Seung Il Lee

Newly formed cystic lesions for the development of pneumomediastinum in Pneumocystis jirovecii pneumonia.

BackgroundPneumocystis jirovecii, formerly named Pneumocystis carinii, is one of the most common opportunistic infections in human immunodeficiency virus (HIV)-infected patients.Case presentationsWe encountered two cases of spontaneous pneumomediastinum with subcutaneous emphysema in HIV-infected patients being treated for Pneumocystis jirovecii pneumonia with trimethoprim/sulfamethoxazole.ConclusionClinicians should be aware that cystic lesions and bronchiectasis can develop in spite of trimethoprim/sulfamethoxazole treatment for P. jirovecii pneumonia. The newly formed bronchiectasis and cyst formation that were noted in follow up high resolution computed tomography (HRCT) but were not visible on HRCT at admission could be risk factors for the development of pneumothorax or pneumomediastinum with subcutaneous emphysema in HIV-patients.

Influence of pentobarbital-Na on stimulation-evoked catecholamine secretion in the perfused rat adrenal gland.

Objectives The present study was attempted to investigate the effects of pentobarbital-Na, one of the barbiturates which are known to depress excitatory synaptic transmission in the central nervous system at concentrations similar to those required for the induction and maintenance of anesthesia, on catecholamines (CA) secretion evoked by cholinergic stimulation and membrane-depolarization from the isolated perfused rat adrenal gland, and to clarify the mechanism of its action. Methods Mature male Sprague-Dawley rats were anesthetized with thiopenal-Na(40mg/kg, s.c.). The adrenal gland was isolated by the methods of Wakade. A cannula used for perfusion of the adrenal gland was inserted into the distal end of the renal vein. The adrenal gland was carefully removed from the animal and placed on a platform of a leucite chamber. Results The perfusion of pentobarbital-Na(30–300uM) into an adrenal vein for 20 min produced relatively dose-dependent inhibition in CA secretion evoked by ACh(5.32mM) DMPP(100uM for 1 min), McN-A-343(200uM for 2 min), Bay-K-8644(10uM) and high potassium(56mM), while it did not affect the CA secretion of cyclopiazonic acid(10uM). Also, in the presence of thiopental-Na (100uM), CA secretory responses evoked by ACh, DMPP, McN-A-343 and high K+ were markedly depressed. Moreover, in adrenal glands preloaded with ketamine(100uM for 20 min), which is known to be a dissociative anesthetic, CA secretion evoked by ACh, DMPP, McN-A-343 and high K+ were significantly attenuated. Conclusion Taken together, these experimental results suggest that pentobarbital-Na depresses CA release evoked by both cholinergic stimulation and membrane-depolarization from the isolated rat adrenal medulla and that this inhibitory activity may be due to the result of the direct inhibiton of Ca++ influx into the chromaffin cells without any effect on the calcium mobilization from the intracellular store.