Laterality in familiar face recognition: a meta-analysis

An extensive series of experiments has recently led to the hypothesis that face recognition, which had been considered a right-hemisphere specialization, may actually be bilaterally processed in the two hemispheres. In the present study an attempt was made to solve the conundrum of the laterality of face recognition by performing a meta-analysis on studies of familiar face recognition. Results of six studies measuring reaction time of familiar face naming and of eleven studies measuring accuracy of familiar face naming were transformed to standard Z scores. The average Z scores for reaction time and for accuracy were then tested for their significance. The results suggested that face recognition is not lateralized. This conclusion is consistent with theories of bihemispheric cognitive resources and with the latest brain-imaging data.     

Test models to determine cleaning efficacy with different types of bioburden and its clinical correlation

The importance of cleaning as a first crucial step in reprocessing instruments and endoscopes is recognized worldwide. However, no standards to determine the efficacy of cleaning have been established. We have therefore investigated Bodedex forte, a new cleaner, in various test models derived from critical types of bioburden on flexible endoscopes. Removal of dried blood from metal carriers was determined in comparison with standard instrument disinfectants. Removal of biofilm endotoxin from silicone test pieces and removal of dried X-ray contrast medium from polyethylene pieces was measured in comparison with one other standard cleaner. Residual bacteria in a biopsy channel from duodenoscopes following use of Bodedex forte, compared with two other cleaners, were measured in an endoscopy unit. After 15 min exposure to Bodedex forte, 95% of the dried blood were removed. Removal was between 0 and 86% with the disinfectants. Bodedex forte reduced endotoxin by 1.91+0.19 log(10)-steps compared with 0.43+0.19 log(10)-steps Cidezyme (P < 0.001) two-sided t-test). Removal of dried X-ray contrast medium was 99% with Bodedex forte and 94% with a conventional cleaner. No bacterial contamination after reprocessing was found in 98% of duodenoscopes with Bodedex forte (78 duodenoscopes), in 72% with a conventional cleaner (129 duodenoscopes) and in 69% with an enzymatic cleaner (100 duodenoscopes). The difference between the three cleaners was significant (P < 0.001) chi-squared test). The superiority of the cleaning capacity of the new cleaner was demonstrated in various test models, which were designed according to the clinical relevance of different bioburdens. Implementation of accepted and reproducible standards for testing the cleaning efficacy will remain a goal for the next years.     

Efficacy of alcohol-based gels compared with simple hand wash and hygienic hand disinfection

A recent research letter on the limited efficacy of alcohol-based hand gels has alerted the global infection control community and raised the question of the true significance of data obtained according to EN 1500. It has been described that a 1 min simple hand wash reduces artificial contamination of hands by a log(10) reduction factor of 2.8 and a 1 min reference hand disinfection with 2-propanol (60%, v/v) by a factor of 4.6 steps. The EN 1500 gel data show that the 30 s efficacy of most gels is closer to a simple hand wash than to the reference hand disinfection. The 30 s efficacy of most alcohol-based liquid products and one gel, however, is almost identical to the reference hand disinfection. In many European countries alcohol-based liquid products have been established as a standard practice in hygienic hand disinfection for decades. Replacement of these products with most available gels would be a step backward in terms of efficacy and has still to be seen critically from the efficacy point of view.     

