The mismatch negativity and the P3a components of the auditory event-related potentials in autistic low-functioning subjects.

OBJECTIVE: In order to understand better the psychophysiological basis of auditory processing abnormalities in autism, we decided to study two automatic components of the auditory event-related potentials (ERPs): the mismatch negativity (MMN)--a component of the ERP which is recorded when, during repetitive auditory stimulation, rare changes are introduced--and the novelty-related P3a which is recorded as a response to unexpected novel events occurring in a sequence of repetitive stimuli. METHODS: Ten male subjects, mean age 12.3 years (SD 4.95), affected by autism and mental retardation were admitted to this study. All patients were also mentally retarded. Ten normal male subjects, mean age 12.2 years (SD 3.94), were used as controls. Auditory evoked potentials were recorded from 19 scalp electrodes (10-20 system), and stimuli were presented in sequences consisting of 2000 tones (70 dB, ISI=800 ms). Three types of stimuli were presented: (1) standard stimuli (1000 Hz tones, 80% of total stimuli), (2) deviant stimuli (1300 Hz tones, 10% of total stimuli), and (3) novel stimuli (complex and non-monotonal, 10% of total stimuli). To quantify the MMN, the evoked response to the standard tones was subtracted from the corresponding deviant stimulus response and its amplitude and latency at peak were measured over Fz, Cz and Pz; similarly, the P3a component of the ERP was obtained by subtracting the response to the standard tone from that to the novel stimuli and its amplitude and latency at peak were measured over Fz, Cz and Pz. Also, the amplitude and latency at peak for the N1 component of the auditory evoked potential obtained with the standard stimuli were measured over Fz, Cz and Pz. The correlation between age and MMN and P3a amplitude was also analyzed. RESULTS: N1 showed significantly shorter latencies in the autistic groups. MMN elicited by deviant stimuli, but not that elicited by novel stimuli, was found to be significantly larger in autistic children than in normal controls. P3a showed higher amplitude in autistic subjects than in normal controls during childhood; the opposite was observed during young adulthood. DISCUSSION: Our findings indicate that significant changes in ERPs can also be seen in non-cooperative individuals with autism and mental retardation, which might be different from the changes already reported for high-functioning autistic subjects and deserve further insight. These changes show developmental modifications that should be taken into consideration when analyzing data from autistic subjects.     

Intra-ocular pressure changes associated with intubation with the intubating laryngeal mask airway compared with conventional laryngoscopy

This open, prospective, randomised study was designed to evaluate the changes in intra-ocular pressure and haemodynamics after tracheal intubation using either the intubating laryngeal mask airway (ILMA) or direct laryngoscopy. Sixty adult patients, ASA physical status 1 or 2 with normal intra-ocular pressure were randomly allocated to one of the two techniques. Anaesthesia was induced with propofol followed by rocuronium. Tracheal intubation was performed using either the ILMA or Macintosh laryngoscope. Intra-ocular pressure, heart rate and blood pressure were measured immediately before and after tracheal intubation and then minutely for five minutes. In the laryngoscopy group there was a significant increase in intra-ocular pressure (from 7.2+/-1.4 to 16.8+/-5.3 mmHg, P<0.01), which did not return to pre-intubation levels within five minutes, and also in mean arterial pressure after tracheal intubation, which returned to baseline levels after five minutes. In the ILMA group there were no significant changes in intra-ocular pressure (from 7.6+/-1.8 to 10.4+/-2.8 mmHg, P >0.05) or mean arterial pressure after tracheal intubation. Time to successful intubation was longer with the ILMA, 56.8+/-7.8 seconds, compared with the laryngoscopy group, 33+/-3.6 seconds (P<0.01). Mucosal trauma was more frequent with the ILMA (eight of 30) compared with the laryngoscopy group (three of 30) (P<0.01). The postoperative complications were comparable. In terms of minimising increases in intra-ocular pressure and blood pressure, we conclude that the ILMA has an advantage over direct laryngoscopy for tracheal intubation.     

Niosomal gel for site-specific sustained delivery of anti-arthritic drug: in vitro-in vivo evaluation

Celecoxib, a selective COX-2 inhibitor is commonly used in the treatment of arthritis. Recently, cardiotoxic effects associated with conventional modes of delivery of celecoxib have made it pertinent to develop alternate dosage forms capable of selectively delivering the drug topically to affected joints. The aim of the present study was to prepare and characterize niosomal gel formulation for sustained and site-specific delivery of celecoxib. Celecoxib loaded niosomes were prepared and characterized in vitro, ex-vivo and in vivo. The results of organ localization (deep skin layer + muscle) study showed that niosomal gel provided 6.5 times higher drug deposition as compared to carbopol gel (195.2+/-8.7 and 30.0+/-1.5 microg, respectively). The muscle to plasma concentration ratio for niosomal gel formulation was six (2.16+/-0.12 microg/g vs. 0.34+/-0.01 microg/ml) and for carbopol gel it was one (0.36+/-0.01 microg/g vs. 0.43+/-0.02 microg/ml). Biological effectiveness of optimized formulation was evaluated using carrageenan induced rat paw edema model. The application of niosomal gel produced significant reduction of rat paw edema as compared to that after application of conventional gel indicating better skin permeation and deposition of celecoxib from niosomes. The results of the present study demonstrated niosomal gel formulation possess great potential for enhanced skin accumulation, prolonging drug release and improving the site specificity of celecoxib.     

Alternative medicine in atrial fibrillation treatment—Yoga,acupuncture, biofeedback and more

The last decade has seen a significant improvement in the management of atrial fibrillation (AF) with the development of newer medications and improvement in catheter ablation techniques. Recurrence of AF remains a significant problem in these patients and medications offer limited supportive role. Complementary and alternative treatment strategies therefore remain a viable option for these AF patients. Several studies have shown improvement in AF symptoms with yoga therapy, acupuncture and biofeedback. There are also several herbal medicine and supplements such as omega-3 fatty acids, antioxidant vitamins, barberry, motherwort, cinchona, Shensongyangxin, hawthorn, Kella and Wenxin Keli that have been evaluated as potential therapeutic options in AF. These studies are however limited by small sample sizes with mixed results. Besides the pharmacological action, metabolism, interactions with other medications and the adverse effects of the herbal medications and supplements remain poorly understood. In spite of the above limitations, complementary therapies remain a promising option in the management of AF and further studies are necessary to validate their safety and efficacy.