclusion dans l’étude correspondait à la date de confirmation histologique du cancer. L’estimation de la survie a été réalisée par la méthode de Kaplan Meier, et la comparaison entre les différentes classes d’une variable a été réalisée par le test de log rank. L’étude des facteurs associés à la survie a été effectuée par le modèle de Cox. Résultats Durant la période d’étude 628 cas de cancer du sein ont été collectés. Le pourcentage de décès était de 19,9%. La survie globale à un an était de 97,1%, elle était de 89,2% à 3 ans et de 80,6 % à 5 ans. En analyse multivariée la survie au cancer du sein était statistiquement moins bonne chez les patientes âgées de plus de 70 ans (p<0,001), ayantune grande taille de tumeur (p<0,001), un stade avancé d’adénopathies (p=0,007), présentant des métastases (p<0,001) et non traitées par hormonothérapie (p=0,002). Conclusion Une grande taille de la tumeur et la présence de métastases sont des facteurs de mauvais pronostic du cancer du sein d’où la nécessité de renforcer les programmes de dépistage. PMID:28292106

Ganglion cell-inner plexiform layer and retinal nerve fibre layer changes within the macula in retinitis pigmentosa: a spectral domain optical coherence tomography study.

PubMed

Yoon, Chang Ki; Yu, Hyeong Gon

2018-03-01

To investigate how macular ganglion cell-inner plexiform layer (GCIPL) and retinal nerve fibre layer (RNFL) thicknesses within the macula change with retinitis pigmentosa (RP) severity. Spectral domain optical coherence tomography (SD-OCT) was used to examine 177 patients with RP and 177 normal controls. An optical coherence tomography (OCT) line scan was used to grade RP severity. Retinitis pigmentosa (RP) was categorized as more advanced if there was no identifiable inner segment ellipsoid (ISe) band (NISE) and as less advanced if an ISe band could be identified and peripheral loss of ISe was apparent (IISE). Ganglion cell-inner plexiform layer (GCIPL) and RNFL thicknesses were manually measured on OCT images and analysed. Pearson's correlation analyses were used to examine correlations between GCIPL thickness, RNFL thickness, visual acuity (VA) and visual field extent in patients and controls. Ganglion cell-inner plexiform layer (GCIPL) was significantly thicker in IISE than in control eyes (p < 0.001), but significantly thinner in NISE than in IISE eyes (p < 0.001) in both horizontal and vertical OCT scans. Retinal nerve fibre layer (RNFL) was significantly thicker in eyes with IISE and NISE than in control eyes in both horizontal and vertical meridians (all p < 0.001). Ganglion cell-inner plexiform layer (GCIPL) thickness showed a weak positive correlation with vision, and RNFL thickness showed a weak negative correlation with vision and visual field extent. Based on these results, the inner retina, including the GCIPL and RNFL, maintains its gross integrity longer than the photoreceptor layer in RP. Additionally, thickening of the inner retina may have some functional implications in patients with RP. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Metabotropic and ionotropic glutamate receptors regulate calcium channel currents in salamander retinal ganglion cells

PubMed Central

Shen, Wen; Slaughter, Malcolm M

1998-01-01

Glutamate suppressed high-voltage-activated barium currents (IBa,HVA) in tiger salamander retinal ganglion cells. Both ionotropic (iGluR) and metabotropic (mGluR) receptors contributed to this calcium channel inhibition. Trans-ACPD (1-aminocyclopentane-trans-1S,3R-dicarboxylic acid), a broad-spectrum metabotropic glutamate receptor agonist, suppressed a dihydropyridine-sensitive barium current. Kainate, an ionotropic glutamate receptor agonist, reduced an ω-conotoxin GVIA-sensitive current. The relative effectiveness of selective agonists indicated that the predominant metabotropic receptor was the L-2-amino-4-phosphonobutyrate (l-AP4)-sensitive, group III receptor. This receptor reversed the action of forskolin, but this was not responsible for calcium channel suppression. l-AP4 raised internal calcium concentration. Antagonists of phospholipase C, inositol trisphosphate (IP3) receptors and ryanodine receptors inhibited the action of metabotropic agonists, indicating that group III receptor transduction was linked to this pathway. The action of kainate was partially suppressed by BAPTA, by calmodulin antagonists and by blockers of calmodulin-dependent phosphatase. Suppression by kainate of the calcium channel current was more rapid when calcium was the charge carrier, instead of barium. The results indicate that calcium influx through kainate-sensitive glutamate receptors can activate calmodulin, which stimulates phosphatases that may directly suppress voltage-sensitive calcium channels. Thus, ionotropic and metabotropic glutamate receptors inhibit distinct calcium channels. They could act synergistically, since both increase internal calcium. These pathways provide negative feedback that can reduce calcium influx when ganglion cells are depolarized. PMID:9660896

DU Processing Efficiency and Reclamation: Plasma Arc Melting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imhoff, Seth D.; Aikin, Jr., Robert M.; Swenson, Hunter

The work described here corresponds to one piece of a larger effort to increase material usage efficiency during DU processing operations. In order to achieve this goal, multiple technologies and approaches are being tested. These technologies occupy a spectrum of technology readiness levels (TRLs). Plasma arc melting (PAM) is one of the technologies being investigated. PAM utilizes a high temperature plasma to melt materials. Depending on process conditions, there are potential opportunities for recycling and material reclamation. When last routinely operational, the LANL research PAM showed extremely promising results for recycling and reclamation of DU and DU alloys. The currentmore » TRL is lower due to machine idleness for nearly two decades, which has proved difficult to restart. This report describes the existing results, promising techniques, and the process of bringing this technology back to readiness at LANL.« less

Macular Ganglion Cell Imaging Study: Covariate Effects on the Spectral Domain Optical Coherence Tomography for Glaucoma Diagnosis.

PubMed

Jeong, Jae Hoon; Choi, Yun Jeong; Park, Ki Ho; Kim, Dong Myung; Jeoung, Jin Wook

2016-01-01

To evaluate the effect of multiple covariates on the diagnostic performance of the Cirrus high-definition optical coherence tomography (HD-OCT) for glaucoma detection. A prospective case-control study was performed and included 173 recently diagnosed glaucoma patients and 63 unaffected individuals from the Macular Ganglion Cell Imaging Study. Regression analysis of receiver operating characteristic were conducted to evaluate the influence of age, spherical equivalent, axial length, optic disc size, and visual field index on the macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) measurements. Disease severity, as measured by visual field index, had a significant effect on the diagnostic performance of all Cirrus HD-OCT parameters. Age, axial length and optic disc size were significantly associated with diagnostic accuracy of average peripapillary RNFL thickness, whereas axial length had a significant effect on the diagnostic accuracy of average GCIPL thickness. Diagnostic performance of the Cirrus HD-OCT may be more accurate in the advanced stages of glaucoma than at earlier stages. A smaller optic disc size was significantly associated with improved the diagnostic ability of average RNFL thickness measurements; however, GCIPL thickness may be less affected by age and optic disc size.

RdgB2 is required for dim-light input into intrinsically photosensitive retinal ganglion cells

PubMed Central

Walker, Marquis T.; Rupp, Alan; Elsaesser, Rebecca; Güler, Ali D.; Sheng, Wenlong; Weng, Shijun; Berson, David M.; Hattar, Samer; Montell, Craig

2015-01-01

A subset of retinal ganglion cells is intrinsically photosensitive (ipRGCs) and contributes directly to the pupillary light reflex and circadian photoentrainment under bright-light conditions. ipRGCs are also indirectly activated by light through cellular circuits initiated in rods and cones. A mammalian homologue (RdgB2) of a phosphoinositide transfer/exchange protein that functions in Drosophila phototransduction is expressed in the retinal ganglion cell layer. This raised the possibility that RdgB2 might function in the intrinsic light response in ipRGCs, which depends on a cascade reminiscent of Drosophila phototransduction. Here we found that under high light intensities, RdgB2−/− mutant mice showed normal pupillary light responses and circadian photoentrainment. Consistent with this behavioral phenotype, the intrinsic light responses of ipRGCs in RdgB2−/− were indistinguishable from wild-type. In contrast, under low-light conditions, RdgB2−/− mutants displayed defects in both circadian photoentrainment and the pupillary light response. The RdgB2 protein was not expressed in ipRGCs but was in GABAergic amacrine cells, which provided inhibitory feedback onto bipolar cells. We propose that RdgB2 is required in a cellular circuit that transduces light input from rods to bipolar cells that are coupled to GABAergic amacrine cells and ultimately to ipRGCs, thereby enabling ipRGCs to respond to dim light. PMID:26269578

Selective labeling of retinal ganglion cells with calcium indicators by retrograde loading in vitro

PubMed Central

Behrend, Matthew R.; Ahuja, Ashish K.; Humayun, Mark S.; Weiland, James D.; Chow, Robert H.

2012-01-01

Here we present a retrograde loading technique that makes it possible for the first time to rapidly load a calcium indicator in the majority of retinal ganglion cells (RGCs) in salamander retina, and then to observe physiological activity of these dye-loaded cells. Dextran-conjugated calcium indicator, dissolved in water, was applied to the optic nerve stump. Following dye loading, the isolated retina was mounted on a microelectrode array to demonstrate that electrical activity and calcium activity were preserved, as the retina responded to electrical stimuli. PMID:19428523

I h and HCN channels in murine spiral ganglion neurons: tonotopic variation, local heterogeneity, and kinetic model.

PubMed

Liu, Qing; Manis, Paul B; Davis, Robin L

2014-08-01

One of the major contributors to the response profile of neurons in the auditory pathways is the I h current. Its properties such as magnitude, activation, and kinetics not only vary among different types of neurons (Banks et al., J Neurophysiol 70:1420-1432, 1993; Fu et al., J Neurophysiol 78:2235-2245, 1997; Bal and Oertel, J Neurophysiol 84:806-817, 2000; Cao and Oertel, J Neurophysiol 94:821-832, 2005; Rodrigues and Oertel, J Neurophysiol 95:76-87, 2006; Yi et al., J Neurophysiol 103:2532-2543, 2010), but they also display notable diversity in a single population of spiral ganglion neurons (Mo and Davis, J Neurophysiol 78:3019-3027, 1997), the first neural element in the auditory periphery. In this study, we found from somatic recordings that part of the heterogeneity can be attributed to variation along the tonotopic axis because I h in the apical neurons have more positive half-activation voltage levels than basal neurons. Even within a single cochlear region, however, I h current properties are not uniform. To account for this heterogeneity, we provide immunocytochemical evidence for variance in the intracellular density of the hyperpolarization-activated cyclic nucleotide-gated channel α-subunit 1 (HCN1), which mediates I h current. We also observed different combinations of HCN1 and HCN4 α-subunits from cell to cell. Lastly, based on the physiological data, we performed kinetic analysis for the I h current and generated a mathematical model to better understand varied I h on spiral ganglion function. Regardless of whether I h currents are recorded at the nerve terminals (Yi et al., J Neurophysiol 103:2532-2543, 2010) or at the somata of spiral ganglion neurons, they have comparable mean half-activation voltage and induce similar resting membrane potential changes, and thus our model may also provide insights into the impact of I h on synaptic physiology.

Cancer du sein bilatéral synchrone au Maroc: caractéristiques épidémiologiques et cliniques

PubMed Central

Boufettal, Houssine; Samouh, Naïma

2015-01-01

Préciser la fréquence, les facteurs de risque et le pronostic du cancer du sein bilatéral, à partir d'une étude rétrospective de 22 cas de cancer du sein bilatéral synchrone dans un pays du Maghreb. De 2002 à 2010, 625 patientes étaient prises en charge pour cancer du sein au service de Gynécologie-Obstétrique «C» du centre hospitalier universitaire de Casablanca. 22 cas de cancer bilatéral synchrone étaient diagnostiqués. Nos résultats sont comparés avec ceux de la littérature. La fréquence de la bilatéralité du cancer du sein synchrone était de 3,52% (22/625). L'intervalle de temps moyen entre les deux cancers est de 4 mois (0 à 6 mois). Les patientes âgées de moins de 40 ans lors du premier cancer avaient six fois plus de risque de développer un cancer au niveau du sein controlatéral que les femmes âgées de plus de 40 ans. Les patientes atteintes d'une tumeur T3 ou T4 avaient un risque neuf fois plus élevé que les autres. 90,9% (2/22) des cas des premiers cancers sont des adénocarcinomes infiltrants. Les types histologiques du premier et du douzième cancer étaient identiques dans 86,4% (19/22) des cas. Quant au pronostic, il dépend à la fois du stade du premier et du deuxième cancer et le traitement de ce dernier doit obéir aux mêmes règles du traitement du premier cancer. L'incidence du cancer bilatéral synchrone du sein est de 3,52% dans notre série. Le cancer du sein unilatéral constitue un facteur de risque de développement d'un cancer du sein controlatéral. Une surveillance à vie est nécessaire au cours d'un cancer du sein pour détecter un cancer controlatéral. PMID:26090066

Les inconvénients de perdre du poids

PubMed Central

Bosomworth, N. John

2012-01-01

Résumé Objectif Explorer les raisons pour lesquelles la perte de poids à long terme échoue la plupart du temps et évaluer les conséquences de diverses trajectoires pondérales, y compris la stabilité, la perte et le gain. Source des données Les études qui évaluent les paramètres pondéraux dans la population sont en majorité observationnelles. Des données probantes de niveau I ont été publiées pour évaluer l’influence des interventions relatives au poids sur la mortalité et la qualité de vie. Message principal Seulement un petit pourcentage des personnes qui désirent perdre du poids réussissent à le faire de manière durable. La mortalité est la plus faible chez les personnes se situant dans la catégorie de poids élevé-normal et surpoids. La trajectoire pondérale la plus sécuritaire est la stabilité du poids avec une optimisation de la condition physique et métabolique. Il est démontré que la mortalité est plus faible chez les personnes ayant des comorbidités reliées à l’obésité si elles perdent du poids. Il est aussi établi que la qualité de vie sur le plan de la santé est meilleure chez les personnes obèses qui perdent du poids. Par contre, la perte de poids chez une personne obèse autrement en santé est associée à une mortalité accrue. Conclusion La perte de poids est recommandable seulement chez les personnes qui ont des comorbidités reliées à l’obésité. Les personnes obèses en santé qui veulent perdre du poids devraient être informées qu’il peut y avoir des risques à le faire. Une stratégie qui se traduit par un indice de masse corporelle stable avec une condition physique et métabolique optimisée, peu importe le poids, est l’option d’intervention la plus sécuritaire en ce qui concerne le poids.

The production of nitric oxide in the coeliac ganglion modulates the effect of cholinergic neurotransmission on the rat ovary during the preovulatory period.

PubMed

Delsouc, María B; Della Vedova, María C; Ramírez, Darío; Delgado, Silvia M; Casais, Marilina

2018-05-01

The aim of the present work was to investigate whether the nitric oxide produced by the nitric oxide/nitric oxide synthase (NO/NOS) system present in the coeliac ganglion modulates the effects of cholinergic innervation on oxidative status, steroidogenesis and apoptotic mechanisms that take place in the rat ovary during the first proestrous. An ex vivo Coeliac Ganglion- Superior Ovarian Nerve- Ovary (CG-SON-O) system was used. Cholinergic stimulation of the CG was achieved by 10 -6  M Acetylcholine (Ach). Furthermore, 400 μM Aminoguanidine (AG) - an inhibitor of inducible-NOS was added in the CG compartment in absence and presence of Ach. It was found that Ach in the CG compartment promotes apoptosis in ovarian tissue, probably due to the oxidative stress generated. AG in the CG compartment decreases the release of NO and progesterone, and increases the release of estradiol from the ovary. The CG co-treatment with Ach and AG counteracts the effects of the ganglionic cholinergic agonist on ovarian oxidative stress, increases hormone production and decreases Fas mRNA expression. These results suggest that NO is an endogenous modulator of cholinergic neurotransmission in CG, with implication in ovarian steroidogenesis and the apoptotic mechanisms that take place in the ovary during the preovulatory period in rats. Copyright © 2018 Elsevier Inc. All rights reserved.

Dépistage précoce des retards du développement moteur

PubMed Central

Harris, Susan R.

2016-01-01

Résumé Objectif Décrire le test HINT (Harris Infant Neuromotor Test), un test d’évaluation du développement neuromoteur chez les nourrissons publié en 2010, qui s’appuie sur les normes canadiennes et peut être utilisé pour dépister les retards du développement moteur durant la première année de la vie. Qualité des données D’abondantes recherches ont été publiées sur la fiabilité intra-évaluateur, inter-évaluateur et test-retest ainsi que sur la validité convergente, prédictive, du contenu et des groupes connus du test HINT, de même que sur la sensibilité, la spécificité et les valeurs prédictives négatives et positives des inquiétudes des parents, telles qu’évaluées par le test HINT. La plupart des données probantes sont de niveau II. Message principal Il est important de diagnostiquer les retards du développement moteur durant la première année de vie, car ils sont souvent le signe de retards du développement généralisés ou de déficiences précises, telles que la paralysie cérébrale. Les inquiétudes des parents quant au développement moteur de leur enfant sont une valeur prédictive robuste de diagnostics subséquents de retard du développement moteur. Conclusion Seul le dépistage précoce des retards du développement moteur, initialement par l’entremise d’outils de dépistage comme le test HINT, permet de recommander le patient à une intervention précoce qui profiterait tant à l’enfant qu’à sa famille. PMID:27521405

Response profiles of murine spiral ganglion neurons on multi-electrode arrays

NASA Astrophysics Data System (ADS)

Hahnewald, Stefan; Tscherter, Anne; Marconi, Emanuele; Streit, Jürg; Widmer, Hans Rudolf; Garnham, Carolyn; Benav, Heval; Mueller, Marcus; Löwenheim, Hubert; Roccio, Marta; Senn, Pascal

2016-02-01

Objective. Cochlear implants (CIs) have become the gold standard treatment for deafness. These neuroprosthetic devices feature a linear electrode array, surgically inserted into the cochlea, and function by directly stimulating the auditory neurons located within the spiral ganglion, bypassing lost or not-functioning hair cells. Despite their success, some limitations still remain, including poor frequency resolution and high-energy consumption. In both cases, the anatomical gap between the electrode array and the spiral ganglion neurons (SGNs) is believed to be an important limiting factor. The final goal of the study is to characterize response profiles of SGNs growing in intimate contact with an electrode array, in view of designing novel CI devices and stimulation protocols, featuring a gapless interface with auditory neurons. Approach. We have characterized SGN responses to extracellular stimulation using multi-electrode arrays (MEAs). This setup allows, in our view, to optimize in vitro many of the limiting interface aspects between CIs and SGNs. Main results. Early postnatal mouse SGN explants were analyzed after 6-18 days in culture. Different stimulation protocols were compared with the aim to lower the stimulation threshold and the energy needed to elicit a response. In the best case, a four-fold reduction of the energy was obtained by lengthening the biphasic stimulus from 40 μs to 160 μs. Similarly, quasi monophasic pulses were more effective than biphasic pulses and the insertion of an interphase gap moderately improved efficiency. Finally, the stimulation with an external electrode mounted on a micromanipulator showed that the energy needed to elicit a response could be reduced by a factor of five with decreasing its distance from 40 μm to 0 μm from the auditory neurons. Significance. This study is the first to show electrical activity of SGNs on MEAs. Our findings may help to improve stimulation by and to reduce energy consumption of CIs and

Rhythmic Ganglion Cell Activity in Bleached and Blind Adult Mouse Retinas

PubMed Central

Menzler, Jacob; Channappa, Lakshmi; Zeck, Guenther

2014-01-01

In retinitis pigmentosa – a degenerative disease which often leads to incurable blindness- the loss of photoreceptors deprives the retina from a continuous excitatory input, the so-called dark current. In rodent models of this disease this deprivation leads to oscillatory electrical activity in the remaining circuitry, which is reflected in the rhythmic spiking of retinal ganglion cells (RGCs). It remained unclear, however, if the rhythmic RGC activity is attributed to circuit alterations occurring during photoreceptor degeneration or if rhythmic activity is an intrinsic property of healthy retinal circuitry which is masked by the photoreceptor’s dark current. Here we tested these hypotheses by inducing and analysing oscillatory activity in adult healthy (C57/Bl6) and blind mouse retinas (rd10 and rd1). Rhythmic RGC activity in healthy retinas was detected upon partial photoreceptor bleaching using an extracellular high-density multi-transistor-array. The mean fundamental spiking frequency in bleached retinas was 4.3 Hz; close to the RGC rhythm detected in blind rd10 mouse retinas (6.5 Hz). Crosscorrelation analysis of neighbouring wild-type and rd10 RGCs (separation distance <200 µm) reveals synchrony among homologous RGC types and a constant phase shift (∼70 msec) among heterologous cell types (ON versus OFF). The rhythmic RGC spiking in these retinas is driven by a network of presynaptic neurons. The inhibition of glutamatergic ganglion cell input or the inhibition of gap junctional coupling abolished the rhythmic pattern. In rd10 and rd1 retinas the presynaptic network leads to local field potentials, whereas in bleached retinas additional pharmacological disinhibition is required to achieve detectable field potentials. Our results demonstrate that photoreceptor bleaching unmasks oscillatory activity in healthy retinas which shares many features with the functional phenotype detected in rd10 retinas. The quantitative physiological differences advance the

Hazardous Waste Cleanup: DuPont Imaging Department in Parlin, New Jersey

EPA Pesticide Factsheets

DuPont has owned and operated a chemical manufacturing plant on Cheesequake Road in Parlin, New Jersey, since 1904. DuPont manufactured a variety of products at the plant including, photographic films, automotive paints, pigments, adhesives, thinners,

Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells.

PubMed

Burblies, Niklas; Schulze, Jennifer; Schwarz, Hans-Christoph; Kranz, Katharina; Motz, Damian; Vogt, Carla; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

2016-01-01

Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs), either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes.

Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells

PubMed Central

Schwarz, Hans-Christoph; Kranz, Katharina; Motz, Damian; Vogt, Carla; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

2016-01-01

Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs), either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes. PMID:27385031

Chlorogenic acid alters the voltage-gated potassium channel currents of trigeminal ganglion neurons

PubMed Central

Zhang, Yu-Jiao; Lu, Xiao-Wen; Song, Ning; Kou, Liang; Wu, Min-Ke; Liu, Fei; Wang, Hang; Shen, Jie-Fei

2014-01-01

Chlorogenic acid (5-caffeoylquinic acid, CGA) is a phenolic compound that is found ubiquitously in plants, fruits and vegetables and is formed via the esterification of caffeic acid and quinic acid. In addition to its notable biological functions against cardiovascular diseases, type-2 diabetes and inflammatory conditions, CGA was recently hypothesized to be an alternative for the treatment of neurological diseases such as Alzheimer's disease and neuropathic pain disorders. However, its mechanism of action is unclear. Voltage-gated potassium channel (Kv) is a crucial factor in the electro-physiological processes of sensory neurons. Kv has also been identified as a potential therapeutic target for inflammation and neuropathic pain disorders. In this study, we analysed the effects of CGA on the two main subtypes of Kv in trigeminal ganglion neurons, namely, the IK,A and IK,V channels. Trigeminal ganglion (TRG) neurons were acutely disassociated from the rat TRG, and two different doses of CGA (0.2 and 1 mmol⋅L−1) were applied to the cells. Whole-cell patch-clamp recordings were performed to observe alterations in the activation and inactivation properties of the IK,A and IK,V channels. The results demonstrated that 0.2 mmol⋅L−1 CGA decreased the peak current density of IK,A. Both 0.2 mmol⋅L−1 and 1 mmol⋅L−1 CGA also caused a significant reduction in the activation and inactivation thresholds of IK,A and IK,V. CGA exhibited a strong effect on the activation and inactivation velocities of IK,A and IK,V. These findings provide novel evidence explaining the biological effects of CGA, especially regarding its neurological effects. PMID:25394592

Neural organisation in the first optic ganglion of the nocturnal bee Megalopta genalis.

PubMed

Greiner, Birgit; Ribi, Willi A; Wcislo, William T; Warrant, Eric J

2004-11-01

Each neural unit (cartridge) in the first optic ganglion (lamina) of the nocturnal bee Megalopta genalis contains nine receptor cell axons (6 short and 3 long visual fibres), and four different types of first-order interneurons, also known as L-fibres (L1 to L4) or lamina monopolar cells. The short visual fibres terminate within the lamina as three different types (svf 1, 2, 3). The three long visual fibres pass through the lamina without forming characteristic branching patterns and terminate in the second optic ganglion, the medulla. The lateral branching pattern of svf 2 into adjacent cartridges is unique for hymenopterans. In addition, all four types of L-fibres show dorso-ventrally arranged, wide, lateral branching in this nocturnal bee. This is in contrast to the diurnal bees Apis mellifera and Lasioglossum leucozonium, where only two out of four L-fibre types (L2 and L4) reach neighbouring cartridges. In M. genalis, L1 forms two sub-types, viz. L1-a and L1-b; L1-b in particular has the potential to contact several neighbouring cartridges. L2 and L4 in the nocturnal bee are similar to L2 and L4 in the diurnal bees but have dorso-ventral arborisations that are twice as wide. A new type of laterally spreading L3 has been discovered in the nocturnal bee. The extensive neural branching pattern of L-fibres in M. genalis indicates a potential role for these neurons in the spatial summation of photons from large groups of ommatidia. This specific adaptation in the nocturnal bee could significantly improve reliability of vision in dim light.

Expression of polysialylated neural cell adhesion molecules on adult stem cells after neuronal differentiation of inner ear spiral ganglion neurons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Kyoung Ho; Yeo, Sang Won, E-mail: swyeo@catholic.ac.kr; Troy, Frederic A., E-mail: fatroy@ucdavis.edu

Highlights: • PolySia expressed on neurons primarily during early stages of neuronal development. • PolySia–NCAM is expressed on neural stem cells from adult guinea pig spiral ganglion. • PolySia is a biomarker that modulates neuronal differentiation in inner ear stem cells. - Abstract: During brain development, polysialylated (polySia) neural cell adhesion molecules (polySia–NCAMs) modulate cell–cell adhesive interactions involved in synaptogenesis, neural plasticity, myelination, and neural stem cell (NSC) proliferation and differentiation. Our findings show that polySia–NCAM is expressed on NSC isolated from adult guinea pig spiral ganglion (GPSG), and in neurons and Schwann cells after differentiation of the NSC withmore » epidermal, glia, fibroblast growth factors (GFs) and neurotrophins. These differentiated cells were immunoreactive with mAb’s to polySia, NCAM, β-III tubulin, nestin, S-100 and stained with BrdU. NSC could regenerate and be differentiated into neurons and Schwann cells. We conclude: (1) polySia is expressed on NSC isolated from adult GPSG and on neurons and Schwann cells differentiated from these NSC; (2) polySia is expressed on neurons primarily during the early stage of neuronal development and is expressed on Schwann cells at points of cell–cell contact; (3) polySia is a functional biomarker that modulates neuronal differentiation in inner ear stem cells. These new findings suggest that replacement of defective cells in the inner ear of hearing impaired patients using adult spiral ganglion neurons may offer potential hope to improve the quality of life for patients with auditory dysfunction and impaired hearing disorders.« less

Retinal ganglion cell maps in the brain: implications for visual processing.

PubMed

Dhande, Onkar S; Huberman, Andrew D

2014-02-01

Everything the brain knows about the content of the visual world is built from the spiking activity of retinal ganglion cells (RGCs). As the output neurons of the eye, RGCs include ∼20 different subtypes, each responding best to a specific feature in the visual scene. Here we discuss recent advances in identifying where different RGC subtypes route visual information in the brain, including which targets they connect to and how their organization within those targets influences visual processing. We also highlight examples where causal links have been established between specific RGC subtypes, their maps of central connections and defined aspects of light-mediated behavior and we suggest the use of techniques that stand to extend these sorts of analyses to circuits underlying visual perception. Copyright © 2013. Published by Elsevier Ltd.

Immunocytochemical localization of metabotropic (mGluR2/3 and mGluR4a) and ionotropic (GluR2/3) glutamate receptors in adrenal medullary ganglion cells.

PubMed

Sarría, R; Díez, J; Losada, J; Doñate-Oliver, F; Kuhn, R; Grandes, P

2006-02-01

The localization of metabotropic glutamate receptors of groups II (mGluR2/3) and III (mGluR4a) and the subunits 2 and 3 of alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) ionotropic glutamate receptors (GluR2/3) was investigated with immunocytochemical methods in the rat adrenal gland. MGluR2/3, mGluR4a and GluR2/3 immunoreactivities were observed in large-sized, centrally located type I adrenal medullary ganglion neurons. Furthermore, the small-sized type II adrenal ganglion neurons identified by their immunoreactivity to brain nitric oxide synthase (bNOS), also expressed mGluR2/3, mGluR4a and GluR2/3. These cells were disposed in the peripheral portion of the adrenal medulla. None of the type I neurons were positively labeled for bNOS. These morphological observations suggest that activation of glutamate receptors in ganglion neurons may be instrumental in the control of adrenal endocrine systems as well as blood regulation.

Archer fish fast hunting maneuver may be guided by directionally selective retinal ganglion cells.

PubMed

Tsvilling, Vadim; Donchin, Opher; Shamir, Maoz; Segev, Ronen

2012-02-01

Archer fish are known for their unique hunting method, where one fish in a group shoots down an insect with a jet of water while all the other fish are observing the prey's motion. To reap its reward, the archer fish must reach the prey before its competitors. This requires fast computation of the direction of motion of the prey, which enables the fish to initiate a turn towards the prey with an accuracy of 99%, at about 100 ms after the prey is shot. We explored the hypothesis that direction-selective retinal ganglion cells may underlie this rapid processing. We quantified the degree of directional selectivity of ganglion cells in the archer fish retina. The cells could be categorized into three groups: sharply (5%), broadly (37%) and non-tuned (58%) directionally selective cells. To relate the electrophysiological data to the behavioral results we studied a computational model and estimated the time required to accumulate sufficient directional information to match the decision accuracy of the fish. The computational model is based on two direction-selective populations that race against each other until one reaches the threshold and drives the decision. We found that this competition model can account for the observed response time at the required accuracy. Thus, our results are consistent with the hypothesis that the fast response behavior of the archer fish relies on retinal identification of movement direction. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Visual responses of ganglion cells of a New-World primate, the capuchin monkey, Cebus apella.

PubMed

Lee, B B; Silveira, L C; Yamada, E S; Hunt, D M; Kremers, J; Martin, P R; Troy, J B; da Silva-Filho, M

2000-11-01

1. The genetic basis of colour vision in New-World primates differs from that in humans and other Old-World primates. Most New-World primate species show a polymorphism; all males are dichromats and most females trichromats. 2. In the retina of Old-World primates such as the macaque, the physiological correlates of trichromacy are well established. Comparison of the retinae in New- and Old-World species may help constrain hypotheses as to the evolution of colour vision and the pathways associated with it. 3. Ganglion cell behaviour was recorded from trichromatic and dichromatic members of a New-World species (the capuchin monkey, Cebus apella) and compared with macaque data. Despite some differences in quantitative detail (such as a temporal response extended to higher frequencies), results from trichromatic animals strongly resembled those from the macaque. 4. In particular, cells of the parvocellular (PC) pathway showed characteristic frequency-dependent changes in responsivity to luminance and chromatic modulation, cells of the magnocellular (MC) pathway showed frequency-doubled responses to chromatic modulation, and the surround of MC cells received a chromatic input revealed on changing the phase of heterochromatically modulated lights. 5. Ganglion cells of dichromats were colour-blind versions of those of trichromats. 6. This strong physiological homology is consistent with a common origin of trichromacy in New- and Old-World monkeys; in the New-World primate the presence of two pigments in the middle-to-long wavelength range permits full expression of the retinal mechanisms of trichromatic vision.

An intracellular characterization of neurones and neural connexions within the left coeliac ganglion of cats.

PubMed Central

Decktor, D L; Weems, W A

1983-01-01

Intracellular recordings were made in vitro from neurones located within the left coeliac ganglion of the cat solar plexus. Thirty percent of the neurones within left coeliac ganglia were identified as efferent neurones. Within this neuronal population, splenic-efferent and renal-efferent neurones were identified specifically. Neurones within left coeliac ganglia were characterized as either phasic (fast adapting) neurones or tonic (slowly adapting) neurones depending upon their prolonged firing behaviour. Electrophysiological properties of neurones varied considerably. The wide range of values obtained for both input resistance and input capacitance suggest that sizeable differences in either specific membrane resistance or cell geometry exist within the over-all neurone population. Frequency distributions of input resistance, time constant, input capacitance and current threshold for tonic and phasic neurones were found to be significantly different. Compound excitatory post-synaptic potentials were produced by stimulation of the ipsilateral splanchnic nerves in 69% of the neurones tested and in 3% of the neurones tested upon stimulation of the contralateral splanchnic nerves. Electrical stimulation of nerve fibres located in the coeliac plexus, the superior mesenteric plexus or the left renal nerves generated excitatory synaptic potentials in neurones located within left coeliac ganglia. It is concluded that neurones within the left coeliac ganglion are innervated by splanchnic nerve fibres primarily contained within the left splanchnic nerves, receive excitatory synaptic input from splenic, renal and other peripheral preganglionic fibres and have extremely varied electrophysiological properties. PMID:6620179

Macular Ganglion Cell Imaging Study: Covariate Effects on the Spectral Domain Optical Coherence Tomography for Glaucoma Diagnosis

PubMed Central

Jeong, Jae Hoon; Choi, Yun Jeong; Park, Ki Ho; Kim, Dong Myung

2016-01-01

Purpose To evaluate the effect of multiple covariates on the diagnostic performance of the Cirrus high-definition optical coherence tomography (HD-OCT) for glaucoma detection. Methods A prospective case-control study was performed and included 173 recently diagnosed glaucoma patients and 63 unaffected individuals from the Macular Ganglion Cell Imaging Study. Regression analysis of receiver operating characteristic were conducted to evaluate the influence of age, spherical equivalent, axial length, optic disc size, and visual field index on the macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) measurements. Results Disease severity, as measured by visual field index, had a significant effect on the diagnostic performance of all Cirrus HD-OCT parameters. Age, axial length and optic disc size were significantly associated with diagnostic accuracy of average peripapillary RNFL thickness, whereas axial length had a significant effect on the diagnostic accuracy of average GCIPL thickness. Conclusions Diagnostic performance of the Cirrus HD-OCT may be more accurate in the advanced stages of glaucoma than at earlier stages. A smaller optic disc size was significantly associated with improved the diagnostic ability of average RNFL thickness measurements; however, GCIPL thickness may be less affected by age and optic disc size. PMID:27490718

Hazardous Waste Cleanup: E.I. DuPont de Nemours & Company in Pompton Lakes, New Jersey

EPA Pesticide Factsheets

E.I. DuPont De Nemours & Company is located at 2000 Cannonball Road, Pompton Lakes, New Jersey. The DuPont Pompton Lakes Works site (DuPont) occupies approximately 570 acres of land in Pompton Lakes and Wanaque.

Is compensatory hyperhidrosis after thoracic sympathicotomy in palmar hyperhidrosis patients related to the excitability of thoracic sympathetic ganglions?

PubMed Central

Chen, Jun-Peng; Peng, A-Jing; Xu, Chen-Hui; Li, Guo-Ying

2017-01-01

Background The mechanism of compensatory hyperhidrosis remains unclear. The aim of this study was to explore the relationship between compensatory hyperhidrosis and thoracic sympathetic ganglion excitability to assess the effectiveness of thoracoscopic T4 sympathicotomy for treating palmar hyperhidrosis. Methods Sixty-six cases of T4 sympathetic ganglions were prospectively collected from patients with palmar hyperhidrosis who underwent thoracoscopic T4 sympathicotomy from 2013 to 2016 in our department. The expression levels of choline acetyltransferase (ChAT), vasoactive intestinal peptide (VIP), and synaptophysin were detected using immunohistochemistry. Patients with palmar hyperhidrosis were followed-up for examination of postoperative sweating status. Results Thirty-eight cases (57.6%) of compensatory hyperhidrosis were identified. Mild compensatory hyperhidrosis occurred in 26 patients (39.4%), moderate in 11 (16.7%), and severe in 1 (1.5%). The rate of compensatory hyperhidrosis was higher in patients with axilla hyperhidrosis than those without (76.0% vs. 46.3%, P=0.018). However, the clinical data were similar between the compensatory hyperhidrosis group and the no compensatory hyperhidrosis group. In addition, the ChAT, VIP, and synaptophysin expression levels were not significantly different between the two groups (P values of 0.356, 0.071, and 0.141, respectively). Furthermore, the ChAT, VIP, and synaptophysin expression levels in the mild group were similar to those observed in the moderate/intense group (P values of 0.089, 0.124, and 0.149, respectively). The remission rate was 100% in palmar hyperhidrosis, 48.2% (27/56) in pedal hyperhidrosis, 56.0% (14/25) in axilla hyperhidrosis and 88.9% (16/18) in skin symptoms. No signs of chapped skin on the palms were found. Conclusions There was no significant correlation between compensatory hyperhidrosis and thoracic sympathetic ganglion excitability; however, compensatory hyperhidrosis is more likely to

Localisation inhabituelle de la tuberculose: ostéoarthrite tuberculose du pouce

PubMed Central

Mortaji, Aziz; Koulali, Khalid; Galuia, Farid

2014-01-01

L'ostéoarthrite tuberculose est rare au niveau des doigts. Nous rapportons une observation d'atteinte du pouce chez un patient de 55 ans. Il avait présenté une tuméfaction douloureuse du pouce droit suite à un traumatisme du pouce. L’étude bactériologique et une biopsie avaient permis de confirmer le diagnostic. Un traitement antibacillaire de 12 mois avait donné des résultats satisfaisants. Les particularités de la prise en charge sont discutées par rapport aux données de la littérature. PMID:25932075

Zinc oxide nanoparticles decrease the expression and activity of plasma membrane calcium ATPase, disrupt the intracellular calcium homeostasis in rat retinal ganglion cells.

PubMed

Guo, Dadong; Bi, Hongsheng; Wang, Daoguang; Wu, Qiuxin

2013-08-01

Zinc oxide nanoparticle is one of the most important materials with diverse applications. However, it has been reported that zinc oxide nanoparticles are toxic to organisms, and that oxidative stress is often hypothesized to be an important factor in cytotoxicity mediated by zinc oxide nanoparticles. Nevertheless, the mechanism of toxicity of zinc oxide nanoparticles has not been completely understood. In this study, we investigated the cytotoxic effect of zinc oxide nanoparticles and the possible molecular mechanism involved in calcium homeostasis mediated by plasma membrane calcium ATPase in rat retinal ganglion cells. Real-time cell electronic sensing assay showed that zinc oxide nanoparticles could exert cytotoxic effect on rat retinal ganglion cells in a concentration-dependent manner; flow cytometric analysis indicated that zinc oxide nanoparticles could lead to cell damage by inducing the overproduction of reactive oxygen species. Furthermore, zinc oxide nanoparticles could also apparently decrease the expression level and their activity of plasma membrane calcium ATPase, which finally disrupt the intracellular calcium homeostasis and result in cell death. Taken together, zinc oxide nanoparticles could apparently decrease the plasma membrane calcium ATPase expression, inhibit their activity, cause the elevated intracellular calcium ion level and disrupt the intracellular calcium homeostasis. Further, the disrupted calcium homeostasis will trigger mitochondrial dysfunction, generate excessive reactive oxygen species, and finally initiate cell death. Thus, the disrupted calcium homeostasis is involved in the zinc oxide nanoparticle-induced rat retinal ganglion cell death. Copyright © 2013 Elsevier Ltd. All rights reserved.

