RESUMEN
A cluster of toxic reactions among children inadvertently given excessive doses of rifampin for chemoprophylaxis of invasive Haemophilus influenzae disease in a day-care center was investigated. In all 19 children, who received five times the therapeutic dose of rifampin, dramatic adverse reactions developed. A striking, "glowing" red discoloration of the skin and facial or periorbital edema were found to be the hallmarks of rifampin toxicity. These clinical signs of acute toxicity contrast sharply with the adverse side effects of rifampin reported with therapeutic doses.
Asunto(s)
Infecciones por Haemophilus/prevención & control , Trastornos de la Pigmentación/inducido químicamente , Rifampin/efectos adversos , Enfermedades de la Piel/inducido químicamente , Enfermedad Aguda , Guarderías Infantiles , Preescolar , Edema/inducido químicamente , Femenino , Haemophilus influenzae , Humanos , Lactante , Masculino , Errores de Medicación , Rifampin/administración & dosificación , Dermatosis del Cuero Cabelludo/inducido químicamente , Vómitos/inducido químicamenteRESUMEN
Miniature end-plate potentials (MEPPs) recorded at the neuromuscular junction were initially reported to be normally distributed and have been attributed to quantal ACh release. This quantum was later correlated with the release of the content of one clear vesicle. This is the 'classical vesicular hypothesis'. Recent observations of subminiature end-plate potentials (s-MEPPs) and of multimodal distribution of the MEPP amplitudes have led to the formulation of a new 'multivesicular hypothesis'. It attributes the s-MEPP to the release of one vesicle and the MEPP to the simultaneous release of several vesicles at one active zone. The distribution of MEPP intervals, the evaluation of the ACh content of a vesicle and of the ACh necessary to produce a MEPP, estimates of the number of vesicles missing following repeated stimulation, and the freeze fracture studies of the active zone do not permit a definitive rejection of either hypotheses.
Asunto(s)
Placa Motora/fisiología , Unión Neuromuscular/fisiología , Transmisión Sináptica , Vesículas Sinápticas/fisiología , Acetilcolina/metabolismo , Animales , Estimulación Eléctrica , Técnica de Fractura por Congelación , Potenciales de la Membrana , Ratones , Músculos/inervación , Unión Neuromuscular/anatomía & histología , RanidaeRESUMEN
Morphological changes in the synaptic boutons located on the ciliary neurons were observed following stimulation of the Edinger-Westphal nucleus (EWn). A reduction in the number of clear and dense core vesicles (DCVs) per unit area and an increased surface density of vacuoles were observed in boutons located proximal to the afferent axon. Only a slight reduction in the number of DCVs per unit area was observed on boutons located distally to the afferent axon. Several mechanisms are proposed to explain why all boutons do not participate equally in synaptic transmission.