More safety with more energy: survival of electrical storm with 40-J shocks.

We report the first clinical case of ineffective high-voltage therapy with 36 J and subsequent effective therapy with 40 J in a patient with electrical storm who had previously received a high-energy implantable cardioverter defibrillator (ICD, Fortify VR, 1233-40Q St. Jude Medical, Sylmar, CA, USA). Using a combination of high energy and optimized fixed millisecond duration biphasic waveform shock, successful defibrillation could be achieved at 8 J below the programmed maximum energy level.

Field-effect sensors with charged macromolecules: characterisation by capacitance-voltage, constant-capacitance, impedance spectroscopy and atomic-force microscopy methods.

Field-effect-based capacitive electrolyte-insulator-semiconductor (EIS) sensors have been utilised for the deoxyribonucleic acid (DNA) immobilisation and hybridisation detection as well as for monitoring the layer-by-layer adsorption of polyelectrolytes (anionic poly(sodium 4-styrene sulfonate) (PSS) and cationic poly(allylamine hydrochloride) (PAH)). The EIS sensors with charged macromolecules have been systematically characterised by capacitance-voltage, constant-capacitance, impedance spectroscopy and atomic-force microscopy methods. The effect of the number and polarity of the polyelectrolyte layers on the shift of the capacitance-voltage curves has been investigated. Alternating potential shifts of about 30-90 mV have been observed after the adsorption of each polyanion and polycation layer, respectively. The DNA immobilisation and hybridisation signals were 35-55 and 24-33 mV, respectively. The possible mechanisms for the sensor responses are discussed.

Structural dynamics of HIV-1 Rev and its complexes with RRE and 5S RNA.

The Rev protein of the human immunodeficiency virus type 1 (HIV-1) has been studied by time-resolved fluorescence spectroscopy. The single tryptophan residue of Rev, Trp45, located within the arginine-rich RNA-binding domain of the protein, was utilized as an intrinsic spectroscopic probe. In addition, five peptides spanning different lengths of the arginine-rich domain, each containing the tryptophan residue, and two C-terminal deletion mutants of Rev, Rev M9 delta 14 and Rev M11 delta 14, were examined. Rev M9 delta 14 lacks residues 68-112 whereas Rev M11 delta 14 is missing residues 92-112 of the C-terminus of Rev. The fluorescence decay of Trp45 in wild-type Rev was resolved into four discrete lifetime components, and decay-associated spectra (DAS) were obtained for each component. The fluorescence decays of all five peptides and Rev M9 delta 14 were resolved into three lifetime components. The fluorescence decay of Rev M11 delta 14 was resolved into four components similar to those found for wild-type Rev. These results indicate that the activation domain (residues 78-93), present in wild-type Rev and Rev M11 delta 14, induced a unique tryptophan environment, characterized by a short-lived, blue-shifted emission, attributed to higher order assembly of Rev. In addition, fluorescence anisotropy decay data obtained for wild-type Rev and the two C-terminal deletion mutants also indicate that the activation domain mediates self-association of Rev. Based on the anisotropy decay results for wild-type Rev, the distribution of oligomers is independent of salt concentration. The average fluorescence lifetime of Trp45 was reduced upon complexation of Rev with a 40-mer fragment of the Rev response element containing the minimal element for Rev binding (F8-RRE), and the emission was blue-shifted. In addition, the local rotation of the tryptophan side chain was blocked in the protein-RRE complex. These results indicate that Trp45 directly interacts with the RRE. Rev is also shown to bind to 5S RNA, resulting in very similar changes in the time-resolved tryptophan fluorescence to those observed upon complexation of Rev with F8-RRE.