Etude thermo-hydraulique de l'ecoulement du moderateur dans le reacteur CANDU-6

NASA Astrophysics Data System (ADS)

Mehdi Zadeh, Foad

Etant donne la taille (6,0 m x 7,6 m) ainsi que le domaine multiplement connexe qui caracterisent la cuve des reacteurs CANDU-6 (380 canaux dans la cuve), la physique qui gouverne le comportement du fluide moderateur est encore mal connue de nos jours. L'echantillonnage de donnees dans un reacteur en fonction necessite d'apporter des changements a la configuration de la cuve du reacteur afin d'y inserer des sondes. De plus, la presence d'une zone intense de radiations empeche l'utilisation des capteurs courants d'echantillonnage. En consequence, l'ecoulement du moderateur doit necessairement etre etudie a l'aide d'un modele experimental ou d'un modele numerique. Pour ce qui est du modele experimental, la fabrication et la mise en fonction de telles installations coutent tres cher. De plus, les parametres de la mise a l'echelle du systeme pour fabriquer un modele experimental a l'echelle reduite sont en contradiction. En consequence, la modelisation numerique reste une alternative importante. Actuellement, l'industrie nucleaire utilise une approche numerique, dite de milieu poreux, qui approxime le domaine par un milieu continu ou le reseau des tubes est remplace par des resistances hydrauliques distribuees. Ce modele est capable de decrire les phenomenes macroscopiques de l'ecoulement, mais ne tient pas compte des effets locaux ayant un impact sur l'ecoulement global, tel que les distributions de temperatures et de vitesses a proximite des tubes ainsi que des instabilites hydrodynamiques. Dans le contexte de la surete nucleaire, on s'interesse aux effets locaux autour des tubes de calandre. En effet, des simulations faites par cette approche predisent que l'ecoulement peut prendre plusieurs configurations hydrodynamiques dont, pour certaines, l'ecoulement montre un comportement asymetrique au sein de la cuve. Ceci peut provoquer une ebullition du moderateur sur la paroi des canaux. Dans de telles conditions, le coefficient de reactivite peut varier de maniere

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness.

PubMed

Mallery, Robert M; Poolman, Pieter; Thurtell, Matthew J; Wang, Jui-Kai; Garvin, Mona K; Ledolter, Johannes; Kardon, Randy H

2016-07-01

The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure-function relationship between fixation and areas of preserved GCC in patients with ON.

Presence of Functional Neurotrophin TrkB Receptors in the Rat Superior Cervical Ganglion

PubMed Central

Valle-Leija, Pablo; Cancino-Rodezno, Angeles; Sánchez-Tafolla, Berardo M.; Arias, Erwin; Elinos, Diana; Feria, Jessica; Zetina, María E.; Morales, Miguel A.; Cifuentes, Fredy

2017-01-01

Sympathetic neurons express the neurotrophin receptors TrkA, p75NTR, and a non-functional truncated TrkB isoform (TrkB-Tc), but are not thought to express a functional full-length TrkB receptor (TrkB-Fl). We, and others, have demonstrated that nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) modulate synaptic transmission and synaptic plasticity in neurons of the superior cervical ganglion (SCG) of the rat. To clarify whether TrkB is expressed in sympathetic ganglia and contributes to the effects of BDNF upon sympathetic function, we characterized the presence and activity of the neurotrophin receptors expressed in the adult SCG compared with their presence in neonatal and cultured sympathetic neurons. Here, we expand our previous study regarding the immunodetection of neurotrophin receptors. Immunohistochemical analysis revealed that 19% of adult ganglionic neurons expressed TrkB-Fl immunoreactivity (IR), 82% expressed TrkA-IR, and 51% expressed p75NTR-IR; TrkB-Tc would be expressed in 36% of neurons. In addition, using Western-blotting and reverse transcriptase polymerase chain reaction (RT-PCR) analyses, we confirmed the expression of TrkB-Fl and TrkB-Tc protein and mRNA transcripts in adult SCG. Neonatal neurons expressed significantly more TrkA-IR and TrkB-Fl-IR than p75NTR-IR. Finally, the application of neurotrophin, and high frequency stimulation, induced the activation of Trk receptors and the downstream PI3-kinase (phosphatidyl inositol-3-kinase) signaling pathway, thus evoking the phosphorylation of Trk and Akt. These results demonstrate that SCG neurons express functional TrkA and TrkB-Fl receptors, which may contribute to the differential modulation of synaptic transmission and long-term synaptic plasticity. PMID:28744222

Can Retinal Ganglion Cell Dipoles Seed Iso-Orientation Domains in the Visual Cortex?

PubMed Central

Schottdorf, Manuel; Eglen, Stephen J.; Wolf, Fred; Keil, Wolfgang

2014-01-01

It has been argued that the emergence of roughly periodic orientation preference maps (OPMs) in the primary visual cortex (V1) of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs). The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex. PMID:24475081

Presence of Functional Neurotrophin TrkB Receptors in the Rat Superior Cervical Ganglion.

PubMed

Valle-Leija, Pablo; Cancino-Rodezno, Angeles; Sánchez-Tafolla, Berardo M; Arias, Erwin; Elinos, Diana; Feria, Jessica; Zetina, María E; Morales, Miguel A; Cifuentes, Fredy

2017-01-01

Sympathetic neurons express the neurotrophin receptors TrkA, p75NTR, and a non-functional truncated TrkB isoform (TrkB-Tc), but are not thought to express a functional full-length TrkB receptor (TrkB-Fl). We, and others, have demonstrated that nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) modulate synaptic transmission and synaptic plasticity in neurons of the superior cervical ganglion (SCG) of the rat. To clarify whether TrkB is expressed in sympathetic ganglia and contributes to the effects of BDNF upon sympathetic function, we characterized the presence and activity of the neurotrophin receptors expressed in the adult SCG compared with their presence in neonatal and cultured sympathetic neurons. Here, we expand our previous study regarding the immunodetection of neurotrophin receptors. Immunohistochemical analysis revealed that 19% of adult ganglionic neurons expressed TrkB-Fl immunoreactivity (IR), 82% expressed TrkA-IR, and 51% expressed p75NTR-IR; TrkB-Tc would be expressed in 36% of neurons. In addition, using Western-blotting and reverse transcriptase polymerase chain reaction (RT-PCR) analyses, we confirmed the expression of TrkB-Fl and TrkB-Tc protein and mRNA transcripts in adult SCG. Neonatal neurons expressed significantly more TrkA-IR and TrkB-Fl-IR than p75NTR-IR. Finally, the application of neurotrophin, and high frequency stimulation, induced the activation of Trk receptors and the downstream PI3-kinase (phosphatidyl inositol-3-kinase) signaling pathway, thus evoking the phosphorylation of Trk and Akt. These results demonstrate that SCG neurons express functional TrkA and TrkB-Fl receptors, which may contribute to the differential modulation of synaptic transmission and long-term synaptic plasticity.

Can retinal ganglion cell dipoles seed iso-orientation domains in the visual cortex?

PubMed

Schottdorf, Manuel; Eglen, Stephen J; Wolf, Fred; Keil, Wolfgang

2014-01-01

It has been argued that the emergence of roughly periodic orientation preference maps (OPMs) in the primary visual cortex (V1) of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs). The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex.

Le schwannome malin du nerf grand sciatique chez l'enfant

PubMed Central

Lechqar, Maryem; Elbiache, Imad; Atarraf, Karima; Bouabdellah, Youssef; Afifi, My Abderahman

2012-01-01

Le schwannome malin est une tumeur très rare chez l'enfant (1 à 2% des tumeurs des tissus mous), elle se développe au dépend des cellules de schwanne. Dans ce travail, les auteurs rapportent un cas de schwannome malin développé au dépend du nerf grand sciatique. La radiographie de la cuisse de face et de profil était normale. L'imagerie par résonance magnétique a identifié une lésion le long du trajet du nerf grand sciatique. La tumeur a été réséquée en totalité emportant le nerf grand sciatique. L'examen anatomo-pathologique a confirmé le diagnostic. PMID:23133710

Les accidents du travail dans le transport urbain en commun de la ville province de Kinshasa, République Démocratique du Congo: une étude transversale descriptive

PubMed Central

Wangata, Jemima; Elenge, Myriam; De Brouwer, Christophe

2014-01-01

Introduction Le transport en commun urbain constitue un secteur où les travailleurs sont très exposés aux accidents du travail. Cette étude visait une description épidémiologique des accidents du travail dans le secteur informel du transport en commun à Kinshasa en vue d'apporter les pistes d'amélioration de la sécurité des travailleurs dans cette activité. Méthodes Un questionnaire sur les accidents du travail, administré en Décembre 2012 a permis d'explorer les tendances significatives entre les accidents et leurs circonstances, leurs facteurs associés, leurs conséquences au sein d'une population des travailleurs (n = 472) du transport en commun à Kinshasa. Résultats Durant les 12 derniers précédant l’étude 76.5% des travailleurs ont connu au moins un accident du travail, 54,8% ont connu un arrêt d'au moins 1jour. Les accidents liés à la circulation routière étaient plus important suivis des chutes. Les facteurs ayant montré des différences significatives étaient le travail sous l'influence de l'alcool et le port des équipements de protection individuelle. Les plaies (46,3%) et les contusions (39,4%) étaient les lésions les plus courantes. Les membres supérieurs (51,3%) et inférieurs (30,7%) étaient les plus atteints. 76,6% des travailleurs ont assumé seuls leur prise en charge médicale. Conclusion L'incidence des accidents du travail dans ce secteur est très élevée. La mise en place d'une politique de prévention et gestion de différents facteurs associés ainsi qu'un système de déclaration d'accidents est nécessaire dans ce secteur. Les patrons ainsi que les politiques devraient veiller à une prise en charge médicale correcte pour des travailleurs accidentés. PMID:25667703

Fractalkine Signaling Regulates Macrophage Recruitment into the Cochlea and Promotes the Survival of Spiral Ganglion Neurons after Selective Hair Cell Lesion.

PubMed

Kaur, Tejbeer; Zamani, Darius; Tong, Ling; Rubel, Edwin W; Ohlemiller, Kevin K; Hirose, Keiko; Warchol, Mark E

2015-11-11

Macrophages are recruited into the cochlea in response to injury caused by acoustic trauma or ototoxicity, but the nature of the interaction between macrophages and the sensory structures of the inner ear remains unclear. The present study examined the role of fractalkine signaling in regulating the injury-evoked behavior of macrophages following the selective ablation of cochlear hair cells. We used a novel transgenic mouse model in which the human diphtheria toxin receptor (huDTR) is selectively expressed under the control of Pou4f3, a hair cell-specific transcription factor. Administration of diphtheria toxin (DT) to these mice resulted in nearly complete ablation of cochlear hair cells, with no evident pathology among supporting cells, spiral ganglion neurons, or cells of the cochlear lateral wall. Hair cell death led to an increase in macrophages associated with the sensory epithelium of the cochlea. Their numbers peaked at 14 days after DT and then declined at later survival times. Increased macrophages were also observed within the spiral ganglion, but their numbers remained elevated for (at least) 56 d after DT. To investigate the role of fractalkine signaling in macrophage recruitment, we crossed huDTR mice to a mouse line that lacks expression of the fractalkine receptor (CX3CR1). Disruption of fractalkine signaling reduced macrophage recruitment into both the sensory epithelium and spiral ganglion and also resulted in diminished survival of spiral ganglion neurons after hair cell death. Our results suggest a fractalkine-mediated interaction between macrophages and the neurons of the cochlea. It is known that damage to the inner ear leads to recruitment of inflammatory cells (macrophages), but the chemical signals that initiate this recruitment and the functions of macrophages in the damaged ear are unclear. Here we show that fractalkine signaling regulates macrophage recruitment into the cochlea and also promotes the survival of cochlear afferents after

Une forme exceptionnelle de la luxation perilunaire du carpe

PubMed Central

Elouakili, Issam; Ouchrif, Younes; Najib, Abdeljaouad; Ouakrim, Redouane; Lamrani, Omar; Kharmaz, Mohammed; Ismael, Farid; Lahlou, Abdo; Elouadghiri, Mohammed; El Bardouni, Ahmed; Mahfoud, Mustapha; Berrada, Mohammed Saleh; El Yaccoubi, Mouradh

2014-01-01

Les luxations périlunaires (LPL) du carpe sont des lésions extrêmement rares, qui peuvent passer inaperçue en raison d'un tableau clinique souvent trompeur, des radiographies en profil non strict ou d'interprétation difficile. Nous rapportons l'observation d'une luxation périlunaire stade III selon la classification de Witvoët et Allieu chez un patient de 32 ans, il s'agit d'une forme encore plus rare voire exceptionnelle et qui peut induire de sérieux problèmes en raison de la sévérité des dommages ligamentaires et du risque de nécrose du semilunaire plus important dans ce type de lésions. Le traitement est toujours chirurgical et doit être réalisé dans les plus brefs délais afin d’éviter les complications. PMID:25404968

Marihuana: A Conversation with NIDA's Robert L. DuPont.

PubMed

Maugh, T H

1976-05-14

Robert L. DuPont, director of the National Institute on Drug Abuse (NIDA), made headlines recently when he became one of the first Administration officials publicly to recommend a liberalization of marihuana laws. The occasion was a press conference accompanying the release of Marihuana and Health, NIDA's fifth annual report to the Congress on marihuana research. Recently, Science talked with DuPont and asked him to elaborate on those views. DuPont, a 40-year-old Harvard M.D., served as Director of the District of Columbia's Narcotics Treatment Administration from 1970 to 1973, where he conducted a comprehensive program for treatment of heroin addiction. In June 1973, Richard Nixon appointed him director of the White House Special Action Office for Drug Abuse Prevention. He held that position until the office was terminated on 30 June 1975. He has been director of NIDA since September 1973.

Niveaux d'étude du cerveau, et sagesse physique

NASA Astrophysics Data System (ADS)

Toulouse, Gérard

1993-02-01

The brain is a complex spatio-temporal affair. Several brain theories propose the definition of three superposed levels of study. But physics, though the experience of condensed matter physics, suggests that it is unwise to enforce onto brain theories a unified hierarchical scheme, the inspiration for which seems to come from the realm of sub-molecular physics. Le cerveau est une affaire spatio-temporelle complexe. Plusieurs théories du cerveau proposent de définir trois niveaux d'études superposés. Mais la physique, à travers l'expérience de la physique de la matière condensée, suggère qu'il n'est pas sage d'imposer sur les théories du cerveau un schéma hiérarchique unifié, dont l'inspiration semble provenir du domaine de la physique sub-moléculaire.

The developing dorsal ganglion of the salp Thalia democratica, and the nature of the ancestral chordate brain

PubMed Central

C.Lacalli, T.

1998-01-01

The development of the dorsal ganglion of the salp, Thalia democratica, is described from electron microscope reconstructions up to the stage of central neuropile formation. The central nervous system (CNS) rudiment is initially tubular with an open central canal. Early developmental events include: (i) the formation of a thick dorsal mantle of neuroblasts from which paired dorsal paraxial neuropiles arise; (ii) the differentiation of clusters of primary motor neurons along the ventral margin of the mantle; and (iii) the development from the latter of a series of peripheral nerves. The dorsal paraxial neuropiles ultimately connect to the large central neuropile, which develops later. Direct contact between neuroblasts and muscle appears to be involved in the development of some anterior nerves. The caudal nerves responsible for innervating more distant targets in the posterior part of the body develop without such contacts, which suggests that a different patterning mechanism may be employed in this part of the neuromuscular system. The results are compared with patterns of brain organization in other chordates. Because the salp CNS is symmetrical and generally less reduced than that of ascidian larvae, it is more easily compared with the CNS of amphioxus and vertebrates. The dorsal paraxial centres in the salp resemble the dorsolateral tectal centres in amphioxus in both position and organization; the central neuropile in salps likewise resembles the translumenal system in amphioxus. The neurons themselves are similar in that many of their neurites appear to be derived from the apical surface instead of the basal surface of the cell. Such neurons, with extensively developed apical neurites, may represent a new cell type that evolved in the earliest chordates in conjunction with the formation of translumenal or intralumenal integrative centres. In comparing the salp ganglion with vertebrates, we suggest that the main core of the ganglion is most like the mes

Conventional Radiofrequency Thermocoagulation vs Pulsed Radiofrequency Neuromodulation of Ganglion Impar in Chronic Perineal Pain of Nononcological Origin.

PubMed

Usmani, Hammad; Dureja, G P; Andleeb, Roshan; Tauheed, Nazia; Asif, Naiyer

2018-01-10

Chronic nononcological perineal pain has been effectively managed by ganglion Impar block. Chemical neurolysis, cryoablation, and radiofrequency ablation have been the accepted methods of blockade. Recently, pulsed radiofrequency, a novel variant of conventional radiofrequency, has been used for this purpose. This was a prospective, randomized, double-blind study. Two different interventional pain management centers in India. To compare the efficacy of conventional radiofrequency and pulsed radiofrequency for gangliom Impar block. The patients were randomly allocated to one of two groups. In the conventional radiofrequency (CRF) group (N = 34), conventional radiofrequency ablation was done, and in the PRF pulsed radiofrequency (PRF) group (N = 31), pulsed radiofrequency ablation was done. After informed and written consent, fluoroscopy-guided ganglion Impar block was performed through the first intracoccygeal approach. The extent of pain relief was assessed by visual analog scale (VAS) at 24 hours, and at the first, third, and sixth weeks following the intervention. A questionnaire to evaluate subjective patient satisfaction was also used at each follow-up visit. In the CRF group, the mean VAS score decreased significantly from the baseline value at each follow-up visit. But in the PRF group, this decrease was insignificant except at 24-hour follow-up. Intergroup comparison also showed significantly better pain relief in the CRF group as compared with the PRF group. At the end of follow-up, 28 patients (82%) in the CRF group and four patients (13%) in the PRF group had excellent results, as assessed by the subjective patient satisfaction questionnaire. There was no complication in any patient of either study group, except for short-lived infection at the site of skin puncture in a few. Ganglion Impar block by conventional radiofrequency provided a significantly better quality of pain relief with no major side effects in patients with chronic

Dorsal Root Ganglion Stimulation for Complex Regional Pain Syndrome (CRPS) Recurrence after Amputation for CRPS, and Failure of Conventional Spinal Cord Stimulation.

PubMed

Goebel, Andreas; Lewis, Sarah; Phillip, Rhodri; Sharma, Manohar

2018-01-01

Limb amputation is sometimes being performed in long-standing complex regional pain syndrome (CRPS), although little evidence is available guiding management decisions, including how CRPS recurrence should be managed. This report details the management of a young soldier with CRPS recurrence 2 years after midtibial amputation for CRPS. Conventional spinal cord stimulation did not achieve paraesthetic coverage, or pain relief in the stump, whereas L4 dorsal root ganglion stimulation achieved both coverage and initially modest pain relief, and over time, substantial pain relief. Current evidence does not support the use of amputation to improve either pain or function in CRPS. Before a decision is made, in exceptional cases, about referral for amputation, dorsal root ganglion stimulation should be considered as a potentially effective treatment, even where conventional spinal cord stimulator treatment has failed to achieve reliable paraesthetic cover. Furthermore, this treatment may provide pain relief in those patients with CRPS recurrence in the stump after amputation. © 2017 World Institute of Pain.

Application of three-dimensional rendering in joint-related ganglion cysts.

PubMed

Spinner, Robert J; Edwards, Phillip K; Amrami, Kimberly K

2006-05-01

The origin of para-articular cysts is poorly understood and controversial. The relatively common, simple (extraneural) cysts are presumed to be derived from joints, although joint connections are not always established. Rarer complex cysts are thought by many to form de novo within nerves (intraneural ganglion cysts) or within vessels (adventitial cysts) (degenerative theory). We believe that these simple and complex ganglion cysts are joint-related (articular theory). Joint connections are often not readily appreciated with routine imaging or at surgery. Not identifying and/or treating joint connections frequently leads to cyst recurrence. More sophisticated imaging may enhance visualization of these joint connections. We created a 3D rendering technique to assess potential joint connections of simple and complex cysts localized to the knee and superior tibiofibular joints in patients with fibular (peroneal) neuropathy. Two- and three-dimensional data sets from MRI examinations were segmented semiautomatically by signal intensity with further refinement based on interaction with the user to identify specific anatomic structures, such as small nerves and vessels on serial images. The bone, cysts, nerves, and vessels were each assigned different color representations, and 3D renderings were created in ANALYZE using the data sets closest to isotropic (voxel with equal length in all dimensions) resolution as the primary background rendering. We selected four cases to illustrate the spectrum of pathology. In all of these cases, we demonstrated joint connections and correlated imaging and operative findings. Surgery addressing the cyst and the joint connection resulted in excellent outcomes; postoperative MRIs done more than 6 months later confirmed that there was no recurrence. In addition to highlighting the important relationship of these cysts to neighboring anatomic structures, this 3D technique allows visualization of "occult" connections not readily appreciated

Neuroprotection of a Novel Cyclopeptide C*HSDGIC* from the Cyclization of PACAP (1–5) in Cellular and Rodent Models of Retinal Ganglion Cell Apoptosis

PubMed Central

Cheng, Huanhuan; Ding, Yong; Yu, Rongjie; Chen, Jiansu; Wu, Chunyun

2014-01-01

Purpose To investigate the protective effects of a novel cyclopeptide C*HSDGIC* (CHC) from the cyclization of Pituitary adenylate cyclase-activating polypeptide (PACAP) (1–5) in cellular and rodent models of retinal ganglion cell apoptosis. Methodology/Principal Findings Double-labeling immunohistochemistry was used to detect the expression of Thy-1 and PACAP receptor type 1 in a retinal ganglion cell line RGC-5. The apoptosis of RGC-5 cells was induced by 0.02 J/cm2 Ultraviolet B irradiation. MTT assay, flow cytometry, fluorescence microscopy were used to investigate the viability, the level of reactive oxygen species (ROS) and apoptosis of RGC-5 cells respectively. CHC attenuated apoptotic cell death induced by Ultraviolet B irradiation and inhibited the excessive generation of ROS. Moreover, CHC treatment resulted in decreased expression of Bax and concomitant increase of Bcl-2, as was revealed by western-blot analysis. The in vivo apoptosis of retinal ganglion cells was induced by injecting 50 mM N-methyl-D-aspartate (NMDA) (100 nmol in a 2 µL saline solution) intravitreally, and different dosages of CHC were administered. At day 7, rats in CHC+ NMDA-treated groups showed obvious aversion to light when compared to NMDA rats. Electroretinogram recordings revealed a marked decrease in the amplitudes of a-wave, b-wave, and photopic negative response due to NMDA damage. In retina receiving intravitreal NMDA and CHC co-treatment, these values were significantly increased. CHC treatment also resulted in less NMDA-induced cell loss and a decrease in the proportion of dUTP end-labeling-positive cells in ganglion cell line. Conclusions C*HSDGIC*, a novel cyclopeptide from PACAP (1–5) attenuates apoptosis in RGC-5 cells and inhibits NMDA-induced retinal neuronal death. The beneficial effects may occur via the mitochondria pathway. PACAP derivatives like CHC may serve as a promising candidate for neuroprotection in glaucoma. PMID:25286089

Retinal ganglion cell damage in an experimental rodent model of blast-mediated traumatic brain injury.

PubMed

Mohan, Kabhilan; Kecova, Helga; Hernandez-Merino, Elena; Kardon, Randy H; Harper, Matthew M

2013-05-15

To evaluate retina and optic nerve damage following experimental blast injury. Healthy adult mice were exposed to an overpressure blast wave using a custom-built blast chamber. The effects of blast exposure on retina and optic nerve function and structure were evaluated using the pattern electroretinogram (pERG), spectral domain optical coherence tomography (OCT), and the chromatic pupil light reflex. Assessment of the pupil response to light demonstrated decreased maximum pupil constriction diameter in blast-injured mice using red light or blue light stimuli 24 hours after injury compared with baseline in the eye exposed to direct blast injury. A decrease in the pupil light reflex was not observed chronically following blast exposure. We observed a biphasic pERG decrease with the acute injury recovering by 24 hours postblast and the chronic injury appearing at 4 months postblast injury. Furthermore, at 3 months following injury, a significant decrease in the retinal nerve fiber layer was observed using OCT compared with controls. Histologic analysis of the retina and optic nerve revealed punctate regions of reduced cellularity in the ganglion cell layer and damage to optic nerves. Additionally, a significant upregulation of proteins associated with oxidative stress was observed acutely following blast exposure compared with control mice. Our study demonstrates that decrements in retinal ganglion cell responses can be detected after blast injury using noninvasive functional and structural tests. These objective responses may serve as surrogate tests for higher CNS functions following traumatic brain injury that are difficult to quantify.

Retinal Ganglion Cell Damage in an Experimental Rodent Model of Blast-Mediated Traumatic Brain Injury

PubMed Central

Mohan, Kabhilan; Kecova, Helga; Hernandez-Merino, Elena; Kardon, Randy H.; Harper, Matthew M.

2013-01-01

Purpose. To evaluate retina and optic nerve damage following experimental blast injury. Methods. Healthy adult mice were exposed to an overpressure blast wave using a custom-built blast chamber. The effects of blast exposure on retina and optic nerve function and structure were evaluated using the pattern electroretinogram (pERG), spectral domain optical coherence tomography (OCT), and the chromatic pupil light reflex. Results. Assessment of the pupil response to light demonstrated decreased maximum pupil constriction diameter in blast-injured mice using red light or blue light stimuli 24 hours after injury compared with baseline in the eye exposed to direct blast injury. A decrease in the pupil light reflex was not observed chronically following blast exposure. We observed a biphasic pERG decrease with the acute injury recovering by 24 hours postblast and the chronic injury appearing at 4 months postblast injury. Furthermore, at 3 months following injury, a significant decrease in the retinal nerve fiber layer was observed using OCT compared with controls. Histologic analysis of the retina and optic nerve revealed punctate regions of reduced cellularity in the ganglion cell layer and damage to optic nerves. Additionally, a significant upregulation of proteins associated with oxidative stress was observed acutely following blast exposure compared with control mice. Conclusions. Our study demonstrates that decrements in retinal ganglion cell responses can be detected after blast injury using noninvasive functional and structural tests. These objective responses may serve as surrogate tests for higher CNS functions following traumatic brain injury that are difficult to quantify. PMID:23620426

Kyste épidermoïde du testicule : Étude de cas

PubMed Central

Diarra, Alkadri; Elammari, Jalal Eddine; Kassogue, Amadou; El Fassi, Mohammed Jamal; Farih, My Hassan

2013-01-01

Résumé Le kyste épidermoïde (KE) du testicule est une tumeur bénigne rare. Le diagnostic peut être évoqué par l’échographie et l’IRM. En cas de lésion unique de petite taille, il est possible d’effectuer une chirurgie conservatrice. Ce traitement nécessite une confirmation anatomopathologique. Le présent article fait état de l’observation d’un patient de 34 ans ayant été admis en consultation d’urologie pour désir d’enfant. Le diagnostic de KE associé à une varicocèle gauche a été retenu. L’énucléation du kyste avec cure de varicocèle a été réalisée sans complications postopératoires. Une revue de la littérature nous a permis de mettre en évidence les différents aspects du KE du testicule et les méthodes thérapeutiques envisageables. PMID:24282476

Des proprietes de l'etat normal du modele de Hubbard bidimensionnel

NASA Astrophysics Data System (ADS)

Lemay, Francois

Depuis leur decouverte, les etudes experimentales ont demontre que les supra-conducteurs a haute temperature ont une phase normale tres etrange. Les proprietes de ces materiaux ne sont pas bien decrites par la theorie du liquide de Fermi. Le modele de Hubbard bidimensionnel, bien qu'il ne soit pas encore resolu, est toujours considere comme un candidat pour expliquer la physique de ces composes. Dans cet ouvrage, nous mettons en evidence plusieurs proprietes electroniques du modele qui sont incompatibles avec l'existence de quasi-particules. Nous montrons notamment que la susceptibilite des electrons libres sur reseau contient des singularites logarithmiques qui influencent de facon determinante les proprietes de la self-energie a basse frequence. Ces singularites sont responsables de la destruction des quasi-particules. En l'absence de fluctuations antiferromagnetiques, elles sont aussi responsables de l'existence d'un petit pseudogap dans le poids spectral au niveau de Fermi. Les proprietes du modele sont egalement etudiees pour une surface de Fermi similaire a celle des supraconducteurs a haute temperature. Un parallele est etabli entre certaines caracteristiques du modele et celles de ces materiaux.

Identification of ganglion cell neurites in human subretinal and epiretinal membranes

PubMed Central

Lewis, Geoffrey P; Betts, Kellen E; Sethi, Charanjit S; Charteris, David G; Lesnik‐Oberstein, Sarit Y; Avery, Robert L; Fisher, Steven K

2007-01-01

Aim To determine whether neural elements are present in subretinal and epiretinal proliferative vitreoretinopathy (PVR) membranes as well as in diabetic, fibrovascular membranes removed from patients during vitrectomy surgery. Methods Human subretinal and epiretinal membranes of varying durations were immunolabelled with different combinations of antibodies to glial fibrillary acidic protein, vimentin, neurofilament protein and laminin. Results Anti‐neurofilament‐labelled neurites from presumptive ganglion cells were frequently found in epiretinal membranes and occasionally found in subretinal membranes. In addition, the neurites were only observed in regions that also contained glial processes. Conclusions These data demonstrate that neuronal processes are commonly found in human peri‐retinal cellular membranes similar to that demonstrated in animal models. These data also suggest that glial cells growing out of the neural retina form a permissive substrate for neurite growth and thus may hold clues to factors that support this growth. PMID:17108012

Two-generation reproductive toxicity study of implanted depleted uranium (DU) in CD rats.

PubMed

Arfsten, D P; Still, K R; Wilfong, E R; Johnson, E W; McInturf, S M; Eggers, J S; Schaeffer, D J; Bekkedal, M Y-V

2009-01-01

Depleted uranium (DU) munitions and armor plating have been used in several conflicts over the last 17 yr, including the Persian Gulf War and the Iraq War. Because of its effectiveness and availability, DU will continue to be used in military applications into the foreseeable future. There is much controversy over the use of DU in weapons and equipment because of its potential radiological and toxic hazards, and there is concern over the chronic adverse health effects of embedded DU shrapnel in war veterans and bystanders. This study evaluated the effects of long-term implantation of DU on the reproductive success of F0 generation adults and development and survival of subsequent F1 and F2 generations in a two-generation reproductive toxicity study. F0 generation Sprague-Dawley rats, 8 wk of age, were surgically implanted with 0, 4, 8, 12, or 20 DU pellets (1 x 2 mm). Inert implant control animals were implanted with 12 or 20 tantallum (Ta) pellets. The F0 generation was then mated at 120 d post DU implantation. In the F0 generation, when measured on postimplantation d 27 and 117, uranium was present in the urine of DU-implanted animals in a dose-dependent manner. F0 reproductive success was similar across treatment groups and the maternal retrieval test revealed no changes in maternal behavior. DU implantation exerted no effect on the survival, health, or well-being of the F0 generation. Necropsy results of F0 animals were negative with the exception of a marked inflammatory response surrounding the implanted DU pellets. For the F1 generation, measures of F1 development through postnatal day (PND) 20 were unremarkable and no gross abnormalities were observed in F1 offspring. No uranium was detected in whole-body homogenates of PND 4 or PND 20 pups. Necropsy findings of F1 PND 20 pups were negative and no instances of ribcage malformation were observed in F1 PND 20 pups. Body weight and body weight gain of F1 rats through PND 120 were similar across treatment

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness

PubMed Central

M. Mallery, Robert; Poolman, Pieter; J. Thurtell, Matthew; Wang, Jui-Kai; K. Garvin, Mona; Ledolter, Johannes; Kardon, Randy H.

2016-01-01

Purpose The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. Methods Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. Results Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. Conclusions Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure–function relationship between fixation and areas of preserved GCC in patients with ON. PMID:27409502

Speaking Truth to Power: Du Bois as Educator and Community Activist

ERIC Educational Resources Information Center

Grant, Carl A.; Grant, Paul D.

2017-01-01

This article uses W. E. B. Du Bois's work as an education and community activist to discuss race, oppression, and speaking-back to power in this time of racialized policies enacted by the Trump administration. This article centers a comparative discussion of the racialization of democracy by presidents Wilson and Trump to show the ways Du Bois was…

Radiological anatomy assessment of the fissura pterygomaxillaris for a surgical approach to ganglion pterygopalatinum.

PubMed

Puche-Torres, Miguel; Blasco-Serra, Arantxa; Campos-Peláez, Ana; Valverde-Navarro, Alfonso A

2017-12-01

The ganglion pterygopalatinum has become a therapeutic target to treat various pain syndromes in recent years. It is located in the fossa pterygopalatina, and the fissura pterygomaxillaris is the main access to surgically approach this structure. Recently, the neuromodulation of the ganglion pterygopalatinum by microstimulator implantation has become the first therapeutic line in refractory cluster headache treatment. This invasive technique is performed transorally through the fissura pterygomaxillaris, and is limited by the size of the implantation device, which requires an opening of at least 2 mm. Therefore, extensive knowledge about the anatomy of the fissura pterygomaxillaris prior to surgery is necessary to predict the success of both the approach and intervention. Likewise, establishing a morphological typology of the different fissura pterygomaxillaris variations would be a valuable predictive tool in the clinical practice. In this work, an anatomical analysis was performed of the morphological characteristics of the 242 fissurae pterygomaxillares, which corresponded to 121 adult patients, 58 males and 63 females, aged between 18 and 87 years. For each subject, right and left fissures were studied with radiological computed tomography images. Aperture fissura pterygomaxillaris measurements were taken in an upper (Measure A), middle (Measure B) and lower craneo-caudal third (Measure C). Intra-subject differences were studied between the measurements taken of each patient's right and left fissures, and the inter-subject measures in which fissures were compared according to patients' age and gender. The obtained results showed no significant differences between each patient's right and left fissures in any three measurements taken. Intra-subject differences were not significant for gender or age. No statistically significant differences were found for the inter-subject measures between the measures of fissures according to patients' age. However, our data

Evaluation du niveau de connaissance des patients sur la gestion du traitement par les antis vitamines K dans le service de cardiologie de Ouagadougou

PubMed Central

Samadoulougou, André; Temoua Naibe, Dangwé; Mandi, Germain; Yameogo, Relwendé Aristide; Kabore, Elisé; Millogo, Georges; Yameogo, Nobila Valentin; Kologo, Jonas Koudougou; Thiam/Tall, Anna; Toguyeni, Boubacar Jean Yves; Zabsonre, Patrice

2014-01-01

Introduction Les antivitamines K (AVK), traitement anticoagulant oral le plus largement prescrit, posent un réel problème de santé publique du fait de leur risque iatrogène. L'objectif de cette étude était de préciser le niveau de connaissance des patients sur la gestion de leur traitement par les AVK. Méthodes Il s'est agi d'une enquête transversale descriptive réalisée au CHU-Yalgado Ouédraogo, sur une période de 03 mois : du 1er mars au 31 mai 2012. Un questionnaire a été administré aux patients bénéficiant d'un traitement AVK depuis au moins un mois. Résultats Soixante-dix patients ont été inclus dans l'étude dont 30 hommes. L'âge moyen était de 49 ans ± 16 ans. Les cardiopathies et la maladie thromboembolique veineuse justifiant l'institution du traitement AVK étaient retrouvées respectivement dans 58,6% et 41,4% des cas. Le nom de l'AVK et la raison exacte du traitement étaient connus respectivement dans 91,4% et 67,1% des cas. Plus de la moitié des patients (68,6%) savaient que les AVK rendaient le sang plus fluide. Quarante-six patients (65,7%) citaient l'INR comme examen biologique de surveillance du traitement et seulement 28 patients (40%) connaissaient les valeurs cibles. La majorité des patients ne connaissait pas les risques encourus en cas de surdosage (72,8%) et de sous-dosage (71,4%). Une automédication par anti-inflammatoire non stéroïdien était signalée par 18 patients (25,7%). Les choux (74,3%) et la laitue (62,9%), aliments à consommer avec modération, étaient les plus cités. Conclusion Les connaissances des patients sur la gestion des AVK étaient fragmentaires et insuffisantes pour assurer la sécurité et l'efficacité du traitement. La création d'un programme d'éducation thérapeutique sur les AVK s'avère alors nécessaire. PMID:25870741

Watershed Data Management (WDM) database for West Branch DuPage River streamflow simulation, DuPage County, Illinois, January 1, 2007, through September 30, 2013

USGS Publications Warehouse

Bera, Maitreyee

2017-10-16

The U.S. Geological Survey (USGS), in cooperation with the DuPage County Stormwater Management Department, maintains a database of hourly meteorological and hydrologic data for use in a near real-time streamflow simulation system. This system is used in the management and operation of reservoirs and other flood-control structures in the West Branch DuPage River watershed in DuPage County, Illinois. The majority of the precipitation data are collected from a tipping-bucket rain-gage network located in and near DuPage County. The other meteorological data (air temperature, dewpoint temperature, wind speed, and solar radiation) are collected at Argonne National Laboratory in Argonne, Ill. Potential evapotranspiration is computed from the meteorological data using the computer program LXPET (Lamoreux Potential Evapotranspiration). The hydrologic data (water-surface elevation [stage] and discharge) are collected at U.S.Geological Survey streamflow-gaging stations in and around DuPage County. These data are stored in a Watershed Data Management (WDM) database.This report describes a version of the WDM database that is quality-assured and quality-controlled annually to ensure datasets are complete and accurate. This database is named WBDR13.WDM. It contains data from January 1, 2007, through September 30, 2013. Each precipitation dataset may have time periods of inaccurate data. This report describes the methods used to estimate the data for the periods of missing, erroneous, or snowfall-affected data and thereby improve the accuracy of these data. The other meteorological datasets are described in detail in Over and others (2010), and the hydrologic datasets in the database are fully described in the online USGS annual water data reports for Illinois (U.S. Geological Survey, 2016) and, therefore, are described in less detail than the precipitation datasets in this report.

Rapport sur l'état du patrimoine astronomique dans les observatoires français de la fin du XIXè siècle

NASA Astrophysics Data System (ADS)

Damm, E.; Pécontal, E.

