RESUMEN
Although individuals with Zika virus (ZIKV) antibodies were reported in Malaya in mid-1950s, entomological and human surveillance in Singapore did not identify autochthonous transmission until the outbreak of August-November, 2016. A total of 455 cases from 15 separate clusters were identified. We asked if this ZIKV outbreak increased the incidence of Guillain-Barré syndrome (GBS) and aimed to characterize these cases. Eleven GBS cases, consecutively enrolled into our prospective GBS database from onset to 4 weeks after outbreak, and six controls, comprising three GBS patients enrolled before outbreak and three non-GBS patients, were examined for evidence of recent ZIKV infection. We performed serum, urine ZIKV RT-PCR, ZIKV serology, and virus neutralization assays, accounting for cross-reaction and co-infection with dengue (DENV). We found five GBS cases with only serological evidence of recent ZIKV infection (including one ZIKV-DENV co-infection). A temporal relationship with ZIKV outbreak was unlikely as two cases were GBS controls enrolled 3 months before outbreak. None reported symptoms of ZIKV infection. In addition, compared to last 10 years the national number of GBS hospitalizations did not increase during and immediately after outbreak. We conclude the 2016 Singapore ZIKV outbreak did not cause a change in GBS epidemiology.
Asunto(s)
Brotes de Enfermedades , Síndrome de Guillain-Barré/epidemiología , Infección por el Virus Zika , Adulto , Anciano de 80 o más Años , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Singapur/epidemiología , Infección por el Virus Zika/epidemiologíaRESUMEN
Optical recording with fast voltage sensitive dyes makes it possible, in suitable preparations, to simultaneously monitor the action potentials of large numbers of individual neurons. Here we describe methods for doing this, including considerations of different dyes and imaging systems, methods for correlating the optical signals with their source neurons, procedures for getting good signals, and the use of Independent Component Analysis for spike-sorting raw optical data into single neuron traces. These combined tools represent a powerful approach for large-scale recording of neural networks with high temporal and spatial resolution.
Asunto(s)
Potenciales de Acción/fisiología , Ganglios de Invertebrados/fisiología , Red Nerviosa/fisiología , Neuronas/fisiología , Sinapsis/fisiología , Imagen de Colorante Sensible al Voltaje/métodos , Animales , Colorantes Fluorescentes/química , Ganglios de Invertebrados/ultraestructura , Procesamiento de Imagen Asistido por Computador/métodos , Sanguijuelas , Red Nerviosa/ultraestructura , Neuronas/ultraestructura , Análisis Espacio-Temporal , Sinapsis/ultraestructura , Babosas Marinas Tritonia , Imagen de Colorante Sensible al Voltaje/instrumentaciónRESUMEN
The escape swim response of the marine mollusc Tritonia diomedea is a well-established model system for studies of the neural basis of behavior. Although the swim neural network is reasonably well understood, little is known about the transmitters used by its constituent neurons. In the present study, we provide immunocytochemical and electrophysiological evidence that the S-cells, the afferent neurons that detect aversive skin stimuli and in turn trigger Tritonia's escape swim response, use glutamate as their transmitter. First, immunolabeling revealed that S-cell somata contain elevated levels of glutamate compared to most other neurons in the Tritonia brain, consistent with findings from glutamatergic neurons in many species. Second, pressure-applied puffs of glutamate produced the same excitatory response in the target neurons of the S-cells as the naturally released S-cell transmitter itself. Third, the glutamate receptor antagonist CNQX completely blocked S-cell synaptic connections. These findings support glutamate as a transmitter used by the S-cells, and will facilitate studies using this model system to explore a variety of issues related to the neural basis of behavior.
Asunto(s)
Encéfalo/metabolismo , Reacción de Fuga/fisiología , Ácido Glutámico/metabolismo , Neuronas Aferentes/metabolismo , Natación/fisiología , Babosas Marinas Tritonia/fisiología , 6-Ciano 7-nitroquinoxalina 2,3-diona , Análisis de Varianza , Animales , Electrofisiología , Inmunohistoquímica , Modelos Biológicos , Babosas Marinas Tritonia/metabolismoRESUMEN
The distribution of GABAergic endings was examined histochemically in the ventral cochlear nucleus (VCN) of the cat using an antibody to glutamate decarboxylase (GAD), the synthetic enzyme for GABA. Immunoreactive (GAD+) endings appeared in all subdivisions of the cat VCN. Each of the principal cell types had a characteristic labeling pattern, based on the size, concentration, and distribution of GAD+ endings on its soma. Spherical bushy cell somata were typically contacted by many small (less than 1.5 microns in diameter) and medium-sized (1.5-2 microns in diameter) endings, many of which aggregated into tight clusters. Globular bushy cells had a similar pattern, but the clusters of GAD+ endings were less tightly packed. Reactive endings on stellate cells were more evenly distributed. GAD+ endings on octopus cells were larger (up to 2.5 microns in diameter) than those on the bushy cells and tended to aggregate into small clusters or rows on the somata and dendrites. Reactive endings contained small pleomorphic vesicles and formed symmetrical synaptic contacts on each of the cell types examined. The patterns formed by GAD+ endings on each type of neuron resemble those of certain types of non-cochlear axons previously described with the Golgi methods as projecting from the dorsal cochlear nucleus and the trapezoid body.
Asunto(s)
Cóclea/inervación , Ácido gamma-Aminobutírico/metabolismo , Animales , Gatos , Cóclea/metabolismo , Cóclea/ultraestructura , Glutamato Descarboxilasa/metabolismo , Inmunohistoquímica , Microscopía Electrónica , Terminaciones Nerviosas/metabolismo , Sinapsis/metabolismo , Sinapsis/ultraestructuraRESUMEN
Fracture of the acetabular cup is an uncommon complication in total hip arthroplasties, with only six examples described in the orthopedic literature. A patient is presented to illustrate the plain radiographic findings of acetabular cup fracture and to discuss the possible mechanisms involved.