Acta oto-laryngologica
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Acta oto-laryngologica · Mar 1999
In vivo study of the electrochemical composition of luminal fluid in the guinea pig endolymphatic sac.
The aim of this study was to investigate the ionic composition (sodium, potassium) of the luminal fluid in the endolymphatic sac and to correlate it with the transepithelial potential. Experiments were performed in guinea pigs using either an intradural posterior fossa approach or a translabyrinthine approach. ⋯ The results were: i) the luminal fluid in the endolymphatic sac differs in composition from perilymph, on the one hand, and from both cochlear and vestibular endolymph, on the other hand, indicating that the endolymphatic sac maintains chemical (sodium, potassium) and electrical (ESP) gradients; ii) the calculated osmolarity (Na + K) x 2 was about 230 mosm/l; iii) no correlation was observed between sodium and potassium concentrations; iv) large interindividual variations exist from one animal to another, suggesting physiological variations in the functional status of the endolymphatic sac. In conclusion, the variation in composition of the endolymphatic sac luminal fluid reflected variations in ion transport by the epithelium and thus a possible adaptation of the ion transport to different physiopathological conditions.
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In ancient Egypt mummifications were first carried out around 3000 BC. The visceral organs (lungs, stomach, liver and bowel) were removed from the body, cleansed, desiccated and placed in four canopic jars. The brain was removed from the body but was not preserved. ⋯ In all mummies a communication between the cranial and nasal cavities was found passing through the posterior ethmoids and cribriform plates. The cranial cavity was empty. Our results demonstrate that brain removal during mummification was performed endonasally by trained personnel with a good knowledge of anatomy, using special instruments capable of creating a clean-cut endonasal craniotomy.