2012-12-01

Suite au colloque sur la sauvegarde du patrimoine astronomique organisé par le MAEE et la SAF, sous l'égide de l'UNESCO, qui a conduit à l'adoption de la Déclaration de Paris, les directeurs d'observatoires institutionnels qui étaient absents du colloque ont ressenti le besoin de discuter de ces conclusions prises en leur nom. L'initiative d'organiser une réunion des directeurs des Observatoires des Sciences de l'Univers (OSU) à ce sujet le 30 janvier 2012 a été prise par François Vernotte, directeur de l'Observatoire de Besançon. Le présent compte-rendu de visite résulte d'une initiative spontanée d'Emmanuel Pécontal, astronome responsable du Patrimoine à l'observatoire de Lyon, et d'Evelyne Damm, membre de la Commission Nationale de classement des Monuments Historiques (CNMH) et élue à la communauté d'agglomération des Portes de l'Essonne oû est sis l'observatoire de Camille Flammarion.

A new entity in the differential diagnosis of geniculate ganglion tumours: fibrous connective tissue lesion of the facial nerve.

PubMed

de Arriba, Alvaro; Lassaletta, Luis; Pérez-Mora, Rosa María; Gavilán, Javier

2013-01-01

Differential diagnosis of geniculate ganglion tumours includes chiefly schwannomas, haemangiomas and meningiomas. We report the case of a patient whose clinical and imaging findings mimicked the presentation of a facial nerve schwannoma.Pathological studies revealed a lesion with nerve bundles unstructured by intense collagenisation. Consequently, it was called fibrous connective tissue lesion of the facial nerve. Copyright © 2011 Elsevier España, S.L. All rights reserved.

EFFECT OF INTRAVITREAL RANIBIZUMAB ON GANGLION CELL COMPLEX AND PERIPAPILLARY RETINAL NERVE FIBER LAYER IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

PubMed

Zucchiatti, Ilaria; Cicinelli, Maria V; Parodi, Maurizio Battaglia; Pierro, Luisa; Gagliardi, Marco; Accardo, Agostino; Bandello, Francesco

2017-07-01

To analyze the changes in ganglion cell complex and peripapillary retinal nerve fiber layer thickness, in central macular thickness and choroidal thickness on spectral domain optical coherence tomography in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. All consecutive patients with untreated neovascular age-related macular degeneration received loading phase of three monthly intravitreal ranibizumab, followed by retreatments on a pro re nata protocol for 12 months. changes in ganglion cell complex and retinal nerve fiber layer at the end of follow-up. Secondary outcome: changes in best-corrected visual acuity, central macular thickness, and choroidal thickness at the end of follow-up. Choroidal thickness was measured at 500 μm, 1000 μm, and 1,500 μm intervals nasally, temporally, superiorly, and inferiorly to the fovea, respectively, on horizontal and vertical line scans centered on the fovea. Twenty-four eyes were included. Ganglion cell complex and peripapillary retinal nerve fiber layer thickness did not show statistically significant changes through 12 months (55.6 ± 18.5 and 81.9 ± 9.9 μm at baseline, 52.7 ± 19.3 and 84.6 ± 15.5 μm at month 12, P > 0.05). Central macular thickness showed progressive decrease from baseline to month 12, with maximum reduction at month 3 (P < 0.001). Statistically significant reduction in choroidal thickness was registered in the nasal 500, 1000, and 1,500 μm from the fovea, corresponding to the papillomacular region (from 169.6 ± 45.3 to 153.9 ± 46.9, P < 0.001). Intravitreal ranibizumab injections did not affect retinal nerve fiber layer and ganglion cell complex thickness in 1-year follow-up. Choroidal thickness in papillomacular area and central macular thickness was significantly reduced at the end of treatment. Further studies, with larger sample, longer follow-up, and greater number of injections, are warranted.

Locke and Du Bois: Two Major Black Voices Muzzled by Philanthropic Organizations.

ERIC Educational Resources Information Center

Fitchue, M. Anthony

1997-01-01

In 1935, the Howard University philosopher Alain Locke asked W. E. B. Du Bois to contribute to an adult education project for African Americans. Censorship by white-controlled foundations forced Locke to reject the Du Bois essay to protect contributions for causes of great importance to blacks. (Author/SLD)

Vaccination for protection of retinal ganglion cells against death from glutamate cytotoxicity and ocular hypertension: Implications for glaucoma

NASA Astrophysics Data System (ADS)

Schori, Hadas; Kipnis, Jonathan; Yoles, Eti; Woldemussie, Elizabeth; Ruiz, Guadalupe; Wheeler, Larry A.; Schwartz, Michal

2001-03-01

Our group recently demonstrated that autoimmune T cells directed against central nervous system-associated myelin antigens protect neurons from secondary degeneration. We further showed that the synthetic peptide copolymer 1 (Cop-1), known to suppress experimental autoimmune encephalomyelitis, can be safely substituted for the natural myelin antigen in both passive and active immunization for neuroprotection of the injured optic nerve. Here we attempted to determine whether similar immunizations are protective from retinal ganglion cell loss resulting from a direct biochemical insult caused, for example, by glutamate (a major mediator of degeneration in acute and chronic optic nerve insults) and in a rat model of ocular hypertension. Passive immunization with T cells reactive to myelin basic protein or active immunization with myelin oligodendrocyte glycoprotein-derived peptide, although neuroprotective after optic nerve injury, was ineffective against glutamate toxicity in mice and rats. In contrast, the number of surviving retinal ganglion cells per square millimeter in glutamate-injected retinas was significantly larger in mice immunized 10 days previously with Cop-1 emulsified in complete Freund's adjuvant than in mice injected with PBS in the same adjuvant (2,133 ± 270 and 1,329 ± 121, respectively, mean ± SEM; P < 0.02). A similar pattern was observed when mice were immunized on the day of glutamate injection (1,777 ± 101 compared with 1,414 ± 36; P <0.05), but not when they were immunized 48h later. These findings suggest that protection from glutamate toxicity requires reinforcement of the immune system by antigens that are different from those associated with myelin. The use of Cop-1 apparently circumvents this antigen specificity barrier. In the rat ocular hypertension model, which simulates glaucoma, immunization with Cop-1 significantly reduced the retinal ganglion cell loss from 27.8%±6.8% to 4.3%±1.6%, without affecting the intraocular pressure

Effectiveness of Stellate Ganglion Block Under Fuoroscopy or Ultrasound Guidance in Upper Extremity CRPS.

PubMed

Imani, Farnad; Hemati, Karim; Rahimzadeh, Poupak; Kazemi, Mohamad Reza; Hejazian, Kokab

2016-01-01

Stellate Ganglion Block (SGB) is an effective technique which may be used to manage upper extremities pain due to Chronic Regional Pain Syndrome (CRPS), in this study we tried to evaluate the effectiveness of this procedure under two different guidance for management of this syndrome. The purpose of this study was to evaluate the effectiveness of ultrsound guide SGB by comparing it with the furoscopy guided SGB in upper extermities CRPS patients in reducing pain & dysfuction of the affected link. Fourteen patients with sympathetic CRPS in upper extremities in a randomized method with block randomization divided in two equal groups (with ultrasound or fluoroscopic guidance). First group was blocked under fluoroscopic guidance and second group blocked under ultrasound guidance. After correct positioning of the needle, a mixture of 5 ml bupivacaine 0.25% and 1 mL of triamcinolone was injected. These data represent no meaningful statistical difference between the two groups in terms of the number of pain attacks before the blocks, a borderline correlation between two groups one week and one month after the block and a significant statistical correlation between two groups three month after the block. These data represent no meaningful statistical difference between the patients of any group in terms of the pain intensity (from one week to six months after block), p-value = 0.61. These data represent a meaningful statistical difference among patients of any group and between the two groups in terms of the pain intensity (before the block until six months after block), p-values were 0.001, 0.031 respectively. According the above mentioned data, in comparison with fluoroscopic guidance, stellate ganglion block under ultrasound guidance is a safe and effective method with lower complication and better improvement in patient's disability indexes.

Pulsed Infrared Releases Ca2+ from the Endoplasmic Reticulum of Cultured Spiral Ganglion Neurons.

PubMed

Barrett, John N; Rincon, Samantha; Singh, Jayanti; Matthewman, Cristina; Pasos, Julio; Barrett, Ellen F; Rajguru, Suhrud M

2018-04-18

We investigated the effects of pulsed infrared radiation (IR, 1863 nm) stimulation on cytosolic [Ca 2+ ] in inner ear spiral ganglion neurons cultured from day 4 postnatal mice and loaded with a fluorescent Ca 2+ indicator (fluo-4, -5F or -5N). IR pulse trains (200 µs, 200-250 Hz, 2-5 s) delivered via an optical fiber coupled to IR source produced a rapid, transient temperature increase of 6-11ºC (above a baseline of 24-30 ºC) and evoked transient increases in both nuclear and cytosolic [Ca 2+ ] of 0.20 - 1.4 µM, with a simultaneous reduction of [Ca 2+ ] in regions containing endoplasmic reticulum (ER). IR-induced increases in cytosolic [Ca 2+ ] continued in medium containing no added Ca 2+ ({plus minus} Ca 2+ buffers) and low [Na + ], indicating that the [Ca 2+ ] increase was mediated by release from intracellular stores. Consistent with this hypothesis, the IR-induced [Ca 2+ ] response was prolonged and eventually blocked by inhibition of ER Ca-ATPase with cyclopiazonic acid, and was also inhibited by a high concentration of ryanodine and by inhibitors of IP 3 -mediated Ca 2+ release (xestospongin C and 2-APB). The thermal sensitivity of the response suggested involvement of warm-sensitive transient receptor potential (TRP) receptors. Immunostaining of the spiral ganglion demonstrated the presence of intracellular TRPV4 and TRPM2, and the IR-induced [Ca 2+ ] increase was inhibited by TRPV4 inhibitors (HC067047 and GSK2193874). These results suggest that the temperature-sensitivity of IR-induced [Ca 2+ ] elevations is conferred by TRP channels on ER membranes, which facilitate Ca 2+ efflux into the cytosol and initiate Ca 2+ -induced Ca 2+ -release via IP 3 and ryanodine receptors.

Topographic prominence discriminator for the detection of short-latency spikes of retinal ganglion cells

NASA Astrophysics Data System (ADS)

Choi, Myoung-Hwan; Ahn, Jungryul; Park, Dae Jin; Lee, Sang Min; Kim, Kwangsoo; Cho, Dong-il Dan; Senok, Solomon S.; Koo, Kyo-in; Goo, Yong Sook

2017-02-01

Objective. Direct stimulation of retinal ganglion cells in degenerate retinas by implanting epi-retinal prostheses is a recognized strategy for restoration of visual perception in patients with retinitis pigmentosa or age-related macular degeneration. Elucidating the best stimulus-response paradigms in the laboratory using multielectrode arrays (MEA) is complicated by the fact that the short-latency spikes (within 10 ms) elicited by direct retinal ganglion cell (RGC) stimulation are obscured by the stimulus artifact which is generated by the electrical stimulator. Approach. We developed an artifact subtraction algorithm based on topographic prominence discrimination, wherein the duration of prominences within the stimulus artifact is used as a strategy for identifying the artifact for subtraction and clarifying the obfuscated spikes which are then quantified using standard thresholding. Main results. We found that the prominence discrimination based filters perform creditably in simulation conditions by successfully isolating randomly inserted spikes in the presence of simple and even complex residual artifacts. We also show that the algorithm successfully isolated short-latency spikes in an MEA-based recording from degenerate mouse retinas, where the amplitude and frequency characteristics of the stimulus artifact vary according to the distance of the recording electrode from the stimulating electrode. By ROC analysis of false positive and false negative first spike detection rates in a dataset of one hundred and eight RGCs from four retinal patches, we found that the performance of our algorithm is comparable to that of a generally-used artifact subtraction filter algorithm which uses a strategy of local polynomial approximation (SALPA). Significance. We conclude that the application of topographic prominence discrimination is a valid and useful method for subtraction of stimulation artifacts with variable amplitudes and shapes. We propose that our algorithm

Spatial consequences of bleaching adaptation in cat retinal ganglion cells.

PubMed Central

Bonds, A B; Enroth-Cugell, C

1981-01-01

1. Experiments were conducted to study the effects of localized bleaching on the centre responses of rod-driven cat retinal ganglion cells. 2. Stimulation as far as 2 degrees from the bleaching site yielded responses which were reduced nearly as much as those generated at the bleaching site. Bleaching in the receptive field middle reduced responsiveness at a site 1 degrees peripheral more than bleaching at that peripheral site itself. 3. The effectiveness of a bleach in reducing centre responsiveness is related to the sensitivity of the region in which the bleach is applied. 4. Response reduction after a 0.2 degree bleach followed the same temporal pattern for concentric test spots of from 0.2 to 1.8 degrees in diameter, implying a substantially uniform spread of adaptation within these bounds. 5. A linear trade-off between fraction of rhodopsin and area bleached over a range of 8:1 yields the same pattern of response reduction, implying that the non-linear nature of bleaching adaptation is a property of the adaptation pool rather than independent photoreceptors. PMID:7320894

Coalition Battle Management Language (C-BML) (Language de gestion du champ de bataille (C-BML)

DTIC Science & Technology

2012-02-01

de gestion du champ de bataille (C-BML)) NMSG-048 Final Report. This document...BML) (Langage de gestion du champ de bataille (C-BML)) NMSG-048 Final Report. This document contains information authorized by NATO RTA for...Technical Readiness Level (TRL) that is consistent with an operational deployment. ES - 2 RTO-TR-MSG-048 Langage de gestion du champ de

Hématome spontané du méso de l'angle colique droit et du colon transverse compliquant un traitement par anti vitamine K: à propos d'un cas et revue de la littérature

PubMed Central

Traoré, Ibrahim Alain; Zaré, Cyprien; Barro, Sié Drissa; Guibla, Ismaël

2016-01-01

L'hématome spontané du méso de l'angle colique droit et du transverse est une complication rare du traitement anticoagulant par antivitamine K. Nous rapportons un cas d'hématome spontané du méso de l'angle colique droit et du transverse associé à un hémopéritoine de grande abondance chez un patient traité par antivitamine K pour embolie pulmonaire consécutive à une fracture des plateaux tibiaux droits. Le diagnostic doit être fait en urgence. L’échographie abdominale et la tomodensitométrie confirment le diagnostic. Le traitement non opératoire est la règle. Le traitement chirurgical est indiqué en cas de complications telles que la rupture de l'hématome. PMID:27217878

Photoacoustic microscopy of complex regional pain syndrome type I (CRPS-1) after stellate ganglion blocks in vivo

NASA Astrophysics Data System (ADS)

Zhou, Yong; Yi, Xiaobin; Xing, Wenxin; Hu, Song; Maslov, Konstantin I.; Wang, Lihong V.

2015-03-01

We used photoacoustic microscopy (PAM) to assist diagnoses and monitor the progress and treatment outcome of complex regional pain syndrome type 1 (CRPS-1). Blood vasculature and oxygen saturation (sO2) were imaged by PAM in eight adult patients with CRPS-1. Patients' hands and cuticles were imaged both before and after stellate ganglion block (SGB) for comparison. For all patients, both the vascular structure and sO2 could be assessed by PAM. In addition, more vessels and stronger signals were observed after SGB.

Characterization of FaDu-R, a radioresistant head and neck cancer cell line, and cancer stem cells.

PubMed

Cho, Kwang-Jae; Park, Eun-Ji; Kim, Min-Sik; Joo, Young-Hoon

2018-06-01

The aim of this study was to evaluate the impact of CSC on insensitivity to radiotherapy in HNSCC. A radioresistant cell line, FaDu-R, was established using fractionated ionizing radiation. Cells with high and low CD44/ALDH activity were isolated. FaDu-R cells demonstrated significantly increased cell viability after radiation exposure compared with parental cells. CD44 high /ALDH high FaDu-R cells demonstrated significantly faster wound closure (p<0.05) and more efficient invasion (p<0.05) compared to the CD44 high /ALDH high FaDu cells or the CD44 low /ALDH low FaDu-R cells. There was a significant difference in tumor volume between the CD44 high /ALDH high FaDu-R cells and the CD44 high /ALDH high FaDu cells (p<0.05) as well as the CD44 low /ALDH low FaDu-R cells (p<0.05). Cancer stem cells (CSC) were associated with invasion and tumorigenesis in a radioresistant head and neck squamous cell carcinoma (HNSCC) cell line. This concept might help to improve the understanding of these mechanisms and to develop drugs that can overcome radioresistance during radiotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Genetics Home Reference: cri-du-chat syndrome

MedlinePlus

... Pinkel D. High-resolution mapping of genotype-phenotype relationships in cri du chat syndrome using array comparative ... for Links Data Files & API Site Map Subscribe Customer Support USA.gov Copyright Privacy Accessibility FOIA Viewers & ...

Sloppy morphological tuning in identified neurons of the crustacean stomatogastric ganglion

PubMed Central

Otopalik, Adriane G; Goeritz, Marie L; Sutton, Alexander C; Brookings, Ted; Guerini, Cosmo; Marder, Eve

2017-01-01

Neuronal physiology depends on a neuron’s ion channel composition and unique morphology. Variable ion channel compositions can produce similar neuronal physiologies across animals. Less is known regarding the morphological precision required to produce reliable neuronal physiology. Theoretical studies suggest that moraphology is tightly tuned to minimize wiring and conduction delay of synaptic events. We utilize high-resolution confocal microscopy and custom computational tools to characterize the morphologies of four neuron types in the stomatogastric ganglion (STG) of the crab Cancer borealis. Macroscopic branching patterns and fine cable properties are variable within and across neuron types. We compare these neuronal structures to synthetic minimal spanning neurite trees constrained by a wiring cost equation and find that STG neurons do not adhere to prevailing hypotheses regarding wiring optimization principles. In this highly modulated and oscillating circuit, neuronal structures appear to be governed by a space-filling mechanism that outweighs the cost of inefficient wiring. DOI: http://dx.doi.org/10.7554/eLife.22352.001 PMID:28177286

Modelisation frequentielle de la permittivite du beton pour le controle non destructif par georadar

NASA Astrophysics Data System (ADS)

Bourdi, Taoufik

Le georadar (Ground Penetrating Radar (GPR)) constitue une technique de controle non destructif (CND) interessante pour la mesure des epaisseurs des dalles de beton et la caracterisation des fractures, en raison de ses caracteristiques de resolution et de profondeur de penetration. Les equipements georadar sont de plus en plus faciles a utiliser et les logiciels d'interpretation sont en train de devenir plus aisement accessibles. Cependant, il est ressorti dans plusieurs conferences et ateliers sur l'application du georadar en genie civil qu'il fallait poursuivre les recherches, en particulier sur la modelisation et les techniques de mesure des proprietes electriques du beton. En obtenant de meilleures informations sur les proprietes electriques du beton aux frequences du georadar, l'instrumentation et les techniques d'interpretation pourraient etre perfectionnees plus efficacement. Le modele de Jonscher est un modele qui a montre son efficacite dans le domaine geophysique. Pour la premiere fois, son utilisation dans le domaine genie civil est presentee. Dans un premier temps, nous avons valide l'application du modele de Jonscher pour la caracterisation de la permittivite dielectrique du beton. Les resultats ont montre clairement que ce modele est capable de reproduire fidelement la variation de la permittivite de differents types de beton sur la bande de frequence georadar (100 MHz-2 GHz). Dans un deuxieme temps, nous avons montre l'interet du modele de Jonscher en le comparant a d'autres modeles (Debye et Debye-etendu) deja utilises dans le domaine genie civil. Nous avons montre aussi comment le modele de Jonscher peut presenter une aide a la prediction de l'efficacite de blindage et a l'interpretation des ondes de la technique GPR. Il a ete determine que le modele de Jonscher permet de donner une bonne presentation de la variation de la permittivite du beton dans la gamme de frequence georadar consideree. De plus, cette modelisation est valable pour differents

Prediction du profil de durete de l'acier AISI 4340 traite thermiquement au laser

NASA Astrophysics Data System (ADS)

Maamri, Ilyes

Les traitements thermiques de surfaces sont des procedes qui visent a conferer au coeur et a la surface des pieces mecaniques des proprietes differentes. Ils permettent d'ameliorer la resistance a l'usure et a la fatigue en durcissant les zones critiques superficielles par des apports thermiques courts et localises. Parmi les procedes qui se distinguent par leur capacite en terme de puissance surfacique, le traitement thermique de surface au laser offre des cycles thermiques rapides, localises et precis tout en limitant les risques de deformations indesirables. Les proprietes mecaniques de la zone durcie obtenue par ce procede dependent des proprietes physicochimiques du materiau a traiter et de plusieurs parametres du procede. Pour etre en mesure d'exploiter adequatement les ressources qu'offre ce procede, il est necessaire de developper des strategies permettant de controler et regler les parametres de maniere a produire avec precision les caracteristiques desirees pour la surface durcie sans recourir au classique long et couteux processus essai-erreur. L'objectif du projet consiste donc a developper des modeles pour predire le profil de durete dans le cas de traitement thermique de pieces en acier AISI 4340. Pour comprendre le comportement du procede et evaluer les effets des differents parametres sur la qualite du traitement, une etude de sensibilite a ete menee en se basant sur une planification experimentale structuree combinee a des techniques d'analyse statistiques eprouvees. Les resultats de cette etude ont permis l'identification des variables les plus pertinentes a exploiter pour la modelisation. Suite a cette analyse et dans le but d'elaborer un premier modele, deux techniques de modelisation ont ete considerees, soient la regression multiple et les reseaux de neurones. Les deux techniques ont conduit a des modeles de qualite acceptable avec une precision d'environ 90%. Pour ameliorer les performances des modeles a base de reseaux de neurones, deux

Cobalamin C Deficiency Shows a Rapidly Progressing Maculopathy With Severe Photoreceptor and Ganglion Cell Loss.

PubMed

Bonafede, Lucas; Ficicioglu, Can H; Serrano, Leona; Han, Grace; Morgan, Jessica I W; Mills, Monte D; Forbes, Brian J; Davidson, Stefanie L; Binenbaum, Gil; Kaplan, Paige B; Nichols, Charles W; Verloo, Patrick; Leroy, Bart P; Maguire, Albert M; Aleman, Tomas S

2015-12-01

To describe in detail the retinal structure and function of a group of patients with cobalamin C (cblC) disease. Patients (n = 11, age 4 months to 15 years) with cblC disease (9/11, early onset) diagnosed by newborn screening underwent complete ophthalmic examinations, fundus photography, near-infrared reflectance imaging, and spectral-domain optical coherence tomography (SD-OCT). Electroretinograms (ERGs) were performed in a subset of patients. Patients carried homozygous or compound heterozygote mutations in the methylmalonic aciduria and homocystinuria type C (MMACHC) gene. Late-onset patients had a normal exam. All early-onset patients showed a maculopathy; older subjects had a retina-wide degeneration (n = 4; >7 years of age). In general, retinal changes were first observed before 1 year of age and progressed within months to a well-established maculopathy. Pseudocolobomas were documented in three patients. Measurable visual acuities ranged from 20/200 to 20/540. Nystagmus was present in 8/11 patients; 5/6 patients had normal ERGs; 1/6 had reduced rod-mediated responses. Spectral-domain OCT showed macular thinning, with severe ganglion cell layer (GCL) and outer nuclear layer (ONL) loss. Inner retinal thickening was observed in areas of total GCL/ONL loss. A normal lamination pattern in the peripapillary nasal retina was often seen despite severe central and/or retina-wide disease. Patients with early-onset cblC and MMACHC mutations showed an early-onset, unusually fast-progressing maculopathy with severe central ONL and GCL loss. An abnormally thickened inner retina supports a remodeling response to both photoreceptor and ganglion cell degeneration and/or an interference with normal development in early-onset cblC.

RdgB2 is required for dim-light input into intrinsically photosensitive retinal ganglion cells.

PubMed

Walker, Marquis T; Rupp, Alan; Elsaesser, Rebecca; Güler, Ali D; Sheng, Wenlong; Weng, Shijun; Berson, David M; Hattar, Samer; Montell, Craig

2015-10-15

A subset of retinal ganglion cells is intrinsically photosensitive (ipRGCs) and contributes directly to the pupillary light reflex and circadian photoentrainment under bright-light conditions. ipRGCs are also indirectly activated by light through cellular circuits initiated in rods and cones. A mammalian homologue (RdgB2) of a phosphoinositide transfer/exchange protein that functions in Drosophila phototransduction is expressed in the retinal ganglion cell layer. This raised the possibility that RdgB2 might function in the intrinsic light response in ipRGCs, which depends on a cascade reminiscent of Drosophila phototransduction. Here we found that under high light intensities, RdgB2(-/-) mutant mice showed normal pupillary light responses and circadian photoentrainment. Consistent with this behavioral phenotype, the intrinsic light responses of ipRGCs in RdgB2(-/-) were indistinguishable from wild-type. In contrast, under low-light conditions, RdgB2(-/-) mutants displayed defects in both circadian photoentrainment and the pupillary light response. The RdgB2 protein was not expressed in ipRGCs but was in GABAergic amacrine cells, which provided inhibitory feedback onto bipolar cells. We propose that RdgB2 is required in a cellular circuit that transduces light input from rods to bipolar cells that are coupled to GABAergic amacrine cells and ultimately to ipRGCs, thereby enabling ipRGCs to respond to dim light. © 2015 Walker et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Cobalamin C Deficiency Shows a Rapidly Progressing Maculopathy With Severe Photoreceptor and Ganglion Cell Loss

PubMed Central

Bonafede, Lucas; Ficicioglu, Can H.; Serrano, Leona; Han, Grace; Morgan, Jessica I. W.; Mills, Monte D.; Forbes, Brian J.; Davidson, Stefanie L.; Binenbaum, Gil; Kaplan, Paige B.; Nichols, Charles W.; Verloo, Patrick; Leroy, Bart P.; Maguire, Albert M.; Aleman, Tomas S.

2015-01-01

Purpose To describe in detail the retinal structure and function of a group of patients with cobalamin C (cblC) disease. Methods Patients (n = 11, age 4 months to 15 years) with cblC disease (9/11, early onset) diagnosed by newborn screening underwent complete ophthalmic examinations, fundus photography, near-infrared reflectance imaging, and spectral-domain optical coherence tomography (SD-OCT). Electroretinograms (ERGs) were performed in a subset of patients. Results Patients carried homozygous or compound heterozygote mutations in the methylmalonic aciduria and homocystinuria type C (MMACHC) gene. Late-onset patients had a normal exam. All early-onset patients showed a maculopathy; older subjects had a retina-wide degeneration (n = 4; >7 years of age). In general, retinal changes were first observed before 1 year of age and progressed within months to a well-established maculopathy. Pseudocolobomas were documented in three patients. Measurable visual acuities ranged from 20/200 to 20/540. Nystagmus was present in 8/11 patients; 5/6 patients had normal ERGs; 1/6 had reduced rod-mediated responses. Spectral-domain OCT showed macular thinning, with severe ganglion cell layer (GCL) and outer nuclear layer (ONL) loss. Inner retinal thickening was observed in areas of total GCL/ONL loss. A normal lamination pattern in the peripapillary nasal retina was often seen despite severe central and/or retina-wide disease. Conclusions Patients with early-onset cblC and MMACHC mutations showed an early-onset, unusually fast-progressing maculopathy with severe central ONL and GCL loss. An abnormally thickened inner retina supports a remodeling response to both photoreceptor and ganglion cell degeneration and/or an interference with normal development in early-onset cblC. PMID:26658511

Hmx1 is required for the normal development of somatosensory neurons in the geniculate ganglion

PubMed Central

Quina, Lely A.; Tempest, Lynne; Hsu, Yun-Wei A.; Cox, Timothy C.; Turner, Eric E.

2012-01-01

Hmx1 is a variant homeodomain transcription factor expressed in the developing sensory nervous system, retina, and craniofacial mesenchyme. Recently, mutations at the Hmx1 locus have been linked to craniofacial defects in humans, rats, and mice, but its role in nervous system development is largely unknown. Here we show that Hmx1 is expressed in a subset of sensory neurons in the cranial and dorsal root ganglia which does not correspond to any specific sensory modality. Sensory neurons in the dorsal root and trigeminal ganglia of Hmx1dm/dm mouse embryos have no detectable Hmx1 protein, yet they undergo neurogenesis and express sensory subtype markers normally, demonstrating that Hmx1 is not globally required for the specification of sensory neurons from neural crest precursors. Loss of Hmx1 expression has no obvious effect on the early development of the trigeminal (V), superior (IX/X), or dorsal root ganglia neurons in which it is expressed, but results in marked defects in the geniculate (VII) ganglion. Hmx1dm/dm mouse embryos possess only a vestigial posterior auricular nerve, and general somatosensory neurons in the geniculate ganglion are greatly reduced by mid-gestation. Although Hmx1 is expressed in geniculate neurons prior to cell cycle exit, it does not appear to be required for neurogenesis, and the loss of geniculate neurons is likely to be the result of increased cell death. Fate mapping of neural crest-derived tissues indicates that Hmx1-expressing somatosensory neurons at different axial levels may be derived from either the neural crest or the neurogenic placodes. PMID:22586713

Cytoarchitectonic study of the trigeminal ganglion in humans.

PubMed

Krastev, Dimo Stoyanov; Apostolov, Alexander

2013-01-01

The trigeminal ganglion (TG), a cluster of pseudounipolar neurons, is located in the trigeminal impression of the temporal pyramid. It is covered by a sheath of the dura mater and arachnoid and is near the rear end of the cavernous sinus. The peripheral processes of the pseudounipolar cells are involved in the formation of the first and second branch and the sensory part of the third branch of the fifth cranial nerve, and the central ones form the sensory root of the nerve, which penetrates at the level of the middle cerebellar peduncle, aside from the pons, and terminate in the sensory nuclei of the trigeminal complex. We found that the primary sensory neurons involved in sensory innervation of the orofacial complex are a diverse group. Although they possess the general structure of pseudounipolar neurons, there are significant differences among them, seen in varying intensities of staining. Based on our investigations we classified the neurons into 7 groups, i.e. large, subdivided into light and dark, medium, also light and dark, and small light and dark, and, moreover, neurons with an irregular shape of their perikarya. Further research by applying various immunohistochemical methods will clarify whether differences in the morphological patterns of the neurons are associated with differences in the neurochemical composition of various neuronal types.

Cytoarchitectonic study of the trigeminal ganglion in humans

PubMed Central

KRASTEV, DIMO STOYANOV; APOSTOLOV, ALEXANDER

2013-01-01

The trigeminal ganglion (TG), a cluster of pseudounipolar neurons, is located in the trigeminal impression of the temporal pyramid. It is covered by a sheath of the dura mater and arachnoid and is near the rear end of the cavernous sinus. The peripheral processes of the pseudounipolar cells are involved in the formation of the first and second branch and the sensory part of the third branch of the fifth cranial nerve, and the central ones form the sensory root of the nerve, which penetrates at the level of the middle cerebellar peduncle, aside from the pons, and terminate in the sensory nuclei of the trigeminal complex. We found that the primary sensory neurons involved in sensory innervation of the orofacial complex are a diverse group. Although they possess the general structure of pseudounipolar neurons, there are significant differences among them, seen in varying intensities of staining. Based on our investigations we classified the neurons into 7 groups, i.e. large, subdivided into light and dark, medium, also light and dark, and small light and dark, and, moreover, neurons with an irregular shape of their perikarya. Further research by applying various immunohistochemical methods will clarify whether differences in the morphological patterns of the neurons are associated with differences in the neurochemical composition of various neuronal types. PMID:26527926

Upper stimulation threshold for retinal ganglion cell activation.

PubMed

Meng, Kevin; Fellner, Andreas; Rattay, Frank; Ghezzi, Diego; Meffin, Hamish; Ibbotson, Michael R; Kameneva, Tatiana

2018-08-01

The existence of an upper threshold in electrically stimulated retinal ganglion cells (RGCs) is of interest because of its relevance to the development of visual prosthetic devices, which are designed to restore partial sight to blind patients. The upper threshold is defined as the stimulation level above which no action potentials (direct spikes) can be elicited in electrically stimulated retina. We collected and analyzed in vitro recordings from rat RGCs in response to extracellular biphasic (anodic-cathodic) pulse stimulation of varying amplitudes and pulse durations. Such responses were also simulated using a multicompartment model. We identified the individual cell variability in response to stimulation and the phenomenon known as upper threshold in all but one of the recorded cells (n  =  20/21). We found that the latencies of spike responses relative to stimulus amplitude had a characteristic U-shape. In silico, we showed that the upper threshold phenomenon was observed only in the soma. For all tested biphasic pulse durations, electrode positions, and pulse amplitudes above lower threshold, a propagating action potential was observed in the distal axon. For amplitudes above the somatic upper threshold, the axonal action potential back-propagated in the direction of the soma, but the soma's low level of hyperpolarization prevented action potential generation in the soma itself. An upper threshold observed in the soma does not prevent spike conductance in the axon.

BAX to basics: How the BCL2 gene family controls the death of retinal ganglion cells

PubMed Central

Maes, Margaret E.; Schlamp, Cassandra L.; Nickells, Robert W.

2017-01-01

Retinal ganglion cell (RGC) death is the principal consequence of injury to the optic nerve. For several decades, we have understood that the RGC death process was executed by apoptosis, suggesting that there may be ways to therapeutically intervene in this cell death program and provide a more direct treatment to the cells and tissues affected in diseases like glaucoma. A major part of this endeavor has been to elucidate the molecular biological pathways active in RGCs from the point of axonal injury to the point of irreversible cell death. A major component of this process is the complex interaction of members of the BCL2 gene family. Three distinct family members of proteins orchestrate the most critical junction in the apoptotic program of RGCs, culminating in the activation of pro-apoptotic BAX. Once active, BAX causes irreparable damage to mitochondria, while precipitating downstream events that finish off a dying ganglion cell. This review is divided into two major parts. First, we summarize the extent of knowledge of how BCL2 gene family proteins interact to facilitate the activation and function of BAX. This area of investigation has rapidly changed over the last few years and has yielded a dramatically different mechanistic understanding of how the intrinsic apoptotic program is run in mammalian cells. Second, we provided a comprehensive analysis of nearly two decades of investigation of the role of BAX in the process of RGC death, much of which has provided many important insights into the overall pathophysiology of diseases like glaucoma. PMID:28064040

BAX to basics: How the BCL2 gene family controls the death of retinal ganglion cells.

PubMed

Maes, Margaret E; Schlamp, Cassandra L; Nickells, Robert W

2017-03-01

Retinal ganglion cell (RGC) death is the principal consequence of injury to the optic nerve. For several decades, we have understood that the RGC death process was executed by apoptosis, suggesting that there may be ways to therapeutically intervene in this cell death program and provide a more direct treatment to the cells and tissues affected in diseases like glaucoma. A major part of this endeavor has been to elucidate the molecular biological pathways active in RGCs from the point of axonal injury to the point of irreversible cell death. A major component of this process is the complex interaction of members of the BCL2 gene family. Three distinct family members of proteins orchestrate the most critical junction in the apoptotic program of RGCs, culminating in the activation of pro-apoptotic BAX. Once active, BAX causes irreparable damage to mitochondria, while precipitating downstream events that finish off a dying ganglion cell. This review is divided into two major parts. First, we summarize the extent of knowledge of how BCL2 gene family proteins interact to facilitate the activation and function of BAX. This area of investigation has rapidly changed over the last few years and has yielded a dramatically different mechanistic understanding of how the intrinsic apoptotic program is run in mammalian cells. Second, we provided a comprehensive analysis of nearly two decades of investigation of the role of BAX in the process of RGC death, much of which has provided many important insights into the overall pathophysiology of diseases like glaucoma. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hypoxia Induces a Metabolic Shift and Enhances the Stemness and Expansion of Cochlear Spiral Ganglion Stem/Progenitor Cells

PubMed Central

Chao, Ting-Ting; Sytwu, Huey-Kang; Li, Shiue-Li; Fang, Mei-Cho; Chen, Hang-Kang; Lin, Yi-Chun; Kuo, Chao-Yin

2015-01-01

Previously, we demonstrated that hypoxia (1% O2) enhances stemness markers and expands the cell numbers of cochlear stem/progenitor cells (SPCs). In this study, we further investigated the long-term effect of hypoxia on stemness and the bioenergetic status of cochlear spiral ganglion SPCs cultured at low oxygen tensions. Spiral ganglion SPCs were obtained from postnatal day 1 CBA/CaJ mouse pups. The measurement of oxygen consumption rate, extracellular acidification rate (ECAR), and intracellular adenosine triphosphate levels corresponding to 20% and 5% oxygen concentrations was determined using a Seahorse XF extracellular flux analyzer. After low oxygen tension cultivation for 21 days, the mean size of the hypoxia-expanded neurospheres was significantly increased at 5% O2; this correlated with high-level expression of hypoxia-inducible factor-1 alpha (Hif-1α), proliferating cell nuclear antigen (PCNA), cyclin D1, Abcg2, nestin, and Nanog proteins but downregulated expression of p27 compared to that in a normoxic condition. Low oxygen tension cultivation tended to increase the side population fraction, with a significant difference found at 5% O2 compared to that at 20% O2. In addition, hypoxia induced a metabolic energy shift of SPCs toward higher basal ECARs and higher maximum mitochondrial respiratory capacity but lower proton leak than under normoxia, where the SPC metabolism was switched toward glycolysis in long-term hypoxic cultivation. PMID:26236724

Sex-, stress-, and sympathetic post-ganglionic-dependent changes in identity and proportions of immune cells in the dura.

PubMed

McIlvried, Lisa A; Cruz, J Agustin; Borghesi, Lisa A; Gold, Michael S

2017-01-01

Aim of investigation Due to compelling evidence in support of links between sex, stress, sympathetic post-ganglionic innervation, dural immune cells, and migraine, our aim was to characterize the impacts of these factors on the type and proportion of immune cells in the dura. Methods Dural immune cells were obtained from naïve or stressed adult male and female Sprague Dawley rats for flow cytometry. Rats with surgical denervation of sympathetic post-ganglionic neurons of the dura were also studied. Results Immune cells comprise ∼17% of all cells in the dura. These included: macrophages/granulocytes ("Macs"; 63.2% of immune cells), dendritic cells (0.88%), T-cells (4.51%), natural killer T-cells (0.51%), natural killer cells (3.08%), and B-cells (20.0%). There were significantly more Macs and fewer B- and natural killer T-cells in the dura of females compared with males. Macs and dendritic cells were significantly increased by stress in males, but not females. In contrast, T-cells were significantly increased in females with a 24-hour delay following stress. Lastly, Macs, dendritic cells, and T-cells were significantly higher in sympathectomized-naïve males, but not females. Conclusions It may not only be possible, but necessary to use different strategies for the most effective treatment of migraine in men and women.

