含丙醇基质护手霜中的润肤剂能显著减轻刺激性接触性皮炎

本研究旨在确定含丙醇护手霜的润肤剂对皮肤干燥和红斑的作用。35例受试者参与该前瞻性、随机、对照、双盲试验，其中约半数具有遗传过敏体质（改进的Erlanger遗传过敏体质评分≥8）。应用两种含丙醇基质的制剂进行反复开放敷贴试验，其中一种含混和润肤剂（0．81％，w／w）。每一制剂两等分各为0．7ml，随机分配给所有受试者后涂至肘窝皮肤，2次／d，持续两周以上。在每次用药前和最后一次用药3d后，根据标准评分，通过视觉检测评估治疗部位的红斑和干燥情况。所有评价时点的总分作为原始参数。     

Evaluation of Mannitol Salt Agar for Detection of Oxacillin Resistance in Staphylococcus aureus by Disk Diffusion and Agar Screening

Mannitol salt agar was evaluated for detection of oxacillin resistance in 136 Staphylococcus aureus isolates. All mecA-positive isolates (n = 54) were correctly categorized as oxacillin resistant by the disk diffusion test (1-μg disk; zone diameter, <16 mm); the specificity was 97.6%. Agar screening (2 μg of oxacillin per ml) revealed a sensitivity of 98.1% and a specificity of 95.1%.     

Comparison of screening methods to identify methicillin-resistantStaphylococcus aureus

Screening methods to identify methicillin-resistantStaphylococcus aureus (MRSA) were compared using 96 isolates representing 17 distinct clones. The sensitivity of four commercial agglutination tests was determined in comparison to the tube coagulation test, and the results related to the presence of the coagulase gene. The broth screening test, agar dilution test and disc diffusion test were carried out, and the results related to the presence of themecA gene. Mannitol salt agar and Iso-Sensitest agar with varying salt supplements were used. All agglutination tests had high rates of detection ofStaphylococcus aureus (95.8–99.0%). Resistance in mecA gene-positiveStaphylococcus aureus isolates was correctly detected by the oxacillin broth test, the agar dilution test and the disc diffusion test on mannitol salt agar, whereas on Iso-Sensitest agar detection rates were lower (between 68.5% and 94.4%, depending on the salt supplement). Incubation of the Iso-Sensitest plates for 48 hours significantly improved the rate of detection of resistance, but increased the major error rate up to 71.4%.MecA genepositiveStaphylococcus aureus isolates not detected by the disc diffusion test on Iso-Sensitest agar had significantly lower oxacillin minimal inhibitory concentration values and were significantly less resistant to a variety of antibiotics. Thus, mannitol salt agar might be a suitable medium for use in the disc diffusion and agar dilution test to detect resistance to oxacillin inStaphylococcus aureus.     

Urinary excretion ofD-glucaric acid,an indicator of drug metabolizing enzyme activity,in patients with impaired renal function

Summary The urinary excretion rate ofD-glucaric acid, an in vivo parameter of the activity of drug metabolizing enzymes, has been determined in patients with chronic renal insufficiency (glomerular filtration rate 4.5–80 ml/min/1.73 m²). The mean value of 22.3 µmoles/d (SD 7.2; n 28) was almost identical to that of healthy controls (22.1 µmoles/d, SD 7.3; n 22). Thus, no inhibitory or enhancing effect of renal insufficiency could be detected. The ability of this parameter to indicate alterations in the activity of hepatic drug metabolism, even in patients with renal insufficiency, was demonstrated by the increased excretion rate of glucaric acid (107 µmoles/d, SD 43.5; n 8; p<0.001) after treatment for 7 days with the enzyme inducer phenobarbital. No significant correlation was found between glucaric acid excretion and sex, age, body weight or body surface in 50 patients. Glucaric acid excretion, therefore, should not be related to the creatinine content of urine samples, since creatinine excretion decreases with severity of renal insufficiency and varies with sex, age, body weight and many other conditions. A single dose of dipyrone (Novalgin^®), a further in vivo indicator of drug metabolism, increased glucaric acid excretion on the same day, but no interference was found after a single dose of cortisol.     

Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted Achromobacter species 3, when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%). Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation.Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential.     

Is peracetic acid suitable for the cleaning step of reprocessing flexible endoscopes?

