Aberrant plasticity in the hippocampus after neonatal seizures.

Purpose/aim of the study: Neonatal seizures are the most frequent type of neurological disorder, and those newborn babies that experience seizures carry an increased risk of epileptogenesis and other long-term morbidities. The aims of this review were to summarize the different effects on hippocampal neurogenesis between neonatal seizures and adult seizures. MATERIALS AND METHODS: Pubmed, Medline and Cochrane Library were searched for articles that examined the aberrant plasticity in the hippocampus after neonatal seizures. RESULTS: Different from the adult animals, the proliferation of newly formed dentate granule cells is reduced in the acute phase and enhanced in the chronic phase after neonatal seizures. Neonatal seizures cause less ectopic migration of newborn neurons. Recurrent neonatal seizures also switch the effect of gamma-aminobutyric acid receptor activation from inhibition to excitation, which may contribute to increased seizure susceptibility. Similar to adult seizures, mossy fiber sprouting and sprouting of basal dendrites had been seen after neonatal seizures. CONCLUSIONS: The effects of seizures on neurogenesis in the hippocampus are age-dependent.

Seizure severity-dependent selective vulnerability of the granule cell layer and aberrant neurogenesis in the rat hippocampus.

The pilocarpine-induced status epilepticus rodent model has been commonly used to analyze the mechanisms of human temporal lobe epilepsy. Recent studies using this model have demonstrated that epileptic seizures lead to increased adult neurogenesis of the dentate granule cells, and cause abnormal cellular organization in dentate neuronal circuits. In this study, we examined these structural changes in rats with seizures of varying severity. In rats with frequent severe seizures, we found a clear loss of Prox1 and NeuN expression in the dentate granule cell layer (GCL), which was confined mainly to the suprapyramidal blade of the GCL at the septal and middle regions of the septotemporal axis of the hippocampus. In the damaged suprapyramidal region, the number of immature neurons in the subgranular zone was markedly reduced. In contrast, in rats with less frequent severe seizures, there was almost no loss of Prox1 and NeuN expression, and the number of immature neurons was increased. In rats with no or slight loss of Prox1 expression in the GCL, ectopic immature neurons were detected in the molecular layer of the suprapyramidal blade in addition to the hilus, and formed chainlike aggregated structures along the blood vessels up to the hippocampal fissure, suggesting that newly generated neurons migrate at least partially along blood vessels to the hippocampal fissure. These results suggest that seizures of different severity cause different effects on GCL damage, neurogenesis, and the migration of new neurons, and that these structural changes are selective to subdivisions of the GCL and the septotemporal axis of the hippocampus.

A rare case of ectopic dioctophymosis in Leopardus pardalis (Carnivora, Felidae) in Paraguay.

An adult female Leopardus pardalis from Jardín Botánico y Zoológico de Asunción, Paraguay was brought in from the wild, and inspected for a parasitic structure attached to the vulva. The parasite was removed and was identified as a Dioctophyme renale female. Blood samples and ultrasound did not show abnormalities in any organ, confirming the ectopic presentation of the parasite. This is the first report of D. renale in the L. pardalis and a first time for ectopic location in vagina and spontaneous elimination in a felid.

Ectopic infection by Dioctophyme renale in a dog from Georgia, USA, and a review of cases of ectopic dioctophymosis in companion animals in the Americas.

We report a case of ectopic dioctophymosis in an outdoor, eight-year-old spayed female, Coonhound-mix dog from Murrayville, Hall County, Georgia, USA. The dog presented to the clinic with an apparent puncture wound on her right, most caudal mammary gland, draining a serosanguinous discharge along with significant edema and thickening of the surrounding tissues. After initial physical examination the dog was placed into a cage awaiting diagnostic procedures. A couple of hours later, a bright red, live nematode was found in the bottom of the cage and submitted to the Parasitology Diagnostic Laboratory, Department of Infectious Diseases of the University of Georgia College of Veterinary Medicine. The specimen was morphologically identified as a female Dioctophyme renale, measuring 30 cm in length. The wound was cleaned with chlorhexidine solution. The patient was started on cefpodoxime 100 mg orally, once daily for 10 days. The dog had recent history of a mammary tumor on the left chain. After a week, an ultrasound examination confirmed integrity of the kidneys. Herein, we also provide a review on cases of ectopic dioctophymosis in companion animals in the Americas. Such cases are not uncommon, and nematodes may be found in various organs and tissues including the abdominal and thoracic cavities, scrotum, uterus, and mammary glands.