L'Abondance du Deutérium, de l'Ultraviolet au Visible

NASA Astrophysics Data System (ADS)

Hébrard, Guillaume

2000-12-01

Dans le cadre du modèle standard du Big Bang, le deutérium est l'élément dont l'abondance primordiale est la plus sensible à la densité baryonique de l'Univers. Cet élément est uniquement créé lors de la nucléosynthèse primordiale, quelques minutes après le Big Bang ; aucune théorie standard n'en prédit actuellement d'autres sources significatives. Au contraire, étant brûlé dans les étoiles, son abondance D/H décroît au cours de l'évolution cosmique. Les mesures de D/H apportent ainsi des contraintes sur les modèles de Big Bang et d'évolution chimique des galaxies. On peut distinguer trois types de mesures de D/H: les abondances primordiale, proto-solaire et interstellaire, respectivement représentatives de l'Univers il y a environ 15 milliards d'années, 4.5 milliards d'années et à l'époque actuelle. Si l'évolution du deutérium semble qualitativement claire, les résultats concernant ces trois types d'abondance ne convergent pas pour l'instant vers trois valeurs bien définies. Les travaux entrepris durant cette thèse sont reliés à la mesure de l'abondance interstellaire du deutérium. Celle-ci s'obtient habituellement par l'observation spectroscopique en absorption des séries de Lyman de l'hydrogène et du deutérium. Ces observations se font dans le domaine ultraviolet, au moyen d'observatoires spatiaux. Les résultats présentés ici ont été obtenus avec le Télescope spatial Hubble puis le satellite FUSE, récemment mis en orbite. D'autre part, une nouvelle méthode d'observation du deutérium a été proposée, dans le domaine visible à partir de télescopes au sol. Ce travail a mené aux premières détections et à l'identification de la série de Balmer du deutérium, observée en émission dans des régions HII avec le Télescope Canada-France-Hawaii et le Very Large Telescope. On-line Thesis, Guillaume Hébrard

College of DuPage Planning Process: College of DuPage Planning, the Foundation for Decision Making.

ERIC Educational Resources Information Center

College of DuPage, Glen Ellyn, IL. Office of Research and Planning.

At College of DuPage (CD), in Glen Ellyn, Illinois, institutional planning is a multi-level, on-going process involving continuous college-wide input. The nine schematic levels in the CD planning process are interconnected and progress from global and broad-based issues, answering such questions as why the college exists, to concrete levels…

W.E.B. Du Bois and Caste Education: Racial Capitalist Schooling from Reconstruction to Jim Crow

ERIC Educational Resources Information Center

Pierce, Clayton

2017-01-01

This essay provides the first account and examination of caste education in the work of W.E.B. Du Bois. In so doing, I argue that caste education plays a central role in realizing the political and social goals of racial capitalist society for Du Bois. Using Du Bois's caste analytic, I take up and articulate three biopolitical governing strategies…

Expression, purification, and characterization of almond (Prunus dulcis) allergen Pru du 4.

PubMed

Zhang, Yuzhu; Du, Wen-Xian; Fregevu, Cécile; Kothary, Mahendra H; Harden, Leslie; McHugh, Tara H

2014-12-31

Biochemical characterizations of food allergens are required for understanding the allergenicity of food allergens. Such studies require a relatively large amount of highly purified allergens. The level of Pru du 4 in almond is low, and its expression in a soluble form in Escherichia coli required an expression tag. An MBP tag was used to enhance its expression and solubility. Sumo was used for the first time as a peptidase recognition site. The expression tag was removed with a sumo protease, and the resulting wild-type Pru du 4 was purified chromatographically. The stability of the allergen was investigated with chemical denaturation. The Gibbs free energy of Pru du 4 folding-unfolding transition was determined to be 5.4 ± 0.7 kcal/mol.

Prox1 Regulates the Subtype-Specific Development of Caudal Ganglionic Eminence-Derived GABAergic Cortical Interneurons

PubMed Central

Young, Allison; Petros, Timothy; Karayannis, Theofanis; McKenzie Chang, Melissa; Lavado, Alfonso; Iwano, Tomohiko; Nakajima, Miho; Taniguchi, Hiroki; Huang, Z. Josh; Heintz, Nathaniel; Oliver, Guillermo; Matsuzaki, Fumio; Machold, Robert P.

2015-01-01

Neurogliaform (RELN+) and bipolar (VIP+) GABAergic interneurons of the mammalian cerebral cortex provide critical inhibition locally within the superficial layers. While these subtypes are known to originate from the embryonic caudal ganglionic eminence (CGE), the specific genetic programs that direct their positioning, maturation, and integration into the cortical network have not been elucidated. Here, we report that in mice expression of the transcription factor Prox1 is selectively maintained in postmitotic CGE-derived cortical interneuron precursors and that loss of Prox1 impairs the integration of these cells into superficial layers. Moreover, Prox1 differentially regulates the postnatal maturation of each specific subtype originating from the CGE (RELN, Calb2/VIP, and VIP). Interestingly, Prox1 promotes the maturation of CGE-derived interneuron subtypes through intrinsic differentiation programs that operate in tandem with extrinsically driven neuronal activity-dependent pathways. Thus Prox1 represents the first identified transcription factor specifically required for the embryonic and postnatal acquisition of CGE-derived cortical interneuron properties. SIGNIFICANCE STATEMENT Despite the recognition that 30% of GABAergic cortical interneurons originate from the caudal ganglionic eminence (CGE), to date, a specific transcriptional program that selectively regulates the development of these populations has not yet been identified. Moreover, while CGE-derived interneurons display unique patterns of tangential and radial migration and preferentially populate the superficial layers of the cortex, identification of a molecular program that controls these events is lacking. Here, we demonstrate that the homeodomain transcription factor Prox1 is expressed in postmitotic CGE-derived cortical interneuron precursors and is maintained into adulthood. We found that Prox1 function is differentially required during both embryonic and postnatal stages of development to

Muscarinic acetylcholine receptor subtype expression in avian vestibular hair cells, nerve terminals and ganglion cells.

PubMed

Li, G Q; Kevetter, G A; Leonard, R B; Prusak, D J; Wood, T G; Correia, M J

2007-04-25

Muscarinic acetylcholine receptors (mAChRs) are widely expressed in the CNS and peripheral nervous system and play an important role in modulating the cell activity and function. We have shown that the cholinergic agonist carbachol reduces the pigeon's inwardly rectifying potassium channel (pKir2.1) ionic currents in native vestibular hair cells. We have cloned and sequenced pigeon mAChR subtypes M2-M5 and we have studied the expression of all five mAChR subtypes (M1-M5) in the pigeon vestibular end organs (semicircular canal ampullary cristae and utricular maculae), vestibular nerve fibers and the vestibular (Scarpa's) ganglion using tissue immunohistochemistry (IH), dissociated single cell immunocytochemistry (IC) and Western blotting (WB). We found that vestibular hair cells, nerve fibers and ganglion cells each expressed all five (M1-M5) mAChR subtypes. Two of the three odd-numbered mAChRs (M1, M5) were present on the hair cell cilia, supporting cells and nerve terminals. And all three odd numbered mAChRs (M1, M3 and M5) were expressed on cuticular plates, myelin sheaths and Schwann cells. Even-numbered mAChRs were seen on the nerve terminals. M2 was also shown on the cuticular plates and supporting cells. Vestibular efferent fibers and terminals were not identified in our studies. Results from WB of the dissociated vestibular epithelia, nerve fibers and vestibular ganglia were consistent with the results from IH and IC. Our findings suggest that there is considerable co-expression of the subtypes on the neural elements of the labyrinth. Further electrophysiological and pharmacological studies should delineate the mechanisms of action of muscarinic acetylcholine receptors on structures in the labyrinth.

Glial cell line-derived neurotrophic factor (GDNF) induces neuritogenesis in the cochlear spiral ganglion via neural cell adhesion molecule (NCAM)

PubMed Central

Euteneuer, Sara; Yang, Kuo H.; Chavez, Eduardo; Leichtle, Anke; Loers, Gabriele; Olshansky, Adel; Pak, Kwang; Schachner, Melitta; Ryan, Allen F.

2013-01-01

Glial cell line-derived neurotrophic factor (GDNF) increases survival and neurite extension of spiral ganglion neurons (SGNs), the primary neurons of the auditory system, via yet unknown signaling mechanisms. In other cell types, signaling is achieved by the GPI-linked GDNF family receptor α1 (GFRα1) via recruitment of transmembrane receptors: Ret (re-arranged during transformation) and/or NCAM (neural cell adhesion molecule). Here we show that GDNF enhances neuritogenesis in organotypic cultures of spiral ganglia from 5-day-old rats and mice. Addition of GFRα1-Fc increases this effect. GDNF/GFRα1-Fc stimulation activates intracellular PI3K/Akt and MEK/Erk signaling cascades as detected by Western blot analysis of cultures prepared from rats at postnatal days 5 (P5, before the onset of hearing) and 20 (P20, after the onset of hearing). Both cascades mediate GDNF stimulation of neuritogenesis, since application of the Akt inhibitor Wortmannin or the Erk inhibitor U0126 abolished GDNF/GFRα1-Fc stimulated neuritogenesis in P5 rats. Since cultures of P5 NCAM-deficient mice failed to respond by neuritogenesis to GDNF/GFRα1-Fc, we conclude that NCAM serves as a receptor for GDNF signaling responsible for neuritogenesis in early postnatal spiral ganglion. PMID:23262364

[Effect of bee venom injection on TrkA and TRPV1 expression in the dorsal root ganglion of rats with collagen-induced arthritis].

PubMed

Xian, Pei-Feng; Chen, Ying; Yang, Lu; Liu, Guo-Tao; Peng, Peng; Wang, Sheng-Xu

2016-06-01

To investigate the therapeutic effect of acupoint injection of bee venom on collagen-induced arthritis (CIA) in rats and explore the mechanism of bee venom therapy in the treatment of rheumatoid arthritis. Fifteen male Wistar rats were randomly divided into bee venom treatment group (BV group), CIA model group, and control group. In the former two groups, CIA was induced by injections of collagen II+IFA (0.2 mL) via the tail vein, and in the control group, normal saline was injected instead. The rats in BV group received daily injection of 0.1 mL (3 mg/mL) bee venom for 7 consecutive days. All the rats were assessed for paw thickness and arthritis index from days 14 to 21, and the pain threshold was determined on day 21. The expressions of TRPV1 and TrkA in the dorsal root ganglion at the level of L4-6 were detected using immunohistochemistry and Western blotting, respectively. The rats in CIA model group started to show paw swelling on day 10, and by day 14, all the rats in this group showed typical signs of CIA. In BV group, the rats receiving been venom therapy for 7 days showed a significantly smaller paw thickness and a low arthritis index than those in the model group. The pain threshold was the highest in the control group and the lowest in the model group. TRPV1-positive cells and TrkA expression in the dorsal root ganglion was significantly reduced in BV group as compared with that in the model group. s Injection of bee venom can decrease expression of TRPV1 and TrkA in the dorsal root ganglion to produce anti-inflammatory and analgesic effects, suggesting the potential value of bee venom in the treatment of rheumatoid arthritis.

Stimulation of ganglionated plexus attenuates cardiac neural remodeling and heart failure progression in a canine model of acute heart failure post-myocardial infarction.

PubMed

Luo, Da; Hu, Huihui; Qin, Zhiliang; Liu, Shan; Yu, Xiaomei; Ma, Ruisong; He, Wenbo; Xie, Jing; Lu, Zhibing; He, Bo; Jiang, Hong

2017-12-01

Heart failure (HF) is associated with autonomic dysfunction. Vagus nerve stimulation has been shown to improve cardiac function both in HF patients and animal models of HF. The purpose of this present study is to investigate the effects of ganglionated plexus stimulation (GPS) on HF progression and autonomic remodeling in a canine model of acute HF post-myocardial infarction. Eighteen adult mongrel male dogs were randomized into the control (n=8) and GPS (n=10) groups. All dogs underwent left anterior descending artery ligation followed by 6-hour high-rate (180-220bpm) ventricular pacing to induce acute HF. Transthoracic 2-dimensional echocardiography was performed at different time points. The plasma levels of norepinephrine, B-type natriuretic peptide (BNP) and Ang-II were measured using ELISA kits. C-fos and nerve growth factor (NGF) proteins expressed in the left stellate ganglion as well as GAP43 and TH proteins expressed in the peri-infarct zone were measured using western blot. After 6h of GPS, the left ventricular end-diastolic volume, end-systolic volume and ejection fraction showed no significant differences between the 2 groups, but the interventricular septal thickness at end-systole in the GPS group was significantly higher than that in the control group. The plasma levels of norepinephrine, BNP, Ang-II were increased 1h after myocardial infarction while the increase was attenuated by GPS. The expression of c-fos and NGF proteins in the left stellate ganglion as well as GAP43 and TH proteins in cardiac peri-infarct zone in GPS group were significantly lower than that in control group. GPS inhibits cardiac sympathetic remodeling and attenuates HF progression in canines with acute HF induced by myocardial infarction and ventricular pacing. Copyright © 2017 Elsevier B.V. All rights reserved.

Diagnostic ability of macular ganglion cell inner plexiform layer measurements in glaucoma using swept source and spectral domain optical coherence tomography.

PubMed

Yang, Zhiyong; Tatham, Andrew J; Weinreb, Robert N; Medeiros, Felipe A; Liu, Ting; Zangwill, Linda M

2015-01-01

To evaluate the diagnostic ability of macular ganglion cell and inner plexiform layer measurements in glaucoma, obtained using swept source (SS) and spectral domain (SD) optical coherence tomography (OCT) and to compare to circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements. The study included 106 glaucomatous eyes of 80 subjects and 41 eyes of 22 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Macular ganglion cell and inner plexiform layer (mGCIPL), macular ganglion cell complex (mGCC) and cpRNFL thickness were assessed using SS-OCT and SD-OCT, and area under the receiver operating characteristic curves (AUCs) were calculated to determine ability to differentiate glaucomatous and healthy eyes and between early glaucomatous and healthy eyes. Mean (± standard deviation) mGCIPL and mGCC thickness were thinner in both healthy and glaucomatous eyes using SS-OCT compared to using SD-OCT. Fixed and proportional biases were detected between SS-OCT and SD-OCT measures. Diagnostic accuracy (AUCs) for differentiating between healthy and glaucomatous eyes for average and sectoral mGCIPL was similar in SS-OCT (0.65 to 0.81) and SD-OCT (0.63 to 0.83). AUCs for average cpRNFL acquired using SS-OCT and SD-OCT tended to be higher (0.83 and 0.85, respectively) than for average mGCC (0.82 and 0.78, respectively), and mGCIPL (0.73 and 0.75, respectively) but these differences did not consistently reach statistical significance. Minimum SD-OCT mGCIPL and mGCC thickness (unavailable in SS-OCT) had the highest AUC (0.86) among macular measurements. Assessment of mGCIPL thickness using SS-OCT or SD-OCT is useful for detecting glaucomatous damage, but measurements are not interchangeable for patient management decisions. Diagnostic accuracies of mGCIPL and mGCC from both SS-OCT and SD-OCT were similar to that of cpRNFL for glaucoma detection.

Diagnostic Ability of Macular Ganglion Cell Inner Plexiform Layer Measurements in Glaucoma Using Swept Source and Spectral Domain Optical Coherence Tomography

PubMed Central

Yang, Zhiyong; Tatham, Andrew J.; Weinreb, Robert N.; Medeiros, Felipe A.; Liu, Ting; Zangwill, Linda M.

2015-01-01

Purpose To evaluate the diagnostic ability of macular ganglion cell and inner plexiform layer measurements in glaucoma, obtained using swept source (SS) and spectral domain (SD) optical coherence tomography (OCT) and to compare to circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements. Methods The study included 106 glaucomatous eyes of 80 subjects and 41 eyes of 22 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Macular ganglion cell and inner plexiform layer (mGCIPL), macular ganglion cell complex (mGCC) and cpRNFL thickness were assessed using SS-OCT and SD-OCT, and area under the receiver operating characteristic curves (AUCs) were calculated to determine ability to differentiate glaucomatous and healthy eyes and between early glaucomatous and healthy eyes. Results Mean (± standard deviation) mGCIPL and mGCC thickness were thinner in both healthy and glaucomatous eyes using SS-OCT compared to using SD-OCT. Fixed and proportional biases were detected between SS-OCT and SD-OCT measures. Diagnostic accuracy (AUCs) for differentiating between healthy and glaucomatous eyes for average and sectoral mGCIPL was similar in SS-OCT (0.65 to 0.81) and SD-OCT (0.63 to 0.83). AUCs for average cpRNFL acquired using SS-OCT and SD-OCT tended to be higher (0.83 and 0.85, respectively) than for average mGCC (0.82 and 0.78, respectively), and mGCIPL (0.73 and 0.75, respectively) but these differences did not consistently reach statistical significance. Minimum SD-OCT mGCIPL and mGCC thickness (unavailable in SS-OCT) had the highest AUC (0.86) among macular measurements. Conclusion Assessment of mGCIPL thickness using SS-OCT or SD-OCT is useful for detecting glaucomatous damage, but measurements are not interchangeable for patient management decisions. Diagnostic accuracies of mGCIPL and mGCC from both SS-OCT and SD-OCT were similar to that of cpRNFL for glaucoma detection. PMID:25978420

Nouvelles approches en theorie du champ moyen dynamique: le cas du pouvoir thermoelectrique et celui de l'effet orbital d'un champ magnetique

NASA Astrophysics Data System (ADS)

Arsenault, Louis-Francois

Les applications reliees a la generation d'energie motivent la recherche de materiaux ayant un fort pouvoir thermoelectrique (S). De plus, S nous renseigne sur certaines proprietes fondamentales des materiaux, comme, par exemple, la transition entre l'etat coherent et incoherent des quasi-particules lorsque la temperature augmente. Empiriquement, la presence de fortes interactions electron-electron peut mener a un pouvoir thermoelectrique geant. Nous avons donc etudie le modele le plus simple qui tient compte de ces fortes interactions, le modele de Hubbard. La theorie du champ moyen dynamique (DMFT) est tout indiquee dans ce cas. Nous nous sommes concentres sur un systeme tridimensionnel (3d) cubique a face centree (fcc), et ce, pour plusieurs raisons. A) Ce type de cristal est tres commun dans la nature. B) La DMFT donne de tres bons resultats en 3d et donc ce choix sert aussi de preuve de principe de la methode. C) Finalement, a cause de la frustration electronique intrinseque au fcc, celui-ci ne presente pas de symetrie particule-trou, ce qui est tres favorable a l'apparition d'une grande valeur de S. Ce travail demontre que lorsque le materiau est un isolant a demi-remplissage a cause des fortes interactions (isolant de Mott), il est possible d'obtenir de grands pouvoirs thermoelectriques en le dopant legerement. C'est un resultat pratique important. Du point de vue methodologique, nous avons montre comment la limite de frequence infinie de S et l'approche dite de Kelvin, qui considere la limite de frequence nulle avant la limite thermodynamique pour S, donnent des estimations fiables de la vraie limite continue (DC) dans les domaines de temperature appropriee. Ces deux approches facilitent grandement les calculs en court-circuit ant la necessite de recourir a de problematiques prolongements analytiques. Nous avons trouve que la methode de calcul a frequence infinie fonctionne bien lorsque les echelles d'energie sont relativement faibles. En d'autres termes

Mesure de haute resolution de la fonction de distribution radiale du silicium amorphe pur

NASA Astrophysics Data System (ADS)

Laaziri, Khalid

1999-11-01

Cette these porte sur l'etude de la structure du silicium amorphe prepare par irradiation ionique. Elle presente des mesures de diffraction de rayons X sur de la poudre de silicium cristallin, du silicium amorphe relaxe et non relaxe, ainsi que tous les developpements mathematiques et physiques necessaires pour extraire la fonction de distribution radiale correspondant a chaque echantillon. Au Chapitre I, nous presentons une methode de fabrication de membranes minces de silicium amorphe pur. Il y a deux etapes majeures lors du processus de fabrication: l'implantation ionique, afin de creer une couche amorphe de plusieurs microns et l'attaque chimique, pour enlever le reste du materiau cristallin. Nous avons caracterise premierement les membranes de silicium amorphe par spectroscopie Raman pour verifier qu'il ne reste plus de trace de materiau cristallin dans les films amorphes. Une deuxieme caracterisation par detection de recul elastique (ERD-TOF) sur ces memes membranes a montre qu'il y a moins de 0.1% atomique de contaminants tels que l'oxygene, le carbone, et l'hydrogene. Au Chapitre II, nous proposons une nouvelle methode de correction de la contribution inelastique "Compton" des spectres de diffusion totale afin d'extraire les pics de diffusion elastique, responsable de la diffraction de Bragg. L'article presente tout d'abord une description simplifiee d'une theorie sur la diffusion inelastique dite "Impulse Approximation" (IA) qui permet de calculer des profils de Compton en fonction de l'energie et de l'angle de diffusion 2theta. Ces profils sont utilises comme fonction de lissage de la diffusion Compton experimentale. Pour lisser les pics de diffusion elastique, nous avons utilise une fonction pic de nature asymetrique. Aux Chapitre III, nous exposons de maniere detaillee les resultats des experiences de diffraction de rayons X sur les membranes de silicium amorphe et la poudre de silicium cristallin que nous avons preparees. Nous abordons aussi les

DuSable High School Program Flourishes.

ERIC Educational Resources Information Center

Graff, Pat

1995-01-01

Describes the fall and rise of the Panther Press, the scholastic newspaper of the DuSable High School in Chicago. States that despite being located in the midst of public housing projects, the school's newspaper is thriving where others in similar circumstances have failed. Describes how the school's principal and an advisor revitalized and…

Prejudice: From Allport to DuBois.

ERIC Educational Resources Information Center

Gaines, Stanley O., Jr.; Reed, Edward S.

1995-01-01

Examines the differences between Gordon Allport's and W. E. B. DuBois's theories on the origins of prejudice and the impact of discrimination on the personality and social development of blacks. The article argues that prejudice is a historically developed process, not a universal feature of human psychology. Implications for U.S. race relations…

Roles of PACAP-containing retinal ganglion cells in circadian timing.

PubMed

Hannibal, Jens

2006-01-01

The brain's biological clock located in the suprachiasmatic nucleus (SCN) generates circadian rhythms in physiology and behavior. The clock-driven rhythms need daily adjustment (entrainment) to be synchronized with the astronomical day of 24 h. The most important stimulus for entrainment of the clock is the light-dark (LD) cycle. In this review functional elements of the light entrainment pathway will be considered with special focus on the neurotransmitter pituitary adenylate cyclase-activating polypeptide (PACAP), which is found exclusively in the monosynaptic neuronal pathway mediating light information to the SCN, the retinohypothalamic tract (RHT). The retinal ganglion cells of the RHT are intrinsically photosensitive due to the expression of melanopsin and seem to constitute a non-image forming photosensitive system in the mammalian eye regulating circadian timing, masking behavior, light-regulated melatonin secretion, and the pupillary light reflex. Evidence from in vitro and in vivo studies and studies of mice lacking PACAP and the specific PACAP receptor (PAC1) indicate that PACAP and glutamate are neurotransmitters in the RHT which in a clock and concentration-dependent manner interact during light entrainment of the clock.

Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling

PubMed Central

Lumbreras, Vicente; Bas, Esperanza; Gupta, Chhavi

2014-01-01

Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca2+ imaging. Both types of neurons responded consistently with robust intracellular Ca2+ ([Ca2+]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25–1 pps). Radiant exposures of ∼637 mJ/cm2 resulted in continual neuronal activation. Temperature or [Ca2+] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca2+ involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na+, K+, and Ca2+ plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca2+ cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca2+]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca2+ release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses. PMID:24920028

Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling.

PubMed

Lumbreras, Vicente; Bas, Esperanza; Gupta, Chhavi; Rajguru, Suhrud M

2014-09-15

Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses. Copyright © 2014 the American Physiological Society.

Neuronal couplings between retinal ganglion cells inferred by efficient inverse statistical physics methods

PubMed Central

Cocco, Simona; Leibler, Stanislas; Monasson, Rémi

2009-01-01

Complexity of neural systems often makes impracticable explicit measurements of all interactions between their constituents. Inverse statistical physics approaches, which infer effective couplings between neurons from their spiking activity, have been so far hindered by their computational complexity. Here, we present 2 complementary, computationally efficient inverse algorithms based on the Ising and “leaky integrate-and-fire” models. We apply those algorithms to reanalyze multielectrode recordings in the salamander retina in darkness and under random visual stimulus. We find strong positive couplings between nearby ganglion cells common to both stimuli, whereas long-range couplings appear under random stimulus only. The uncertainty on the inferred couplings due to limitations in the recordings (duration, small area covered on the retina) is discussed. Our methods will allow real-time evaluation of couplings for large assemblies of neurons. PMID:19666487

Facteurs de risque cardiovasculaires au cours du lupus systémique

PubMed Central

Harzallah, Amel; Hajji, Mariem; Kaaroud, Hayet; Hamida, Fethi Ben; Abdallah, Taieb Ben

2015-01-01

Cette étude a pour objectif d’évaluer la fréquence des facteurs de risque cardiovasculaires au cours du lupus et de préciser leur prévalence. Etude rétrospective portant sur 250 patients ayant un lupus, diagnostiqué selon les critères de l'ACR, hospitalisés entre 1970 et 2013. Les données cliniques et para cliniques ont été recueillies à partir des observations médicales. Il s'agit de 228 femmes et 22 hommes d’âge moyen au diagnostic du lupus de 30, 32 ans (extrêmes: 16-69). La durée moyenne du suivi des patients était de 64 mois (extrêmes: 7 jours- 382mois). Quatre vingt dix patients (36%) étaient hypertendus, 74% avaient une hypercholestérolémie et 22% étaient diabétiques. Pour les autres facteurs de risque cardiovasculaire traditionnels, un âge > 50 ans a été retrouvé dans 40% des cas, le sexe masculin dans 8% des cas, l'obésité dans 76% des cas et le tabagisme dans 11% des cas. Les facteurs de risque surajoutés sont représentés par la présence des anticorps antiphospholipides (47% des cas), la néphropathie lupique (49% des cas), l'insuffisance rénale (42% des cas), la corticothérapie au long cours (74% des cas) et la chronicité de la maladie dans 35% des cas. Les complications cardiovasculaires retrouvées dans notre série étaient: les accidents vasculaires cérébraux (2%) et l'insuffisance coronarienne (5,6%). Devant l'importance du risque cardiovasculaire au cours du lupus, une surveillance rapprochée des facteurs de risque cardio-vasculaires semble primordiale chez les lupiques. PMID:27022427

Primary culture of glial cells from mouse sympathetic cervical ganglion: a valuable tool for studying glial cell biology.

PubMed

de Almeida-Leite, Camila Megale; Arantes, Rosa Maria Esteves

2010-12-15

Central nervous system glial cells as astrocytes and microglia have been investigated in vitro and many intracellular pathways have been clarified upon various stimuli. Peripheral glial cells, however, are not as deeply investigated in vitro despite its importance role in inflammatory and neurodegenerative diseases. Based on our previous experience of culturing neuronal cells, our objective was to standardize and morphologically characterize a primary culture of mouse superior cervical ganglion glial cells in order to obtain a useful tool to study peripheral glial cell biology. Superior cervical ganglia from neonatal C57BL6 mice were enzymatically and mechanically dissociated and cells were plated on diluted Matrigel coated wells in a final concentration of 10,000cells/well. Five to 8 days post plating, glial cell cultures were fixed for morphological and immunocytochemical characterization. Glial cells showed a flat and irregular shape, two or three long cytoplasm processes, and round, oval or long shaped nuclei, with regular outline. Cell proliferation and mitosis were detected both qualitative and quantitatively. Glial cells were able to maintain their phenotype in our culture model including immunoreactivity against glial cell marker GFAP. This is the first description of immunocytochemical characterization of mouse sympathetic cervical ganglion glial cells in primary culture. This work discusses the uses and limitations of our model as a tool to study many aspects of peripheral glial cell biology. Copyright © 2010 Elsevier B.V. All rights reserved.

Acid-sensing ion channels in trigeminal ganglion neurons innervating the orofacial region contribute to orofacial inflammatory pain.

PubMed

Fu, Hui; Fang, Peng; Zhou, Hai-Yun; Zhou, Jun; Yu, Xiao-Wei; Ni, Ming; Zheng, Jie-Yan; Jin, You; Chen, Jian-Guo; Wang, Fang; Hu, Zhuang-Li

2016-02-01

Orofacial pain is a common clinical symptom that is accompanied by tooth pain, migraine and gingivitis. Accumulating evidence suggests that acid-sensing ion channels (ASICs), especially ASIC3, can profoundly affect the physiological properties of nociception in peripheral sensory neurons. The aim of this study is to examine the contribution of ASICs in trigeminal ganglion (TG) neurons to orofacial inflammatory pain. A Western blot (WB), immunofluorescence assay of labelled trigeminal ganglion neurons, orofacial formalin test, cell preparation and electrophysiological experiments are performed. This study demonstrated that ASIC1, ASIC2a and ASIC3 are highly expressed in TG neurons innervating the orofacial region of rats. The amplitude of ASIC currents in these neurons increased 119.72% (for ASIC1-like current) and 230.59% (for ASIC3-like current) in the formalin-induced orofacial inflammatory pain model. In addition, WB and immunofluorescence assay demonstrated a significantly augmented expression of ASICs in orofacial TG neurons during orofacial inflammation compared with the control group. The relative protein density of ASIC1, ASIC2a and ASIC3 also increased 58.82 ± 8.92%, 45.30 ± 11.42% and 55.32 ± 14.71%, respectively, compared with the control group. Furthermore, pharmacological blockade of ASICs and genetic deletion of ASIC1 attenuated the inflammation response. These findings indicate that peripheral inflammation can induce the upregulation of ASICs in TG neurons, causing orofacial inflammatory pain. Additionally, the specific inhibitor of ASICs may have a significant analgesic effect on orofacial inflammatory pain. © 2016 John Wiley & Sons Australia, Ltd.

Cocoa Enriched Diets Enhance Expression of Phosphatases and Decrease Expression of Inflammatory Molecules in Trigeminal Ganglion Neurons

PubMed Central

Cady, Ryan J.; Durham, Paul L.

2010-01-01

Activation of trigeminal nerves and release of neuropeptides that promote inflammation are implicated in the underlying pathology of migraine and temporomandibular joint (TMJ) disorders. The overall response of trigeminal nerves to peripheral inflammatory stimuli involves a balance between enzymes that promote inflammation, kinases, and those that restore homeostasis, phosphatases. The goal of this study was to determine the effects of a cocoa-enriched diet on the expression of key inflammatory proteins in trigeminal ganglion neurons under basal and inflammatory conditions. Rats were fed a control diet or an isocaloric diet enriched in cocoa for 14 days prior to an injection of noxious stimuli to cause acute or chronic excitation of trigeminal neurons. In animals fed a cocoa-enriched diet, basal levels of the mitogen-activated kinase (MAP) phosphatases MKP-1 and MKP-3 were elevated in neurons. Importantly, the stimulatory effects of acute or chronic peripheral inflammation on neuronal expression of the MAPK p38 and extracellular signal-regulated kinases (ERK) were significantly repressed in response to cocoa. Similarly, dietary cocoa significantly suppressed basal neuronal expression of calcitonin gene-related peptide (CGRP) as well as stimulated levels of the inducible form of nitric oxide synthase (iNOS), proteins implicated in the underlying pathology of migraine and TMJ disorders. To our knowledge, this is first evidence that a dietary supplement can cause upregulation of MKP, and that cocoa can prevent inflammatory responses in trigeminal ganglion neurons. Furthermore, our data provide evidence that cocoa contains biologically active compounds that would be beneficial in the treatment of migraine and TMJ disorders. PMID:20138852

World heritage site - Bien du Patrimoine Mondial - Kluane/Wrangell-St. Elias/Glacier Bay/Tatshenshini-Alsek

USGS Publications Warehouse

Labay, Keith A.; Wilson, Frederic H.

2004-01-01

The four parks depicted on this map make up a single World Heritage Site that covers 24.3 million acres. Together, they comprise the largest internationally protected land-based ecosystem on the planet. The United Nations Educational, Scientific and Cultural Organization (UNESCO) established the World Heritage Program in 1972 for the identification and protection of the world?s irreplaceable natural and cultural resources. World Heritage Sites are important as storehouses of memory and evolution, as anchors for sustainable tourism and community, and as laboratories for the study and understanding of the earth and culture. This World Heritage Site protects the prominent mountain ranges of Kluane, Wrangell, Saint Elias, and Chugach. It includes many of the tallest peaks on the continent, the world's largest non-polar icefield, extensive glaciers, vital watersheds, and expanses of dramatic wilderness. [Les quatre parcs figurant sur cette carte ne constituent qu?un seul site du patrimoine mondial recouvrant plus de 99 millions de km2, ce qui en fait le plus grand ecosysteme terrestre protege par loi internationale. En 1972, L?UNESCO (l?organisation des Nations Unies pour les sciences, l'education et la culture) a etabli le programme du patrimoine mondial afin d?identifier et de proteger les ressources naturelles et culturelles irremplacables de notre plan?te. Si les sites du patrimoine mondial sont si importants c'est parce qu'ils representent a la fois des livres ouverts sur l?histoire de la Terre, le point de depart du tourisme durable et du developpement des collectivites, des laboratoires pour etudier et comprendre la nature et la culture. Ce site du patrimoine mondial assure la protection des chaines de montagnes de Kluane, Wrangell, Saint Elias, et Chugach. On y trouve plusieurs des plus hauts sommets du continent, le plus grand champ de glace non-polaire du monde, d?immenses glaciers, des bassins hydrologiques essentiels, et de la nature sauvage a perte de vue.

Aspects épidémiologiques des traumatismes du rachis: à propos de 139 cas

PubMed Central

Bemora, Joseph Synèse; Rakotondraibe, Willy Francis; Ramarokoto, Mijoro; Ratovondrainy, Willy; Andriamamonjy, Clément

2017-01-01

Les traumatismes du rachis représentent une des lésions les plus fréquemment observées, chez les victimes d’accidents de circulation, d’accident de sportifs, domestique et du travail. Il s’agissait d’une étude rétrospective de 3 ans portant sur 139 cas de traumatismes du rachis hospitalisés et pris en charge dans le service de neurochirurgie du CHUJRA Madagascar. A travers cette étude, 25,17% des traumatisés étaient entre 21 et 30 ans avec une nette prédominance masculine de 69,78% (sexe ratio 2,3). L’étiologie était dominéepar la chute dans 33,09% des cas avec des facteurs de risque dont prise d’alcool (8,63%). Le traumatisme entrait dans le cadre d’un polytraumatisme dont un traumatisme crânien dans 34,63%. Les patients étaient admis dans le service 1 à 5h après le traumatisme dans 31,65% en utilisant comme moyen de transport une voiture personnelle dans 36,69%. Pendant l’hospitalisation 20 patients ont signé une décharge et 6,34% des patients sont décédés. Les traumatismes du rachis posent un problème de santé publique avec une prise en charge lourde surtout pour les patients déficitaires à vie. Devant tout traumatisme du rachis, il faut rechercher systématiquement une lésion crânienne. PMID:28450995

Évaluation des caractéristiques mécaniques du polissoir en polyuréthanne utilisé comme porte abrasifs durant le processus du polissage du verre optique

NASA Astrophysics Data System (ADS)

Aliouane, T.; Bouzid, D.; Belkhir, N.; Bouzid, S.; Herold, V.

2005-05-01

La fabrication des composants en verre optique nécessite des moyens de grande précision dans les procédés de finition vue l'importance accordée à leur qualité.
Durant le processus de polissage des verres optiques, le polissoir est un élément clé et a un impact direct sur les performances des composants optiques, non seulement il est utilisé comme support de grains abrasifs mais il doit posséder la fonction de transmission de la pression aux grains. La connaissance de ses propriétés, essentiellement mécanique, est impérative afin d'obtenir un état de surface optimal des composants optiques destinés à remplir des fonctions très précises dans des appareils optiques très performants.
Dans cette étude, nous avons constaté que les propriétés des polissoirs en polyuréthanne tel que la dureté, le module d'élasticité et la densité varient au cours du polissage. Ce changement a des effets sur l'état de surface de verre optique, causé par le changement microstructural de la surface du polissoir (distribution et dimensions des pores) et par conséquent sur la quantité des abrasifs (en oxyde de cérium) insérée dans les pores, ce qui influe sur la quantité de verre enlevée et sur l'état de surface du composant.
Sur la base des résultats obtenus, il a été prouvé que le polissoir subit des modifications très importantes ce qui influe considérablement sur son efficacité de polissage.

Association between Fatigue and Autistic Symptoms in Children with Cri du Chat Syndrome

ERIC Educational Resources Information Center

Claro, Anthony; Cornish, Kim; Gruber, Reut

2011-01-01

In the current study, the authors examined whether the fatigue level of children diagnosed with cri du chat syndrome was associated with the expression of autistic symptoms. Sixty-nine children with cri du chat syndrome were compared with 47 children with moderate to severe intellectual disabilities who did not differ on intellectual severity.…

The ciliary margin zone of the mammalian retina generates retinal ganglion cells

PubMed Central

Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol

2016-01-01

Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

Protective Effect of Edaravone on Glutamate-Induced Neurotoxicity in Spiral Ganglion Neurons

PubMed Central

Bai, Xiaohui; Zhang, Chi; Chen, Aiping; Liu, Wenwen; Li, Jianfeng; Sun, Qian

2016-01-01

Glutamate is an important excitatory neurotransmitter in mammalian brains, but excessive amount of glutamate can cause “excitotoxicity” and lead to neuronal death. As bipolar neurons, spiral ganglion neurons (SGNs) function as a “bridge” in transmitting auditory information from the ear to the brain and can be damaged by excessive glutamate which results in sensorineural hearing loss. In this study, edaravone, a free radical scavenger, elicited both preventative and therapeutic effects on SGNs against glutamate-induced cell damage that was tested by MTT assay and trypan blue staining. Ho.33342 and PI double staining revealed that apoptosis as well as necrosis took place during glutamate treatment, and apoptosis was the main type of cell death. Oxidative stress played an important role in glutamate-induced cell damage but pretreatment with edaravone alleviated cell death. Results of western blot demonstrated that mechanisms underlying the toxicity of glutamate and the protection of edaravone were related to the PI3K pathway and Bcl-2 protein family. PMID:27957345

Imaging light responses of foveal ganglion cells in the living macaque eye.

PubMed

Yin, Lu; Masella, Benjamin; Dalkara, Deniz; Zhang, Jie; Flannery, John G; Schaffer, David V; Williams, David R; Merigan, William H

2014-05-07

The fovea dominates primate vision, and its anatomy and perceptual abilities are well studied, but its physiology has been little explored because of limitations of current physiological methods. In this study, we adapted a novel in vivo imaging method, originally developed in mouse retina, to explore foveal physiology in the macaque, which permits the repeated imaging of the functional response of many retinal ganglion cells (RGCs) simultaneously. A genetically encoded calcium indicator, G-CaMP5, was inserted into foveal RGCs, followed by calcium imaging of the displacement of foveal RGCs from their receptive fields, and their intensity-response functions. The spatial offset of foveal RGCs from their cone inputs makes this method especially appropriate for fovea by permitting imaging of RGC responses without excessive light adaptation of cones. This new method will permit the tracking of visual development, progression of retinal disease, or therapeutic interventions, such as insertion of visual prostheses.

