Determination of binding capacity and adsorption enthalpy between Human Glutamate Receptor (GluR1) peptide fragments and kynurenic acid by surface plasmon resonance experiments.

The interaction between kynurenic acid (KYNA) and two peptide fragments (ca. 30 residues) of Human Glutamate Receptor 201-300 (GluR1) using surface plasmon resonance (SPR) spectroscopy was investigated. Because of the medical interest in the neuroscience, GluR1 is one of the important subunits of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR). AMPARs are ionotoropic glutamate receptors, which are mediating fast synaptic transmission and are crucial for plasticity in the brain. On the other hand, KYNA has been suggested to have neuroprotective activity and it has been considered for apply in therapy in certain neurobiological disorders. In this article the adsorption of the GluR1201-230 and GluR1231-259 peptides were studied on gold biosensor chip. The peptides were chemically bonded onto the gold surface via thiol group of L-cysteine resulted in the formation of peptide monolayer on the SPR chip surface. Because the GluR1231-259 peptide does not contain L-cysteine the Val256 was replaced by Cys256. The cross sectional area and the surface orientation of the studied peptides were determined by SPR and theoretical calculations (LOMETS) as well. The binding capability of KYNA on the peptide monolayer was studied in the concentration range of 0.1-5.0 mM using 150 mM NaCl ionic strength at pH 7.4 (±0.02) in phosphate buffer solutions. In order to determine the binding enthalpy the experiments were carried out between +10°C and +40°C. The heat of adsorption was calculated by using adsorption isotherms at different surface loading of KYNA on the SPR chip.

Blood pressure and heart rate reactivity to mental strain in adolescent judo athletes.

This exploratory investigation examined the association between maximal aerobic power (VO2max) and blood pressure (BP) and heart rate (HR) reactivity to mental challenge. Adolescent male judo athletes (n = 20) performed a 2-min mental arithmetic. Heart rate was recorded before, during, and after the arithmetic, and BP was recorded before and after the mental challenge. Blood pressure in the immediate stress-recovery period was not related to VO2max, but subjects having a higher maximal aerobic power showed faster HR recovery from mental stress than those having a lower VO2max. Subjects who showed earlier peak HR responses, during the stress episode, demonstrated lower average HR reactivity than subjects who attained the maximal HR response later in the stress period. The relationship between the interval to reach peak HR and the magnitude of reactivity deserves further attention. However, at present these findings should be viewed as tentative because of the uniqueness and size of the sample.

[Experience with surgical treatment of ascendant varicophlebitis]. / Az ascendáló varicophlebitis mütéti kezelésével szerzett tapasztalataink.

In ascendant varicophlebitis, the authors suggest not only crossectomy, but also radical removal of the dilated part of the great saphenous vein and of all thrombosed and non-thrombosed varicose veins in one session. They consider it important to clear the extension of the thrombosis by using an ultrasonic doppler flowmeter or the duplex scan technique; phlebography is needed only if deep venous affection is suspected. Cardinal questions of the operative technique are discussed. In cases of deep venous affection, thrombectomy is performed with Fogarty catheter. Antibiotics are generally held to be unnecessary, but early mobilisation and postoperative low-dose heparin prophylaxis are of great importance. No significant complications were detected after 37 interventions. Every patient was controlled one year after surgery. Residual complaints were found more rarely in the radically treated group. As concerns the quick and definitive recovery, mention is made of favourable economic consequences of the active surgical treatment.