RESUMEN
One Health Surveillance (OHS) implements the One Health approach to improving health by collecting data and producing information to support integrated action across the animal health, human health and environment sectors. The purpose of this study was to survey the biosurveillance community to assess its OHS practices and capabilities, its attitudes towards OHS (perceived value), and the factors that motivate its members to implement OHS practices. The authors used a convenience sample of 185 professionals from multiple domains and 44 nations. They examined the extent to which these professionals implemented OHS, gathered their opinions on the value of OHS, assessed their perceptions of the capacity to perform specific OHS tasks and identified their priorities for change. Over 85% of all respondents said that they considered OHS to be beneficial, with no significant differences between work domains or country income groups; over 50% indicated that they already applied OHS. Obtaining access to data collected by other domains was both the most frequent challenge and the most difficult to improve. The highest priority for improvement was having the ability to send and receive electronic data. Respondents from low-income or middle-income countries were more motivated to make improvements than stakeholders from high-income countries. These findings provide a snapshot of current opinions and practices and, together with suggestions for improvements from professionals in the field, can help to target priority needs for OHS information, training and resources.
La surveillance Une seule santé opérationnalise la méthode Une seule santé pour une meilleure santé à travers la collecte de données et la production d'informations visant à soutenir la mobilisation transversale des secteurs de la santé animale, de la santé publique et de la santé environnementale en vue d'une action intégrée. Les auteurs présentent les résultats d'une enquête menée auprès des professionnels en charge de la biosurveillance afin d'évaluer leurs pratiques et capacités en matière de surveillance Une seule santé, leurs attitudes à l'égard de cette surveillance (c'est-à-dire leur perception de l'intérêt de la démarche) et les facteurs susceptibles de les motiver à la mettre en oeuvre. Les auteurs ont procédé à un échantillonnage de commodité de 185 intervenants issus de plusieurs secteurs dans 44 pays. Ils ont ensuite analysé le niveau de mise en oeuvre de la surveillance Une seule santé chez ces intervenants, recueilli leurs opinions concernant l'intérêt de la démarche, évalué la perception qu'ils avaient de leur capacité à mener à bien certaine tâches spécifiques dans ce domaine et identifié leurs priorités en vue du changement. Plus de 85 % des répondants ont déclaré considérer la surveillance Une seule santé comme étant bénéfique, résultat ne présentant pas de corrélation significative avec le secteur professionnel des personnes interrogées ni avec le niveau de revenu de leur pays ; plus de 50 % des répondants ont par ailleurs indiqué qu'ils appliquaient déjà les principes d'une surveillance Une seule santé. La difficulté la plus fréquente et qui paraissait la plus difficile à résoudre était celle de pouvoir accéder aux données enregistrées par d'autres secteurs. La première des priorités identifiées en vue d'une amélioration concernait la capacité d'envoyer et de recevoir des données électroniques. La motivation à introduire des améliorations était plus forte chez les répondants des pays à revenu faible ou intermédiaire que chez les parties prenantes des pays à revenus élevés. Ces résultats, qui offrent un instantané des opinions et des pratiques actuelles assorti de propositions concrètes d'amélioration formulées par les professionnels de terrain devraient pouvoir contribuer à cibler les besoins prioritaires en matière d'information, de formation et de ressources dédiées à la surveillance Une seule santé.
Practicar la vigilancia en clave de Una sola salud significa traducir esta idea en la práctica con el fin de mejorar la salud reuniendo datos y generando información a partir de la cual actuar de forma integrada en los sectores de la sanidad animal, la salud humana y el medio ambiente. Los autores describen un estudio de los círculos dedicados a la vigilancia biológica que tenía por objetivo evaluar sus procedimientos y capacidades de vigilancia en clave de Una sola salud, sus actitudes al respecto (valor atribuido) y los factores que los motivan a instaurar procedimientos concebidos desde la lógica de Una sola salud. Para ello los autores utilizaron una muestra de conveniencia de 185 profesionales de múltiples disciplinas y 44 países. Tras determinar en qué medida esos profesionales practicaban la vigilancia en clave de Una sola salud, les pidieron su opinión sobre la utilidad de este tipo de vigilancia, evaluaron la capacidad que subjetivamente se atribuían de efectuar labores específicas de vigilancia en clave de Una sola salud y determinaron aquellos cambios que esas personas juzgaban prioritarios. Más de un 85% de los encuestados dijo considerar beneficiosa la vigilancia en clave de Una sola salud, sin que se observaran diferencias significativas por ámbito de trabajo o por países según el grupo de ingresos. Más de un 50% afirmó que ya aplicaba este tipo de vigilancia. El problema señalado con más frecuencia y juzgado a la vez más difícil de resolver era el del acceso a datos obtenidos desde otros ámbitos de trabajo. El aspecto que más urgía mejorar era el de la capacidad de enviar y recibir datos electrónicos. Los encuestados de países de nivel bajo o medio de ingresos mostraban mayor motivación a la hora de introducir mejoras que sus homólogos de países de ingresos altos. Estas conclusiones, que ofrecen una «instantánea¼ de las opiniones y prácticas imperantes, pueden ayudar, junto con las propuestas de mejora procedentes de esos profesionales que trabajan sobre el terreno, a seleccionar las necesidades prioritarias de información, formación y recursos para la práctica de la vigilancia en clave de Una sola salud.