The bioburden(blood, protein, pathogens and biofilm) on flexible endoscopes after use is often high and its removal is essential to allow effective disinfection, es-pecially in the case of peracetic acid-based disinfect-ants, which are easily inactivated by organic material. Cleaning processes using conventional cleaners remove a variable but often sufficient amount of the biobur-den. Some formulations based on peracetic acid are recommended by manufacturers for the cleaning step. We performed a systematic literature search and re-viewed the available evidence to clarify the suitability of peracetic acid-based formulations for cleaning flex-ible endoscopes. A total of 243 studies were evaluated. No studies have yet demonstrated that peracetic acid-based cleaners are as effective as conventional clean-ers. Some peracetic acid-based formulations have dem-onstrated some biofilm-cleaning effects and no biofilm-fixation potential, while others have a limited cleaning effect and a clear biofilm-fixation potential. All published data demonstrated a limited blood cleaning effect and a substantial blood and nerve tissue fixation potential of peracetic acid. No evidence-based guidelines on reproc-essing flexible endoscopes currently recommend using cleaners containing peracetic acid, but some guidelines clearly recommend not using them because of their fixa-tion potential. Evidence from some outbreaks, especially those involving highly multidrug-resistant gram-negative pathogens, indicated that disinfection using peracetic acid may be insufficient if the preceding cleaning step is not performed adequately. Based on this review we conclude that peracetic acid-based formulations should not be used for cleaning flexible endoscopes.     

Direct measurement of the viscoelectric effect in water

The viscoelectric effect concerns the increase in viscosity of a polar liquid in an electric field due to its interaction with the dipolar molecules and was first determined for polar organic liquids more than 80 y ago. For the case of water, however, the most common polar liquid, direct measurement of the viscoelectric effect is challenging and has not to date been carried out, despite its importance in a wide range of electrokinetic and flow effects. In consequence, estimates of its magnitude for water vary by more than three orders of magnitude. Here, we measure the viscoelectric effect in water directly using a surface force balance by measuring the dynamic approach of two molecularly smooth surfaces with a controlled, uniform electric field between them across highly purified water. As the water is squeezed out of the gap between the approaching surfaces, viscous damping dominates the approach dynamics; this is modulated by the viscoelectric effect under the uniform transverse electric field across the water, enabling its magnitude to be directly determined as a function of the field. We measured a value for this magnitude, which differs by one and by two orders of magnitude, respectively, from its highest and lowest previously estimated values.

