Browsing by Subject "Spatial distribution"
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- PublicationRestrictedAxotomy-induced retinal ganglion cell death in adult mice: quantitative and topographic time course analyses(Elsevier, 2011-02-24) Galindo Romero, Caridad; Avilés Trigueros, Marcelino; Jiménez López, Manuel; Valiente Soriano, Francisco Javier; Salinas Navarro, Manuel Ángel; Nadal-Nicolás, Francisco Manuel; Villegas Pérez, Maria Paz; Vidal Sanz, Manuel; Agudo Barriuso, Marta; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Anatomía Humana y Psicobiología; Facultades de la UMU::Facultad de MedicinaThe fate of retinal ganglion cells after optic nerve injury has been thoroughly described in rat, but not in mice, despite the fact that this species is amply used as a model to study different experimental paradigms that affect retinal ganglion cell population. Here we have analyzed, quantitatively and topographically, the course of mice retinal ganglion cells loss induced by intraorbital nerve transection. To do this, we have doubly identified retinal ganglion cells in all retinas by tracing them from their main retinorecipient area, the superior colliculi, and by their expression of BRN3A (product of Pou4f1 gene). In rat, this transcription factor is expressed by a majority of retinal ganglion cells; however in mice it is not known how many out of the whole population of these neurons express it. Thus, in this work we have assessed, as well, the total population of BRN3A positive retinal ganglion cells. These were automatically quantified in all whole-mounted retinas using a newly developed routine. In control retinas, tracedretinal ganglion cells were automatically quantified, using the previously reported method (SalinasNavarro et al., 2009b). After optic nerve injury, though, traced-retinal ganglion cells had to be manually quantified by retinal sampling and their total population was afterwards inferred. In naïve whole-mounts, the mean ( standard deviation) total number of traced-retinal ganglion cells was 40,437 ( 3196) andofBRN3Apositive ones was 34,697( 1821). Retinal ganglion cell loss was first significant for both markers 5 days post-axotomy and by day 21, the last time point analyzed, only 15% or 12% of traced or BRN3A positive retinal ganglion cells respectively, survived. Isodensity maps showed that, in control retinas, BRN3A and traced-retinal ganglion cells were distributed similarly, being densest in the dorsal retina along the naso-temporal axis. After axotomy the progressive loss of BRN3A positive retinal ganglion cells was diffuse and affected the entire retina. In conclusion, this is the first study assessing the values, in terms of total number and density, of the retinal ganglion cells surviving axotomy from 2 till 21 days post-lesion. Besides, we have demonstrated that BRN3A is expressed by 85.6% of the total retinal ganglion cell population, and because BRN3A positive retinal ganglion cells show the same spatial distribution and temporal course of degeneration than traced ones, BRN3A is a reliable marker to identify, quantify and assess, ex-vivo, retinal ganglion cell loss in this species.
- PublicationOpen AccessBDNF Rescues RGCs But Not Intrinsically Photosensitive RGCs in Ocular Hypertensive Albino Rat Retinas(Association for Research in Vision and Ophthalmology., 2015-02-26) Valiente Soriano, Francisco Javier; Nadal-Nicolás, Francisco Manuel; Salinas Navarro, Manuel Ángel; Jiménez López, Manuel; Bernal Garro, José M.; Villegas Pérez, Maria Paz; Agudo Barriuso, Marta; Vidal Sanz, Manuel; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Facultades de la UMU::Facultad de MedicinaPurpose: To study the responses of the general population of retinal ganglion cells (Brn3a(+)RGCs) versus the intrinsically