Mechanism of blood pressure and R-R variability: insights from ganglion blockade in humans

NASA Technical Reports Server (NTRS)

Zhang, Rong; Iwasaki, Kenichi; Zuckerman, Julie H.; Behbehani, Khosrow; Crandall, Craig G.; Levine, Benjamin D.; Blomqvist, C. G. (Principal Investigator)

2002-01-01

Spontaneous blood pressure (BP) and R-R variability are used frequently as 'windows' into cardiovascular control mechanisms. However, the origin of these rhythmic fluctuations is not completely understood. In this study, with ganglion blockade, we evaluated the role of autonomic neural activity versus other 'non-neural' factors in the origin of BP and R-R variability in humans. Beat-to-beat BP, R-R interval and respiratory excursions were recorded in ten healthy subjects (aged 30 +/- 6 years) before and after ganglion blockade with trimethaphan. The spectral power of these variables was calculated in the very low (0.0078-0.05 Hz), low (0.05-0.15 Hz) and high (0.15-0.35 Hz) frequency ranges. The relationship between systolic BP and R-R variability was examined by cross-spectral analysis. After blockade, R-R variability was virtually abolished at all frequencies; however, respiration and high frequency BP variability remained unchanged. Very low and low frequency BP variability was reduced substantially by 84 and 69 %, respectively, but still persisted. Transfer function gain between systolic BP and R-R interval variability decreased by 92 and 88 % at low and high frequencies, respectively, while the phase changed from negative to positive values at the high frequencies. These data suggest that under supine resting conditions with spontaneous breathing: (1) R-R variability at all measured frequencies is predominantly controlled by autonomic neural activity; (2) BP variability at high frequencies (> 0.15 Hz) is mediated largely, if not exclusively, by mechanical effects of respiration on intrathoracic pressure and/or cardiac filling; (3) BP variability at very low and low frequencies (< 0.15 Hz) is probably mediated by both sympathetic nerve activity and intrinsic vasomotor rhythmicity; and (4) the dynamic relationship between BP and R-R variability as quantified by transfer function analysis is determined predominantly by autonomic neural activity rather than other

Genetically Identified Suppressed-by-Contrast Retinal Ganglion Cells Reliably Signal Self-Generated Visual Stimuli

PubMed Central

Tien, Nai-Wen; Pearson, James T.; Heller, Charles R.; Demas, Jay

2015-01-01

Spike trains of retinal ganglion cells (RGCs) are the sole source of visual information to the brain; and understanding how the ∼20 RGC types in mammalian retinae respond to diverse visual features and events is fundamental to understanding vision. Suppressed-by-contrast (SbC) RGCs stand apart from all other RGC types in that they reduce rather than increase firing rates in response to light increments (ON) and decrements (OFF). Here, we genetically identify and morphologically characterize SbC-RGCs in mice, and target them for patch-clamp recordings under two-photon guidance. We find that strong ON inhibition (glycine > GABA) outweighs weak ON excitation, and that inhibition (glycine > GABA) coincides with decreases in excitation at light OFF. These input patterns explain the suppressive spike responses of SbC-RGCs, which are observed in dim and bright light conditions. Inhibition to SbC-RGC is driven by rectified receptive field subunits, leading us to hypothesize that SbC-RGCs could signal pattern-independent changes in the retinal image. Indeed, we find that shifts of random textures matching saccade-like eye movements in mice elicit robust inhibitory inputs and suppress spiking of SbC-RGCs over a wide range of texture contrasts and spatial frequencies. Similarly, stimuli based on kinematic analyses of mouse blinking consistently suppress SbC-RGC spiking. Receiver operating characteristics show that SbC-RGCs are reliable indicators of self-generated visual stimuli that may contribute to central processing of blinks and saccades. SIGNIFICANCE STATEMENT This study genetically identifies and morphologically characterizes suppressed-by-contrast retinal ganglion cells (SbC-RGCs) in mice. Targeted patch-clamp recordings from SbC-RGCs under two-photon guidance elucidate the synaptic mechanisms mediating spike suppression to contrast steps, and reveal that SbC-RGCs respond reliably to stimuli mimicking saccade-like eye movements and blinks. The similarity of

A Conversation with Lee Alvin DuBridge - Part I

NASA Astrophysics Data System (ADS)

Goodstein, Judith R.

Physicist Lee A. DuBridge became president of the California Institute of Technology in 1946. In this interview he recalls the immediate problems he faced, including his dealings with Robert A. Millikan, whom he replaced as chief administrator of the institute; institute financing and inadequate salaries. DuBridge also talks about the advent of federal support for peacetime science and Millikan's distaste for it; his close working relationship with Robert F. Bacher, who came to the institute in 1949 as chairman of the Division of Physics, Mathematics, and Astronomy; his recollections of the meteorologist Irving P. Krick, the physicist Alexander Goetz, and the chemist Linus Pauling; and his attempts to build up the Humanities Division.

Diagnostic et prévalence du syndrome métabolique chez les diabétiques suivis dans un contexte de ressources limitées: cas du Burkina-Faso

PubMed Central

Marceline, Yaméogo Téné; Issiaka, Sombié; Gilberte, Kyélem Carole; Nadège, Rouamba; Macaire, Ouédraogo Sampawindé; Arsène, Yaméogo Aimé; Djingri, Lankoandé; Apollinaire, Sawadogo; Joseph, Drabo Youssouf

2014-01-01

Introduction Les conséquences du syndrome métabolique impliquent son diagnostic effectif pour une prise en charge globale des comorbidités dépistées. Objectif: Déterminer la capacité à diagnostiquer le syndrome métabolique en routine, sa prévalence chez les diabétiques, leurs connaissances et pratiques vis-à-vis du risque cardio-métabolique. Méthodes Il s'est agi d'une étude transversale auprès de 388 diabétiques au CHU de Bobo-Dioulasso. Les critères de la fédération internationale du diabète (2009) ont été utilisés. Résultats l’âge moyen était de 53,5±13,5 ans, le sex ratio de 0,7. L'obésité abdominale était présente dans 61,9% des cas; L'HTA l’était dans 56,4% des cas. La prescription du bilan lipidique a été documentée dans 55,4% des cas pour le HDL et 56,2% pour les triglycérides pour un taux de réalisation de 49,3% et 62,9%. Le taux de dépistage des critères lipidiques était de 26,8%. Un taux de HDL bas a été noté dans 46 cas (43,4%) et une hypertriglycéridémie dans 24 cas (17,6%). In fine, la prévalence du syndrome métabolique était de 48,9% (n = 190). Seuls 27,4% savaient que d'autres facteurs de risque cardiovasculaire pouvaient être associés au diabète et seulement 6,7% pratiquaient une activité physique régulière. Conclusion Malgré la faible contribution du laboratoire, le syndrome métabolique est fréquent parmi nos diabétiques. Les patients sont peu sensibilisés sur le risque vasculaire et la pratique d'une activité physique régulière reste faible. Un programme d’éducation adaptée contribuerait à un meilleur dépistage et à une prise en charge optimale des cas. PMID:25932077

Parkin overexpression protects retinal ganglion cells against glutamate excitotoxicity.

PubMed

Hu, Xinxin; Dai, Yi; Sun, Xinghuai

2017-01-01

To investigate the role of parkin in regulating mitochondrial homeostasis of retinal ganglion cells (RGCs) under glutamate excitotoxicity. Rat RGCs were purified from dissociated retinal tissue with a modified two-step panning protocol. Cultured RGCs were transfected with parkin using an adenovirus system. The distribution and morphology of mitochondria in the RGCs were assessed with MitoTracker. The expression and distribution of parkin and optineurin proteins were measured with western blot analysis and immunofluorescence. Cytotoxicity of RGCs was evaluated by measuring lactate dehydrogenase (LDH) activity. Mitochondrial membrane potential was determined with the JC-1 assay. The expression of Bax and Bcl-2 were measured with western blot analysis. In the presence of glutamate-induced excitotoxicity, the number of mitochondria in the axons of the RGCs was predominantly increased, and the mitochondrial membrane potential in RGCs was depolarized. The expression of the parkin and optineurin proteins was upregulated and distributed mostly in the axons of the RGCs. Overexpression of parkin stabilized the mitochondrial membrane potential of RGCs, decreased cytotoxicity and apoptosis, attenuated the expression of Bax, and promoted the expression of optineurin under glutamate excitotoxicity. Overexpression of parkin exerted a significant protective effect on cultured RGCs against glutamate excitotoxicity. Interventions to alter the parkin-mediated mitochondria pathway may be useful in protecting RGCs against excitotoxic RGC damage.

Ganglion cell loss in relation to visual disability in multiple sclerosis.

PubMed

Walter, Scott D; Ishikawa, Hiroshi; Galetta, Kristin M; Sakai, Reiko E; Feller, Daniel J; Henderson, Sam B; Wilson, James A; Maguire, Maureen G; Galetta, Steven L; Frohman, Elliot; Calabresi, Peter A; Schuman, Joel S; Balcer, Laura J

2012-06-01

We used high-resolution spectral-domain optical coherence tomography (SD-OCT) with retinal segmentation to determine how ganglion cell loss relates to history of acute optic neuritis (ON), retinal nerve fiber layer (RNFL) thinning, visual function, and vision-related quality of life (QOL) in multiple sclerosis (MS). Cross-sectional study. A convenience sample of patients with MS (n = 122; 239 eyes) and disease-free controls (n = 31; 61 eyes). Among MS eyes, 87 had a history of ON before enrollment. The SD-OCT images were captured using Macular Cube (200×200 or 512×128) and ONH Cube 200×200 protocols. Retinal layer segmentation was performed using algorithms established for glaucoma studies. Thicknesses of the ganglion cell layer/inner plexiform layer (GCL+IPL), RNFL, outer plexiform/inner nuclear layers (OPL+INL), and outer nuclear/photoreceptor layers (ONL+PRL) were measured and compared in MS versus control eyes and MS ON versus non-ON eyes. The relation between changes in macular thickness and visual disability was also examined. The OCT measurements of GCL+IPL and RNFL thickness; high contrast visual acuity (VA); low-contrast letter acuity (LCLA) at 2.5% and 1.25% contrast; on the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and 10-Item Neuro-Ophthalmic Supplement composite score. Macular RNFL and GCL+IPL were significantly decreased in MS versus control eyes (P<0.001 and P = 0.001) and in MS ON versus non-ON eyes (P<0.001 for both measures). Peripapillary RNFL, macular RNFL, GCL+IPL, and the combination of macular RNFL+GCL+IPL were significantly correlated with VA (P≤0.001), 2.5% LCLA (P<0.001), and 1.25% LCLA (P≤0.001). Among OCT measurements, reductions in GCL+IPL (P<0.001), macular RNFL (P = 0.006), and the combination (macular RNFL+GCL+IPL; P<0.001) were most strongly associated with lower (worse) NEI-VFQ-25 and 10-Item Supplement QOL scores; GCL+IPL thinning was significant even accounting for macular RNFL thickness (P

Prevalence of Autism Spectrum Phenomenology in Cornelia de Lange and Cri du Chat Syndromes

ERIC Educational Resources Information Center

Moss, Joanna F.; Oliver, Chris; Berg, Katy; Kaur, Gurmeash; Jephcott, Lesley; Cornish, Kim

2008-01-01

Autism spectrum disorder characteristics have not been evaluated in Cornelia de Lange and Cri du Chat syndromes using robust assessments. The Autism Diagnostic Observation Schedule and Social Communication Questionnaire were administered to 34 participants with Cornelia de Lange syndrome and a comparison group of 23 participants with Cri du Chat…

[Herbal textual research of common Mongolian medicine "Du Ge Mo Nong"].

PubMed

Xi, Jie; Zhong, Hua-Rong; Wucharila-Tu; Buhe Bater; Li, Hui-Hu; Zhong, Guo-Yue

2016-11-01

This study is aimed to provide the source for clinical medication by clarifing the common base of Mongolia medicinal materials "Du Ge Mo Nong". In this paper literature research and plant taxonomy method were adopted combined with investigation of the markets and clinical use status to clarify the origin of common traditional Mongolian medicine "Du Ge Mo Nong". The results showed that the Mongolian medicine "Du Ge Mo Nong" and Tibetan medicine "Du Mu Niu" were the same crude drug and originated from the seeds of Holarrhena antidysenteriaca of family Apocynaceae in earliest time. In Mongolian medicine clinic, the seed of Cynanchum thesioides of family Asclepiadaceae and the fruit of Forsythia suspense of family Oleaceae was used respectively about 18 century and recent time, as the substitutes of H. antidysenteriaca. In present standards on Mongolian material medicine, C. thesioides is including only, and H. antidysenterica is not used almost. In Tibetan medicine clinic, H. antidysenterica is being used so far. But there are various substitutes including the seeds, fruits or grass of many species classified to family Apocynaceae, Asclepiadaceae and Onagraceae from ancient time to the present, and C. forrestii and C. komarovii may be used at present. It's necessary to strengthen the arrangement on Mongolian medicine's varieties by the multidisciplinary methods including literature research, investigation of resources and the use state, and comparison of active substances and biological activities between the different substitutes,and so on. Copyright© by the Chinese Pharmaceutical Association.

A morphometric study of the endocytosis of wheat germ agglutinin-horseradish peroxidase conjugates by retinal ganglion cells in the rat.

PubMed

Trojanowski, J Q; Gonatas, N K

1983-08-08

In order to elucidate the sequence for the intraneuronal translocation of ligands after internalization in vivo, the adsorptive endocytosis of horseradish peroxidase (HRP) conjugates of the lectin wheat germ agglutinin (WGHRP) by retinal ganglion cells of the rat was studied by ultrastructural morphometry after intravitreal injections of this probe. Retinas were harvested at post-injection survival times of 15 min to 7 days and processed for the electron microscopic visualization of WGHRP in subcellular organelles. The labeled organelles included vesicles, tubules, lysosomes and the cisterns and coated as well as uncoated vesicles of GERL (Golgi Apparatus-Endoplasmic-Reticulum-Lysosomes). For quantitation, labeled organelles were classed as vesicles, lysosomes and GERL. From 15 min to 3 h the number of labeled GERL and vesicles progressively increased to a maximum at 3 h and then declined to zero by 7 days. In contrast, the number of labeled lysosomes continued to increase beyond 3 h to reach a maximum at 24 h before declining to near zero by 7 days. These results are consistent with the hypothesis that the adsorptive endocytosis of WGHRP entails the passage of the ligand through GERL prior to being deposited in lysosomes. They do not exclude the possibility that other endocytic pathways for WGHRP and possible WGHRP-membrane complexes may exist in retinal ganglion cells including a plasma membrane to lysosome route.

Two distinct classes of functional α7-containing nicotinic receptor on rat superior cervical ganglion neurons

PubMed Central

Cuevas, Javier; Roth, Adelheid L; Berg, Darwin K

2000-01-01

Nicotinic acetylcholine receptors (nAChRs) that bind α-bungarotoxin (αBgt) were studied on isolated rat superior cervical ganglion (SCG) neurons using whole-cell patch clamp recording techniques.Rapid application of ACh onto the soma of voltage clamped neurons evoked a slowly desensitizing current that was reversibly blocked by αBgt (50 nm). The toxin-sensitive current constituted on average about half of the peak whole-cell response evoked by ACh.Nanomolar concentrations of methyllycaconitine blocked the αBgt-sensitive component of the ACh-evoked current as did intracellular dialysis with an anti-α7 monoclonal antibody. The results indicate that the slowly reversible toxin-sensitive response elicited by ACh arises from activation of an unusual class of α7-containing receptor (α7-nAChR) similar to that reported previously for rat intracardiac ganglion neurons.A second class of functional α7-nAChR was identified on some SCG neurons by using rapid application of choline to elicit responses. In these cases a biphasic response was obtained, which included a rapidly desensitizing component that was blocked by αBgt in a pseudo-irreversible manner. The pharmacology and kinetics of the responses resembled those previously attributed to α7-nAChRs in a number of other neuronal cell types.Experiments measuring the dissociation rate of 125I-labelled αBgt from SCG neurons revealed two classes of toxin-binding site. The times for toxin dissociation were consistent with those required to reverse blockade of the two kinds of αBgt-sensitive response.These results indicate that rat SCG neurons express two types of functional α7-nAChR, differing in pharmacology, desensitization and reversibility of αBgt blockade. PMID:10856125

Frequency Responses of Rat Retinal Ganglion Cells

PubMed Central

Cloherty, Shaun L.; Hung, Yu-Shan; Kameneva, Tatiana; Ibbotson, Michael R.

2016-01-01

There are 15–20 different types of retinal ganglion cells (RGC) in the mammalian retina, each encoding different aspects of the visual scene. The mechanism by which post-synaptic signals from the retinal network generate spikes is determined by each cell’s intrinsic electrical properties. Here we investigate the frequency responses of morphologically identified rat RGCs using intracellular injection of sinusoidal current waveforms, to assess their intrinsic capabilities with minimal contributions from the retinal network. Recorded cells were classified according to their morphological characteristics (A, B, C or D-type) and their stratification (inner (i), outer (o) or bistratified) in the inner plexiform layer (IPL). Most cell types had low- or band-pass frequency responses. A2, C1 and C4o cells were band-pass with peaks of 15–30 Hz and low-pass cutoffs above 56 Hz (A2 cells) and ~42 Hz (C1 and C4o cells). A1 and C2i/o cells were low-pass with peaks of 10–15 Hz (cutoffs 19–25 Hz). Bistratified D1 and D2 cells were also low-pass with peaks of 5–10 Hz (cutoffs ~16 Hz). The least responsive cells were the B2 and C3 types (peaks: 2–5 Hz, cutoffs: 8–11 Hz). We found no difference between cells stratifying in the inner and outer IPL (i.e., ON and OFF cells) or between cells with large and small somas or dendritic fields. Intrinsic physiological properties (input resistance, spike width and sag) had little impact on frequency response at low frequencies, but account for 30–40% of response variability at frequencies >30 Hz. PMID:27341669

Epidémiologie et prise en charge des infections du per-partum à la maternité du centre hospitalier départemental de l'Ouémé-Plateau au Bénin

PubMed Central

Saizonou, Jacques; Ouédraogo, Laurent; Paraiso, Moussiliou Noël; Ayélo, Paul; Kpozèhouen, Alphonse; Daraté, René; Traoré, Esther

2014-01-01

Introduction La présente étude avait pour objectif de mesurer l'ampleur des infections du per-partum à la maternité du Centre Hospitalier Départemental de l'Ouémé-Plateau d'analyser les conditions de survenue et de prise en charge dans la perspective de l'amélioration des soins et services maternels et néonataux. Méthodes Une étude descriptive et analytique a été conduite de Août 2009 à Février 2010 et a impliqué 110 mères victimes d'infections du per-partum; elles ont été soumises à un questionnaire durant tout leur séjour hospitalier; des observations des pratiques de prise en charge des prestataires de soins ont été menées et des registres et autres supports de données sanitaires ont été exploités. L'analyse des données a été effectuée à l'aide du logiciel Epi Info 6.4 dans sa version française. Résultats L'incidence des infections du per-partum était de 5,9 pour 100 accouchements (110/ 1875); les types d'infections les plus incriminés étaient les endométrites (27,3%), les chorioamniotites (18,2%), les infections du site opératoire (12,7%) et les infections urinaires (2,7%). Les examens cliniques ont été relativement acceptables. En revanche, les examens biologiques ont été très insuffisants expliquant l'imprécision importante au niveau des diagnostics. L'antibiothérapie a été instaurée systématiquement. Le taux de mortinaissance était de 25,6% et les enfants de petit poids représentaient 23,2%. Conclusion L'incidence des infections du per-partum dans la présente étude était assez élevée. Des efforts de préventions et de dépistage de ces infections sont nécessaire afin d'améliorer la qualité des soins PMID:25120854

W. E. B. Du Bois at the center: from science, civil rights movement, to Black Lives Matter.

PubMed

Morris, Aldon

2017-03-01

I am honoured to present the 2016 British Journal of Sociology Annual Lecture at the London School of Economics. My lecture is based on ideas derived from my new book, The Scholar Denied: W.E.B. Du Bois and the Birth of Modern Sociology. In this essay I make three arguments. First, W.E.B. Du Bois and his Atlanta School of Sociology pioneered scientific sociology in the United States. Second, Du Bois pioneered a public sociology that creatively combined sociology and activism. Finally, Du Bois pioneered a politically engaged social science relevant for contemporary political struggles including the contemporary Black Lives Matter movement. © London School of Economics and Political Science 2017.

Les traces matérielles de la Carte du Ciel. Le cas des observatoires d'Alger et de Bordeaux.

NASA Astrophysics Data System (ADS)

Le Guet Tully, F.; Davoigneau, J.; Lamy, J.; de La Noë, J.; Rousseau, J.-M.; Sadsaoud, H.

2008-06-01

Le chapitre évoque les traces matérielles de la Carte du ciel subsistant dans les observatoires d'Alger et de Bordeaux. Les auteurs examinent d'abord l'opération d'inventaire du patrimoine astronomique entreprise à partir du milieu des années 1990. Ils examinent ensuite les éléments concrets constituant aujourd'hui le patrimoine de la Carte du Ciel : lunettes, abris, accessoires, laboratoires, réseaux, plaques de verre, registres, machines à mesurer les clichés, et cartes.

Orofacial neuropathic pain induced by oxaliplatin: downregulation of KCNQ2 channels in V2 trigeminal ganglion neurons and treatment by the KCNQ2 channel potentiator retigabine.

PubMed

Ling, Jennifer; Erol, Ferhat; Viatchenko-Karpinski, Viacheslav; Kanda, Hirosato; Gu, Jianguo G

2017-01-01

Neuropathic pain induced by chemotherapy drugs such as oxaliplatin is a dose-limiting side effect in cancer treatment. The mechanisms underlying chemotherapy-induced neuropathic pain are not fully understood. KCNQ2 channels are low-threshold voltage-gated K+ channels that play a role in controlling neuronal excitability. Downregulation of KCNQ2 channels has been proposed to be an underlying mechanism of sensory hypersensitivity that leads to neuropathic pain. However, it is currently unknown whether KCNQ channels may be downregulated by chemotherapy drugs in trigeminal ganglion neurons to contribute to the pathogenesis of chemotherapy-induced orofacial neuropathic pain. In the present study, mechanical sensitivity in orofacial regions is measured using the operant behavioral test in rats treated with oxaliplatin. Operant behaviors in these animals show the gradual development of orofacial neuropathic pain that manifests with orofacial mechanical allodynia. Immunostaining shows strong KCNQ2 immunoreactivity in small-sized V2 trigeminal ganglion neurons in controls, and the numbers of KCNQ2 immunoreactivity positive V2 trigeminal ganglion neurons are significantly reduced in oxaliplatin-treated animals. Immunostaining is also performed in brainstem and shows strong KCNQ2 immunoreactivity at the trigeminal afferent central terminals innervating the caudal spinal trigeminal nucleus (Vc) in controls, but the KCNQ2 immunoreactivity intensity is significantly reduced in oxaliplatin-treated animals. We further show with the operant behavioral test that oxaliplatin-induced orofacial mechanical allodynia can be alleviated by the KCNQ2 potentiator retigabine. Taken together, these findings suggest that KCNQ2 downregulation may be a cause of oxaliplatin-induced orofacial neuropathic pain and KCNQ2 potentiators may be useful for alleviating the neuropathic pain.

THE NISSL SUBSTANCE OF LIVING AND FIXED SPINAL GANGLION CELLS

PubMed Central

Deitch, Arline D.; Moses, Montrose J.

1957-01-01

Living chick spinal ganglion neurons grown for 19 to 25 days in vitro were photographed with a color-translating ultraviolet microscope (UV-91) at 265, 287, and 310 mµ. This instrument was unique in permitting rapid accumulation of ultraviolet information with minimal damage to the cell. In the photographs taken at 265 mµ of the living neurons, discrete ultraviolet-absorbing cytoplasmic masses were observed which were found to be virtually unchanged in appearance after formalin fixation. These were identical with the Nissl bodies of the same cells seen after staining with basic dyes. The correlation of ultraviolet absorption, ribonuclease extraction, and staining experiments with acid and basic dyes confirmed the ribonucleoprotein nature of these Nissl bodies in the living and fixed cells. No change in distribution or concentration of ultraviolet-absorbing substance was observed in the first 12 ultraviolet photographs of a neuron, and it is concluded that the cells had not been subjected to significant ultraviolet damage during the period of photography. On the basis of these observations, as well as previous findings with phase contrast microscopy, it is concluded that Nissl bodies preexist in the living neuron as discrete aggregates containing high concentrations of nucleoprotein. PMID:13438929

Cirque du Monde as a health intervention: perceptions of medical students and social circus experts.

PubMed

Fournier, Cynthia; Drouin, Mélodie-Anne; Marcoux, Jérémie; Garel, Patricia; Bochud, Emmanuel; Théberge, Julie; Aubertin, Patrice; Favreau, Gil; Fleet, Richard

2014-11-01

To present Cirque du Soleil's social circus program, Cirque du Monde, to explore its potential as a primary health care tool for family physicians. A review of the literature in PubMed, the Cochrane Library, PsycINFO, LaPresse, Eureka, Google Scholar, and Érudit using the key words circus, social circus, Cirque du Monde, and Cirque du Soleil; a Montreal-based initiative, Espace Transition, modeled on Cirque du Monde; and personal communication with Cirque du Soleil's Social Circus Training Advisor. The first 50 articles or websites identified for each key word in each of the databases were examined on the basis of their titles and abstracts in the case of articles, and on the basis of their titles and page content in the case of websites. Articles and websites that explored an aspect of social circuses or that described an intervention that involved circuses were then retained for analysis. Because all literature on social circuses was searched, no criterion for year of publication was used. No articles on the social circus as a health intervention were found. One study on the use of the circus as an intervention in schools was identified. It demonstrated an increase in self-esteem in the children who took part. One study on the use of the circus in a First Nations community was found; it contained nonspecific, qualitative findings. The other articles identified were merely descriptions of social circuses. One website was identified on the use of the social circus to help youth who had been treated in a hospital setting for major psychiatric disorders to re-enter the community. The team in the pediatric psychiatry department at Centre Hospitalier Universitaire Sainte-Justine, the children's hospital in Montreal, Que, was contacted; they were leading this project, called Espace Transition. The unpublished preliminary findings of its pilot project demonstrate substantial improvements in overall patient functioning. According to Cirque du Soleil, there are several

A role for Runx transcription factor signaling in dorsal root ganglion sensory neuron diversification.

PubMed

Kramer, Ina; Sigrist, Markus; de Nooij, Joriene C; Taniuchi, Ichiro; Jessell, Thomas M; Arber, Silvia

2006-02-02

Subpopulations of sensory neurons in the dorsal root ganglion (DRG) can be characterized on the basis of sensory modalities that convey distinct peripheral stimuli, but the molecular mechanisms that underlie sensory neuronal diversification remain unclear. Here, we have used genetic manipulations in the mouse embryo to examine how Runx transcription factor signaling controls the acquisition of distinct DRG neuronal subtype identities. Runx3 acts to diversify an Ngn1-independent neuronal cohort by promoting the differentiation of proprioceptive sensory neurons through erosion of TrkB expression in prospective TrkC+ sensory neurons. In contrast, Runx1 controls neuronal diversification within Ngn1-dependent TrkA+ neurons by repression of neuropeptide CGRP expression and controlling the fine pattern of laminar termination in the dorsal spinal cord. Together, our findings suggest that Runx transcription factor signaling plays a key role in sensory neuron diversification.

Restauration fonctionnelle du rachis : effet du niveau initial de douleur sur les performances des sujets lombalgiques chroniques

PubMed Central

Caby, Isabelle; Olivier, N; Mendelek, F; Kheir, R Bou; Vanvelcenaher, J; Pelayo, P

2014-01-01

HISTORIQUE : La lombalgie chronique est une douleur lombaire persistante d’origine multifactorielle. Le niveau de douleur initial reste faiblement utilisé pour analyser et comparer les réponses des patients lombalgiques au programme de reconditionnement. OBJECTIFS : Apprécier et évaluer les réponses des sujets lombalgiques chroniques très douloureux à une prise en charge dynamique et intensive. MÉTHODOLOGIE : 144 sujets atteints de lombalgie chronique ont été inclus dans un programme de restauration fonctionnelle du rachis de 5 semaines. Les sujets ont été classés en deux groupes de niveau de douleur: un groupe atteint de douleur sévère (n = 28) et un groupe atteint de douleur légère à modérée (n = 106). L’ensemble des sujets ont bénéficié d’une prise en charge identique comprenant principalement de la kinésithérapie, de l’ergothérapie, du reconditionnement musculaire et cardio-vasculaire ainsi qu’un suivi psychologique. Les paramètres physiques (flexibilité, force musculaire) et psychologiques (qualité de vie) ont été mesurés avant (T0) et après le programme (T5sem). RÉSULTATS : L’ensemble des performances physiques et fonctionnelles des sujets très douloureux sont moins bonnes et le retentissement de la lombalgie sur la qualité de vie, pour ces mêmes sujets, est majoré à T0. Toutes les différences significatives constatées à T0 entre les deux groupes s’effacent à T5sem. CONCLUSIONS : Les sujets lombalgiques chroniques très douloureux répondent favorablement au programme dynamique et intensif. L’intensité douloureuse de la lombalgie n’aurait pas d’effet sur les réponses au programme. La restauration fonctionnelle du rachis apporterait aux sujets la possibilité de mieux gérer leur douleur quel que soit son niveau. PMID:25299476

Etude des facteurs de risque du retard de croissance intra-utérin à Lubumbashi

PubMed Central

Moyambe, Jules Ngwe Thaba; Bernard, Pierre; Khang'Mate, Faustin; Nkoy, Albert Mwembo Tambwe A; Mukalenge, Faustin Chenge; Makanda, Daudet; Twite, Eugene; Ndudula, Arthur Munkana; Lubamba, Cham; Kadingi, Arnauld Kabulu; Kayomb, Mutach; Kayamba, Prosper Kalenga Muenze

2013-01-01

Introduction Dans notre milieu, il n'existe aucune politique de prévention du Retard de Croissance Intra-Utérin (RCIU) clairement défini. L'objectif de ce travail était d'identifier les facteurs de risque de RCIU afin de proposer une stratégie de lutte contre cette pathologie en agissant surtout sur des facteurs pouvant faire l'objet d'une action préventive. Méthodes Une étude cas-témoins a été menée dans 11 centres hospitaliers de Lubumbashi en République Démocratique du Congo, de Janvier 2010 à Juin 2011, dans le but d'identifier les facteurs de risque du retard de croissance intra-utérin (RCIU). Au total 420 gestantes (cas et témoins) avec grossesse monofoetale d'au moins 24 semaines d'aménorrhée ont été inclues dans l'étude. Les cas correspondaient aux gestantes dont le poids du fœtus était resté inférieur au 10 eme percentile des courbes de référence d'Alexander, après 2 échographies successives réalisées à intervalle de 4 semaines. Les témoins correspondaient aux gestantes dont le poids du fœtus était supérieur ou égal au 10 eme percentile de mêmes courbes. A chaque cas a été apparié un témoin de même parité porteur d'une grossesse de même âge. Résultats L'analyse univariée a identifié comme facteurs de risque: la taille maternelle. Conclusion L'amélioration du niveau socio-économique des populations, la lutte contre le paludisme et les consultations prénatales mieux organisées couplées à une meilleure éducation sanitaire et nutritionnelle peuvent contribuer sensiblement à la réduction de la fréquence du RCIU à Lubumbashi. PMID:23504392

Modelisation par elements finis du muscle strie

NASA Astrophysics Data System (ADS)

Leonard, Mathieu

Ce present projet de recherche a permis. de creer un modele par elements finis du muscle strie humain dans le but d'etudier les mecanismes engendrant les lesions musculaires traumatiques. Ce modele constitue une plate-forme numerique capable de discerner l'influence des proprietes mecaniques des fascias et de la cellule musculaire sur le comportement dynamique du muscle lors d'une contraction excentrique, notamment le module de Young et le module de cisaillement de la couche de tissu conjonctif, l'orientation des fibres de collagene de cette membrane et le coefficient de poisson du muscle. La caracterisation experimentale in vitro de ces parametres pour des vitesses de deformation elevees a partir de muscles stries humains actifs est essentielle pour l'etude de lesions musculaires traumatiques. Le modele numerique developpe est capable de modeliser la contraction musculaire comme une transition de phase de la cellule musculaire par un changement de raideur et de volume a l'aide des lois de comportement de materiau predefinies dans le logiciel LS-DYNA (v971, Livermore Software Technology Corporation, Livermore, CA, USA). Le present projet de recherche introduit donc un phenomene physiologique qui pourrait expliquer des blessures musculaires courantes (crampes, courbatures, claquages, etc.), mais aussi des maladies ou desordres touchant le tissu conjonctif comme les collagenoses et la dystrophie musculaire. La predominance de blessures musculaires lors de contractions excentriques est egalement exposee. Le modele developpe dans ce projet de recherche met ainsi a l'avant-scene le concept de transition de phase ouvrant la porte au developpement de nouvelles technologies pour l'activation musculaire chez les personnes atteintes de paraplegie ou de muscles artificiels compacts pour l'elaboration de protheses ou d'exosquelettes. Mots-cles Muscle strie, lesion musculaire, fascia, contraction excentrique, modele par elements finis, transition de phase

Melanopsin-expressing retinal ganglion cells are resistant to cell injury, but not always.

PubMed

Georg, Birgitte; Ghelli, Anna; Giordano, Carla; Ross-Cisneros, Fred N; Sadun, Alfredo A; Carelli, Valerio; Hannibal, Jens; La Morgia, Chiara

2017-09-01

Melanopsin retinal ganglion cells (mRGCs) are intrinsically photosensitive RGCs deputed to non-image forming functions of the eye such as synchronization of circadian rhythms to light-dark cycle. These cells are characterized by unique electrophysiological, anatomical and biochemical properties and are usually more resistant than conventional RGCs to different insults, such as axotomy and different paradigms of stress. We also demonstrated that these cells are relatively spared compared to conventional RGCs in mitochondrial optic neuropathies (Leber's hereditary optic neuropathy and Dominant Optic Atrophy). However, these cells are affected in other neurodegenerative conditions, such as glaucoma and Alzheimer's disease. We here review the current evidences that may underlie this dichotomy. We also present our unpublished data on cell experiments demonstrating that melanopsin itself does not explain the robustness of these cells and some preliminary data on immunohistochemical assessment of mitochondria in mRGCs. Copyright © 2017 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Electrophysiological effects of tachykinin analogues on ganglion cell activity in cyprinid fish retina.

PubMed

Downing, J E; Djamgoź, M B

1993-02-01

Electrical spike activity of ganglion cells has been recorded extracellularly in the teleost (roach) retina, and effects of a variety of tachykinins studied at a working concentration of 1 microM. Application of substance P mostly caused a slow and prolonged increase in background activity. In contrast, the response to carbachol was very brisk and short-lasting. Substance P and physalaemin predominantly induced an enhancement of 'On' and 'Off' components of light-evoked responses, whilst eledoisin and neurokinin A were mostly inhibitory. All effects were independent of chromatic and spatial aspects of the responses. Interestingly, in the presence of a tachykinin antagonist, 'Spantide' [D-Arg1,D-Pro2, D-Trp7.9, Leu11]SP, the profile of the effect of substance P reversed, inhibitory actions becoming much more common. Taken together, the results suggest that a tachykinin system utilising two subtypes of the receptor may be active in the roach retina and these may be involved in differential control of visual sensitivity.

Painful Pathways Induced by Toll-like Receptor Stimulation of Dorsal Root Ganglion Neurons

PubMed Central

Qi, Jia; Buzas, Krisztina; Fan, Huiting; Cohen, Jeffrey I.; Wang, Kening; Mont, Erik; Klinman, Dennis; Oppenheim, Joost J.; Howard, O.M. Zack

2011-01-01

We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that toll-like receptors 3/7/9 (TLRs) are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP10), interleukin-1alpha, interleukin-1beta, and prostaglandin E2 (PGE2), which have previously been shown to augment pain. Further, TLR ligands up-regulated the expression of a nociceptive receptor transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1 expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive ODN, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain. PMID:21515789

Melanopsin-expressing retinal ganglion-cell photoreceptors: cellular diversity and role in pattern vision

PubMed Central

Ecker, Jennifer L.; Dumitrescu, Olivia N.; Wong, Kwoon Y.; Alam, Nazia M.; Chen, Shih-Kuo; LeGates, Tara; Renna, Jordan M.; Prusky, Glen T.; Berson, David M.; Hattar, Samer

2010-01-01

Using the photopigment melanopsin, intrinsically photosensitive retinal ganglion cells (ipRGCs) respond directly to light to drive circadian clock resetting and pupillary constriction. We now report that ipRGCs are more abundant and diverse than previously appreciated, project more widely within the brain, and can support spatial visual perception. A Cre-based melanopsin reporter mouse line revealed at least five subtypes of ipRGCs with distinct morphological and physiological characteristics. Collectively, these cells project beyond the known brain targets of ipRGCs to heavily innervate the superior colliculus and dorsal lateral geniculate nucleus, retinotopically-organized nuclei mediating object localization and discrimination. Mice lacking classical rod-cone photoreception, and thus entirely dependent on melanopsin for light detection, were able to discriminate grating stimuli from equiluminant gray, and had measurable visual acuity. Thus, non-classical retinal photoreception occurs within diverse cell types, and influences circuits and functions encompassing luminance as well as spatial information. PMID:20624591

PKA-induced internalization of slack KNa channels produces dorsal root ganglion neuron hyperexcitability.

PubMed

Nuwer, Megan O; Picchione, Kelly E; Bhattacharjee, Arin

2010-10-20

Inflammatory mediators through the activation of the protein kinase A (PKA) pathway sensitize primary afferent nociceptors to mechanical, thermal, and osmotic stimuli. However, it is unclear which ion conductances are responsible for PKA-induced nociceptor hyperexcitability. We have previously shown the abundant expression of Slack sodium-activated potassium (K(Na)) channels in nociceptive dorsal root ganglion (DRG) neurons. Here we show using cultured DRG neurons, that of the total potassium current, I(K), the K(Na) current is predominantly inhibited by PKA. We demonstrate that PKA modulation of K(Na) channels does not happen at the level of channel gating but arises from the internal trafficking of Slack channels from DRG membranes. Furthermore, we found that knocking down the Slack subunit by RNA interference causes a loss of firing accommodation analogous to that observed during PKA activation. Our data suggest that the change in nociceptive firing occurring during inflammation is the result of PKA-induced Slack channel trafficking.

The Ciliary Margin Zone of the Mammalian Retina Generates Retinal Ganglion Cells.

