Miniaturized biosensor for avian influenza virus detection

5th Maghreb/Europe Meeting on Materials and Their Applications for Devices and Physical, Chemical and Biological Sensors (MADICA 2006), Mahdia, TUNISIA, OCT 30-NOV 01, 2006International audienceAvian Influenza Virus (AIV) infections are a major cause of mortality and rapid identification of the virus has important clinical, economical and epidemiological implications The traditional methods for avian influenza vir-us diagnostic are Enzyme Linked Immunosorbent Assay (ELISA) and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) which are time consuming and expensive. In this paper we describe the development of miniaturized gold electrode biosensor for H7N1 detection with electrochemical technique such us impedance spectroscopy. The biosensor is based on the immobilization of specific H7N1 antibodies onto biofunctionnalized gold electrode. Each grafted layer on the gold electrode was characterized with impedance spectroscopy and modelised with an equivalent electric circuit. The affinity interaction of the antibody with the specific antigen can be measured with a low limit detection (5 mu g/ml) and with a good reproductibility. The non-specific interaction has been tested with the Newcastle antigen. (c) 2007 Elsevier B.V. All rights reserved

The effects of daytime melatonin ingestion on arousal and vigilance vanish after sub-maximal exercise: a pilot study

OBJECTIVE Daytime melatonin ingestion is known to induce sleep at rest, which may affect arousal and vigilance. Physical exercise is known to produce an increase in core temperature and circulating cortisol which can enhance arousal and vigilance. The effect of submaximal exercise on vigilance and arousal following acute melatonin ingestion has not yet been studied. The present study aimed at investigating the effect of submaximal exercise on vigilance and arousal following daytime melatonin ingestion. PATIENTS AND METHODS Eight physical education students undertook 45 min of submaximal exercise (at 60% of maximal aerobic speed) on a treadmill after melatonin-(6 mg) or placebo ingestion, in a randomized and counterbalanced order. RESULTS Heart rate (HR), rectal temperature (Tre), felt arousal scale (FAS), and thermal sensations (TS) were recorded at baseline (pre-exercise), immediately after exercise (post-exercise), and after 30 min of recovery (30 min post-exercise). Blood was sampled for lactate and cortisol. At 30 min post-exercise, the Tre, HR, blood pressure, lactate, FAS, and TS were measured. The participants performed vigilance tests pre-exercise, post-exercise and 30 min post-exercise. Daytime melatonin ingestion affected arousal and vigilance in the pre-exercise period (p 0.05). CONCLUSIONS The negative effects of melatonin ingestion on vigilance and arousal vanished after a 45 min of submaximal exercise. The hypnotic effect of melatonin observed in the pre-exercise dissipated in the post-exercise period, possibly due to the significant elevation of Tre, HR, and cortisol at the end of submaximal exercise