photosensitive RGCs (melanopsin-expressing RGCs [m(+)RGCs]) to ocular hypertension (OHT), the effects of brain-derived neurotrophic factor (BDNF) on the survival of axonally intact and axonally nonintact RGCs, and the correlation of vascular integrity with sectorial RGC loss. Methods: In Sprague-Dawley rats, 5 μg BDNF or vehicle was intravitreally injected into the left eye followed by laser photocoagulation of the limbal tissues. To identify RGCs with an active retrograde axonal transport, Fluorogold was applied to both superior colliculi 1 week before euthanasia (FG(+)RGCs). Retinas were dissected 12 or 15 days after lasering and immunoreacted against Brn3a (to identify all RGCs except m(+)RGCs), melanopsin, or RECA1 (inner retinal vasculature). Results: Ocular hypertension resulted at 12 to 15 days in sectorial loss of FG(+)RGCs (78%-84%, respectively) while Brn3a(+)RGCs were significantly greater, indicating that a substantial proportion (approximately 21%-26%) of RGCs with their retrograde axonal transport impaired survive in the retina. Brain-derived neurotrophic factor increased the survival of Brn3a(+)RGCs to 81% to 67% at 12 to 15 days, respectively. The inner retinal vasculature showed no abnormalities that could account for the sectorial loss of RGCs. At 12 to 15 days, m(+)RGCs decreased to approximately 50% to 51%, but this loss was diffuse across the retina and was not prevented by BDNF. Conclusions: The responses of m(+)RGCs against OHT-induced retinal degeneration and neuroprotection differ from those of Brn3a(+)RGCs; while OHT induces similar loss of Brn3a(+)RGCs and m(+)RGCs, Brn3a(+)RGCs are lost in sectors and can be rescued with BDNF, but m(+)RGCs do not respond to BDNF and their loss is diffuse.
- PublicationRestrictedBrain derived neurotrophic factor maintains Brn3a expression in axotomized rat retinal ganglion cells(Elsevier, 2009-08-16) Sánchez Migallón, María del Cielo; Nadal-Nicolás, Francisco Manuel; Jiménez López, Manuel; Sobrado Calvo, Paloma; Vidal Sanz, Manuel; Agudo Barriuso, Marta; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Facultades de la UMU::Facultad de MedicinaThe transcription factor Brn3a has been reported to be a good marker for adult rat retinal ganglion cells in control and injured retinas. However, it is still unclear if Brn3a expression declines progressively by the injury itself or otherwise its expression is maintained in retinal ganglion cells that, though being injured, are still alive, as might occur when assessing neuroprotective therapies. Therefore, we have automatically quantified the whole population of surviving Brn3a positive retinal ganglion cells in retinas subjected to intraorbital optic nerve transection and treated with either brain derived neurotrophic factor or vehicle. Brain derived neurotrophic factor is known to delay retinal ganglion cell death after axotomy. Thus, comparison of both groups would inform of the suitability of Brn3a as a retinal ganglion cell marker when testing neuroprotective molecules. As internal control, retinal ganglion cells were, as well, identified in all retinas by retrogradely tracing them with fluorogold. Our data show that at all the analyzed times post-lesion, the numbers of Brn3a positive retinal ganglion cells and of fluorogold positive retinal ganglion cells are significantly higher in the brain derived neurotrophic factor-treated retinas compared to the vehicle-treated ones. Moreover, detailed isodensity maps of the surviving Brn3a positive retinal ganglion cells show that a single injection of brain derived neurotrophic factor protects retinal ganglion cells throughout the entire retina. In conclusion, Brn3a is a reliable retinal ganglion cell marker that can be used to accurately measure the potential effect of a given neuroprotective therapy.