PubMed

Marcucci, Florencia; Murcia-Belmonte, Veronica; Wang, Qing; Coca, Yaiza; Ferreiro-Galve, Susana; Kuwajima, Takaaki; Khalid, Sania; Ross, M Elizabeth; Mason, Carol; Herrera, Eloisa

2016-12-20

The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. Because Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2 -/- mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2 + cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Assessment of orofacial characteristics and oral pathology associated with cri-du-chat syndrome.

PubMed

Rodríguez-Caballero, A; Torres-Lagares, D; Yáñez-Vico, R-M; Gutiérrez-Pérez, J-L; Machuca-Portillo, G

2012-03-01

To obtain a deeper insight into the difficulties individuals with cri-du-chat syndrome experience by means of the analysis of the most common features and oral pathology observed in the subjects enrolled in the study. Intra-oral and extra-oral features of a total of 33 patients with cri-du-chat syndrome (the larger sample so far analyzed) through their clinical and photographic examination. Models, orthopantomographies, and teleradiographies have been collected to establish a pattern as accurate as possible of the oral pathology associated with these patients. The present descriptive study shows that patients with cri-du-chat syndrome present with a series of orofacial features such as mandibular retrognathism, high palate, and variable malocclusion, more commonly anterior open-bite. Most patients also present with perioral muscle relaxation with labial incompetence and short philtrum. As regards oral pathology, these patients suffer dental erosions provoked by gastroesophageal reflux and attritions because of intense day-and-night bruxism. The odontologists' familiarity with the orofacial pathology associated with cri-du-chat syndrome and with the specific needs such disorder conveys should improve the quality of the buccodental treatment these professionals may offer to these patients. © 2011 John Wiley & Sons A/S.

EPA may modify Du Pont waiver for methanol fuel blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, E.V.

1985-09-02

The Environmental Protection Agency (EPA) granted a Clean Air ACt waiver to DuPont's blendstock of methanol and other cosolvent alcohols for use in unleaded gasoline. The waiver included some stringent fuel volatility requirements to control evaporative emissions that have kept the waiver from becoming the marketing tool for fuel alcohols that everyone expected it to be. EPA seems willing to amend the waiver as long as evaporative emissions controls are kept, but there are some difficult procedural issues to resolve first. To date, only small amounts of alcohol blends have been sold under the DuPont waiver because the blendstock tendsmore » to increase the volatility of gasoline.« less

Cancer du sein au Cameroun, profil histo-épidémiologique: à propos de 3044 cas

PubMed Central

Engbang, Jean Paul Ndamba; Essome, Henri; Koh, Valère Mve; Simo, Godefroy; Essam, Jean Daniel Sime; Mouelle, Albert Sone; Essame, Jean Louis Oyono

2015-01-01

Décrire les caractéristiques épidémiologiques et histo-pathologiques des tumeurs malignes du sein au Cameroun. Il s'agissait d'une étude rétrospective descriptive portant sur les tumeurs malignes du sein, colligées, dans les registres des différents laboratoires d'Anatomie Pathologique publiques et privés repartis dans cinq régions (centre, littoral, Ouest, Nord-ouest, Sud-ouest), pendant une période de 10 ans (2004-2013). Les paramètres étudiés étaient la fréquence, l’âge, le sexe, la localisation, le type et le grade histologique, et les récepteurs hormonaux. Un total de 3044 cas de cancers du sein a été recensé, soit une fréquence annuelle de 304,4 cas en moyenne. Le sexe féminin était le plus représenté avec 2971 cas (97,60%) et les hommes avec 73 cas (2,40%), soit un sexe ratio (H/F) de 0,02. L’âge moyen des patients était de 46±15,87 ans, avec des extrêmes de 13 et 95 ans. Selon la localisation, le sein gauche était atteint dans 1244 cas (52%) et le sein droit dans 1115 cas (47%). Au plan histologique, on retrouvait essentiellement des carcinomes avec 96,50% des cas, des sarcomes 1,39%, des lymphomes 1,07% et la maladie de Paget du mamelon, 1,03%. Les tumeurs épithéliales étaient infiltrantes dans 2049 cas (84,46%), avec une prédominance du carcinome canalaire infiltrant (1870 cas) et non infiltrantes dans 377 cas (15,54%). Le grade histo-pronostic de SBR avait révélé une prédominance du grade II dans 66% des cas. Les cancers du sein restent une pathologie fréquente au Cameroun et atteignent principalement la population féminine en âge de procréer. Ils sont caractérisés par la prédominance du carcinome canalaire infiltrant. PMID:26523182

Etude des phenomenes dynamiques ultrarapides et des caracteristiques impulsionnelles d'emission terahertz du supraconducteur YBCO

NASA Astrophysics Data System (ADS)

Savard, Stephane

Les premieres etudes d'antennes a base de supraconducteurs a haute temperature critique emettant une impulsion electromagnetique dont le contenu en frequence se situe dans le domaine terahertz remontent a 1996. Une antenne supraconductrice est formee d'un micro-pont d'une couche mince supraconductrice sur lequel un courant continu est applique. Un faisceau laser dans le visible est focalise sur le micro-pont et place le supraconducteur dans un etat hors-equilibre ou des paires sont brisees. Grace a la relaxation des quasiparticules en surplus et eventuellement de la reformation des paires supraconductrices, nous pouvons etudier la nature de la supraconductivite. L'analyse de la cinetique temporelle du champ electromagnetique emis par une telle antenne terahertz supraconductrice s'est averee utile pour decrire qualitativement les caracteristiques de celle-ci en fonction des parametres d'operation tels que le courant applique, la temperature et la puissance d'excitation. La comprehension de l'etat hors-equilibre est la cle pour comprendre le fonctionnement des antennes terahertz supraconductrices a haute temperature critique. Dans le but de comprendre ultimement cet etat hors-equilibre, nous avions besoin d'une methode et d'un modele pour extraire de facon plus systematique les proprietes intrinseques du materiau qui compose l'antenne terahertz a partir des caracteristiques d'emission de celle-ci. Nous avons developpe une procedure pour calibrer le spectrometre dans le domaine temporel en utilisant des antennes terahertz de GaAs bombarde aux protons H+ comme emetteur et detecteur. Une fois le montage calibre, nous y avons insere une antenne emettrice dipolaire de YBa 2Cu3O7-delta . Un modele avec des fonctions exponentielles de montee et de descente du signal est utilise pour lisser le spectre du champ electromagnetique de l'antenne de YBa 2Cu3O7-delta, ce qui nous permet d'extraire les proprietes intrinseques de ce dernier. Pour confirmer la validite du modele

Methane rescues retinal ganglion cells and limits retinal mitochondrial dysfunction following optic nerve crush.

PubMed

Wang, Ruobing; Sun, Qinglei; Xia, Fangzhou; Chen, Zeli; Wu, Jiangchun; Zhang, Yuelu; Xu, Jiajun; Liu, Lin

2017-06-01

Secondary degeneration is a common event in traumatic central nervous system disorders, which involves neuronal apoptosis and mitochondrial dysfunction. Exogenous methane exerts the therapeutic effects in many organ injury. Our study aims to investigate the potential neuroprotection of methane in a rat model of optic nerve crush (ONC). Adult male Sprague-Dawley rats were subjected to ONC and administrated intraperitoneally with methane-saturated or normal saline (10 ml/kg) once per day for one week after ONC. The retinal ganglion cells (RGCs) density was assessed by hematoxylin and eosin staining and Fluoro-Gold retrogradely labeling. Visual function was evaluated by flash visual evoked potentials (FVEP). The retinal apoptosis was measured by terminal-deoxy-transferase-mediated dUTP nick end labeling (TUNEL) assay and the expression of apoptosis-related factors, such as phosphorylated Bcl-2-associated death promoter (pBAD), phosphorylated glycogen synthase kinase-3β (pGSK-3β), Bcl-2 associated X protein (Bax) and Bcl-2 extra large (Bcl-xL). Retinal mitochondrial function was assessed by the mRNA expressions of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), the mitochondrial DNA (mtDNA) copy number, citrate synthase activity and ATP content. Methane treatment significantly improved the RGC loss and visual dysfunction following ONC. As expected, methane also remarkably inhibited the retinal neural apoptosis, such as the fewer TUNEL-positive cells in ganglion cell layer, accompanied by the up-regulations of anti-apoptotic factors (pGSK-3β, pBAD, Bcl-xL) and the down-regulation of pro-apoptotic factor (Bax). Furthermore, methane treatment suppressed up-regulations of critical mitochondrial components (PGC-1α, NRF1 and TFAM) mRNA and mtDNA copy number, as well as improved the reduction of functional mitochondria markers, including citrate synthase

Characterization of intravitreally delivered capsid mutant AAV2-Cre vector to induce tissue-specific mutations in murine retinal ganglion cells.

PubMed

Langouet-Astrie, Christophe J; Yang, Zhiyong; Polisetti, Sraavya M; Welsbie, Derek S; Hauswirth, William W; Zack, Donald J; Merbs, Shannath L; Enke, Raymond A

2016-10-01

Targeted expression of Cre recombinase in murine retinal ganglion cells (RGCs) by viral vector is an effective strategy for creating tissue-specific gene knockouts for investigation of genetic contribution to RGC degeneration associated with optic neuropathies. Here we characterize dosage, efficacy and toxicity for sufficient intravitreal delivery of a capsid mutant Adeno-associated virus 2 (AAV2) vector encoding Cre recombinase. Wild type and Rosa26 (R26) LacZ mice were intravitreally injected with capsid mutant AAV2 viral vectors. Murine eyes were harvested at intervals ranging from 2 weeks to 15 weeks post-injection and were assayed for viral transduction, transgene expression and RGC survival. 10(9) vector genomes (vg) were sufficient for effective in vivo targeting of murine ganglion cell layer (GCL) retinal neurons. Transgene expression was observed as early as 2 weeks post-injection of viral vectors and persisted to 11 weeks. Early expression of Cre had no significant effect on RGC survival, while significant RGC loss was detected beginning 5 weeks post-injection. Early expression of viral Cre recombinase was robust, well-tolerated and predominantly found in GCL neurons suggesting this strategy can be effective in short-term RGC-specific mutation studies in experimental glaucoma models such as optic nerve crush and transection experiments. RGC degeneration with Cre expression for more than 4 weeks suggests that Cre toxicity is a limiting factor for targeted mutation strategies in RGCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modelling the spatio-temporal modulation response of ganglion cells with difference-of-Gaussians receptive fields: relation to photoreceptor response kinetics.

PubMed

Donner, K; Hemilä, S

1996-01-01

Difference-of-Gaussians (DOG) models for the receptive fields of retinal ganglion cells accurately predict linear responses to both periodic stimuli (typically moving sinusoidal gratings) and aperiodic stimuli (typically circular fields presented as square-wave pulses). While the relation of spatial organization to retinal anatomy has received considerable attention, temporal characteristics have been only loosely connected to retinal physiology. Here we integrate realistic photoreceptor response waveforms into the DOG model to clarify how far a single set of physiological parameters predict temporal aspects of linear responses to both periodic and aperiodic stimuli. Traditional filter-cascade models provide a useful first-order approximation of the single-photon response in photoreceptors. The absolute time scale of these, plus a time for retinal transmission, here construed as a fixed delay, are obtained from flash/step data. Using these values, we find that the DOG model predicts the main features of both the amplitude and phase response of linear cat ganglion cells to sinusoidal flicker. Where the simplest model formulation fails, it serves to reveal additional mechanisms. Unforeseen facts are the attenuation of low temporal frequencies even in pure center-type responses, and the phase advance of the response relative to the stimulus at low frequencies. Neither can be explained by any experimentally documented cone response waveform, but both would be explained by signal differentiation, e.g. in the retinal transmission pathway, as demonstrated at least in turtle retina.

Relation Between Macular Retinal Ganglion Cell/Inner Plexiform Layer Thickness and Multifocal Electroretinogram Measures in Experimental Glaucoma

PubMed Central

Luo, Xunda; Patel, Nimesh B.; Rajagopalan, Lakshmi P.; Harwerth, Ronald S.; Frishman, Laura J.

2014-01-01

Purpose. We investigated relations between macular retinal ganglion cell plus inner plexiform layer (RGC+IPL) thickness and macular retinal function revealed by multifocal electroretinonography (mfERG) in a nonhuman primate model of experimental glaucoma. Methods. Retinal ganglion cell (RGC) structure and function were followed with spectral-domain optical coherence tomography (SD-OCT) and ERGs in five macaques with unilateral experimental glaucoma. Linear regression was used to study correlations in control (Con) and experimental (Exp) eyes between peripapillary retinal nerve fiber layer (RNFL) thickness, macular RGC+IPL thickness, multifocal photopic negative response (mfPhNR) and high-frequency multifocal oscillatory potentials (mfOP) in slow-sequence mfERG, and low-frequency component (mfLFC) in global-flash mfERG. We used ANOVA and paired t-tests to compare glaucoma-related mfERG changes between superior and inferior hemifields, foveal hexagon, inner three rings, and four quadrants of macula. Results. Average macular RGC+IPL and temporal RNFL thickness were strongly correlated (r2 = 0.90, P < 0.001). In hexagon-by-hexagon analysis, all three mfERG measures were correlated (P < 0.001) with RGC+IPL thickness for Con (r2, 0.33–0.51) and Exp eyes (r2, 0.17–0.35). The RGC structural and functional metrics decreased as eccentricity increased. The reduction in amplitude of mfERG measures in Exp eyes relative to Con eyes was proportionally greater, in general, than the relative thinning of RGC+IPL at the same location for eyes in which structural loss was not evident, or mild to moderate. Although not statistically significant, percent amplitude reduction of mfERG measures was greatest in the inferior temporal quadrant. Conclusions. Macular RGC+IPL thickness and mfERG measures of RGC function can be complementary tools in assessing glaucomatous neuropathy. PMID:24970256

Acute effects of unilateral temporary stellate ganglion block on human atrial electrophysiological properties and atrial fibrillation inducibility.

PubMed

Leftheriotis, Dionyssios; Flevari, Panayota; Kossyvakis, Charalampos; Katsaras, Dimitrios; Batistaki, Chrysanthi; Arvaniti, Chrysa; Giannopoulos, Georgios; Deftereos, Spyridon; Kostopanagiotou, Georgia; Lekakis, John

2016-11-01

In experimental models, stellate ganglion block (SGB) reduces the induction of atrial fibrillation (AF), while data in humans are limited. The aim of this study was to assess the effect of unilateral SGB on atrial electrophysiological properties and AF induction in patients with paroxysmal AF. Thirty-six patients with paroxysmal AF were randomized in a 2:1 order to temporary, transcutaneous, pharmaceutical SGB with lidocaine or placebo before pulmonary vein isolation. Lidocaine was 1:1 randomly infused to the right or left ganglion. Before and after randomization, atrial effective refractory period (ERP) of each atrium, difference between right and left atrial ERP, intra- and interatrial conduction time, AF inducibility, and AF duration were assessed. After SGB, right atrial ERP was prolonged from a median (1st-3rd quartile) of 240 (220-268) ms to 260 (240-300) ms (P < .01) and left atrial ERP from 235 (220-260) ms to 245 (240-280) ms (P < .01). AF was induced by atrial pacing in all 24 patients before SGB, but only in 13 patients (54%) after the intervention (P < .01). AF duration was shorter after SGB: 1.5 (0.0-5.8) minutes from 5.5 (3.0-12.0) minutes (P < .01). Intra- and interatrial conduction time was not significantly prolonged. No significant differences were observed between right and left SGB. No changes were observed in the placebo group. Unilateral temporary SGB prolonged atrial ERP, reduced AF inducibility, and decreased AF duration. An equivalent effect of right and left SGB on both atria was observed. These findings may have a clinical implication in the prevention of drug refractory and postsurgery AF and deserve further clinical investigation. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Sodium channel diversity in the vestibular ganglion: NaV1.5, NaV1.8, and tetrodotoxin-sensitive currents

PubMed Central

2016-01-01

Firing patterns differ between subpopulations of vestibular primary afferent neurons. The role of sodium (NaV) channels in this diversity has not been investigated because NaV currents in rodent vestibular ganglion neurons (VGNs) were reported to be homogeneous, with the voltage dependence and tetrodotoxin (TTX) sensitivity of most neuronal NaV channels. RT-PCR experiments, however, indicated expression of diverse NaV channel subunits in the vestibular ganglion, motivating a closer look. Whole cell recordings from acutely dissociated postnatal VGNs confirmed that nearly all neurons expressed NaV currents that are TTX-sensitive and have activation midpoints between −30 and −40 mV. In addition, however, many VGNs expressed one of two other NaV currents. Some VGNs had a small current with properties consistent with NaV1.5 channels: low TTX sensitivity, sensitivity to divalent cation block, and a relatively negative voltage range, and some VGNs showed NaV1.5-like immunoreactivity. Other VGNs had a current with the properties of NaV1.8 channels: high TTX resistance, slow time course, and a relatively depolarized voltage range. In two NaV1.8 reporter lines, subsets of VGNs were labeled. VGNs with NaV1.8-like TTX-resistant current also differed from other VGNs in the voltage dependence of their TTX-sensitive currents and in the voltage threshold for spiking and action potential shape. Regulated expression of NaV channels in primary afferent neurons is likely to selectively affect firing properties that contribute to the encoding of vestibular stimuli. PMID:26936982

Unraveling of the Effect of Nodose Ganglion Degeneration on the Coronary Artery Vasospasm After Subarachnoid Hemorrhage: An Experimental Study.

PubMed

Yolas, Coskun; Kanat, Ayhan; Aydin, Mehmet Dumlu; Altas, Ender; Kanat, Ilyas Ferit; Kazdal, Hizir; Duman, Aslihan; Gundogdu, Betul; Gursan, Nesrin

2016-02-01

Cardiac arrest is a major life-threatening complication of subarachnoid hemorrhage (SAH). Although medullary cardiocirculatuar center injury and central sympathetic overactivity have been suspected of initiating coronary artery spasm-induced cardiac arrest, we aimed to elucidate the effects of vagal ischemia at the brainstem on coronary vasospasm and sudden death in SAH. Twenty-six rabbits were randomly divided into 3 groups. Control (n = 5); SHAM (n = 8), and SAH group (n = 13). Experimental SAH was applied by injecting homologous blood into the cisterna magna, and the SHAM group was injected with isotonic saline solution also in the cisterna magna., Twenty-one days after the injection, histopathologic changes of the neuron density of nodose ganglia, the vasospasm index values of the coronary arteries, and the electrocardiographic events were analyzed. Increased vasospasm index of the coronary arteries and degenerated neuron density of nodose ganglion were significantly different between animals with SAH, control, and SHAM groups (P < 0.005). If neurons of the nodose ganglia are lesioned due to ischemic insult during SAH, the heart rhythm regulation by vagus afferent reflexes is disturbed. We found that there is causal relationship between nodose ganglion degeneration and coronary vasospasm. Our finding could be the reason that many cardiac events occur in patients with SAH. Vagal pathway paralysis induced by indirect sympathetic overactivity may trigger coronary vasospasm and heart rhythm disturbances. Our findings will aid in the planning of future experimental studies and in determining the clinical relevance of such studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Redox modulation of A-type K+ currents in pain-sensing dorsal root ganglion neurons.

PubMed

Hsieh, Chi-Pan

2008-06-06

Redox modulation of fast inactivation has been described in certain cloned A-type voltage-gated K(+) (Kv) channels in expressing systems, but the effects remain to be demonstrated in native neurons. In this study, we examined the effects of cysteine-specific redox agents on the A-type K(+) currents in acutely dissociated small diameter dorsal root ganglion (DRG) neurons from rats. The fast inactivation of most A-type currents was markedly removed or slowed by the oxidizing agents 2,2'-dithio-bis(5-nitropyridine) (DTBNP) and chloramine-T. Dithiothreitol, a reducing agent for the disulfide bond, restored the inactivation. These results demonstrated that native A-type K(+) channels, probably Kv1.4, could switch the roles between inactivating and non-inactivating K(+) channels via redox regulation in pain-sensing DRG neurons. The A-type channels may play a role in adjusting pain sensitivity in response to peripheral redox conditions.

Profil anatomopathologique du cancer du sein dans le cap bon tunisien

PubMed Central

Sahraoui, Ghada; Khanchel, Fatma; Chelbi, Emna

2017-01-01

Le cancer du sein est le cancer le plus fréquent de la femme en Tunisie et dans le monde. Dans le Cap Bon tunisien, les particularités anatomopathologiques de ce cancer n'ont pas été précisées auparavant. Leur connaissance est nécessaire pour l'adaptation des systèmes de prévention et de soins dans la région. Le but de notre étude était de déterminer le profil anatomopathologique des carcinomes mammaires dans l'unique laboratoire d'anatomie pathologique publique de la région. Il s'agissait d'une étude descriptive rétrospective des carcinomes mammaires diagnostiqués chez 116 malades dans notre laboratoire sur une période de 5 ans de Juillet 2010 à Juillet 2015. Notre étude a inclus 116 patientes. L'âge moyen était de 51 ans. La taille tumorale histologique moyenne était de 31 mm. Le diagnostic initial était posé sur pièce de tumorectomie dans 83% des cas. Le carcinome infiltrant de type non spécifique était le type histologique le plus fréquent. Le grade SBR III était majoritaire. L'invasion lympho-vasculaire était présente dans 33% des cas. Le curage axillaire était positif dans 72% des cas. Les récepteurs hormonaux étaient positifs dans 73% des cas. Les récepteurs de l'Her2-Neu étaient surexprimés dans 19% des cas. Le ki67 était ≥ 14% dans 38%. Le sous-type moléculaire le plus fréquent était le luminal A. Le carcinome mammaire dans la région du Cap Bon se caractérise par sa survenue à un âge jeune, son importante taille tumorale et la fréquence de facteurs histopronostiques péjoratifs. PMID:28450990

Patterns of innervation of neurones in the inferior mesenteric ganglion of the cat.

PubMed Central

Julé, Y; Krier, J; Szurszewski, J H

1983-01-01

The patterns of peripheral and central synaptic input to non-spontaneous, irregular discharging and regular discharging neurones in the inferior mesenteric ganglion of the cat were studied in vitro using intracellular recording techniques. All three types of neurones in rostral and caudal lobes received central synaptic input primarily from L3 and L4 spinal cord segments. Since irregular discharging neurones received synaptic input from intraganglionic regular discharging neurones, some of the central input to irregular discharging neurones may have been relayed through the regular discharging neurones. In the rostral lobes of the ganglion, more than 70% of the non-spontaneous and irregular discharging neurones tested received peripheral synaptic input from the lumbar colonic, intermesenteric and left and right hypogastric nerves. Most of the regular discharging neurones tested received synaptic input from the intermesenteric and lumbar colonic nerves; none of the regular discharging neurones received synaptic input from the hypogastric nerves. Some of the peripheral synaptic input from the lumbar colonic and intermesenteric nerves to irregular discharging neurones may have been relayed through the regular discharging neurones. Axons of non-spontaneous and irregular discharging neurones located in the rostral lobes travelled to the periphery exclusively in the lumbar colonic nerves. Antidromic responses were not observed in regular discharging neurones during stimulation of any of the major peripheral nerve trunks. This suggests these neurones were intraganglionic. In the caudal lobes, irregular discharging neurones received a similar pattern of peripheral synaptic input as did irregular discharging neurones located in the rostral lobes. The majority of irregular discharging neurones in the caudal lobes projected their axons to the periphery through the lumbar colonic nerves. Non-spontaneous neurones in the caudal lobes, in contrast to those located in the rostral

Patterns of innervation of neurones in the inferior mesenteric ganglion of the cat.

PubMed

Julé, Y; Krier, J; Szurszewski, J H

1983-11-01

The patterns of peripheral and central synaptic input to non-spontaneous, irregular discharging and regular discharging neurones in the inferior mesenteric ganglion of the cat were studied in vitro using intracellular recording techniques. All three types of neurones in rostral and caudal lobes received central synaptic input primarily from L3 and L4 spinal cord segments. Since irregular discharging neurones received synaptic input from intraganglionic regular discharging neurones, some of the central input to irregular discharging neurones may have been relayed through the regular discharging neurones. In the rostral lobes of the ganglion, more than 70% of the non-spontaneous and irregular discharging neurones tested received peripheral synaptic input from the lumbar colonic, intermesenteric and left and right hypogastric nerves. Most of the regular discharging neurones tested received synaptic input from the intermesenteric and lumbar colonic nerves; none of the regular discharging neurones received synaptic input from the hypogastric nerves. Some of the peripheral synaptic input from the lumbar colonic and intermesenteric nerves to irregular discharging neurones may have been relayed through the regular discharging neurones. Axons of non-spontaneous and irregular discharging neurones located in the rostral lobes travelled to the periphery exclusively in the lumbar colonic nerves. Antidromic responses were not observed in regular discharging neurones during stimulation of any of the major peripheral nerve trunks. This suggests these neurones were intraganglionic. In the caudal lobes, irregular discharging neurones received a similar pattern of peripheral synaptic input as did irregular discharging neurones located in the rostral lobes. The majority of irregular discharging neurones in the caudal lobes projected their axons to the periphery through the lumbar colonic nerves. Non-spontaneous neurones in the caudal lobes, in contrast to those located in the rostral

1. Historic American Buildings Survey, drawn by Pierre du Simitiere ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Historic American Buildings Survey, drawn by Pierre du Simitiere (papers in Philadelphia Library) DRAWING OF REDWOOD LIBRARY IN 1768. - Redwood Library, 50 Bellevue Avenue, Newport, Newport County, RI

Etude de facteurs de risque de la transmission du VIH de la mère à l'enfant dans la stratégie « option A » à Lubumbashi, République Démocratique du Congo

PubMed Central

Ngwej, Dieudonné Tshikwej; Mukuku, Olivier; Mudekereza, Rachel; Karaj, Eugénie; Odimba, Etienne Bwana Fwamba; Luboya, Oscar Numbi; Kakoma, Jean-Baptiste Sakatolo; Wembonyama, Stanis Okitotshio

2015-01-01

Introduction L'infection à VIH chez la femme enceinte a pour principal risque la contamination du nouveau-né. L'objectif est de déterminer le taux de transmission du VIH de la mère à l'enfant (TME) dans la ville de Lubumbashi et en évaluer les facteurs de risque. Méthodes Il s'agissait d'une étude prospective transversale à visée analytique de 157 accouchées séropositives au VIH et de leurs enfants dans 12 structures sanitaires de Lubumbashi (RDCongo) du 1er octobre 2012 au 31 décembre 2013. Les paramètres sociodémographiques, cliniques et les données relatives aux activités de PTME du VIH ont été étudiés. Les statistiques usuelles ont été utilisées pour analyser les résultats. Le seuil de significativité a été fixé à une valeur de p < 0,05. Résultats Le taux de transmission verticale du VIH était de 12,7% (20/157). Il n'y avait pas d'association significative entre les caractéristiques sociodémographiques maternelles telles que l’âge, la parité, le niveau d’étude, la profession et l’état-civil et la TME (p>0,05). La transmission verticale du VIH était significativement associée aux facteurs suivants: le stade clinique 3 de l'OMS (OR=5,18 (1,5-18,1)), la présence d'infection opportuniste (OR=8,7 (2,7-27,8)), le dépistage lors de l'accouchement (OR=6,3 (1,0-39,0)) ou au cours de l'allaitement (OR=7,1 (1,1-76,7)), au taux de CD4 maternel <350/mm3 (OR=2,9 (1,1-7,7)), l'absence de thérapie antirétrovirale chez la mère (OR=19,9 (4,8-81,9)), la naissance avant terme (OR=4,7 (1,4-16,0)), la rupture prématurée de membranes (OR=45,0 (7,4-454,6)), le faible poids de naissance (OR=5,6 (1,9-16,7)), la notion de réanimation néonatale (OR=12,4 (3,8-40,1)), la non administration de la névirapine à la naissance (OR=26,4 (7,6-92,3)) et l'alimentation mixte (OR=12,6 (1,3-115,9)). Le sexe du nourrisson et le mode d'accouchement n’étaient pas non plus associés à la transmission verticale du VIH (p>0,05). Conclusion Le taux

Non-effect of hexamethonium, a ganglionic blocker, on the response of ileal apolipoprotein A-IV mRNA following a massive small bowel resection in rats.

PubMed

Sonoyama, K; Fujiwara, R; Kasai, T

2000-06-01

An intravenous infusion of hexamethonium, a ganglionic blocker, did not affect the increase in the apolipoprotein A-IV mRNA level in the residual ileum following a massive small bowel resection in unrestrained conscious rats. The result suggests that upregulation of the apolipoprotein A-IV gene in the residual ileum is not mediated by a neural pathway, including the nicotinic synapse route.

Miners, masculinity and the "Bataille du Charbon" in France, 1944-1948.

PubMed

Diamond, Hanna

2011-01-01

In 1944, the French provisional government, backed by the Parti communiste français and the Confédération générale du travail, undertook an aggressive propaganda campaign to persuade miners to embark upon a 'battle for coal' which raised their efforts in extracting coal to that of a national endeavour. At the same time, miners had great hopes that nationalisation of the coal industry, under discussion at this time, would bring significant improvement to their working lives. In identifying the ways in which publicists posited miners as an ideal of working-class manhood, this article will argue that "la bataille du charbon" marks a crucial moment in the celebration of working-class masculinity and that the "statut des mineurs" which was passed in 1946 as a part of nationalisation enshrined many of the existing gender assumptions about mining life. What does an incorporation of gender to an analysis of the treatment of miners in the years 1944-1948 add to our understandings of the various economic, political and social dynamics around "la bataille du charbon"? How do these insights inform our perceptions of French coalfield societies in the mid-twentieth century?

Effectiveness and Patient Acceptability of Stellate Ganglion Block (SGB) for Treatment of Posttraumatic Stress Disorder (PTSD) Symptoms among Active Duty Military Members

DTIC Science & Technology

2017-03-01

ORGANIZATION: Research Triangle Institute Research Triangle Park, NC 27709-0155 REPORT DATE: March 2017 TYPE OF REPORT: Annual PREPARED FOR: U.S...ganglion block, Posttraumatic Stress Disorder, randomized controlled trial, qualitative research 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...Posttraumatic Stress Disorder, randomized controlled trial,  qualitative   research     3.  Accomplishments    The major goals of this project for year two

Race towards Freedom: W.E.B. Du Bois and the Tradition of Fugitive Black Study

ERIC Educational Resources Information Center

Tinson, Christopher M.

2017-01-01

This essay centers the defense of black educational possibility in the work of historian, pioneering sociologist, and scholar, W.E.B. Du Bois (1868-1963) as a conduit igniting what critical social theorists Stefano Harney and Fred Moten (2013) call Fugitive Black Study. The critical appreciation of Du Bois forces us to consider the weight of…

Analyse de la dégradation thermique du Poly(éther éther cétone)

NASA Astrophysics Data System (ADS)

Courvoisier, Emilie; Bicaba, Yoann; Colin, Xavier

2018-03-01

La dégradation thermique du PEEK a été étudiée à l'état caoutchoutique dans de larges intervalles de température (entre 180 et 320 °C) et de pression partielle d'oxygène (entre 0,21 et 50 bars). Tout d'abord, les mécanismes de vieillissement thermique ont été analysés et élucidés par spectroscopie IRTF et par calorimétrie différentielle (DSC) sur des films de PEEK suffisamment minces (entre 10 et 60 μm d'épaisseur) pour s'affranchir totalement des effets de la diffusion d'oxygène. L'oxydation se produit sur les cycles aromatiques provoquant la croissance de cinq nouvelles bandes d'absorption IR centrées à 3650, 3525, 1780, 1740 et 1718 cm-1 et attribuées aux vibrations d'élongation des liaisons O-H du phénol et de l'acide benzoïque, et des liaisons C-O de l'anhydride benzoïque, du benzoate de phényle et de la fluorénone respectivement. De plus, l'oxydation conduit à une large prédominance de la réticulation sur les coupures de chaîne (augmentation de Tg) empêchant le recuit du PEEK, en particulier lorsque la température d'exposition est supérieure au pied du pic de fusion. Enfin, les conséquences de l'oxydation sur les propriétés élastiques ont été analysées et élucidées par micro-indentation sur des sections droites préalablement polies de plaquettes de PEEK de 3 mm d'épaisseur. Les variations du module d'Young et du taux de cristallinité se corrèlent parfaitement, vérifiant ainsi la relation de Tobolsky.

Partial purification and characterization of bacteriocin produced by Enterococcus faecalis DU10 and its probiotic attributes.

PubMed

Perumal, Venkatesh; Repally, Ayyanna; Dasari, Ankaiah; Venkatesan, Arul

2016-10-02

A novel bacteriocin produced by avian duck isolated lactic acid bacterium Enterococcus faecalis DU10 was isolated. This bacteriocin showed a broad spectrum of antibacterial activity against important food-borne pathogens and was purified by size exclusion chromatography followed by reverse-phase high-performance liquid chromatography in a C-18 column. Tricine-SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.3 kDa. The zymogram clearly linked the antimicrobial activity with this band. This result was further confirmed by mass-assisted laser desorption ionization time-of-flight mass spectrometry, since a sharp peak corresponding to 6.313 kDa was detected and the functional groups were revealed by Fourier transform infrared spectroscopy. Bacteriocin DU10 activity was found sensitive to proteinase-K and pepsin and partially affected by trypsin and α-chymotrypsin. The activity of bacteriocin DU10 was partially resistant to heat treatments ranging from 30 to 90°C for 30 min. It also withstood a treatment at 121°C for 10 min. Cytotoxicity of bacteriocin DU10 by methyl-thiazolyl-diphenyl-tetrazolium bromide assay showed that the viability of HT-29 and HeLa cells decreased 60 ± 0.7% and 43 ± 4.8%, respectively, in the presence of 3,200 AU/mL of bacteriocin. The strain withstood 0.3% w/v of bile oxgall and pH 2 affected the bacterial growth between 2 and 4 hr of incubation. Adhesion properties examined with HT-29 cell line showed 69.85% initial population of strain E. faecalis DU10, which was found to be strongly adhered to this cell line. These results conclude bacteriocin DU10 may be used as a potential biopreservative and E. faecalis DU10 may be used as a potential probiont to control Salmonella infections.

Dysplasie fibreuse polyostotique unilatérale du membre supérieur

PubMed Central

Boufettal, Monsef; Azouz, Mohamed; Mahfoud, Mustapha; El Bardouni, Ahmed; Berrada, Mohamed Saleh; El Yaacoubi, Moradh

2014-01-01

La dysplasie fibreuse est une maladie osseuse sporadique rare d’étiologie inconnue qui représente environ 2,5% des maladies osseuses et 7% des tumeurs osseuses bénignes. Cette lésion bénigne pseudotumorale se caractérise par la présence dans l'os d'une prolifération de tissu fibreux et de tissu osseux immature dépourvu de couronne ostéoblastique. Elle peut atteindre un ou plusieurs os; l'atteinte du membre supérieur est rarement décrite, nous rapportons ici un cas rare de dysplasie fibreuse polyostotique unilatérale du membre supérieure. PMID:25709739

The molecular basis of retinal ganglion cell death in glaucoma.

PubMed

Almasieh, Mohammadali; Wilson, Ariel M; Morquette, Barbara; Cueva Vargas, Jorge Luis; Di Polo, Adriana

2012-03-01

Glaucoma is a group of diseases characterized by progressive optic nerve degeneration that results in visual field loss and irreversible blindness. A crucial element in the pathophysiology of all forms of glaucoma is the death of retinal ganglion cells (RGCs), a population of CNS neurons with their soma in the inner retina and axons in the optic nerve. Strategies that delay or halt RGC loss have been recognized as potentially beneficial to preserve vision in glaucoma; however, the success of these approaches depends on an in-depth understanding of the mechanisms that lead to RGC dysfunction and death. In recent years, there has been an exponential increase in valuable information regarding the molecular basis of RGC death stemming from animal models of acute and chronic optic nerve injury as well as experimental glaucoma. The emerging landscape is complex and points at a variety of molecular signals - acting alone or in cooperation - to promote RGC death. These include: axonal transport failure, neurotrophic factor deprivation, toxic pro-neurotrophins, activation of intrinsic and extrinsic apoptotic signals, mitochondrial dysfunction, excitotoxic damage, oxidative stress, misbehaving reactive glia and loss of synaptic connectivity. Collectively, this body of work has considerably updated and expanded our view of how RGCs might die in glaucoma and has revealed novel, potential targets for neuroprotection. Copyright © 2011. Published by Elsevier Ltd.

Fentes labiopalatines dans la province du Katanga en République Démocratique du Congo: Aspects épidémiologiques, anatomocliniques et thérapeutiques

PubMed Central

Sangwa, Cedrick Milindi; Mukuku, Olivier; Tshisuz, Christian; Panda, Jules Mulefu; Kakinga, Mireille; Kitembo, Marius Feruzi; Mutomb, Jean-Felix; Odimba, Bwana Fwamba

2014-01-01

Les fentes labiopalatines sont les malformations les plus rencontrées de la sphère orofaciale. L'objectif est de décrire le profil épidémiologique, anatomoclinique et thérapeutique des fentes labiopalatines observées dans la province minière du Katanga au sud-est de la République Démocratique du Congo. Il s'agit d'une étude transversale réalisée dans quatre institutions hospitalières de la province du Katanga dans des districts sanitaires différents (Hôpital Jason Sendwe à Lubumbashi, Hôpital Gécamines Panda à Likasi, Hôpital Gécamines du personnel à Kolwezi, Hôpital General de référence de Kamina) et qui a porté sur 154 cas de fentes labiopalatines enregistrés au cours de la période allant du 1er mai 2010 au 30 septembre 2012. L'âge moyen de consultation était de 11,8 ans et une prédominance masculine (55,2%) était notée. Un pic était noté chez les deux premiers nés de la famille (55,8%). Nous avons enregistré 20,7% des cas de consanguinité dont 54,2% de premier degré. La fréquence des différents types de fentes labiopalatines diminue au fur à mesure que la fente s'étend de la lèvre supérieure au palais en passant par l'alvéole : 72% (labiales), 21,4% (labiopalatines) et 7,7% (palatines). Les variétés unilatérales sont plus fréquentes (76,7%) que les bilatérales (16,1%). Dans les formes unilatérales, le côté gauche est plus concerné (47,1%) par rapport au côté droit (38,6%). L'évaluation de la gravité selon Anastassov montre que 50,6% de nos patients étaient de degré moyen et 16,2% étaient à un degré sévère. Les malformations associées ont été retrouvées dans 5% des cas et elles sont à prédominance squelettique. C'est la technique de Millard qui a été la plus pratiquée (72/130). Les résultats étaient excellents dans 71,5% contre 1,5% de mauvais. Le séjour d'hospitalisation était de 3 jours et le taux de complications post opératoire était de 2,98%. PMID:25328615

Neural Stem Cells Injected into the Sound-Damaged Cochlea Migrate Throughout the Cochlea and Express Markers of Hair Cells, Supporting Cells, and Spiral Ganglion Cells

PubMed Central

Corliss, Deborah A.; Gray, Brianna; Anderson, Julia K.; Bobbin, Richard P.; Snyder, Evan Y.; Cotanche, Douglas A.

