RESUMEN
Retrograde transneuronal degeneration (RTD) of retinal ganglion cells and dorsal lateral geniculate (LGN) neurons are well described following a lesion of the primary visual cortex (V1) in both Old World monkeys and humans. Based on previous studies of New World monkeys and prosimians, it was suggested that these species displayed no RTD following a lesion of V1. In this study of the New World marmoset monkey, 1 year after a unilateral V1 lesion either in adults or at 14 days after birth, we observed ~20 % ganglion cell (GC) loss in adult but ~70 % in infants. This finding is similar to the RTD previously described for Old World Macaca monkeys. Furthermore, in infants we find a similar amount of RTD at 3 weeks and 1 year following lesion, demonstrating that RTD is very rapid in neonates. This highlights the importance of trying to prevent the rapid onset of RTD following a lesion of V1 in early life as a strategy for improved functional recovery. Despite differences in GC loss, there was little difference between LGN degeneration in infant versus adult lesions. A wedge on the horizontal meridian corresponding to the LGN foveal representation revealed extensive neuronal loss. Retinal afferent input was labeled by cholera toxin B subunit. Input to the degenerated parvocellular layers was difficult to detect, while input to magnocellular and koniocellular layers was reduced but still apparent. Our demonstration that the New World marmoset monkey shares many of the features of neuroplasticity with Old World Macaca monkeys and humans emphasizes the opportunity and benefit of marmosets as models of visual cortical injury.
Asunto(s)
Lesiones Encefálicas/complicaciones , Lesiones Encefálicas/patología , Cuerpos Geniculados/patología , Degeneración Nerviosa/etiología , Retina/patología , Corteza Visual/patología , Animales , Calbindina 1/metabolismo , Calbindina 2/metabolismo , Callithrix , Proteínas de Neurofilamentos/metabolismo , Neuronas/metabolismo , Neuronas/patología , Parvalbúminas/metabolismo , Fosfopiruvato Hidratasa/metabolismo , Vías Visuales/patología , Ácido gamma-Aminobutírico/metabolismoRESUMEN
Neurotransmitter amino acids have been measured in several brain regions taken postmortem from 5 adults cases of Down's syndrome and 6 age-matched control subjects. A significant deficit of glutamate was found in the hippocampus in Down's syndrome, and gamma-aminobutyric acid was reduced in the hippocampus and temporal cortex in those patients with neocortical neurofibrillary tangles. These results are consistent with losses of cortical neurones containing these neurotransmitters, and resemble the deficits exhibited by the more severely affected cases of Alzheimer's disease.
Asunto(s)
Ácido Aspártico/análisis , Química Encefálica , Síndrome de Down/metabolismo , Glutamatos/análisis , Ácido gamma-Aminobutírico/análisis , Adulto , Ácido Glutámico , Humanos , Persona de Mediana Edad , Especificidad de Órganos , Valores de ReferenciaRESUMEN
A review of the history and pathophysiology of sickle cell disease is given. The clinical types (crises) are discussed along with their relationship to surgical occurrences, both elective and emergency. Specifics of perioperative management are discussed and the cardinal features of importance are enumerated. A retrospective study of sickle cell disease in a community hospital is presented, outlining the surgical experience over a ten-year period.