- PublicationOpen AccessComparative Analysis of Tyrosine Hydroxylase Amacrine Cells in the Mammalian Retina: Distribution and Quantification in Mouse, Rat, Ground Squirrel and Macaque Retinas(MDPI, 2025-07-20) Kiyoharu J. Miyagishima; Xiaomin Lai; Amurta Nath; William N. Grimes; Xiyuan Ping; Jeffrey S. Diamond; Morven A. Cameron; Wei Li; Francisco M. Nadal-Nicolás; Francisco M. Nadal-Nicolás; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Francisco M. Nadal-Nicolás; Facultades de la UMU::Facultad de MedicinaDopaminergic amacrine cells (DACs) are a subclass of amacrine cells that modulate retinal processing and light adaptation by releasing dopamine. Although the role of dopamine is largely conserved, their retinal distribution across mammals remains incompletely characterized. In mice, rats, thirteen-lined ground squirrels (TLGSs), and macaques, we systematically compared the localization, number, and topography of DACs by their expression of tyrosine hydroxylase (TH), a crucial enzyme in the biosynthesis of dopamine. In all species examined, TH+ cells were primarily located in the inner nuclear layer; however, there was a species-dependent influence on their number and distribution. Mice exhibited the highest density of TH+cells but completely lacked displaced TH+cells (dTH+cells) in the ganglion cell layer. Despite interspecies variation in the total number of TH+cells in the retina, the overall density in rats, TLGSs, and macaques was similar. Most species displayed a higher density of DACs toward central retinal regions. However, rats exhibited a distinctive dorsal concentration, particularly among dTH+cells. Although most species examined exhibited a similar ratio of TH+cells to Brn3a+ retinal ganglion cells, TLGSs showed a marked reduction, indicating a potentially diminished dopaminergic modulatory role. Species-specific DAC topographies aligned with specialized visual regions, such as the visual streak in TLGS and the macula in macaques. These results reveal both conserved and divergent features of retinal dopamine circuitry, reflecting evolutionary adaptations to visual processing demands.
- PublicationRestrictedDensity-driven habitat use differences across fishing zones by predator fishes (Serranidae) in south-western Mediterranean rocky reefs(Springer, 2019-12-05) Werner Hackradt, Carlos; Félix Hackradt, Fabiana Cézar; Treviño Otón, Jorge; Pérez Ruzafa, Ángel; García Charton, José Antonio; Ecología e HidrologíaThe characterization of habitat use by predator species is crucial to understand its effect over fish distribution. We tested the hypothesis that fish density affects habitat use as well as influence on the relationships between top predators (groupers) and meso-predators (combers) by evaluating their distribution in and outside a marine reserve (MR) in SW Mediterranean Sea. All groupers showed significant higher densities inside MR. All species but Epinephelus costae (grouper) displayed a distinct microhabitat use between high- and low-density locations. When density is reduced, groupers occupied previously rejected microhabitats (shallow habitats) at MR, indicating the density-related distribution. Combers were negatively correlated and showed an opposite microhabitat-depth use demonstrating niche segregation. Groupers overlapped their spatial niche and were positively correlated probably due to food partitioning. We suggest the existence of cascading top-down effects on Serranus scriba (comber) population, at MR, reinforcing the importance of the protected areas for the recovery of top-predator populations and their key role on healthy ecosystem.
- PublicationOpen AccessDisplaced retinal ganglion cells in albino and pigmented rats(Frontiers Media , 2014-10-06) Nadal-Nicolás, Francisco Manuel; Salinas Navarro, Manuel Ángel; Jiménez López, Manuel; Sobrado Calvo, Paloma; Villegas Pérez, Maria Paz; Vidal Sanz, Manuel; Agudo Barriuso, Marta; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Facultades de la UMU::Facultad de MedicinaWe have studied in parallel the population of displaced retinal ganglion cells (dRGCs) and normally placed (orthotopic RGCs, oRGCs) in albino and pigmented rats. Using retrograde tracing from the optic nerve, from both superior colliculi (SC) or from the ipsilateral SC in conjunction with Brn3 and melanopsin immunodetection, we report for the first time their total number and topography as well as the number and distribution of those dRGCs and oRGCs that project ipsi- or contralaterally and/or that express any of the three Brn3 isoforms or melanopsin. The total number of RGCs (oRGCs+dRGCs) is 84,706 ± 1249 in albino and 90,440 ± 2236 in pigmented, out of which 2383 and 2428 are melanopsin positive (m-RGCs), respectively. Regarding dRGCs: i/ albino rats have a significantly lower number of dRGCs than pigmented animals (0.5% of the total number of RGCs vs. 2.5%, respectively), ii/ dRGCs project massively to the contralateral SC, iii/ the percentage of ipsilaterality is higher for dRGCs than for oRGCs, iv/ a higher proportion of ipsilateral dRGCs is observed in albino than pigmented animals, v/ dRGC topography is very specific, they predominate in the equatorial temporal retina, being densest where the oRGCs are densest, vi/ Brn3a detects all dRGCs except half of the ipsilateral ones and those that express melanopsin, vii/ the proportion of dRGCs that express Brn3b or Brn3c is slightly lower than in the oRGC population, viii/ a higher percentage of dRGCs (13% albino, 9% pigmented) than oRGCs (2.6%) express melanopsin, ix/ few m-RGCs (displaced and orthotopic) project to the ipsilateral SC, x/ the topography of m-dRGCs does not resemble the general distribution of dRGCs, xi/ The soma size in m-oRGCs ranges from 10 to 21 μm and in m-dRGCs from 8 to 15 μm, xii/ oRGCs and dRGCs have the same susceptibility to axonal injury and ocular hypertension. Although the role of mammalian dRGCs remains to be determined, our data suggest that they are not misplaced by an ontogenic mistake.