2007-01-01

Most cases of hearing loss are caused by the death or dysfunction of one of the many cochlear cell types. We examined whether cells from a neural stem cell line could replace cochlear cell types lost after exposure to intense noise. For this purpose, we transplanted a clonal stem cell line into the scala tympani of sound damaged mice and guinea pigs. Utilizing morphological, protein expression and genetic criteria, stem cells were found with characteristics of both neural tissues (satellite, spiral ganglion and Schwann cells) and cells of the organ of Corti (hair cells, supporting cells). Additionally, noise-exposed, stem cell-injected animals exhibited a small but significant increase in the number of satellite cells and Type I spiral ganglion neurons compared to non-injected noise-exposed animals. These results indicate that cells of this neural stem cell line migrate from the scala tympani to Rosenthal's canal and the organ of Corti. Moreover, it suggests that cells of this neural stem cell line may derive some information needed from the microenvironment of the cochlea to differentiate into replacement cells in the cochlea. PMID:17659854

Inner ear development: building a spiral ganglion and an organ of Corti out of unspecified ectoderm.

PubMed

Fritzsch, Bernd; Pan, Ning; Jahan, Israt; Elliott, Karen L

2015-07-01

The mammalian inner ear develops from a placodal thickening into a complex labyrinth of ducts with five sensory organs specialized to detect position and movement in space. The mammalian ear also develops a spiraled cochlear duct containing the auditory organ, the organ of Corti (OC), specialized to translate sound into hearing. Development of the OC from a uniform sheet of ectoderm requires unparalleled precision in the topological developmental engineering of four different general cell types, namely sensory neurons, hair cells, supporting cells, and general otic epithelium, into a mosaic of ten distinctly recognizable cell types in and around the OC, each with a unique distribution. Moreover, the OC receives unique innervation by ear-derived spiral ganglion afferents and brainstem-derived motor neurons as efferents and requires neural-crest-derived Schwann cells to form myelin and neural-crest-derived cells to induce the stria vascularis. This transformation of a sheet of cells into a complicated interdigitating set of cells necessitates the orchestrated expression of multiple transcription factors that enable the cellular transformation from ectoderm into neurosensory cells forming the spiral ganglion neurons (SGNs), while simultaneously transforming the flat epithelium into a tube, the cochlear duct, housing the OC. In addition to the cellular and conformational changes forming the cochlear duct with the OC, changes in the surrounding periotic mesenchyme form passageways for sound to stimulate the OC. We review molecular developmental data, generated predominantly in mice, in order to integrate the well-described expression changes of transcription factors and their actions, as revealed in mutants, in the formation of SGNs and OC in the correct position and orientation with suitable innervation. Understanding the molecular basis of these developmental changes leading to the formation of the mammalian OC and highlighting the gaps in our knowledge might guide in

Inner ear development: Building a spiral ganglion and an organ of Corti out of unspecified ectoderm

PubMed Central

Fritzsch, Bernd; Pan, Ning; Jahan, Israt; Elliott, Karen L.

2014-01-01

The mammalian inner ear develops from a placodal thickening into a complex labyrinth of ducts with five sensory organs specialized to detect position and movement in space. In addition, the mammalian ear develops a spiraled cochlear duct containing the auditory organ, the organ of Corti (OC), specialized to translate sound into hearing. Developing the OC out of a uniform sheet of ectoderm requires an unparalleled precision in topological developmental engineering of four different general cell types, sensory neurons, hair cells, supporting cells, and general otic epithelium, into a mosaic of ten distinctly recognizable cell types in and around the OC, each with a unique distribution. In addition, the OC receives a unique innervation by ear-derived spiral ganglion afferents and brainstem-derived motor neurons as efferents, and requires neural crest-derived Schwann cells to form myelin and neural crest-derived cells to induce the stria vascularis. To achieve this transformation of a sheet of cells into a complicated interdigitating set of cells necessitates the orchestrated expression of multiple transcription factors that enable the cellular transformation from ectoderm into neurosensory cells forming the spiral ganglion neurons (SGN) while simultaneously transforming the flat epithelium into a tube, the cochlear duct housing the OC. In addition to the cellular and conformational changes to make the cochlear duct with the OC, additional changes in the surrounding periotic mesenchyme form passageways for sound to stimulate the OC. This article reviews molecular developmental data generated predominantly in mice. The available data are ordered into a plausible scenario that integrates the well described expression changes of transcription factors and their actions revealed in mouse mutants for formation of SGNs and OC in the right position and orientation with the right kind of innervation. Understanding the molecular basis of these developmental changes leading to

The DuPont Conference: Implications for the Chemical Technology Curriculum

NASA Astrophysics Data System (ADS)

Kenkel, John; Rutledge, Sue; Kelter, Paul B.

1998-05-01

Southeast Community College (SCC) hosted the first DuPont Conference for Chemical Technology Education at its Lincoln, Nebraska campus October 4-6, 1997. The conference brought together fourteen practicing chemists and chemistry technicians and five college and university faculty members for the express purpose of suggesting new laboratory activities that would help relate the real world of work to the education of chemical laboratory technicians in community colleges. Participants included seven men and seven women from DuPont, Procter & Gamble, Eastman Chemical, Eastman Kodak, Dow Chemical, Air Products and Chemicals, Monsanto, Union Carbide, the Nebraska Agriculture Laboratory, and the University of Nebraska Biological Process Development Facility, Department of Food Science. The conference, sponsored by the E. I. DuPont DeNemours & Company through a grant awarded to SCC in June 1997, was intended to help further the goals of the two major projects underway at SCC, funded by the National Science Foundation's Advanced Technological Education Program. These projects, dubbed "Assignment: Chemical Technology I and II", or ACT-I and ACT-II, are curriculum and materials development projects. The invited scientists had between 2 and 32 years of experience that ranged from bench work to management levels. Many are or have been active on the national scene as members and officers of the American Chemical Society's Division of Chemical Technicians and the ACS Committee on Technician Activities.

Dedicated Caravan Sites for French Gens du Voyage: Public Health Policy or Construction of Health and Environmental Inequalities?

PubMed

Foisneau, Lise

2017-12-01

In France, gens du voyage ("people who travel" or "travellers") is a term used by the government to categorize various itinerant populations, the majority of which are diverse Romani groups. People categorized as gens du voyage are legally required to reside in particular locations called "dedicated caravan sites." Parliamentary debates about these dedicated caravan sites have clarified that one of the objectives of such sites is to help fulfill the gens du voyage 's right to health. However, there is a significant gap between the officially stated goals of such sites and the reality of life within them. This paper draws on research finding that the conditions in most dedicated caravan sites do not conform with the rights of gens du voyage to acceptable sanitary conditions and other underlying determinants of health.

Guideline on Scenario Development for (Distributed) Simulation Environments (Guide en vue du developpement de scenario dans le cadre de simulation distribuee)

DTIC Science & Technology

2015-01-01

des lacunes de M&S du MORS du NMSG a déterminé que le manque d’interopérabilité de la simulation constituait la lacune prioritaire à combler en...matière de capacité, une équipe exploratoire (ET-027) a été constituée au sein du NMSG pour étudier l’interopérabilité de la simulation. L’ET-027 a...élevés (autrement dit, aux niveaux pratique, dynamique et conceptuel) de même que l’automatisation relative du développement, de

Fibres Optiques En Therapie Laser Au Contact Du Tissu

NASA Astrophysics Data System (ADS)

Lenz, P.; Sabben, G.; Lambert, R.; Berger, F.

1984-03-01

Les fibres en quartz, non protegees par un courant de gaz et placees au contact du tissu, peuvent etre utilisees pratiquement indefiniment grace a un "autonettoyage" et une "regenera-tion". Elles provoquent des lesions tissulaires semblables a celles obtenues avec les fibres conventionnelles.

Melanopsin retinal ganglion cell loss in Alzheimer disease

PubMed Central

Ross‐Cisneros, Fred N.; Koronyo, Yosef; Hannibal, Jens; Gallassi, Roberto; Cantalupo, Gaetano; Sambati, Luisa; Pan, Billy X.; Tozer, Kevin R.; Barboni, Piero; Provini, Federica; Avanzini, Pietro; Carbonelli, Michele; Pelosi, Annalisa; Chui, Helena; Liguori, Rocco; Baruzzi, Agostino; Koronyo‐Hamaoui, Maya; Sadun, Alfredo A.; Carelli, Valerio

2015-01-01

Objective Melanopsin retinal ganglion cells (mRGCs) are photoreceptors driving circadian photoentrainment, and circadian dysfunction characterizes Alzheimer disease (AD). We investigated mRGCs in AD, hypothesizing that they contribute to circadian dysfunction. Methods We assessed retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) in 21 mild‐moderate AD patients, and in a subgroup of 16 we evaluated rest–activity circadian rhythm by actigraphy. We studied postmortem mRGCs by immunohistochemistry in retinas, and axons in optic nerve cross‐sections of 14 neuropathologically confirmed AD patients. We coimmunostained for retinal amyloid β (Aβ) deposition and melanopsin to locate mRGCs. All AD cohorts were compared with age‐matched controls. Results We demonstrated an age‐related optic neuropathy in AD by OCT, with a significant reduction of RNFL thickness (p = 0.038), more evident in the superior quadrant (p = 0.006). Axonal loss was confirmed in postmortem AD optic nerves. Abnormal circadian function characterized only a subgroup of AD patients. Sleep efficiency was significantly reduced in AD patients (p = 0.001). We also found a significant loss of mRGCs in postmortem AD retinal specimens (p = 0.003) across all ages and abnormal mRGC dendritic morphology and size (p = 0.003). In flat‐mounted AD retinas, Aβ accumulation was remarkably evident inside and around mRGCs. Interpretation We show variable degrees of rest–activity circadian dysfunction in AD patients. We also demonstrate age‐related loss of optic nerve axons and specifically mRGC loss and pathology in postmortem AD retinal specimens, associated with Aβ deposition. These results all support the concept that mRGC degeneration is a contributor to circadian rhythm dysfunction in AD. ANN NEUROL 2016;79:90–109 PMID:26505992

Sulbutiamine counteracts trophic factor deprivation induced apoptotic cell death in transformed retinal ganglion cells.

PubMed

Kang, Kui Dong; Majid, Aman Shah Abdul; Kim, Kyung-A; Kang, Kyungsu; Ahn, Hong Ryul; Nho, Chu Won; Jung, Sang Hoon

2010-11-01

Sulbutiamine is a highly lipid soluble synthetic analogue of vitamin B(1) and is used clinically for the treatment of asthenia. The aim of our study was to demonstrate whether sulbutiamine is able to attenuate trophic factor deprivation induced cell death to transformed retinal ganglion cells (RGC-5). Cells were subjected to serum deprivation for defined periods and sulbutiamine at different concentrations was added to the cultures. Various procedures (e.g. cell viability assays, apoptosis assay, reactive oxygen species analysis, Western blot analysis, flow cytometric analysis, glutathione (GSH) and glutathione-S-transferase (GST) measurement) were used to demonstrate the effect of sulbutiamine. Sulbutiamine dose-dependently attenuated apoptotic cell death induced by serum deprivation and stimulated GSH and GST activity. Moreover, sulbutiamine decreased the expression of cleaved caspase-3 and AIF. This study demonstrates for the first time that sulbutiamine is able to attenuate trophic factor deprivation induced apoptotic cell death in neuronal cells in culture.

Dysfonctionnements radio-induits du transport colique chez le rat

NASA Astrophysics Data System (ADS)

François, A.; Lebrun, F.; Ksas, B.; Aigueperse, J.; Gourmelon, P.; MacNaughton, W. K.; Griffiths, N. M.

1998-04-01

The symptom commonly associated with whole body irradiation is diarrhoea, a still quite obscure phenomenon, which leads to decreased chance of cure of irradiated people. The aim of this study was to provide evidence for dysfunction of intestinal water and electrolyte transport regulation by the enteric nervous system after exposure to ionising radiation. This study shows decreased capacity of enteric nervous system to influence colonic transport 3days after irradiation, correlated to a diminished response to a neurotransmitter: serotonin. Radio-induced diarrhea may result from epithelial structural injury but also from impaired regulatory processes of intestinal transport. L'un des symptômes majeurs d'une irradiation corporelle totale ou abdominale est l'apparition de diarrhées, dont les causes sont encore mal connues, et qui mettent en jeu le pronostique vital de l'individu irradié. Cette étude vise à mettre en évidence l'atteinte de la régulation du transport intestinal d'eau et d'électrolytes par les rayonnements ionisants. On observe une diminution de la capacité du système nerveux entérique à influencer le transport colique 3jours après irradiation, corrélée à une diminution de la réponse épithéliale à un neurotransmetteur : la sérotonine. Les diarrhées radio-induites résulteraient d'une atteinte structurelle de l'épithélium mais également des processus de régulation du transport intestinal.

Kyste épidermoïde du quatrième ventricule: à propos d’un cas

PubMed Central

El Saqui, Abderrazzak; Aggouri, Mohamed; Benzagmout, Mohamed; Chakour, Khalid; Chaoui, Mohamed El Faiz

2017-01-01

Les kystes épidermoïdes sont des tumeurs bénignes rares développées à partir d'inclusions ectodermiques. Ils siègent habituellement au niveau de l'angle ponto-cérébelleux, la région para-sellaire et la fosse temporale. Leur siège au niveau du quatrième ventricule est exceptionnel. Nous rapportons le cas d'une patiente de 47 ans admise pour un syndrome d'hypertension intracrânienne associé à des troubles de la marche. Le diagnostic de kyste épidermoïde du V4 fut évoqué sur les données de l'IRM en séquences de diffusion puis confirmé en per opératoire et en histologie. L'exérèse chirurgicale a été subtotale en raison d'une adhérence de la capsule à la partie supérieure du plancher du V4. Après un recul de 36 mois, la patiente ne manifeste aucun signe de ré-évolution tumorale. PMID:28690753

Diagnostic et prise en charge du psoriasis

PubMed Central

Kim, Whan B.; Jerome, Dana; Yeung, Jensen

2017-01-01

Résumé Objectif Présenter aux cliniciens en soins primaires un aperçu pratique et à jour du diagnostic et de la prise en charge du psoriasis. Sources des données Une recension a été effectuée dans les bases de données de PubMed, MEDLINE, EMBASE et Cochrane pour trouver des méta-analyses, des études randomisées contrôlées, des revues systématiques et des études observationnelles pertinentes portant sur le diagnostic et la prise en charge du psoriasis. Message principal Le psoriasis est une maladie inflammatoire chronique et multisystémique qui affecte principalement la peau et les articulations. En plus des dimensions physiques de la maladie, le psoriasis a des répercussions émotionnelles et psychosociales considérables sur les patients, et nuit au fonctionnement social et aux relations interpersonnelles. En tant que maladie inflammatoire systémique, le psoriasis est associé à de multiples comorbidités, dont les maladies cardiovasculaires et les cancers. Le diagnostic est principalement d’ordre clinique et une biopsie de la peau est rarement nécessaire. Selon la sévérité de la maladie, un traitement approprié peut être amorcé. Pour les cas de légers à modérés, le traitement de première intention comporte des thérapies topiques, dont les corticostéroïdes, les analogues de la vitamine D3 et des produits combinés. Ces traitements topiques sont efficaces et peuvent être initiés et prescrits en toute sécurité par des médecins de soins primaires. Les patients dont les symptômes sont plus graves et réfractaires pourraient devoir être envoyés en consultation auprès d’un dermatologue pour une évaluation plus approfondie et une thérapie systémique. Conclusion De nombreux patients atteints de psoriasis consultent leur médecin de soins primaires pour une évaluation initiale et pour recevoir un traitement. La reconnaissance du psoriasis, de même que des comorbidités médicales et psychiatriques qui lui sont associ

Évolution nycthémérale des composantes biochimiques du phytoplancton de la retenue du barrage Idriss premier (Fès, Maroc)

NASA Astrophysics Data System (ADS)

Bahhou, J.; Alaoui Mhamdi, M.

1999-03-01

The diel changes of the biochemical composition of the phytoplankton were studied in the Idriss first reservoir (located on the Inaouen river at thirty Km from the city of Fes, Morrocco) during September 1994. Several biomass and metabolic indicators (proteins, carbohydrates, lipids, chlorophyll a and primary production) were assessed every fourth hour over tow days (7, 8 and 9 September). Since the Protein/Carbohydrates ratio (P/C) is largely recognised as a good integrator of the metabolic functions of the cells, we examined its distribution pattern concomitantly with aforementioned parameters. The results demonstrated enhanced P/C ratios clearly indicating that nutrients were sufficiently available for growth. In addition, this index showed a diel significant variation with levels higher in the night than in the day. Moreover, these results suggest that phytoplankton species during the night used the day-synthesised carbohydrates to insure the cell metabolic functioning. The P/C presents relatively high values in proposition to the ones that have been recorded in temperate regions, and seems to be related to azotic inputs of the Inaouen river. Dans le but de parfaire nos connaissances sur le fonctionnement du sous écosystème phytoplancton, nous nous sommes intéressés à étudier son cycle nycthéméral et son métabolisme cellulaire dans la retenue du barrage Idriss premier. Cette dernière, construite sur l'Oued Inaouène, est située à une trentaine de Km de la ville de Fès. Au cours de ce cycle, les prélèvements ont été effectués selon une séquence temporelle de 4 heures pendant 48 heures, les 7, 8 et 9 septembre 1994. L'étude de l'évolution des composantes biochimiques des cellules phytoplanctoniques à savoir les protéines, les glucides et les lipides a permis de mettre en évidence des variations nycthémérales importantes. Ces variations sont d'autant plus importantes que les variations spatiales observées entre les profondeurs. De plus

Who's lost first? Susceptibility of retinal ganglion cell types in experimental glaucoma.

PubMed

Della Santina, Luca; Ou, Yvonne

2017-05-01

The purpose of this article is to summarize our current knowledge about the susceptibility of specific retinal ganglion cell (RGC) types in experimental glaucoma, and to delineate the initial morphological and functional alterations that occur in response to intraocular pressure (IOP) elevation. There has been debate in the field as to whether RGCs with large somata and axons are more vulnerable, with definitive conclusions still in progress because of the wide diversity of RGC types. Indeed, it is now estimated that there are greater than 30 different RGC types, and while we do not yet understand the complete details, we discuss a growing body of work that supports the selective vulnerability hypothesis of specific RGC types in experimental glaucoma. Specifically, structural and functional degeneration of various RGC types have been examined across different rodent models of experimental glaucoma (acute vs. chronic) and different strains, and an emerging consensus is that OFF RGCs appear to be more vulnerable to IOP elevation compared to ON RGCs. Understanding the mechanisms by which this selective vulnerability manifests across different RGC types should lead to novel and improved strategies for neuroprotection and neuroregeneration in glaucoma. Copyright © 2016 Elsevier Ltd. All rights reserved.

BARHL2 differentially regulates the development of retinal amacrine and ganglion neurons

PubMed Central

Ding, Qian; Chen, Hui; Xie, Xiaoling; Libby, Richard T.; Tian, Ning; Gan, Lin

2009-01-01

Summary Through transcriptional regulations the BarH family of homeodomain proteins play essential roles in cell fate specification, cell differentiation, migration and survival. Barhl2, a member of the Barh gene family, is expressed in retinal ganglion cells (RGCs), amacrine cells (ACs) and horizontal cells. Here, to investigate the role of Barhl2 in retinal development, Barhl2 deficient mice were generated. Analysis of AC subtypes in Barhl2 deficient retinas suggests that Barhl2 plays a critical role in AC subtype determination. A significant reduction of glycinergic and GABAergic ACs with a substantial increase in the number of cholinergic ACs was observed in Barhl2-null retinas. Barhl2 is also critical for the development of a normal complement of RGCs. Barhl2 deficiency resulted in a 35% increase in RGCs undergoing apoptosis during development. Genetic analysis revealed that Barhl2 functions downstream of the Atoh7-Pou4f3 regulatory pathway and regulates the maturation and/or survival of RGCs. Thus, BARHL2 appears to have numerous roles in retinal development, including regulating neuronal subtype specification, differentiation, and survival. PMID:19339595

PKC regulates capsaicin-induced currents of dorsal root ganglion neurons in rats.

PubMed

Zhou, Y; Zhou, Z S; Zhao, Z Q

2001-10-01

Capsaicin activates a non-specific cation conductance in a subset of dorsal root ganglion (DRG) neurons. The inward current and membrane potential of acutely isolated DRG neurons were examined using whole-cell patch recording methods. We report here that the current and voltage responses activated by capsaicin were markedly increased by phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC). The mean current, after application of 0.3 microM PMA, was 153.5+/-5.7% of control (n=32) in Ca(2+)-free external solution and 181.6+/-6.8% of control (n=15) in standard external solution. Under current-clamp conditions, 0.3 microM PMA facilitated capsaicin-induced depolarization and action potential generation. Bindolylmaleimide I (BIM), a specific inhibitor of PKC activity, abolished the effect of PMA. In addition, capsaicin-evoked current was attenuated to 68.3+/-5.0% of control (n=13) by individual administration of 1 microM BIM in standard external solution, while 0.3 microM BIM did not have this effect. These data suggest that PKC can directly regulate the capsaicin response in DRG neurons, which could increase nociceptive sensory transmission and contribute to hyperalgesia.

Stellate ganglion block promotes recovery of Bell's palsy in patients with diabetes mellitus.

PubMed

Liu, Guo-Dong; He, Chun-Jing

2014-06-01

Stellate ganglion block (SGB) is effective for treatment of Bell's palsy in patients with diabetes mellitus. Corticosteroids are widely used for treatment of Bell's palsy in patients with diabetes mellitus but may induce complications like hyperglycemia, which calls for an alternative therapy. This study aimed to ascertain the effect of SGB on Bell's palsy in patients with diabetes mellitus. This randomized and single-blinded clinical trial involved 96 diabetic patients with Bell's palsy that were randomly divided into a control group (n = 48) and a treatment group (SGB group, n = 48). The House-Brackmann scale and facial disability index (FDI, including FDIP and FDIS) were observed before treatment and at 1 and 3 months after treatment for assessment of the outcome. No statistically significant difference was found between the two groups before treatment as regards the House-Brackmann scale and FDI. There was a statistically significant difference in FDIP score in the two groups after treatment in comparison with before treatment. The FDIS score showed a statistical difference between the two groups after treatment.

Response properties of ON-OFF retinal ganglion cells to high-order stimulus statistics.

PubMed

Xiao, Lei; Gong, Han-Yan; Gong, Hai-Qing; Liang, Pei-Ji; Zhang, Pu-Ming

2014-10-17

The visual stimulus statistics are the fundamental parameters to provide the reference for studying visual coding rules. In this study, the multi-electrode extracellular recording experiments were designed and implemented on bullfrog retinal ganglion cells to explore the neural response properties to the changes in stimulus statistics. The changes in low-order stimulus statistics, such as intensity and contrast, were clearly reflected in the neuronal firing rate. However, it was difficult to distinguish the changes in high-order statistics, such as skewness and kurtosis, only based on the neuronal firing rate. The neuronal temporal filtering and sensitivity characteristics were further analyzed. We observed that the peak-to-peak amplitude of the temporal filter and the neuronal sensitivity, which were obtained from either neuronal ON spikes or OFF spikes, could exhibit significant changes when the high-order stimulus statistics were changed. These results indicate that in the retina, the neuronal response properties may be reliable and powerful in carrying some complex and subtle visual information. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Multiunit Activity-Based Real-Time Limb-State Estimation from Dorsal Root Ganglion Recordings

PubMed Central

Han, Sungmin; Chu, Jun-Uk; Kim, Hyungmin; Park, Jong Woong; Youn, Inchan

2017-01-01

Proprioceptive afferent activities could be useful for providing sensory feedback signals for closed-loop control during functional electrical stimulation (FES). However, most previous studies have used the single-unit activity of individual neurons to extract sensory information from proprioceptive afferents. This study proposes a new decoding method to estimate ankle and knee joint angles using multiunit activity data. Proprioceptive afferent signals were recorded from a dorsal root ganglion with a single-shank microelectrode during passive movements of the ankle and knee joints, and joint angles were measured as kinematic data. The mean absolute value (MAV) was extracted from the multiunit activity data, and a dynamically driven recurrent neural network (DDRNN) was used to estimate ankle and knee joint angles. The multiunit activity-based MAV feature was sufficiently informative to estimate limb states, and the DDRNN showed a better decoding performance than conventional linear estimators. In addition, processing time delay satisfied real-time constraints. These results demonstrated that the proposed method could be applicable for providing real-time sensory feedback signals in closed-loop FES systems. PMID:28276474

Crocin prevents retinal ischaemia/reperfusion injury-induced apoptosis in retinal ganglion cells through the PI3K/AKT signalling pathway.

PubMed

Qi, Yun; Chen, Li; Zhang, Lei; Liu, Wen-Bo; Chen, Xiao-Yan; Yang, Xin-Guang

2013-02-01

Crocin is a pharmacologically active component of Crocus sativus L. (saffron) and has been reported to be useful in the treatment of neuronal damage. In the present study, we investigated the neuroprotective effect of crocin on retinal ganglion cells (RGCs) after retinal ischaemia/reperfusion (IR) injury, and our results show that crocin acts through the PI3K/AKT signalling pathway. Retinal IR injury was induced by raising the intraocular pressure of Sprague-Dawley rats to 110 mmHg for 60 min. The neuroprotective effect of crocin was determined by quantifying the surviving RGCs and apoptotic RGCs following IR injury by means of retrograde labelling and TUNEL staining, respectively. The phosphorylated AKT protein level was determined by western blot and immunohistochemical analysis. To determine the extent to which the PI3K/AKT pathway contributes to the neuroprotective effect of crocin, experiments were also performed using the PI3K inhibitor LY294002. Compared with the IR + vehicle group, crocin (50 mg/kg) treatment enhanced RGC survival by approximately 36% and decreased RGC apoptosis by 44% after retinal IR injury. Western blot and immunohistochemical analysis demonstrated that the PI3K/AKT pathway was activated by crocin in the ganglion cell layer after retinal IR injury. Intravitreal injection of LY294002 blocked the neuroprotective effect of crocin on IR-induced RGC death. In conclusion, crocin prevents retinal IR-induced apoptosis of RGCs by activating the PI3K/AKT signalling pathway. Copyright © 2012 Elsevier Ltd. All rights reserved.

Electrical stimulation at the dorsal root ganglion preserves trabecular bone mass and microarchitecture of the tibia in hindlimb-unloaded rats.

PubMed

Lau, Y-C; Qian, X; Po, K-T; Li, L-M; Guo, X

2015-02-01

This study seeks to investigate the effect of electrical stimulation (ES) at dorsal root ganglion (DRG) on disuse bone loss in a rat model. Hindlimb unloading for 14 days resulted in significant bone loss in rat tibia while rats with ES at DRG showed a significant reduced bone loss Mechanical unloading induces osteoporosis in both human and animals. Previous studies demonstrated that electrical stimulation (ES) to dorsal root ganglion (DRG) could trigger secretion of calcitonin gene-related peptide (CGRP) which plays an important role in bone modeling and remodeling. This study seeks to investigate the effect of ES to DRG on disuse bone loss in a rat model. Twenty-four rats were randomly assigned in three experimental groups: cage control (CC), hindlimb unloading (HU), and hindlimb unloading with ES (HUES). ES was applied via implantable micro-electrical stimulators (IMES) to right DRGs at vertebral levels L4-L6 in HUES group. Hindlimb unloading for 14 days resulted in 25.9% decrease in total bone mineral content (BMC), 29.2% decrease in trabecular BMD and trabecular microarchitecture and connectivity were significantly deteriorated in the proximal tibia metaphysis in HU group, while rats with ES at DRG showed significant reduced bone loss that there was 3.8% increase in total BMC, 2.3% decrease in trabecular BMD, and significant improvement in trabecular microarchitecture. There was a concurrent enhancement of expression of CGRP in stimulated DRGs. The results confirm the effect of ES at DRG on enhancing CGRP expression and suggest potential applications of IMES for the prevention and treatment of disuse bone loss.

Prickle1 regulates neurite outgrowth of apical spiral ganglion neurons but not hair cell polarity in the murine cochlea

PubMed Central

Kersigo, Jennifer; Wu, Shu; Fritzsch, Bernd; Bassuk, Alexander G.

2017-01-01

In the mammalian organ of Corti (OC), the stereocilia on the apical surface of hair cells (HCs) are uniformly organized in a neural to abneural axis (or medial-laterally). This organization is regulated by planar cell polarity (PCP) signaling. Mutations of PCP genes, such as Vangl2, Dvl1/2, Celsr1, and Fzd3/6, affect the formation of HC orientation to varying degrees. Prickle1 is a PCP signaling gene that belongs to the prickle / espinas / testin family. Prickle1 protein is shown to be asymmetrically localized in the HCs of the OC, and this asymmetric localization is associated with loss of PCP in Smurf mutants, implying that Prickle1 is involved in HC PCP development in the OC. A follow-up study found no PCP polarity defects after loss of Prickle1 (Prickle1-/-) in the cochlea. We show here strong Prickle1 mRNA expression in the spiral ganglion by in situ hybridization and β-Gal staining, and weak expression in the OC by β-Gal staining. Consistent with this limited expression in the OC, cochlear HC PCP is unaffected in either Prickle1C251X/C251X mice or Prickle1f/f; Pax2-cre conditional null mice. Meanwhile, type II afferents of apical spiral ganglion neurons (SGN) innervating outer hair cells (OHC) have unusual neurite growth. In addition, afferents from the apex show unusual collaterals in the cochlear nuclei that overlap with basal turn afferents. Our findings argue against the role of Prickle1 in regulating hair cell polarity in the cochlea. Instead, Prickle1 regulates the polarity-related growth of distal and central processes of apical SGNs. PMID:28837644

Differences in Optic Nerve Head, Retinal Nerve Fiber Layer, and Ganglion Cell Complex Parameters Between Caucasian and Chinese Subjects.

PubMed

Chansangpetch, Sunee; Huang, Guofu; Coh, Paul; Oldenburg, Catherine; Amoozgar, Behzad; He, Mingguang; Lin, Shan C

2018-04-01

To compare optic nerve head, peripapillary retinal nerve fiber layer (pRNFL), and ganglion cell complex (GCC) parameters between Caucasian and ethnic Chinese. Normal subjects above 40 years old and self-identified as being Caucasian and Chinese were recruited. They were evaluated with spectral-domain optical coherence tomography (RTVue-100). Parameters related to the optic nerve head, pRNFL, and GCC analysis protocols were acquired. Multivariable linear regression was performed adjusting for potential confounders. Data from 116 Caucasian and 130 Chinese subjects were available for analysis. Mean age of all participants was 66.72 (SD 10.82) years. There were statistically significant differences for disc area (DA), area cup-to-disc, vertical cup-to-disc, and cup volume (P=0.02, 0.004, 0.02, and 0.03, respectively), greater in Chinese. After adjusting for age, sex, axial length (AL), intraocular pressure (IOP), DA, and GCC thickness, Chinese subjects had significantly greater thickness in all pRNFL parameters (mean differences ranged between 4.29 and 9.93 μm; all P<0.001) except the nasal quadrant. GCC outcomes were also adjusted for DA and pRNFL; Caucasians had significantly higher average GCC and inferior GCC (mean difference 2.97 and 3.45 μm, respectively; P<0.01), whereas the Chinese group had significantly higher ganglion cell global loss volume (mean difference 2.47 %, P<0.001). This study suggests there is significantly greater pRNFL thickness in Chinese, which were independent of age, AL, IOP, and DA, and possibly greater GCC in Caucasians after adjustment for age, AL, IOP, DA, and pRNFL thickness.

Modulation of ATP-induced inward currents by docosahexaenoic acid and other fatty acids in rat nodose ganglion neurons.

PubMed

Eto, Kei; Arimura, Yukiko; Mizuguchi, Hiroko; Nishikawa, Masazumi; Noda, Mami; Ishibashi, Hitoshi

2006-11-01

The effects of docosahexaenoic acid (DHA) and other fatty acids on P2X-receptor-mediated inward currents in rat nodose ganglion neurons were studied using the nystatin perforated patch-clamp technique. DHA accelerated the desensitization rate of the ATP-induced current. DHA showed use-dependent inhibition of the peak ATP-induced current. Other polyunsaturated fatty acids, such as arachidonic acid and eicosapentaenoic acid, displayed a similar use-dependent inhibition. The inhibitory effects of saturated fatty acids including palmitic acid and arachidic acid were weaker than those of polyunsaturated fatty acids. The results suggest that fatty acids may modulate the P2X receptor-mediated response when the channel is in the open-state.

Particularités de la cardiomyopathie du péripartum en Afrique: le cas du Togo sur une étude prospective de 41 cas au Centre Hospitalier et Universitaire Sylvanus Olympio de Lomé

PubMed Central

Pio, Machihude; Afassinou, Yaovi; Baragou, Soodougoua; Akue, Edem Goeh; Péssinaba, Souleymane; Atta, Borgatia; Ehlan, Koffi; Alate, Amouzou; Damorou, Findibe

2014-01-01

Introduction La cardiomyopathie du péripartum (CMPP) est une défaillance cardiaque dont l’étiologie demeure encore méconnue. Méthodes Il s'agit d'une étude prospective descriptive réalisée dans le service de cardiologie du CHU Sylvanus olympio de Lomé du 1er janvier 2010 au 30 avril 2012. Elle a concerné 41 patientes ayant présenté une insuffisance cardiaque entre le 8eme mois de la grossesse et les 5 premiers mois du post-partum. Résultats L’âge moyen des patientes était de 31,47 ans (extrêmes 21 et 44ans). L'incidence de la CMPP était de 1/362 grossesses. La parité moyenne était de 3,07 (extrêmes 1 et 6). Les symptômes étaient apparus dans le post-partum dans 90,24% des cas. Un retard important de diagnostic était observé. L'insuffisance cardiaque globale était le mode de décompensation dans 65,85%. Les signes électrocardiographiques étaient essentiellement la tachycardie sinusale (97,56%) et l'hypertrophie ventriculaire gauche (97,56%). L’échographie cardiaque a montré dans tous les cas une cardiomyopathie dilatée. Quatre cas de thrombus intraventriculaire gauche étaient notés. La FEVG était sévèrement altérée. L'HTAP était importante dans 56,09%. Conclusion La cardiomyopathie du péripartum est une complication cardiaque grave de la grossesse de cause inconnue, fréquente dans la population africaine. PMID:25309645

Visualization of spiral ganglion neurites within the scala tympani with a cochlear implant in situ

PubMed Central

Chikar, Jennifer A.; Batts, Shelley A.; Pfingst, Bryan E.; Raphael, Yehoash

2009-01-01

Current cochlear histology methods do not allow in situ processing of cochlear implants. The metal components of the implant preclude standard embedding and mid-modiolar sectioning, and whole mounts do not have the spatial resolution needed to view the implant within the scala tympani. One focus of recent auditory research is the regeneration of structures within the cochlea, particularly the ganglion cells and their processes, and there are multiple potential benefits to cochlear implant users from this work. To facilitate experimental investigations of auditory nerve regeneration performed in conjunction with cochlear implantation, it is critical to visualize the cochlear tissue and the implant together to determine if the nerve has made contact with the implant. This paper presents a novel histological technique that enables simultaneous visualization of the in situ cochlear implant and neurofilament – labeled nerve processes within the scala tympani, and the spatial relationship between them. PMID:19428528

Visualization of spiral ganglion neurites within the scala tympani with a cochlear implant in situ.

PubMed

Chikar, Jennifer A; Batts, Shelley A; Pfingst, Bryan E; Raphael, Yehoash

2009-05-15

Current cochlear histology methods do not allow in situ processing of cochlear implants. The metal components of the implant preclude standard embedding and mid-modiolar sectioning, and whole mounts do not have the spatial resolution needed to view the implant within the scala tympani. One focus of recent auditory research is the regeneration of structures within the cochlea, particularly the ganglion cells and their processes, and there are multiple potential benefits to cochlear implant users from this work. To facilitate experimental investigations of auditory nerve regeneration performed in conjunction with cochlear implantation, it is critical to visualize the cochlear tissue and the implant together to determine if the nerve has made contact with the implant. This paper presents a novel histological technique that enables simultaneous visualization of the in situ cochlear implant and neurofilament-labeled nerve processes within the scala tympani, and the spatial relationship between them.

Comparative study on DuPont analysis and DEA models for measuring stock performance using financial ratio

NASA Astrophysics Data System (ADS)

Arsad, Roslah; Shaari, Siti Nabilah Mohd; Isa, Zaidi

2017-11-01

Determining stock performance using financial ratio is challenging for many investors and researchers. Financial ratio can indicate the strengths and weaknesses of a company's stock performance. There are five categories of financial ratios namely liquidity, efficiency, leverage, profitability and market ratios. It is important to interpret the ratio correctly for proper financial decision making. The purpose of this study is to compare the performance of listed companies in Bursa Malaysia using Data Envelopment Analysis (DEA) and DuPont analysis Models. The study is conducted in 2015 involving 116 consumer products companies listed in Bursa Malaysia. The estimation method of Data Envelopment Analysis computes the efficiency scores and ranks the companies accordingly. The Alirezaee and Afsharian's method of analysis based Charnes, Cooper and Rhodes (CCR) where Constant Return to Scale (CRS) is employed. The DuPont analysis is a traditional tool for measuring the operating performance of companies. In this study, DuPont analysis is used to evaluate three different aspects such as profitability, efficiency of assets utilization and financial leverage. Return on Equity (ROE) is also calculated in DuPont analysis. This study finds that both analysis models provide different rankings of the selected samples. Hypothesis testing based on Pearson's correlation, indicates that there is no correlation between rankings produced by DEA and DuPont analysis. The DEA ranking model proposed by Alirezaee and Asharian is unstable. The method cannot provide complete ranking because the values of Balance Index is equal and zero.

Silencing the Kir4.1 potassium channel subunit in satellite glial cells of the rat trigeminal ganglion results in pain-like behavior in the absence of nerve injury.

PubMed

Vit, Jean-Philippe; Ohara, Peter T; Bhargava, Aditi; Kelley, Kanwar; Jasmin, Luc

2008-04-16

Growing evidence suggests that changes in the ion buffering capacity of glial cells can give rise to neuropathic pain. In the CNS, potassium ion (K+) buffering is dependent on the glia-specific inward rectifying K+ channel Kir4.1. We recently reported that the satellite glial cells that surround primary sensory neurons located in sensory ganglia of the peripheral nervous system also express Kir4.1, whereas the neurons do not. In the present study, we show that, in the rat trigeminal ganglion, the location of the primary sensory neurons for face sensation, specific silencing of Kir4.1 using RNA interference leads to spontaneous and evoked facial pain-like behavior in freely moving rats. We also show that Kir4.1 in the trigeminal ganglion is reduced after chronic constriction injury of the infraorbital nerve. These findings suggests that neuropathic pain can result from a change in expression of a single K+ channel in peripheral glial cells, raising the possibility of targeting Kir4.1 to treat pain in general and particularly neuropathic pain that occurs in the absence of nerve injury.

