OCD-like checking in the lab: A meta-analysis and improvement of an experimental paradigm

Van den Hout and Kindt (2003a) developed a Virtual Gas Stove Checking paradigm. They demonstrated that repeated checking resulted in lower confidence and reduced the vividness and detail of recollections. Over the past decades, many experiments have used (an adaptation of) this experimental paradigm to study phenomena related to obsessive compulsive disorders (OCD). The first aim of the present study was to conduct a meta-analysis of experiments (k = 28; N = 1662) on the repeated checking paradigm. Repeated checking was found to have large effects on decreases in memory confidence, vividness and detail. Unexpectedly, repeated checking also produced small reductions in memory accuracy. The second aim of the present study was to develop an improved version of the checking paradigm in which 1) stimuli presentations were fully balanced; and 2) the checking latency was comparable across stimuli in order to 3) assess actual checking behavior. The improved version (Virtual checking task 2.0) replicated earlier findings on meta-memory.FSW – Publicaties zonder aanstelling Universiteit Leide

Low prevalence of non-typable Methicillin-resistant Staphylococcus aureus in meat products in The Netherlands

Recently, a new clone of methicillin resistant Staphylococcus (S.) aureus (MRSA) emerged in the Netherlands that was related to pigfarming. A survey in pigs showed that nearly 40% carried this new clone. This new type is characterised by bemg untypable with pulsed field gel electrophoresis (PFGE). This study was undertaken to determme the prevalence and genetic relationship of S.aureus and MRSA in meal products

Differential epitope recognition in the immunodominant staphylococcal antigen A of Staphylococcus aureus by mouse versus human IgG antibodies

The immunodominant staphylococcal antigen A (IsaA) is a potential target for active or passive immunization against the important human pathogen _Staphylococcus aureus_. Consistent with this view, monoclonal antibodies against IsaA were previously shown to be protective against _S. aureus_ infections in mouse models. Further, patients with the genetic blistering disease epidermolysis bullosa (EB) displayed high IsaA-specific IgG levels that could potentially be protective. Yet, mice actively immunized with IsaA were not protected against _S. aureus_ infection. The present study was aimed at explaining these differences in IsaA-specific immune responses. By epitope mapping, we show that the protective human monoclonal antibody (humAb) 1D9 recognizes a conserved 62-residue N-terminal domain of IsaA. The same region of IsaA is recognized by IgGs in EB patient sera. Further, we show by immunofluorescence microscopy that this N-terminal IsaA domain is exposed on the _S. aureus_ cell surface. In contrast to the humAb 1D9 and IgGs from EB patients, the non-protective IgGs from mice immunized with IsaA were shown to predominantly bind the C-terminal domain of IsaA. Altogether, these observations focus attention on the N-terminal region of IsaA as a potential target for future immunization against _S. aureus_

Differential epitope recognition in the immunodominant staphylococcal antigen A of Staphylococcus aureus by mouse versus human IgG antibodies

The immunodominant staphylococcal antigen A (IsaA) is a potential target for active or passive immunization against the important human pathogen Staphylococcus aureus. Consistent with this view, monoclonal antibodies against IsaA were previously shown to be protective against S. aureus infections in mouse models. Further, patients with the genetic blistering disease epidermolysis bullosa (EB) displayed high IsaA-specific IgG levels that could potentially be protective. Yet, mice actively immunized with IsaA were not protected against S. aureus infection. The present study was aimed at explaining these differences in IsaA-specific immune responses. By epitope mapping, we show that the protective human monoclonal antibody (humAb) 1D9 recognizes a conserved 62-residue N-terminal domain of IsaA. The same region of IsaA is recognized by IgGs in EB patient sera. Further, we show by immunofluorescence microscopy that this N-terminal IsaA domain is exposed on the S. aureus cell surface. In contrast to the humAb 1D9 and IgGs from EB patients, the non-protective IgGs from mice immunized with IsaA were shown to predominantly bind the C-terminal domain of IsaA. Altogether, these observations focus attention on the N-terminal region of IsaA as a potential target for future immunization against S. aureus

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil