RESUMO
The silver amplification technique, autometallography, has been used to reveal silver accumulation in neurons in the hypothalamus of male Wistar-Kyoto rats. Silver penetrated the blood-brain barrier after exposure to silver nitrate, and differences in staining intensity were found between the hypothalamic nuclei. When using light microscopy, the silver staining of the hypothalamic neurons was highly heterogeneous. Silver was detected exclusively in lysosomes of the loaded neurons. Aspects of this heterogeneous localization are discussed in relation to the distribution of autometallographically developed gold and mercury.
Assuntos
Histocitoquímica/métodos , Hipotálamo/metabolismo , Prata/farmacocinética , Animais , Hipotálamo/ultraestrutura , Masculino , Microscopia Eletrônica , Neurônios/metabolismo , Ratos , Ratos Endogâmicos WKY , Nitrato de Prata/metabolismo , Nitrato de Prata/farmacocinéticaRESUMO
A histochemical technique has been used to reveal mercury deposits in the hypothalamic arcuate nucleus and median eminence of adult male rats. After exposure to long-term, low-level or short-term, high-level mercury vapor, silver-enhanced mercury grains were found in neurons of the arcuate nucleus. In addition mercury deposits were found in tanycytes, ciliated ependymal cells, and in the walls of capillaries. The mechanisms underlying uptake and possible induction of toxic effects are discussed.
Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Eminência Mediana/metabolismo , Mercúrio/farmacocinética , Neurônios/metabolismo , Administração por Inalação , Animais , Núcleo Arqueado do Hipotálamo/patologia , Núcleo Arqueado do Hipotálamo/ultraestrutura , Capilares/metabolismo , Capilares/ultraestrutura , Lisossomos/metabolismo , Lisossomos/ultraestrutura , Masculino , Eminência Mediana/patologia , Eminência Mediana/ultraestrutura , Mercúrio/administração & dosagem , Microscopia Eletrônica , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/ultraestrutura , Neurônios/patologia , Neurônios/ultraestrutura , Ratos , Ratos Wistar , Distribuição TecidualRESUMO
Ultraviolet light autometallography, a very sensitive method for gold detection, was applied to sections of dorsal root ganglia from adult male Wistar rats treated with intraperitoneal injections of sodium aurothiomalate. Silver-amplified traces of gold were detected within the cytoplasm of ganglion cells, satellite cells, Schwann cells, macrophages, endothelial cells, and fibroblasts throughout the ganglia. Gold was never detected in axons nor myelin sheaths. In the electron microscope, gold deposits were restricted to the lysosomes irrespective of cell type or dosage.
Assuntos
Gânglios Espinais/química , Tiomalato Sódico de Ouro/farmacologia , Ouro/análise , Animais , Citoplasma/química , Citoplasma/ultraestrutura , Endotélio/química , Endotélio/citologia , Endotélio/ultraestrutura , Fibroblastos/química , Fibroblastos/citologia , Fibroblastos/ultraestrutura , Gânglios Espinais/citologia , Gânglios Espinais/ultraestrutura , Lisossomos/química , Lisossomos/ultraestrutura , Macrófagos/química , Macrófagos/citologia , Macrófagos/ultraestrutura , Masculino , Métodos , Microscopia Eletrônica , Ratos , Ratos Endogâmicos , Células de Schwann/química , Células de Schwann/citologia , Células de Schwann/ultraestrutura , Prata , Raios UltravioletaAssuntos
Gânglios Espinais/efeitos dos fármacos , Mercúrio/toxicidade , Animais , Transporte Biológico Ativo , Feminino , Gânglios Espinais/metabolismo , Gânglios Espinais/ultraestrutura , Histocitoquímica , Lisossomos/metabolismo , Masculino , Mercúrio/farmacocinética , Microscopia Eletrônica , Ratos , Ratos EndogâmicosAssuntos
Ouro/farmacocinética , Glândula Tireoide/metabolismo , Animais , Tiomalato Sódico de Ouro/administração & dosagem , Tiomalato Sódico de Ouro/farmacocinética , Histocitoquímica , Lisossomos/metabolismo , Masculino , Microscopia Eletrônica , Ratos , Ratos Endogâmicos , Glândula Tireoide/ultraestruturaRESUMO
The presence of gold was investigated in sections of the adrenal glands from rats which had been exposed to intraperitoneal sodium aurothiomalate (32 to 120 mg). Gold was histochemically detected in cortical endocrine cells, chromaffin cells and in fibroblasts and macrophages of both the cortex and medulla. Invisible traces of gold were silver enhanced by autometallography making them readily visible at both the light and electron microscopic levels. The intracellular staining intensity was dose-dependent. In general, the number as well as the staining intensity of individual cells, were highest in the zona glomerulosa and zona reticularis. In gold-containing cells the silver-amplified deposits were present in lysosomes.
Assuntos
Glândulas Suprarrenais/análise , Tiomalato Sódico de Ouro/metabolismo , Ouro/análise , Animais , Lisossomos/ultraestrutura , Masculino , Especificidade de Órgãos , Ratos , Ratos Endogâmicos , Raios UltravioletaRESUMO
Heart frequency was recorded in 10 infants during the delivery and the following day. It was found that during vaginal birth, in cephalic presentation, heart frequency decreased during the last 3 minutes before delivery of the head. In breech presentation the initial deceleration was shorter, while with cesarean section there was no initial deceleration. Shortly after delivery of the head and in close connection with the first cry, a tachycardia lasting approx. 10 minutes was observed in all infants. On the day after birth, all infants had a normal heart frequency. It is concluded that the heart frequency changes correspond to the alterations expected on the basis of the caput compression and the relative fetal hypovolemia arising during the final stage of the vaginal delivery. These observations also indicate that the variable deceleration is caused partly by fetal hypovolemia. The neonatal tachycardia is presumably a response to the ordinary placental transfusion and neonatal adaptation to extra-uterine life.
Assuntos
Monitorização Fetal , Frequência Cardíaca Fetal , Pressão Sanguínea , Volume Sanguíneo , Apresentação Pélvica , Cesárea , Feminino , Humanos , Recém-Nascido , Segunda Fase do Trabalho de Parto , GravidezRESUMO
Central corneal thickness was measured optically in premature and full-term babies and in children. The thickness was found to decrease from the values found in premature and full-term babies to those found in small children aged between 2-4 years. The thickness of the adult cornea is reached at the age of about 3 years. These findings are discussed with respect to the possible role of corneal thickness as a biometric parameter, to intraocular pressure measurement, and to corneal thickness steady state regulation.
