No abstract

Neuropeptide Y (NPY) has been reported to profoundly influence and regulate brain circuits involved in a number of behaviours, like anxiety, alcohol intake, pain and energy homeostasis. Here we show that NPY increases sedation induced by different types of anaesthetics through interactions with the Y1 receptor. Consistently, in Y1-/- (homozygote knockout) mice NPY does not potentiate the pentobarbital-induced sedation. Similar results were obtained for avertin but not for ketalar- (NMDA antagonist) induced sedation. Local microinjection of NPY exhibited the strongest potentiating effect on pentobarbital-induced sedation in the posterior hypothalamic area and Y1 expression was found in the dorsal-premammillary and medial part of medial mammillary nuclei. These results show that Y1 is essential for NPY-induced enhancement of sedation and place this activity of NPY in the posterior hypothalamic area, a region of the brain previously implicated in the regulation of the wake-sleep cycle.

A retrospective study of 60 pediatric patients with dry tympanic membrane perforation undergoing type I tympanoplasty during a 15-year period was carried out. Seventy-seven percent of patients were followed up for 5 years. The overall success rate was 90%. All failures occurred in patients who previously had undergone adenoidectomy or adenotonsillectomy. However, sex was found to be the only statistically significant prognostic factor of tympanoplasty success: female patients had higher success rates than male patients. Neither patient age, prior ventilation tube placement, size of perforation, status of the contralateral ear, surgical technique (underlay or overlay), nor competence of the surgeon (resident or senior) affected the success rate. The possible reasons for these findings will be discussed.

The effect of aerobic bacteriology on the clinical presentation, complications of the disease and long-term results of surgical treatment was assessed in a cohort of 368 patients with chronic suppurative otitis media. Bacteriological findings showed no significant difference between child and adult patients. Staphylococcus aureus was isolated in cholesteatoma ears more frequently than Pseudomonas aeruginosa, in chronic ears without cholesteatoma the situation was reversed. Bacteriological findings had no significant effect on the incidence of complications caused by the disease. Failures after surgical treatment were most common in Pseudomonas ears. The bacteriology had no significant effect on pre-operative hearing levels nor postoperative hearing results. It was concluded that, in order to improve results of chronic ear sugery, more attention should be paid to pre-operative conservative treatment of chronically discharging ears, especially those infected by P. aeruginosa.

Histaminergic H3 receptor antagonists stimulate neuronal histamine release and could consequently have a number of physiological effects in the brain. The effects of H3 receptor blockade, induced by systemically administered thioperamide, were assessed on the frontal cortex electroencephalographic (EEG) properties in freely behaving rats. The relationship of EEG activity variables to endogenous brain histaminergic markers was also examined, both in controls and in portocaval anastomosis (PCA)-operated rats (which show increased levels of brain histamine and t-methylhistamine). Thioperamide reduced the incidence of thalamus-regulated EEG spindles, while it slightly increased their amplitude. It furthermore reduced the spectral power of low-frequency (1.5-5Hz) EEG, which effect was equally distributed over the spindle and non-spindle EEG states. These EEG effects were accompanied by increased motor activity of the animals. Both the low-frequency EEG activity and spindle incidence correlated inversely with the histamine level of the brain (hypothalamus and cerebellum excluded) while t-methylhistamine level correlated with the degree of thioperamide-induced reduction of slow-wave EEG activity. The present results provide evidence for the involvement of endogenous brain histamine level, histamine release (as assessed by t-methylhistamine level) and H3 receptors in the histaminergic regulation of neocortical synchronization patterns assumed to be linked to arousal control.