Comparing the error‐related negativity across groups: The impact of error‐ and trial‐number differences

The error‐related negativity (ERN or Ne) is increasingly being investigated as a marker discriminating interindividual factors and moves toward a surrogate marker for disorders or interventions. Although reproducibility and validity of neuroscientific and psychological research has been criticized, clear data on how different quantification methods of the ERN and their relation to available trial numbers affect within‐ and across‐participant studies is sparse. Within a large sample of 863 healthy human participants, we demonstrate that, across participants, the number of errors correlates with the amplitude of the ERN independently of the number of errors included in ERN quantification per participant, constituting a possible confound when such variance is unaccounted for. Additionally, we find that ERN amplitudes reach high consistency within participants at lower trial numbers, yet when comparisons between groups of participants are desired, increasing error‐trial numbers lead to higher statistical power. We derive concrete suggestions for specific types of analyses, which may help researchers to more effectively design studies and analyze error‐related EEG data with the most appropriate measurement technique for the question at hand and trial number available.     

Penetration enhancement of two topical 5‐aminolaevulinic acid formulations for photodynamic therapy by erbium:YAG laser ablation of the stratum corneum: continuous versus fractional ablation

Please cite this paper as: Penetration enhancement of two topical 5‐aminolaevulinic acid formulations for photodynamic therapy by erbium:YAG laser ablation of the stratum corneum: continuous versus fractional ablation. Experimental Dermatology 2010; 19 : 806–812. Abstract: 5‐Aminolaevulinic acid (ALA) is used in photodynamic therapy (PDT). Response rates of PDT vary widely, which may be because of the limited uptake of topically applied photosensitisers. We investigated skin penetration and fluorescence induction of protoporphyrin IX (PpIX) after applying either 20% ALA cream or 20% aminolaevulinic acid solution on laser‐stripped stratum corneum (SC) in an ex vivo full‐thickness porcine skin model. Both formulations are used in clinical practice. To enhance the skin penetration of ALA, we used two different 2940‐nm erbium:yttrium–aluminium–garnet (Er:YAG) laser systems to partially ablate the SC: continuous and fractional ablation. Different fluences were applied ranging from 0.5 to 1.5 J/cm² (continuous ablation) and from 4 to 24 J/cm² (fractional ablation). Fluorescence microscopy was used for detecting PpIX‐induced fluorescence. Compared to skin without laser pretreatment, mean fluorescence intensity (MFI) of PpIX was enhanced 13.8‐fold after continuous ablation with 1.0 J/cm² and 7.3‐fold after fractional ablation with 4 J/cm²; each laser procedure was followed by 4‐h incubation with lipophilic ALA cream. Optimal parameters for continuous ablation without damage to the epidermis were 1 J/cm² for both formulations, fractional ablation was best with 4 J/cm². Histological evaluations of laser‐treated skin showed necrosis and apoptosis, depending on light dose. In laser‐stripped skin, PpIX fluorescence was detected earlier and reached deeper epidermal layers than in untreated skin. Continuous laser ablation induced higher PpIX fluorescence levels than fractional ablation. This method offers a promising new tool for enhancing ALA penetration in PDT without damaging the underlying tissue.     

The European Trauma Course (ETC) and the team approach: Past,present and future

The European Trauma Course (ETC) was officially launched during the international conference of the European Resuscitation Council (ERC) in 2008. The ETC was developed on behalf of ESTES (European Society of Trauma and Emergency Surgery), EuSEM (European Society of Emergency Medicine), the ESA (European Society of Anaesthesiology) and the ERC. The objective of the ETC is to provide an internationally recognised and certified life support course, and to teach healthcare professionals the key principles of the initial care of severely injured patients. Its core elements, that differentiates it from other trauma courses, are a strong focus on team training and a novel modular design that is adaptable to the differing regional European requirements.This article describes the lessons learnt during the European Trauma Course development and provides an outline of the planned future development.     

Degradation of cytoplasmic substrates by FtsH,a membrane-anchored protease with many talents

Control of cellular processes by regulated proteolysis is conserved among all organisms. FtsH, the only membrane-anchored AAA protease in bacteria, fulfills a variety of regulatory functions. This review focuses on soluble FtsH substrates in Escherichia coli and in other bacteria and outlines emerging substrate recognition principles.     

Melatonin protects kidney grafts from ischemia/reperfusion injury through inhibition of NF-kB and apoptosis after experimental kidney transplantation

Abstract:  Free radicals are involved in pathophysiology of ischemia/reperfusion injury (IRI). Melatonin is a potent scavenger of reactive oxygen and nitrogen species. Thus, this study was designed to elucidate its effects in a model of rat kidney transplantation. Twenty Lewis rats were randomly divided into 2 groups (n = 10 animals each). Melatonin (50 mg/kg BW) dissolved in 5 mL milk was given to one group via gavage 2 hr before left donor nephrectomy. Controls were given the same volume of milk only. Kidney grafts were then transplanted into bilaterally nephrectomized syngeneic recipients after 24 hr of cold storage in Histidine–Tryptophan–Ketoglutarate solution. Both graft function and injury were assessed after transplantation through serum levels of blood urea nitrogen (BUN), creatinine, transaminases, and lactate dehydrogenase (LDH). Biopsies were taken to evaluate tubular damage, the enzymatic activity of superoxide dismutase (SOD) and lipid hydroperoxide (LPO), and the expression of NF-kBp65, inducible nitric oxide synthase (iNOS), caspase-3 as indices of oxidative stress, necrosis, and apoptosis, respectively. Melatonin improved survival ( P  < 0.01) while decreasing BUN, creatinine, transaminases, and LDH values up to 39–71% ( P  < 0.05). Melatonin significantly reduced the histological index for tubular damage, induced tissue enzymatic activity of SOD while reducing LPO. At the same time, melatonin down-regulated the expression of NF-kBp65, iNOS, and caspase-3. In conclusion, donor preconditioning with melatonin protected kidney donor grafts from IRI-induced renal dysfunction and tubular injury most likely through its anti-oxidative, anti-apoptotic and NF-kB inhibitory capacity.