Selective Vulnerability of Specific Retinal Ganglion Cell Types and Synapses after Transient Ocular Hypertension.

PubMed

Ou, Yvonne; Jo, Rebecca E; Ullian, Erik M; Wong, Rachel O L; Della Santina, Luca

2016-08-31

Key issues concerning ganglion cell type-specific loss and synaptic changes in animal models of experimental glaucoma remain highly debated. Importantly, changes in the structure and function of various RGC types that occur early, within 14 d after acute, transient intraocular pressure elevation, have not been previously assessed. Using biolistic transfection of individual RGCs and multielectrode array recordings to measure light responses in mice, we examined the effects of laser-induced ocular hypertension on the structure and function of a subset of RGCs. Among the α-like RGCs studied, αOFF-transient RGCs exhibited higher rates of cell death, with corresponding reductions in dendritic area, dendritic complexity, and synapse density. Functionally, OFF-transient RGCs displayed decreases in spontaneous activity and receptive field size. In contrast, neither αOFF-sustained nor αON-sustained RGCs displayed decreases in light responses, although they did exhibit a decrease in excitatory postsynaptic sites, suggesting that synapse loss may be one of the earliest signs of degeneration. Interestingly, presynaptic ribbon density decreased to a greater degree in the OFF sublamina of the inner plexiform layer, corroborating the hypothesis that RGCs with dendrites stratifying in the OFF sublamina may be damaged early. Indeed, OFF arbors of ON-OFF RGCs lose complexity more rapidly than ON arbors. Our results reveal type-specific differences in RGC responses to injury with a selective vulnerability of αOFF-transient RGCs, and furthermore, an increased susceptibility of synapses in the OFF sublamina. The selective vulnerability of specific RGC types offers new avenues for the design of more sensitive functional tests and targeted neuroprotection. Conflicting reports regarding the selective vulnerability of specific retinal ganglion cell (RGC) types in glaucoma exist. We examine, for the first time, the effects of transient intraocular pressure elevation on the structure

PHOTOMETRIC ANALYSIS OF HS Aqr, EG Cep, VW LMi, AND DU Boo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djurasevic, G.; Latkovic, O.; Bastuerk, Oe.

2013-03-15

We analyze new multicolor light curves for four close late-type binaries: HS Aqr, EG Cep, VW LMi, and DU Boo, in order to determine the orbital and physical parameters of the systems and estimate the distances. The analysis is done using the modeling code of G. Djurasevic, and is based on up-to-date measurements of spectroscopic elements. All four systems have complex, asymmetric light curves that we model by including bright or dark spots on one or both components. Our findings indicate that HS Aqr and EG Cep are in semi-detached, while VW LMi and DU Boo are in overcontact configurations.

Differents aspects du fer dans l'organisme

PubMed Central

Bessis, Marcel; Breton-Gorius, Janine

1959-01-01

On voit des molécules de ferritine apparaitre dans le cytoplasme des cellules réticulaires au cours de la digestion des érythrocytes, autour des stromas phagocytés. Cette ferritine s'accumule en amas dans lesquels entrent d'autres substances, en particulier des lipides, provenant aussi des stromas globulaires et qui apparaissent sous forme myélinique. Souvent la ferritine se dispose d'une manière cristalline. Parfois la ferritine et l'apoferritine alternent dans ces cristaux. Parfois l'hémosidérine contient des cristaux qui semblent bien être de l'apoferritine pure. L'injection de sels de fer donne lieu à l'apparition de ferritine dans les cellules réticulaires. Dans les conditions de nos expériences, la plus grande partie du fer injecté était sous forme de ferritine dans un délai de 3 jours. Un aspect intermédiaire entre celui du fer injecté et celui de la ferritine a été trouvé. Dans le cas des injections de saccharate de fer ce sont de fines aiguilles; dans le cas des injections de lactate de fer, il s'agit de masses fibreuses. PMID:13800106

Sensitivity of spiral ganglion neurons to damage caused by mobile phone electromagnetic radiation will increase in lipopolysaccharide-induced inflammation in vitro model.

PubMed

Zuo, Wen-Qi; Hu, Yu-Juan; Yang, Yang; Zhao, Xue-Yan; Zhang, Yuan-Yuan; Kong, Wen; Kong, Wei-Jia

2015-05-29

With the increasing popularity of mobile phones, the potential hazards of radiofrequency electromagnetic radiation (RF-EMR) on the auditory system remain unclear. Apart from RF-EMR, humans are also exposed to various physical and chemical factors. We established a lipopolysaccharide (LPS)-induced inflammation in vitro model to investigate whether the possible sensitivity of spiral ganglion neurons to damage caused by mobile phone electromagnetic radiation (at specific absorption rates: 2, 4 W/kg) will increase. Spiral ganglion neurons (SGN) were obtained from neonatal (1- to 3-day-old) Sprague Dawley® (SD) rats. After the SGN were treated with different concentrations (0, 20, 40, 50, 100, 200, and 400 μg/ml) of LPS, the Cell Counting Kit-8 (CCK-8) and alkaline comet assay were used to quantify cellular activity and DNA damage, respectively. The SGN were treated with the moderate LPS concentrations before RF-EMR exposure. After 24 h intermittent exposure at an absorption rate of 2 and 4 W/kg, DNA damage was examined by alkaline comet assay, ultrastructure changes were detected by transmission electron microscopy, and expression of the autophagy markers LC3-II and Beclin1 were examined by immunofluorescence and confocal laser scanning microscopy. Reactive oxygen species (ROS) production was quantified by the dichlorofluorescin-diacetate assay. LPS (100 μg/ml) induced DNA damage and suppressed cellular activity (P < 0.05). LPS (40 μg/ml) did not exhibit cellular activity changes or DNA damage (P > 0.05); therefore, 40 μg/ml was used to pretreat the concentration before exposure to RF-EMR. RF-EMR could not directly induce DNA damage. However, the 4 W/kg combined with LPS (40 μg/ml) group showed mitochondria vacuoles, karyopyknosis, presence of lysosomes and autophagosome, and increasing expression of LC3-II and Beclin1. The ROS values significantly increased in the 4 W/kg exposure, 4 W/kg combined with LPS (40 μg/ml) exposure, and H2O2 groups (P < 0.05, 0

The Pic du Midi solar survey

NASA Astrophysics Data System (ADS)

Koechlin, L.

2015-12-01

We carry a long term survey of the solar activity with our coronagraphic system at Pic du Midi de Bigorre in the French Pyrenees (CLIMSO). It is a set of two solar telescopes and two coronagraphs, taking one frame per minute for each of the four channels : Solar disk in H-α (656.28 nm), prominences in H-α, disk in Ca II (393.3 nm), prominences in He I (1083 nm), all year long, weather permitting. Since 2015 we also take images of the FeXIII corona (1074.7 nm) at the rate of one every 10 minutes. These images cover a large field: 1.25 solar diameter, 2k*2K pixels, and are freely downloadable form a database. The improvements made since 2015 concern an autoguiding system for better centering of the solar disk behind the coronagraphic masks, and a new Fe XIII channel at λ=1074.7 nm. In the near future we plan to provide radial velocity maps of the disc and polarimetry maps of the disk and corona. This survey took its present form in 2007 and we plan to maintain image acquisition in the same or better experimental conditions for a long period: one or several solar cycles if possible. During the partial solar eclipse of March 20, 2015, the CLIMSO instruments and the staff at Pic du Midi operating it have provided several millions internet users with real time images of the Sun and Moon during all the phenomenon.

Activity of Palythoa caribaeorum Venom on Voltage-Gated Ion Channels in Mammalian Superior Cervical Ganglion Neurons.

PubMed

Lazcano-Pérez, Fernando; Castro, Héctor; Arenas, Isabel; García, David E; González-Muñoz, Ricardo; Arreguín-Espinosa, Roberto

2016-05-05

The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV1.7), voltage-gated calcium channel (CaV2.2), the A-type transient outward (IA) and delayed rectifier (IDR) currents of KV channels of the superior cervical ganglion (SCG) neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels.

Modulating nitric oxide levels in dorsal root ganglion neurons of rat with low-level laser therapy

NASA Astrophysics Data System (ADS)

Zheng, Li-qin; Wang, Yu-hua; He, Yi-peng; Zhou, Jie; Yang, Hong-qin; Zhang, Yan-ding; Xie, Shu-sen

2015-05-01

Nitric oxide (NO) and nitric oxide synthase (NOS) have an important role in pain signaling transmission in animal models. Low-level laser therapy (LLLT) is known to have an analgesic effect, but the mechanism is unclear. The aim of the study is to investigate the influence of LLLT on NO release and NOS synthesis in dorsal root ganglion (DRG) neurons, in order to find whether LLLI can ameliorate pain through modulating NO production at the cellular level. The results show that in stress conditions, the laser irradiation at 658 nm can modulate NO production in DRG neurons with soma diameter of about 20 μm in a short time after illumination, and affect NOS synthesis in a dose-dependent manner. It is demonstrated that LLLT might treat pain by altering NO release directly and indirectly in DRG neurons.

Thermoplastic composite parts manufacture at Du Pont

NASA Astrophysics Data System (ADS)

Medwin, Steven J.; Coyle, Edward J.

1993-01-01

Low-cost routes to the manufacture of complex shaped composite parts have been defined using metal forming techniques and Du Pont's long discontinuous fiber (LDF) Technology. These manufacturing techniques include roll forming, stretch forming, and press forming. Near equivalence between the static, dynamic, and damage tolerance properties of LDF and continuous fiber composites have been demonstrated. Several examples are cited which demonstrate the potential for this technology to significantly reduce the cost of aerospace components.

L'effet des deformations plastiques severes sur les proprietes d'hydruration du magnesium

NASA Astrophysics Data System (ADS)

Lang, Julien

Le travail de recherche effectue durant mon projet de maitrise en physique a l'Universite du Quebec a Trois-Rivieres dans les laboratoires de l'Institut de Recherche sur l'Hydrogene etait de comparer l'effet du laminage a froid de la poudre de MgH2 avec celui du broyage mecanique. Nous avons etudie cette nouvelle technique en utilisant un laminoir vertical concu specialement pour laminer de la poudre. Nous avons lamine la poudre de MgH2 5, 25, 50 et 100 fois. La comparaison de la morphologie de la poudre de MgH 2 telle que recu du manufacturier et broye mecaniquement pendant 30 minutes avec celle de la poudre laminee ete faite a l'aide d'un microscope electronique a balayage. Nous avons par la suite mesure les proprietes de sorption d'hydrogene grace un appareil PCT de type Sievert. Nous avons aussi determine la structure cristalline par diffraction de rayons X. A partir de ces resultats, nous avons constate que le nombre optimal de laminages est de cinq et a les caracteristiques d'absorption/desorption d'hydrogene similaires a un broyage mecanique de 30 minutes. Nous avons aussi utilise les courbes de cinetiques d'absorption et de desorption d'hydrogene pour calculer l'etape limitative dans les reactions de sorption des echantillons lamines. Comme cinq laminages se font en environ 10 secondes, on voit que le laminage a froid est une technique plus interessante industriellement que le broyage mecanique a cause de l'important gain en temps et en energie.

W.E.B. DuBois's Challenge to Scientific Racism.

ERIC Educational Resources Information Center

Taylor, Carol M.

1981-01-01

Proposes that a direct and authoritative challenge to the scientific racism of the late eighteenth and early twentieth centuries was urgently needed, and was one of the leading rhetorical contributions of W.E.B. DuBois. Specifically examines three issues: social Darwinism, the eugenics movement, and psychologists' measurement of intelligence.…

L’effet du yoga chez les patients atteints de cancer

PubMed Central

Côté, Andréanne; Daneault, Serge

2012-01-01

Résumé Objectif Déterminer si le yoga thérapeutique améliore la qualité de vie de patients atteints de cancer. Sources des données Recherche effectuée avec la base de données MEDLINE (1950–2010) en utilisant les mots-clés yoga, cancer et quality of life. Sélection des études Priorité accordée aux études cliniques randomisées contrôlées évaluant l’effet du yoga sur différents symptômes susceptibles de se présenter chez des patients atteints de cancer en Amérique du Nord. Synthèse Quatre études cliniques randomisées contrôlées ont d’abord été analysées, puis 2 études sans groupe-contrôle. Trois études réalisées en Inde et au Proche-Orient ont également apporté des éléments intéressants au plan méthodologique. Les interventions proposées comprenaient des séances de yoga d’une durée et d’une fréquence variables. Les paramètres mesurés variaient également d’une étude à l’autre. Plusieurs symptômes ont connu des améliorations significatives avec le yoga (meilleure qualité du sommeil, diminution des symptômes anxieux ou dépressifs, amélioration du bien-être spirituel, etc.). Il a aussi semblé que la qualité de vie, dans sa globalité ou dans certaines de ses composantes spécifiques, s’améliorait. Conclusion La variété des effets bénéfiques produits, l’absence d’effet secondaire et le rapport coût-bénéfice avantageux du yoga thérapeutique en fait une intervention intéressante à suggérer par les médecins de famille aux patients atteints de cancer. Certaines lacunes méthodologiques ont pu diminuer la puissance statistique des études présentées, à commencer par la taille restreinte des échantillons et par l’assiduité variable des patients soumis à l’intervention. Il est également possible que les échelles de mesure utilisées ne convenaient pas à ce type de situation et de clientèle pour qu’en soit dégagé un effet significatif. Toutefois, les commentaires

RNA interference-based functional knockdown of the voltage-gated potassium channel Kv7.2 in dorsal root ganglion neurons after in vitro and in vivo gene transfer by adeno-associated virus vectors.

PubMed

Valdor, Markus; Wagner, Anke; Röhrs, Viola; Berg, Johanna; Fechner, Henry; Schröder, Wolfgang; Tzschentke, Thomas M; Bahrenberg, Gregor; Christoph, Thomas; Kurreck, Jens

2018-01-01

Activation of the neuronal potassium channel Kv7.2 encoded by the KCNQ2 gene has recently been shown to be an attractive mechanism to inhibit nociceptive transmission. However, potent, selective, and clinically proven activators of Kv7.2/Kv7.3 currents with analgesic properties are still lacking. An important prerequisite for the development of new drugs is a model to test the selectivity of novel agonists by abrogating Kv7.2/Kv7.3 function. Since constitutive knockout mice are not viable, we developed a model based on RNA interference-mediated silencing of KCNQ2. By delivery of a KCNQ2-specific short hairpin RNA with adeno-associated virus vectors, we completely abolished the activity of the specific Kv7.2/Kv7.3-opener ICA-27243 in rat sensory neurons. Results obtained in the silencing experiments were consistent between freshly prepared and cryopreserved dorsal root ganglion neurons, as well as in dorsal root ganglion neurons dissociated and cultured after in vivo administration of the silencing vector by intrathecal injections into rats. Interestingly, the tested associated virus serotypes substantially differed with respect to their transduction capability in cultured neuronal cell lines and primary dorsal root ganglion neurons and the in vivo transfer of transgenes by intrathecal injection of associated virus vectors. However, our study provides the proof-of-concept that RNA interference-mediated silencing of KCNQ2 is a suitable approach to create an ex vivo model for testing the specificity of novel Kv7.2/Kv7.3 agonists.

Efavirenz DuPont Pharmaceuticals Co.

PubMed

Dong, B J

1998-10-01

Efavirenz is the lead compound of a series of benzoxazinones originally developed by DuPont Merck. It is a non-nucleoside reverse transcriptase inhibitor (NNRTI) under development for the potential treatment of viral infections, including HIV. In June 1998, the company submitted an NDA to the US FDA for the use of efavirenz (as Sustiva) for the treatment of HIV infection [289361]. In July 1998, DuPont purchased Merck's interest in DuPont Merck and the company's name changed to DuPont Pharmaceuticals. The two companies decided to continue to share marketing rights to Sustiva (to be marketed by Merck as Stocrin outside the US, Canada, and certain European countries) [291738]. As of October 1997, triple combination studies of efavirenz were ongoing, or planned, with nelfinavir, indinavir or ritonavir, or other retroviral inhibitors, for the treatment of opportunistic and pediatric viral infections [265945]. Efavirenz is also being evaluated as monotherapy and in combination with zidovudine (Retrovir, AZT) and lamivudine (Epivir, 3TC) (qv). Results of a study in eight HIV-infected patients, reported at the 12th World AIDS Conference in July 1998, showed that efavirenz administration, in dual and triple combinations, achieved HIV-RNA levels in plasma and cerebrospinal fluid (CSF) below the level of detection (fewer than 400 copies/ml) [290881,293994]. In March 1998, Merck signed a letter of intent with Trimeris to conduct a trial of efavirenz in combination with Trimeris's HIV fusion inhibitor, T-20, (qv). The trial will enroll up to 48 HIV-infected individuals at three sites in the US. All enrolled patients will be those who have begun to fail their existing triple combination therapy. Prior exposure to NNRTIs and protease inhibitors, other than indinavir, will be among the exclusion criteria for the study. The first 10 days of the study were planned as a dose-optimization period to assess the safety, pharmacokinetics and antiviral activity of multiple ascending doses

Up-regulating of RASD1 and apoptosis of DU-145 human prostate cancer cells induced by formononetin in vitro.

PubMed

Liu, Xiao-Jia; Li, Yun-Qian; Chen, Qiu-Yue; Xiao, Sheng-Jun; Zeng, Si-En

2014-01-01

Prostate cancer is one of the most prevalent malignant cancers in men. The isoflavone formononetin is a main active component of red clover plants. In the present study, we assessed the effect of formononetin on human prostate cancer DU-145 cells in vitro, and elucidated possible mechanisms. DU-145 cells were treated with different concentrations of formononetin and cell proliferation was assessed by MTT assay, cell apoptosis by Hoechst 33258 and flow cytometry, and protein levels of RASD1, Bcl-2 and Bax by Western blotting. The results showed that formononetin inhibited the proliferation of DU-145 cells in a dose-dependent manner. DU-145 cells treated with different concentrations of formononetin displayed obvious morphological changes of apoptosis under fluorescence microscopy. In addition, formononetin increased the proportion of early apoptotic DU-145 cells, down-regulated the protein levels of Bcl-2 and up-regulated those of RASD1 and Bax. The level of RASD1 reached its maximum at 48 h post-treatment, and rapidly decreased thereafter. Together, we present evidence that formononetin triggered cell apoptosis through the mitochondrial apoptotic pathway by up-regulating RASD1.

Canagliflozin, a sodium glucose cotransporter 2 inhibitor, attenuates obesity-induced inflammation in the nodose ganglion, hypothalamus, and skeletal muscle of mice.

PubMed

Naznin, Farhana; Sakoda, Hideyuki; Okada, Tadashi; Tsubouchi, Hironobu; Waise, T M Zaved; Arakawa, Kenji; Nakazato, Masamitsu

2017-01-05

Chronic inflammation in systemic organs, such as adipose tissue, nodose ganglion, hypothalamus, and skeletal muscles, is closely associated with obesity and diabetes mellitus. Because sodium glucose cotransporter 2 (SGLT2) inhibitors exert both anti-diabetic and anti-obesity effects by promoting urinary excretion of glucose and subsequent caloric loss, we investigated the effect of canagliflozin, an SGLT2 inhibitor, on obesity-induced inflammation in neural tissues and skeletal muscles of mice. High-fat diet (HFD)-fed male C57BL/6J mice were treated with canagliflozin for 8 weeks. Canagliflozin attenuated the HFD-mediated increases in body weight, liver weight, and visceral and subcutaneous fat weight. Additionally, canagliflozin decreased blood glucose as well as the fat, triglyceride, and glycogen contents of the liver. Along with these metabolic corrections, canagliflozin attenuated the increases in the mRNA levels of the proinflammatory biomarkers Iba1 and Il6 and the number of macrophages/microglia in the nodose ganglion and hypothalamus. In the skeletal muscle of HFD-fed obese mice, canagliflozin decreased inflammatory cytokine levels, macrophage accumulation, and the mRNA level of the specific atrophic factor atrogin-1. Canagliflozin also increased the mRNA level of insulin-like growth factor 1, protected against muscle mass loss, and restored the contractile force of muscle. These findings suggested that SGLT2 inhibition disrupts the vicious cycle of obesity and inflammation, not only by promoting caloric loss, but also by suppression of obesity-related inflammation in both the nervous system and skeletal muscle. Copyright © 2016 Elsevier B.V. All rights reserved.

Nitric oxide (NO.) stabilizes whereas nitrosonium (NO+) enhances filopodial outgrowth by rat retinal ganglion cells in vitro.

PubMed

Cheung, W S; Bhan, I; Lipton, S A

2000-06-16

Recent observations suggest that nitric oxide (NO(.)) can increase or decrease growth cone motility. Here, these apparently paradoxical results are explained by distinct actions of different NO-related species. Filopodial morphology of 223 rat retinal ganglion cells was monitored under computer-enhanced video microscopy in the presence of NO synthase (NOS) substrates or inhibitors, donors of specific NO-related species, and membrane-permeant cyclic nucleotide analogs. Physiological NOS activity induced filopodial outgrowth, whereas inhibition of NOS stabilized filopodia. Similar to NOS, nitrosonium (NO(+) transfer) and peroxynitrite (ONOO(-)), which can regulate the activity of growth-associated proteins by S-nitrosylation and oxidation, respectively, induced filopodial outgrowth. In contrast, NO(.), which stimulates guanylate cyclase to increase cGMP, stabilized filopodial activity. Thus disparate NO-related species may offer a dynamic process of filopodial growth regulation.

Segmented inner plexiform layer thickness as a potential biomarker to evaluate open-angle glaucoma: Dendritic degeneration of retinal ganglion cell.

PubMed

Kim, Eun Kyoung; Park, Hae-Young Lopilly; Park, Chan Kee

2017-01-01

To evaluate the changes of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and ganglion cell-inner plexiform layer (GCIPL) thicknesses and compare structure-function relationships of 4 retinal layers using spectral-domain optical coherence tomography (SD-OCT) in macular region of glaucoma patients. In cross-sectional study, a total of 85 eyes with pre-perimetric to advanced glaucoma and 26 normal controls were enrolled. The glaucomatous eyes were subdivided into three groups according to the severity of visual field defect: a preperimetric glaucoma group, an early glaucoma group, and a moderate to advanced glaucoma group. RNFL, GCL, IPL, and GCIPL thicknesses were measured at the level of the macula by the Spectralis (Heidelberg Engineering, Heidelberg, Germany) SD-OCT with automated segmentation software. For functional evaluation, corresponding mean sensitivity (MS) values were measured using 24-2 standard automated perimetry (SAP). RNFL, GCL, IPL, and GCIPL thicknesses were significantly different among 4 groups (P < .001). Macular structure losses were positively correlated with the MS values of the 24-2 SAP for RNFL, GCL, IPL, and GCIPL (R = 0.553, 0.636, 0.648 and 0.646, respectively, P < .001). In regression analysis, IPL and GCIPL thicknesses showed stronger association with the corresponding MS values of 24-2 SAP compared with RNFL and GCL thicknesses (R2 = 0.420, P < .001 for IPL; R2 = 0.417, P< .001 for GCIPL thickness). Segmented IPL thickness was significantly associated with the degree of glaucoma. Segmental analysis of the inner retinal layer including the IPL in macular region may provide valuable information for evaluating glaucoma.

Postconditioning with inhaled hydrogen promotes survival of retinal ganglion cells in a rat model of retinal ischemia/reperfusion injury.

PubMed

Wang, Ruobing; Wu, Jiangchun; Chen, Zeli; Xia, Fangzhou; Sun, Qinglei; Liu, Lin

2016-02-01

Retinal ischemia/reperfusion (I/R) injury plays a crucial role in the pathophysiology of various ocular diseases. Intraperitoneal injection or ocular instillation with hydrogen (H2)-rich saline was recently shown to be neuroprotective in the retina due to its anti-oxidative and anti-inflammatory effects. Our study aims to explore whether postconditioning with inhaled H2 can protect retinal ganglion cells (RGCs) in a rat model of retinal I/R injury. Retinal I/R injury was performed on the right eyes of rats and was followed by inhalation of 67% H2 mixed with 33% oxygen immediately after ischemia for 1h daily for one week. RGC density was counted using haematoxylin and eosin (HE) staining and retrograde labeling with cholera toxin beta (CTB). Visual function was assessed using flash visual evoked potentials (FVEP) and pupillary light reflex (PLR). Potential biomarkers of retinal oxidative stress and inflammatory responses were measured, including the expression of 4-Hydroxynonenalv (4-HNE), interleukin-1 beta (IL1-β) and tumor necrosis factor alpha (TNF-α). HE and CTB tracing showed that the survival rate of RGCs in the H2-treated group was significantly higher than the rate in the I/R group. Rats with H2 inhalation showed better visual function in assessments of FVEP and PLR. Moreover, H2 treatment significantly decreased the number of 4-HNE-stained cells in the ganglion cell layer and inhibited the retinal overexpression of IL1-β and TNF-α that was induced by retinal I/R injury. Our results demonstrate that postconditioning with inhaled high-dose H2 appears to confer neuroprotection against retinal I/R injury via anti-oxidative, anti-inflammatory and anti-apoptosis pathways. Copyright © 2015 Elsevier B.V. All rights reserved.

L’identification et traitement du trouble panique avec ou sans agoraphobie

PubMed Central

Foldes-Busque, Guillaume; Marchand, André; Landry, Pierre

2007-01-01

RÉSUMÉ OBJECTIF Renseigner les médecins de première ligne au sujet de l’identification précoce, du diagnostic et du traitement du trouble panique avec ou sans agoraphobie (TP/A). QUALITÉ DES DONNÉES Les données et recommandations présentées proviennent d’une recension des écrits scientifiques réalisée via les banques de données PsycLIT, PsyINFO et MEDLINE (1985 à 2006) en utilisant les descripteurs panic disorder, psychotherapy, psychosocial treatment, treatment et pharmacotherapy. Les recommandations formulées par les auteurs s’appuient sur des données probantes provenant d’études d’excellente qualité. Les informations concernant le diagnostic et l’évaluation du TP/A proviennent d’études épidémiologiques récentes, de consensus et d’opinions d’experts. PRINCIPAL MESSAGE Le TP/A est un trouble psychiatrique souvent rencontré en médecine de première ligne, mais il est fréquemment sous-diagnostiqué et sous-traité. L’identification précoce de ce trouble demande une attention particulière aux symptômes médicalement inexpliqués et, le cas échéant, le médecin doit utiliser des questions spécifiques permettant d’identifier d’éventuelles attaques de panique et de cerner leur signification pour le patient. Le traitement de premier choix pour ce trouble est une psychothérapie d’orientation cognitivo-comportementale administrée par un psychologue ou un psychiatre spécialisé. Si de telles ressources ne sont pas disponibles, le médecin peut opter pour un traitement psychopharmacologique. CONCLUSION Les médecins de famille peuvent jouer un rôle central dans l’identification et le traitement des patients souffrant d’un TP/A. PMID:17934032

Rapid and coordinated processing of global motion images by local clusters of retinal ganglion cells.

PubMed

Matsumoto, Akihiro; Tachibana, Masao

2017-01-01

Even when the body is stationary, the whole retinal image is always in motion by fixational eye movements and saccades that move the eye between fixation points. Accumulating evidence indicates that the brain is equipped with specific mechanisms for compensating for the global motion induced by these eye movements. However, it is not yet fully understood how the retina processes global motion images during eye movements. Here we show that global motion images evoke novel coordinated firing in retinal ganglion cells (GCs). We simultaneously recorded the firing of GCs in the goldfish isolated retina using a multi-electrode array, and classified each GC based on the temporal profile of its receptive field (RF). A moving target that accompanied the global motion (simulating a saccade following a period of fixational eye movements) modulated the RF properties and evoked synchronized and correlated firing among local clusters of the specific GCs. Our findings provide a novel concept for retinal information processing during eye movements.

Impacts de l`élévation du niveau de la mer sur l'évolution future d'une côte basse à lagune de la péninsule du Cap Bon (Nord-Est de la Tunisie): approche cartographique

NASA Astrophysics Data System (ADS)

Brahmi, Noura; Dhieb, Mohsen; Chedly Rabia, Mohamed

2018-05-01

La submersion marine est l'une des principales menaces qui pèsent sur les zones humides littorales de la péninsule du Cap Bon. Or, cette menace est amenée à se renforcer en raison du réchauffement climatique qui entraînera une élévation du niveau marin et vraisemblablement un renforcement de l'intensité des tempêtes et des cyclones tropicaux d'ici à l'horizon 2100. L'objectif a donc été d'évaluer la vulnérabilité de la lagune face à la submersion. Dans cette optique, après avoir identifié les enjeux liés à l'élévation du niveau de la mer pour la lagune, nous avons dressé une cartographie prévisionnelle des risques de submersion par l'intermédiaire d'une application cartographique basée sur une modélisation numérique de terrain et analysé les impacts potentiels de ce phénomène. La cartographie est donc amenée à devenir centrale pour l'étude de l'impact du risque de la submersion marine sur les lagunes côtières et la gestion de ces espaces dans les décennies à venir. La cartographie de l'aléa submersion marine a montré que l'ouverture épisodique de brèches lors des tempêtes pourrait entraîner la submersion de l'ensemble du domaine lagunaire et aurait un impact morphogénique essentiel. En effet, le phénomène d'une accélération de l'élévation du niveau marin et d'un renforcement des tempêtes génère le morcellement du cordon littoral qui sépare la lagune de la mer. Par ailleurs, les pertes de matériel sédimentaire pour la plage augmenteront, dans la mesure où, lors d'une tempête, une grande partie des matériaux déplacés par les vagues dans les étangs par submersion ou par ouverture d'une brèche, ne peut être récupérée par la suite. Tout ceci constitue un facteur d'accélération du recul ou de disparition de la plage déjà très érodée. Les impacts de cette submersion pourraient être importants en absence de mesures préventives. Elle aurait ainsi des répercussions profondes sur les syst

Place du traitement chirurgical sous circulation extracorporelle à cœur battant dans les cancers du rein avec envahissement cave supra-diaphragmatique: à propos de sept cas

PubMed Central

Lahyani, Mounir; Karmouni, Tarik; Elkhader, Khalid; Koutani, Abdellatif; Andaloussi, Ahmed Ibn Attya

2014-01-01

Ce travail vise à analyser les résultats de la néphrectomie avec thrombectomie atrio-cave sous circulation extracorporelle (CEC) chez sept patients ayant un cancer du rein avec envahissement cave supra-diaphragmatique et de discuter les indications opératoires. Sept patients, six hommes et une femme dont l’âge varie entre 46ans et 65ans, ont été opérés d'un cancer du rein avec extension atrio-cave. L’écho-doppler a toujours permis la mise en évidence de l'extension veineuse mais la limite supérieure du thrombus était formellement identifiée par l'examen tomodensitométrique quatre fois, et par la résonance magnétique nucléaire dans tous les cas. Tous les patients ont été opérés sous CEC à cœur battant en normothermie. Un seul décès postopératoire est survenu. La durée du séjour en réanimation a été de 4,5 jours. Cinq patients ont eu à distance une dissémination métastatique. Cinq malades ont eu une médiane de survie de 11,5 mois (de 7 à16). Un malade a subi une métastasectomie pulmonaire 6 mois après la néphrectomie. L'exérèse des thrombi atrio-caves a été facilitée par la CEC avec une mortalité et une morbidité postopératoires acceptables mais les résultats à distance ont été décevants. Cette intervention ne peut être proposée qu'aux patients n'ayant aucune extension locorégionale et générale décelable, ce qui souligne l'importance des examens morphologiques préopératoires. PMID:25995777

Approches pour la reduction de l'impact de defaut dans le transport d'energie du parc eolien offshore via VSC-HVDC =

NASA Astrophysics Data System (ADS)

Benadja, Mounir

Dans ce travail est presente un systeme de generation d'energie d'un parc eolien offshore et un systeme de transport utilisant les stations VSC-HVDC connectees au reseau principal AC onshore. Trois configurations ont ete etudiees, modelisees et validees par simulation. Dans chacune des configurations, des contributions ameliorant les cotes techniques et economiques sont decrites ci-dessous : La premiere contribution concerne un nouvel algorithme MPPT (Maximum Power Point Tracking) utilise pour l'extraction de la puissance maximale disponible dans les eoliennes des parcs offshores. Cette technique d'extraction du MPPT ameliore le rendement energetique de la chaine de conversion des energies renouvelables notamment l'energie eolienne a petite et a grande echelles (parc eolien offshore) qui constitue un probleme pour les constructeurs qui se trouvent confrontes a developper des dispositifs MPPT simples, moins couteux, robustes, fiables et capable d'obtenir un rendement energetique maximal. La deuxieme contribution concerne la reduction de la taille, du cout et de l'impact des defauts electriques (AC et DC) dans le systeme construit pour transporter l'energie d'un parc eolien offshore (OWF) vers le reseau principal AC onshore via deux stations 3L-NPC VSCHVDC. La solution developpee utilise des observateurs non-lineaires bases sur le filtre de Kalman etendu (EKF). Ce filtre permet d'estimer la vitesse de rotation et la position du rotor de chacune des generatrices du parc eolien offshore et de la tension du bus DC de l'onduleur DC-AC offshore et des deux stations 3L-NPC-VSC-HVDC (offshore et onshore). De plus, ce developpement du filtre de Kalman etendu a permis de reduire l'impact des defauts AC et DC. Deux commandes ont ete utilisees, l'une (commande indirect dans le plan abc) avec EKF integre destinee pour controler le convertisseur DC-AC offshore et l'autre (commande d-q) avec EKF integre pour controler les convertisseurs des deux stations AC-DC et DC-AC tout en

Edaravone suppresses retinal ganglion cell death in a mouse model of normal tension glaucoma

PubMed Central

Akaiwa, Kei; Namekata, Kazuhiko; Azuchi, Yuriko; Guo, Xiaoli; Kimura, Atsuko; Harada, Chikako; Mitamura, Yoshinori; Harada, Takayuki

2017-01-01

Glaucoma, one of the leading causes of irreversible blindness, is characterized by progressive degeneration of optic nerves and retinal ganglion cells (RGCs). In the mammalian retina, excitatory amino-acid carrier 1 (EAAC1) is expressed in neural cells, including RGCs. Loss of EAAC1 leads to RGC degeneration without elevated intraocular pressure (IOP) and exhibits glaucomatous pathology including glutamate neurotoxicity and oxidative stress. In the present study, we found that edaravone, a free radical scavenger that is used for treatment of acute brain infarction and amyotrophic lateral sclerosis (ALS), reduces oxidative stress and prevents RGC death and thinning of the inner retinal layer in EAAC1-deficient (KO) mice. In addition, in vivo electrophysiological analyses demonstrated that visual impairment in EAAC1 KO mice was ameliorated with edaravone treatment, clearly establishing that edaravone beneficially affects both histological and functional aspects of the glaucomatous retina. Our findings raise intriguing possibilities for the management of glaucoma by utilizing a widely prescribed drug for the treatment of acute brain infarction and ALS, edaravone, in combination with conventional treatments to lower IOP. PMID:28703795

Pan-retinal characterisation of Light Responses from Ganglion Cells in the Developing Mouse Retina.

PubMed

Hilgen, Gerrit; Pirmoradian, Sahar; Pamplona, Daniela; Kornprobst, Pierre; Cessac, Bruno; Hennig, Matthias H; Sernagor, Evelyne

2017-02-10

We have investigated the ontogeny of light-driven responses in mouse retinal ganglion cells (RGCs). Using a large-scale, high-density multielectrode array, we recorded from hundreds to thousands of RGCs simultaneously at pan-retinal level, including dorsal and ventral locations. Responses to different contrasts not only revealed a complex developmental profile for ON, OFF and ON-OFF responses, but also unveiled differences between dorsal and ventral RGC responses. At eye-opening, dorsal RGCs of all types were more responsive to light, perhaps indicating an environmental priority to nest viewing for pre-weaning pups. The developmental profile of ON and OFF responses exhibited antagonistic behaviour, with the strongest ON responses shortly after eye-opening, followed by an increase in the strength of OFF responses later on. Further, we found that with maturation receptive field (RF) center sizes decrease, spike-triggered averaged responses to white noise become stronger, and centers become more circular while maintaining differences between RGC types. We conclude that the maturation of retinal functionality is not spatially homogeneous, likely reflecting ecological requirements that favour earlier maturation of the dorsal retina.

Sox11 Expression Promotes Regeneration of Some Retinal Ganglion Cell Types but Kills Others.

PubMed

Norsworthy, Michael W; Bei, Fengfeng; Kawaguchi, Riki; Wang, Qing; Tran, Nicholas M; Li, Yi; Brommer, Benedikt; Zhang, Yiming; Wang, Chen; Sanes, Joshua R; Coppola, Giovanni; He, Zhigang

2017-06-21

At least 30 types of retinal ganglion cells (RGCs) send distinct messages through the optic nerve to the brain. Available strategies of promoting axon regeneration act on only some of these types. Here we tested the hypothesis that overexpressing developmentally important transcription factors in adult RGCs could reprogram them to a "youthful" growth-competent state and promote regeneration of other types. From a screen of transcription factors, we identified Sox11 as one that could induce substantial axon regeneration. Transcriptome profiling indicated that Sox11 activates genes involved in cytoskeletal remodeling and axon growth. Remarkably, α-RGCs, which preferentially regenerate following treatments such as Pten deletion, were killed by Sox11 overexpression. Thus, Sox11 promotes regeneration of non-α-RGCs, which are refractory to Pten deletion-induced regeneration. We conclude that Sox11 can reprogram adult RGCs to a growth-competent state, suggesting that different growth-promoting interventions promote regeneration in distinct neuronal types. Copyright © 2017 Elsevier Inc. All rights reserved.

The protective effect of olfactory ensheathing cells on post-injury spiral ganglion cells.

PubMed

Dai, Qi; Zhang, Zhicun; Liu, Quan; Yu, Hongmeng

2016-11-01

Transplantation of OECs into the cochlea may protect and increase the survival of SGCs. To investigate the protective effect of the transplantation of olfactory ensheathing cells (OECs) on injured spiral ganglion cells (SGCs) in rats. OECs were transplanted into the cochlea in rats with SGCs that were injured by kanamycin sulfate (KM). An equal volume of D-Hanks was injected into the cochlea of control rats. Auditory brainstem responses (ABRs) were recorded from the rats in both groups to monitor changes in hearing thresholds. Immunofluorescence was employed to examine the density and morphology of SGCs to assess the ototoxic condition of the cochlea. There was no significant difference in the ABR threshold at each frequency between the control and experimental groups. Notably, in the experimental group, a number of Hoechst 3334-labeled nuclei were detected from the apex to the basal turn of the cochlea, demonstrating that the OECs were successfully transplanted and survived in the cochlea. In the experimental group, most of the SGCs were tightly arranged, and the nuclear membrane, chromatin, and nucleolus were all clear. The SGCs in the control group were loosely arranged, and only a few normal SGCs were observed in this group.