[Nitrogen fixation in monospecific and mixed cultures of Aerobacter aerogenes and Agrobacterium azotophilum using different sources of carbon].
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Biomedical subjects
Publications and source records attributed to J Taboada.
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BACKGROUND: Intrastromal photorefractive keratectomy is a new procedure in which compact linear or area regions of the corneal stroma can be vacuolized, yielding changes in corneal curvature. METHODS: Diffraction-limited 1064-nanometer light pulses from a high rep rate Q-switched Nd-YAG laser were coupled through novel means into a probe with index-matched optical contact with the cornea. The resulting extremely reduced focal region initiated a plasma point that was free of shock front effects where tissue was reduced to liquid. This probe process was applied to the corneas of eye-bank eyes, and to living rabbit and primate eyes. The refractive effects were evaluated with slit-lamp microscopy, keratoscopy light and electron microscopy. RESULTS: Refractive effects similar to refractive keratotomy were observed immediately after treatment. Intrastromal highly localized vacuolized regions were observed at the depth of focus with variability of only 20 microns. The plasma point vacuoles were about 100 microns in diameter. Stromal material that occupied the vacuole space appeared completely reduced to liquid. The transition region between vacuole and normal tissue was less than 0.5 microns. The treatment vacuoles disappeared to the unaided eye 24 to 48 hours after treatment. CONCLUSIONS: Corneal refractive power can be achieved with intrastromal keratectomy.
The object of this investigation was to study the effect of a benzodiazepine upon the cycle wakefulness-sleep. Wistar rats received 0.9 mg/kg of the chlorate derivative of beta lactam 1.5 benzodiazepine intraperitoneally and the action was analyzed by means of continuous polygraphic registers for ten hours long. Results indicate that this substance decreases wakefulness and slightly increases slow wave sleep. Paradoxical sleep increases significantly (p less than 0.05). Latency of the first phase of paradoxical sleep decreases considerably. These effects suggest that this compound favors sleep under present experimental conditions.
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Various substances have been used as sleep inductors, but their use has declined, due to their undesirable side effects, and they have been replaced mainly by benzodiazepines. There currently exists a great variety of benzodiazepines with an increasing, clinical use, although they also present certain disadvantages. The effect on sleep of the intraperitoneal administration (0.9 mg/kg) of 7-(p-cl-phenyl)-8-phenoxy-4,5-benzo-3-aza-2-none, was analysed in chronically implanted wistar rats. Results indicate that this substance decreases wakefulness and increases significantly slow-wave and paradoxical sleep. Latency of the first phase of paradoxical sleep show a tendency to increase. It is concluded that this substance has hypnogenic effects.