Suitability of Sterillium Gel for surgical hand disinfection

In some countries, alcohol-based hand gels are used for hygienic hand disinfection but their efficacy and suitability for surgical hand disinfection has never been investigated. The efficacy of Sterillium Gel was investigated according to prEN 12791 in two separate experiments. Finger tips of 20 volunteers per experiment were sampled for resident skin bacteria before surgical hand disinfection. In a cross-over design, each volunteer carried out a surgical hand disinfection with the reference alcohol [n-propanol 60%, (v/v)] or Sterillium Gel [ethanol 85% (v/v)] for 3 min. After the product application, one hand was sampled for the immediate effect, the other hand was gloved for 3 h and then sampled for the sustained effect. Samples were analysed for remaining resident bacteria. The mean of the pre-value, the 0 h and 3 h values of the reference disinfection and the test product were calculated. With the reference alcohol, respective mean immediate log10-reduction factors of 2.06+/-0.76 and 2.23+/-1.13 were found in both experiments. The mean sustained effects with the reference alcohol were 2.03+/-1.14 and 1.44+/-0.81. Sterillium Gel achieved respective mean immediate effects of 2.48+/-1.06 and 2.13+/-0.81, the mean sustained effects were 2.77+/-0.95 and 2.18+/-0.72. They proved significantly larger than those obtained with the reference alcohol (P<0.05; pair-wise Wilcoxon test). Sterillium Gel, therefore, more than fulfils the efficacy requirements for surgical hand disinfection of prEN 12791. In addition, 25 of 26 operating theatre healthcare workers in an orthopaedic hospital found it suitable for surgical hand disinfection after a single use, which included putting on a pair of surgical gloves. Although none of them had ever used an alcohol-based gel before, they had rather been accustomed to alcohol-based liquid products for years. The main reasons given for the positive assessment were better skin feeling after use, smell and easier donning of the surgical gloves. No significant correlation was found between overall or dermal acceptance and years of professional experience, profession or number of gel portions used for surgical hand disinfection (Pearson's correlation; P>0.05).     

Expression of soma-restricted proteolipid/DM20 proteins in lymphoid cells

A new family of the myelin proteolipid protein (PLP/DM20) gene products, srPLP/DM20, has been identified recently in thymus and brain. In the central nervous system, srPLP/DM20 products are not localized in the myelin membrane, unlike their classic PLP/DM20 counterparts. In the immune system, the classic PLP/DM20 products appear to be expressed predominantly in thymic cortical epithelium. In this study, we examined the cellular expression of sr-PLP/DM20 proteolipids in lymphoid tissues and cells by immunohistochemistry, FACS analysis and RT-PCR. We found that in contrast to the classic PLP/DM20 products, sr-proteins are mainly expressed in developing thymocytes in thymus and in T- and B-lymphocytes in spleen. These results are of importance in our further understanding, not only the different role of these new PLP gene products in central and peripheral tolerance, but also the function of such products in lymphocyte biology.     

Microbicidal Activity of a New Silver-Containing Polymer, SPI-ARGENT II

The survival of three bacterial species and Candida albicans was studied on SPI-ARGENT II. The immediate recovery from silver-impregnated polymer and control polymer (1 cm²) was ~10⁶ to 10⁷ microorganisms. After incubation (37°C) and neutralization of silver with horse serum (5%), surviving organisms were recovered. The survival of the microorganisms on the polymer was not found to be influenced by the silver implantation.     

A 1-minute hand wash does not impair the efficacy of a propanol-based hand rub in two consecutive surgical hand disinfection procedures

We studied the effect of a 1-min hand wash on the bacterial hand flora in two consecutive surgical hand disinfection procedures. A propanol-based hand rub (PBHR; Sterillium®) and n-propanol (60%, v/v) were tested in a Latin-square design according to EN 12791 in four variations. The reference alcohol was always applied for 3 min after a 1-min hand wash (variation 1). The PBHR was applied for 1.5 min (first application) or 0.5 min (second application). Variation 2 included a 1-min hand wash before both applications, variation 3 included the hand wash before application 1, in variation 4 hands were not washed at all before application. Pre- and post-values were obtained according to EN 12791. The reference disinfection reduced bacteria by 2.99 log₁₀ (immediate efficacy) and 2.22 log₁₀ after 3 h. The second reference disinfection reduced bacteria by 0.95 log₁₀ (immediate efficacy) and 0.68 log₁₀ after 3 h. The PBHR always yielded an equivalent reduction with and without a preceding hand wash (p?>?0.05; Friedman test). A 1-min hand wash before application of the PBHR did not significantly change its efficacy for surgical hand disinfection in two consecutive surgical procedures of 3 h.