Asunto(s)
Motivación , Salud Única , Recursos Humanos , Animales , Humanos , Encuestas y Cuestionarios , Recursos Humanos/normas , Recursos Humanos/tendenciasRESUMEN
Transgenic mice expressing a dominant mutation in the gene for the phototransduction molecule rhodopsin undergo retinal degeneration similar to that experienced by patients with the retinal degenerative disease, retinitis pigmentosa (RP). Although the mutation is thought to cause photoreceptor degeneration in a cell-autonomous manner, the fact that rod photoreceptor degeneration is slowed in chimeric wild-type/mutant mice suggests that cellular interactions are also important for maintaining photoreceptor survival. To more fully characterize the nature of the cellular interactions important for rod degeneration in the RP mutant mice, we have used an in vitro approach. We found that when the retinas of the transgenic mice were isolated from the pigmented epithelium and cultured as explants, the rod photoreceptors underwent selective degeneration with a similar time course to that observed in vivo. This selective rod degeneration also occurred when the cells were dissociated and cultured as monolayers. These data indicate that the mutant rod photoreceptors degenerate when removed from their normal cellular relationships and without contact with the pigmented epithelium, thus confirming the relative cell autonomy of the mutant phenotype. We next tested whether normal retinal cells could rescue the mutant photoreceptors in a coculture paradigm. Coculture of transgenic mouse with wild-type mouse or rat retinal cells significantly enhanced transgenic rod photoreceptor survival; this survival-promoting activity was diffusible through a filter, was heat labile, and not present in transgenic retinal cells. Several peptide growth factors known to be present in the retina were tested as the potential survival-promoting molecule responsible for the effects of the conditioned medium; however, none of them promoted survival of the photoreceptors expressing the Pro23His mutant rhodopsin. Nevertheless, we were able to demonstrate that the mutant photoreceptors could be rescued by an antagonist to a retinoic acid receptor, suggesting that the endogeneous survival-promoting activity may function through this pathway. These data thus confirm and extend the findings of previous work that local trophic interactions are important in regulating rod photoreceptor degeneration in retinitis pigmentosa. A diffusible factor found in normal but not transgenic retinal cells has a protective effect on the survival of rod photoreceptors from Pro23His mutant rhodopsin mice.
Asunto(s)
Células Fotorreceptoras Retinianas Bastones/química , Células Fotorreceptoras Retinianas Bastones/citología , Retinitis Pigmentosa/fisiopatología , Animales , Anticuerpos Monoclonales , Antineoplásicos/farmacología , Factor Neurotrófico Derivado del Encéfalo/farmacología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Células Cultivadas , Factor Neurotrófico Ciliar , Medios de Cultivo Condicionados/química , Medios de Cultivo Condicionados/farmacología , Femenino , Factor 2 de Crecimiento de Fibroblastos/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutagénesis/fisiología , Proteínas del Tejido Nervioso/farmacología , Ratas , Ratas Sprague-Dawley , Células Fotorreceptoras Retinianas Bastones/metabolismo , Retinitis Pigmentosa/metabolismo , Rodopsina/análisis , Rodopsina/inmunología , Tretinoina/farmacologíaRESUMEN
In larvae of the hawkmoth, Manduca sexta, accessory planta retractor (APR) motoneurons undergo a segment-specific pattern of programmed cell death at pupation. APR death is triggered hormonally by the prepupal peak of the ecdysteroid, 20-hydroxyecdysone (20-HE). Previous studies found no evidence that cellular interactions regulate the segmental pattern of APR death in vivo. To test the hypothesis that 20-HE acts directly on APRs to trigger a cell-autonomous, segment-specific pattern of death, APRs were labeled with the fluorescent dyes DiI or DiA, removed from the nervous system before the prepupal peak, and placed in low-density cell culture. Physiological levels of 20-HE triggered the same segment-specific pattern of APR death in vitro as seen in vivo, both in cultures containing a single APR and in cultures containing two APRs removed from the same donor animal. The presence or absence of contact with other cells did not influence the APRs' responses to 20-HE. The death of APRs in culture was characterized by fragmentation or rounding up of the cell body and fragmentation of the neurites. These findings suggest that intrinsic segmental identity regulates whether these motoneurons live or die when exposed to a steroid hormone during development.