The viscoelectric effect concerns the change in the viscosity of polar liquids in the presence of an electric field (1–3). It arises from the interaction of the field with the dipolar molecules, and while its molecular origins are still not well understood (4–6), it has considerable relevance in areas ranging from surface potential measurements (7–9) and boundary lubrication (10) to nanofluidics and its applications (11–13). Knowing the magnitude of the viscoelectric effect is thus of clear importance. It was first measured by Andrade and Dodd (1–3) for a range of polar organic liquids, by monitoring their flow in a narrow channel between metal electrodes across which a known electric field E was applied, and quantified via a viscoelectric coefficient f using an empirical relation based on their results:η(E)= η0(1 + f∣E∣2),[1]a simplified analysis leading to such a relation is given in Ref. (8). Here, η₀ is the unperturbed bulk liquid viscosity (i.e., in the absence of any field). For the case of water, however, the most ubiquitous and important polar liquid, measurement of its viscosity in the presence of a strong, uniform field presents a strong challenge (as discussed later in this section), and to our knowledge no such direct measurements have been reported. Over the past six decades, therefore, the magnitude of the viscoelectric effect in water has been only indirectly estimated by extrapolation from its values for organic liquids (8), from estimates of its effect on electrokinetic phenomena (11, 14–19), or by other approaches (7, 12, 20, 21). These estimated values, as expressed in the viscoelectric coefficient f, vary over more than three orders of magnitude, ranging from f ∼10⁻¹⁷–2.5 × 10⁻¹⁴ (V/m)² (SI Appendix, Section 7). For completeness, we note that results contradictory to the viscoelectric model have also been reported (22) (i.e., suggesting a decreased water viscosity in an electric field). The reasons for the large span of these estimated f values were attributed to various factors such as solid/liquid coupling, varying ionic sizes, and varying water permittivity (12, 19); however, while these factors may play some role, there is no evidence that they could lead to such large discrepancies.We believe, rather, that the origin of the large variance in the estimated magnitude of the viscoelectric effect arises because none of the experimental studies on water to date in which the f values were estimated was direct, in the sense of probing how the water viscosity varied with field in a uniform electric field. In all cases, viscosity changes were assumed to occur only in the nonuniform, rapidly decaying electrostatic potential near charged surfaces immersed in water. Changes in electrophoretic mobility, electro-osmosis, or hydrodynamic dissipation or water mobility between similarly charged solid surfaces were then attributed to some mean viscosity increase in these thin surface-adjacent layers (7, 11, 12, 14–21). In practice, however, the effect on these electrokinetic phenomena of viscosity or water mobility changes in the thin layers where such nonuniform, rapidly decaying fields are present is not easy to quantify reliably, especially in the presence of salt ions (12). At the same time, measuring the viscosity of water in a uniform electric field between two surfaces at different potentials, as was done for the polar organic solvents (2, 3) and which would provide a direct determination of its viscoelectric effect, presents a considerable difficulty. This is due to two main factors and arises because, in contrast to organic solvents, water may self-dissociate. Firstly, the potential difference that may be applied between the surfaces across water is limited, if electrolysis is to be avoided (23, 24), and secondly, electrostatic screening implies that the field decays strongly (within a Debye screening length) away from the surfaces (25–27). Even in purified water with no added salt (as in the present study), the potential decays rapidly away from a charged surface (see, e.g., Fig. 1C), so that to measure viscosity in a uniform field between two surfaces, one would require flow channels of width of order some tens of nanometers or less, presenting a major challenge.Open in a separate windowFig. 1.Numerical solution to the nonlinearized PB equation with σ_mica = −8.1 mC/m², ψ_gold = 0.07 V, and ion concentration c_b = 8 × 10⁻⁵ M, corresponding to the conditions of Fig. 4A. (A) Surface potential on the mica surface and surface charge on the gold surface as a function of separation D. (B) Average electric field approximated as (|ψ_gold − ψ_mica|/D). (C) Local potential ψ as a function of distance d from the mica surface for different separations D. Dashed line in larger-scale inset is an eye guide of a linear approximation.In the present study, we overcome this by directly probing the viscosity of purified water across which a uniform electric field acts while it is confined between two surfaces in a surface force balance (SFB). In our experiments, a molecularly smooth gold surface at a controlled (positive) surface potential approaches an atomically smooth mica surface at constant surface (negative) charge density, so that a known electric field acts across the water-filled gap of width D between them; moreover, this field is very close to uniform at the most relevant surface separations (D ≲ 30 nm, Fig. 1C). The dynamics of approach is strongly modulated by the viscous damping due to squeeze-out of the water as D decreases, and hence by its viscosity in the uniform electric field; by monitoring the approach rate of the surfaces at high temporal (millisecond) and spatial (approximately angstrom) resolutions, we are able therefore to directly evaluate the magnitude of the viscoelectric effect (the value of f).     

Surgical hand disinfection with a propanol-based hand rub: equivalence of shorter application times

The aim of this study was to determine the efficacy of a propanol-based hand rub at application times shorter than 3 min. The bacterial pre-value was obtained from the finger tips (prEN 12791). Subjects treated their hands with the reference procedure (n-propanol, 60%) for 3 min or the product (crossover design). Sterillium was applied for 3, 2, 1.5 and 1 min. Four other preparations were tested for 1 min. Post-values (immediate effect) were taken from one hand, and the other hand was gloved for 3h. After the gloves were removed, the second post-value was taken (sustained effect). Sterillium was more effective than the reference procedure at 3, 2 and 1.5 min (immediate and sustained effect). The immediate effect after 1 min was significantly lower [mean log(10) reduction factor (RF): 1.91+/-0.90 vs. 2.52+/-0.95; P=0.001], whereas the sustained effect was not (mean RF: 1.81+/-1.06 vs. 2.05+/-1.14; P=0.204). All other preparations failed the efficacy requirement at 1 min for both the immediate and sustained effect. Using 2 x 3 mL Sterillium for a total of 1.5 min for surgical hand disinfection was at least as effective as the 3-min reference disinfection.