A technical guide to tDCS, and related non-invasive brain stimulation tools.

Transcranial electrical stimulation (tES), including transcranial direct and alternating current stimulation (tDCS, tACS) are non-invasive brain stimulation techniques increasingly used for modulation of central nervous system excitability in humans. Here we address methodological issues required for tES application. This review covers technical aspects of tES, as well as applications like exploration of brain physiology, modelling approaches, tES in cognitive neurosciences, and interventional approaches. It aims to help the reader to appropriately design and conduct studies involving these brain stimulation techniques, understand limitations and avoid shortcomings, which might hamper the scientific rigor and potential applications in the clinical domain.

Four years of monitoring antibiotic resistance in microorganisms from bacteremic patients.

From the second semester of 2002 to the end of the first semester of 2005, a total of 2544 bacterial strains were isolated from the blood stream of patients with clinical sepsis and bacteremia hospitalized in six University Hospitals in the Slovak Republic. Almost 30% of strains were coagulase-negative staphylococci (CONS), about 14% were Staphylococcus aureus and, of the Gram-negative bacteria, up to 9% were Klebsiella pneumoniae. All CONS, S. aureus and Enterococcus spp. strains were found to be still susceptible to vancomycin, but the resistance of CONS and/or S. aureus to macrolides and fluoroquinolones dramatically increased during the period of this study. Among Gram-negative bacteria, increasing levels of resistance to higher generation cephalosporins, to fluoroquinolones resistance in Pseudomonas aeruginosa and Acinetobacter spp. to meropenem was recorded, which is alarming. The results were periodically submitted to cooperating hospitals with proposals for rationalizing the prophylactic and general use of indicated antibiotics as well as for improving hospital hygiene measures and anti-epidemic practices.

Monitoring of antibiotic resistance in bacterial isolates from bacteremic patients.

The aim of the study was to monitor the prevalence of pathogens and development of resistance in bacteria isolated from bacteremic patients. Five University Clinics and/or Regional Hospitals in the Slovak Republic participated in the study and a total of 421 isolates were collected in the second half of the year 2002. The most prevalent organisms were coagulase-negative staphylococci (CONS) (19%), Staphylococcus aureus (18.3%), among Gram-negative bacteria Escherichia coli (13.3%), Klebsiella pneumoniae (11.4%) and Pseudomonas aeruginosa (7.8%) followed by enterococci, Acinetobacter baumannii and Enterobacter sp. All CONS and S. aureus were susceptible to vancomycin; resistance to oxacillin was observed for 55% of the CONS and only for 4% of S. aureus isolates. A higher prevalence of resistance to erythromycin, clindamycin, gentamicin and ofloxacin was found in CONS in comparison to S. aureus. Enterococcus sp. isolates were fully susceptible to vancomycin and teicoplanin. Gentamicin, amoxicillin/clavulanate, third generation cephalosporins and ciprofloxacin showed good activity against E. coli. Although 17% of K. pneumoniae isolates were resistant to ciprofloxacin, it was the most effective drug against K. pneumoniae; the prevalence of resistance to other antibiotics was rather higher. Gentamicin and ciprofloxacin were the most active against Enterobacter sp. isolates and ceftazidime and meropenem against P. aeruginosa.

A technique for fast application of heated solutions of different composition to cultured neurones.

A technique is described that allows the application of fast temperature changes (time constant approximately 300 ms) of solutions superfusing cultured neurones under whole-cell mode of membrane current recording. Its principle is in heating the common outlet of the manifold which consists of 12 tubes connected to barrels containing test solutions of different composition. The outlet is made from a glass capillary (25 mm length, 620/350 microns outer/inner diameter) coated on the outside wall with platinum for a length of 12 mm. The heating element, a platinum layer, is electrically connected to the probe fixed to the micromanipulator used for positioning the manifold. The solutions, driven by gravity, are applied by opening electronic valves controlled either manually or in programmed sequences. The DC current for heating is controlled either manually or by external voltage command. The advantage of the technique is that the same temperature pattern can be applied to 12 different solutions. The technique is used for classifying sensory neurones in culture with respect to their sensitivity to heat and algogens; however, it is applicable to any study of the effects of increased temperature on the activity of ion channels in cultured cells.