Asunto(s)
Apoptosis/efectos de los fármacos , Ecdisterona/farmacología , Manduca/crecimiento & desarrollo , Neuronas Motoras/citología , Animales , Células Cultivadas , Técnicas de Cocultivo , PupaRESUMEN
This review summarizes our current understanding of the neural circuit underlying the larval proleg withdrawal reflex (PWR) of Manduca sexta and describes how PWR function changes in two contexts: metamorphosis and learning. The first form of PWR plasticity occurs during the larval-pupal transformation, when the reflex is lost. One mechanism that contributes to this loss is the weakening of monosynaptic excitatory connection from proleg sensory neurons to proleg retractor motor neurons. This change is associated with the hormonally-mediated regression of proleg motor neuron dendrites, which may break synaptic contacts between the sensory and motor neurons. After pupation, some of the proleg motor neurons die in a segment-specific pattern that persists even after individual motor neurons are isolated from the nervous system and exposed to hormones in vitro. The second form of PWR plasticity involves short-term, activity-dependent changes in neural function during the larval stage. The nicotinic cholinergic connections from proleg sensory neurons to motor neurons exhibit several forms of plasticity including facilitation, depression, post-tetanic potentiation and two types of muscarinic modulation. Larval PWR behavior exhibits two simple forms of learning-habituation and dishabituation-which involve alterations in the central PWR circuit. These studies of a simple circuit illustrate neural mechanisms by which behaviors undergo both short- and long-term modifications.
Asunto(s)
Manduca/fisiología , Recuerdo Mental/fisiología , Metamorfosis Biológica/fisiología , Plasticidad Neuronal/fisiología , Animales , Condicionamiento Clásico/fisiología , Dendritas/fisiología , Habituación Psicofisiológica/fisiología , Neuronas Motoras/fisiología , Red Nerviosa/fisiología , Receptores Colinérgicos/fisiologíaRESUMEN
The proleg withdrawal reflex of Manduca sexta larvae is mediated by mono- and polysynaptic connections from afferents innervating mechanosensory planta hairs (PHs) to ipsilateral proleg retractor motoneurons. During the larval-pupal transformation, a rise in ecdysteroids causes the dendrites of proleg motoneurons to regress and, concurrently, the proleg withdrawal reflex is lost. The objective of this study was to identify synaptic correlates of dendritic regression that contributed to this behavioral change. The accessory planta retractor (APR) motoneuron regresses during the larval-pupal transformation and dies in a segment-specific pattern after pupation. The compound excitatory postsynaptic potential (cEPSP) evoked in APR by electrically stimulating the proleg sensory nerve decreased in amplitude during the larval-pupal transformation. The developmental decrease in cEPSP amplitude, the extent of APR's regression, and several of APR's intrinsic electrical properties were similar in segments in which the motoneuron was fated to live or die. In heterochronic mosaic pupae bearing retained larval PH afferents, APR's dendritic regression was associated with decreases in both the mean amplitude of monosynaptic EPSPs produced by PH afferents and the proportion of PH afferents that produced detectable EPSPs. These changes appeared due to a developmental decrease in the size of the synaptic currents produced by PH afferents. Evidence was also obtained suggesting that PH afferents do not regress at pupation. These findings support the hypothesis that the ecdysteroid-mediated regression of proleg motoneuron dendrites disconnects them from sensory inputs and, thereby, contributes to the elimination of the proleg withdrawal reflex.
