Single tests of implantable cardioverter defibrillators can be performed in selected patients at a low risk of neuronal damage.

BACKGROUND: Defibrillator testing (DFT) is still used in selected patients to ensure adequate therapy. To do so, ventricular fibrillation is induced and terminated by the implanted cardioverter defibrillator (ICD). Studies have shown increases in neuronal damage markers without a measurable clinical effect in patients after defibrillator threshold testing with multiple shocks. OBJECTIVE: The aim of this study was to measure clinical outcomes, neuronal damage parameters (NSE and S100), and intraoperative cerebral perfusion (Doppler, near infra-red spectroscopy [NIRS]) in patients undergoing single DFT after transvenous ICD implantation and comparing them to untested patients. METHOD: We included 23 patients. Nine underwent surgery with a single DFT, 14 were not tested. Cognitive impairment was tested using the Mini-Mental-Status Test (MMST) and the DEMTECt 24 h prior and postsurgery. We also measured S100 and Neuron-Specific Enolase (NSE) at these timepoints. During surgery we measured medial cerebral artery velocity and cerebral tissue oxygen saturation (rSO2 ). RESULTS: We found no significant differences between the patient groups except for a significant increase in mean arterial blood pressure and an increase in rSO2 after testing. One patient with cerebral vasculopathy had a significant increase in his NSE values without showing clinical symptoms. This patient also had low rSO2 measurements and a decrease in medial cerebral artery velocity after DFT, other than the other patients. CONCLUSION: Single DFT did not lead to signs of neuronal damage or cognitive impairment except in one case with pre-existing cerebral vasculopathy. Therefore, our results support the use of DFT in carefully selected patients.

Close genetic relatedness of picornaviruses from European and Asian bats.

Our investigation of 1004 faecal specimens from European bats for picornaviruses by broadly reactive nested reverse transcription-PCR found picornaviral RNA in 28 samples (2.8 %). Phylogenetic analysis of the partial 3D genomic region suggested that one bat virus belonged to the species Enterovirus G (EV-G, formerly Porcine enterovirus B). Bat infection was supported by relatively high EV-G concentrations of 1.1×106 RNA copies per gram of faeces. All other bat viruses belonged either to the bat-associated genus Mischivirus, or to an unclassified Picornaviridae group distantly related to the genus Sapelovirus. Members of this unclassified sapelovirus-related group had RNA secondary structures in their 3'-nontranslated regions that were typical of enteroviruses and that resembled structures that occur in bat-associated coronaviruses, suggesting ancient recombination events. Based on sequence distances, several picornaviruses from European and Chinese bats were likely conspecific, suggesting connectivity of virus populations. Due to their high mutation rates and their diversity, picornaviruses may be useful tools for studies of bat and virus ecology.

A search for functional histamine H4 receptors in the human, guinea pig and mouse brain.

Histamine H4 receptors are expressed in immune cells, but their potential role in the brain is less clear. Although H4 transcripts have been identified in human and rat brain, the presence of H4 receptors on the protein level has so far not been proven since appropriate antibodies fulfilling the strict criteria for G protein-coupled receptors are missing. Here, we searched for functional H4 receptors in human, guinea pig and mouse cortex. We studied whether H4 receptor activation is associated with increased GTPγS binding and reduced noradrenaline release. The latter two effects have been previously shown for H3 receptors, which, like the H4 receptors, are coupled to G i/o protein. G protein activation was studied using (35)S-GTPγS binding in cortical membranes. The electrically induced (3)H-noradrenaline release was determined in superfused cortical slices. The H4 agonist 4-methylhistamine failed to affect (35)S-GTPγS binding and/or noradrenaline release in human, guinea pig and mouse cortex although an H 3 receptor-mediated increase in (35)S-GTPγS binding and inhibition of noradrenaline release occurred in parallel experiments. In conclusion, functional H4 receptors increasing (35)S-GTPγS binding and/or decreasing noradrenaline release are not found in human, guinea pig and mouse cortex.