- PublicationOpen AccessOtodectes cynotis in urban and peri-urban semi-arid areas: a widespread parasite in the cat population(Springer, 2020-03-27) Fanelli, Angela; Doménech Asensi, Guillermo; Alonso de Vega, Francisco-Domingo; Martínez-Carrasco Pleite, Federico; Tizzani, Paolo; Martínez-Carrasco Pleite, Carlos; Sanidad Animal; Facultad de VeterinariaThe ear mite Otodectes cynotis is a parasite of cats and dogs of considerable veterinary importance, being the most common etiological agent of otitis externa in pets. This study investigates the presence of this parasite in 296 cats from Murcia municipality (SE Spain), and describes possible factors associated with the infestation. Cats were grouped by sex, age, lifestyle, season and provenience. Scraping samples were examined by a microscope to identify the mite. Chi square test was computed and odds ratio was used to measure the association of risk factors with parasite prevalence. Additionally, the spatial distribution of prevalences was investigated and represented through GIS software. Around 30% of the cats (CI95 25–35%) were found positives to O. cynotis. The mite infestation was significantly higher in adult cats, during the winter and in individuals from peri-urban areas. The ectoparasite was found to be widely distributed in the catpopulation of the study area, with an increased risk of infestation in specific peri-urban areas. The results highlight that O. cynotis is a common parasite in areas with Mediterranean semi-arid climate. Given the importance of otodectic mange, and considering that O. cynotis is not a parasite specific to cats, but may also affect dogs and wild carnivores, the information provided by this study is of great value to both pet owners and veterinarian practitioners, and it might help to implement appropriate preventive and control strategies, mainly in free-roaming cats.
- PublicationOpen AccessReproducción sociodemográfica de los inmigrantes y descendientes por-tugueses en Estados Unidos : una comunidad consolidada y con larga tra-dición(Universidad de Murcia, Servicio de Publicaciones, 2025) Azevedo, Alda Botellho; Singh, Nachatter; Sin departamento asociadoAunque la inmigración portuguesa en los Estados Unidos tiene una larga historia, existe un conocimiento limitado sobre su reproducción sociodemográfica en el siglo XXI. Este artículo pretende llenar este vacío, proporcionando una visión actual de las personas nacidas en Portugal o con ascendencia portuguesa y que viven en los Estados Unidos. Utilizamos los micro datos quinquenales de la American Community Survey, que abarcan desde 2006 hasta 2022, para 1) explorar el proceso migratorio de los inmigrantes portugueses y el tamaño y la composición de la población portuguesa en los Estados Unidos; 2) examinar la distribución espacial de los inmigrantes portugueses y sus descendientes en diferentes estados de Estados Unidos; 3) para explorar el perfil sociodemográfico de los inmigrantes portugueses y sus descendientes y cómo está evolucionando durante las últimas décadas. Los resultados revelan que los inmigrantes y descendientes portugueses se han reproducido socio demográficamente con éxito durante un siglo y forman una vibrante comunidad en diferentes partes de Estados Unidos. En general, superan a la población residente en Estados Unidos en diversos indicadores socioeconómicos, aunque existen diferencias significativas entre ellos.