Asunto(s)
Dendritas/fisiología , Manduca/crecimiento & desarrollo , Metamorfosis Biológica/fisiología , Neuronas Motoras/fisiología , Sensación/fisiología , Sinapsis/fisiología , Animales , Ecdisteroides , Electrofisiología , Hormonas de Insectos/fisiología , Hormonas de Invertebrados/fisiología , Larva , Manduca/genética , Manduca/fisiología , Mecanorreceptores/fisiología , Mosaicismo , Pupa , Valores de Referencia , Esteroides/fisiologíaRESUMEN
1. The sensitivity of normal and denervated cardiac ganglion cells to the cholinergic agonists acetylcholine and carbamylcholine (carbachol) were compared in the frog, Rana pipiens. Acetylcholine and carbachol bind to the same acetylcholine receptors, but, unlike acetylcholine, carbachol is resistant to hydrolysis by acetylcholinesterase. 2. Sensitivity was assessed by the peak depolarization elicited in response to a sustained pulse of ligand emitted from a pipette positioned 10 microns from the ganglion cell surface. This technique allows the sensitivity of the entire cell to be recorded with a single measurement. 3. The acetylcholine sensitivity of normal cardiac ganglion cells was increased by inhibiting extracellular acetylcholinesterase with echothiophate. 4. Denervation increased the sensitivity of cardiac ganglion cells to acetylcholine but not to carbachol. 5. Following the inhibition of extracellular acetylcholinesterase with echothiophate, sensitivity to acetylcholine was similar in normal and in denervated ganglion cells. 6. The increased sensitivity to acetylcholine of cardiac ganglion cells following denervation is caused by a reduction in the hydrolysis of the transmitter by acetylcholinesterase rather than by changes in the number and/or properties of acetylcholine receptors.
Asunto(s)
Acetilcolinesterasa/fisiología , Ganglios/fisiología , Corazón/inervación , Acetilcolina/farmacología , Animales , Carbacol/farmacología , Desnervación , Yoduro de Ecotiofato/farmacología , Electrofisiología , Femenino , Ganglios/efectos de los fármacos , Corazón/efectos de los fármacos , Masculino , Rana pipiensRESUMEN
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 normally innervated ganglia. These results suggest that denervation alters neither the total number of nicotinic AChRs in the cardiac ganglion nor the number found on the surface of ganglion cells. These autonomic neurons thus respond differently to denervation than do skeletal myofibers. The increase in ACh sensitivity displayed by cardiac ganglion cells upon denervation cannot be explained by changes in AChR number.
Asunto(s)
Bungarotoxinas/metabolismo , Desnervación , Ganglios Autónomos/metabolismo , Neuronas/metabolismo , Rana pipiens/fisiología , Animales , Sitios de Unión , Bungarotoxinas/farmacología , Femenino , Ganglios Autónomos/citología , Masculino , Miocardio/citología , Miocardio/metabolismo , Receptores Colinérgicos/efectos de los fármacos , Receptores Colinérgicos/fisiologíaRESUMEN
The transsynaptic regulation of acetylcholinesterase (AChE) was studied by recording the changes in enzymatic activity following denervation in two types of autonomic ganglia in the frog, Rana pipiens. Opposite effects on AChE were found in the parasympathetic cardiac ganglion and in the sympathetic lumbar ganglion; denervation produced a significant increase in AChE activity in cardiac ganglia but a significant decrease in lumbar ganglia. The relative effects of denervation on intracellular and total AChE were examined by selectively inhibiting extracellular AChE with echothiophate, a poorly lipid-soluble cholinesterase inhibitor. Denervation resulted in a significant increase in intracellular AChE in cholinergic cardiac ganglia but had no effect on intracellular AChE activity in adrenergic lumbar ganglia. Histochemical studies revealed little change in extracellular AChE staining upon denervation in the cardiac ganglion, whereas in the lumbar ganglia there was a loss of AChE-specific reaction product. These results raise the possibility that the transsynaptic control of AChE activity by innervation in the frog is influenced by the transmitter synthetic properties of the postsynaptic ganglion cells.
Asunto(s)
Acetilcolinesterasa/análisis , Ganglios Parasimpáticos/enzimología , Ganglios Simpáticos/enzimología , Simpatectomía , Animales , Yoduro de Ecotiofato/farmacología , Femenino , Ganglios Parasimpáticos/ultraestructura , Ganglios Simpáticos/ultraestructura , Masculino , Fisostigmina/farmacología , Rana pipiensRESUMEN
Postmetamorphic growth in the frog, Xenopus laevis, is accompanied by an increase both in the size of autonomic neurons in the heart and in the number of synaptic boutons that contact their surface. To determine whether the properties of individual boutons change as their number increases, serial-section electron microscopy was used to examine bouton ultrastructure at the end of metamorphosis and in the adult. The area of bouton contact, number of active zones per bouton, active zone size, percent of bouton area occupied by active zone, and vesicle density were examined. No differences were found between the two bouton populations for any of the parameters examined. These results support the hypothesis that boutons are structural units of synaptic growth, whereby the total area of synaptic contact increases through the addition of boutons without a change in their morphological properties.