Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase II).

To replace the Draize skin irritation assay (OECD guideline 404) several test methods based on reconstructed human epidermis (RHE) have been developed and were adopted in the OECD test guideline 439. However, all validated test methods in the guideline are linked to RHE provided by only three companies. Thus, the availability of these test models is dependent on the commercial interest of the producer. To overcome this limitation and thus to increase the accessibility of in vitro skin irritation testing, an open source reconstructed epidermis (OS-REp) was introduced. To demonstrate the capacity of the OS-REp in regulatory risk assessment, a catch-up validation study was performed. The participating laboratories used in-house generated OS-REp to assess the set of 20 reference substances according to the performance standards amending the OECD test guideline 439. Testing was performed under blinded conditions. The within-laboratory reproducibility of 87% and the inter-laboratory reproducibility of 85% prove a high reliability of irritancy testing using the OS-REp protocol. In addition, the prediction capacity was with an accuracy of 80% comparable to previous published RHE based test protocols. Taken together the results indicate that the OS-REp test method can be used as a standalone alternative skin irritation test replacing the OECD test guideline 404.

The role of regulatory T cell (Treg) subsets in gestational diabetes mellitus.

Physiological changes during normal pregnancy are characterized by an inflammatory immune response and insulin resistance. Therefore, we hypothesize that gestational diabetes mellitus (GDM) may be caused by an inappropriate adaption of the maternal immune system to pregnancy. In this study we examined the role of regulatory T cell (Treg) differentiation for the development of GDM during pregnancy. We used six-colour flow cytometric analysis to demonstrate that the total CD4(+) CD127(low+/-) CD25(+) forkhead box protein 3 (FoxP3(+)) T(reg) pool consists of four different T(reg) subsets: naive CD45RA(+) T(regs), HLA-DR(-) CD45RA(-) memory T(regs) (DR(-) T(regs)) and the highly differentiated and activated HLA-DR(low+) CD45RA(-) and HLA-DR(high+) CD45RA(-) memory T(regs) (DR(low+) and DR(high+) T(regs)). Compared to healthy pregnancies, the percentage of CD4(+) CD127(low+/-) CD25(+) FoxP3(+) T(regs) within the total CD4(+) T helper cell pool was not different in patients affected by GDM. However, the suppressive activity of the total CD4(+) CD127(low+/-) CD25(+) T(reg) pool was significantly reduced in GDM patients. The composition of the total T(reg) pool changed in the way that its percentage of naive CD45RA(+) T(regs) was decreased significantly in both patients with dietary-adjusted GDM and patients with insulin-dependent GDM. In contrast, the percentage of DR(-) -memory T(regs) was increased significantly in patients with dietary-adjusted GDM, while the percentage of DR(low+) and DR(high+) memory T(regs) was increased significantly in patients with insulin-dependent GDM. Hence, our findings propose that alterations in homeostatic parameters related to the development and function of naive and memory T(regs) may cause the reduction of the suppressive capacity of the total T(reg) pool in GDM patients. However, as this is an exploratory analysis, the results are only suggestive and require further validation.

The success of assisted reproduction technologies in relation to composition of the total regulatory T cell (Treg) pool and different Treg subsets.

STUDY QUESTION: Are there differences in composition of the total regulatory T cell (Treg) pool and distinct Treg subsets (naïve CD45RA(+)-Tregs, HLA-DR(-)- and HLA-DR(+)-memory Tregs) between successfully and non-successfully IVF/ICSI-treated women? SUMMARY ANSWER: Non-successfully IVF/ICSI-treated women have a decreased percentage of naïve CD45RA(+)-Tregs and an increased percentage of HLA-DR(-)-memory Tregs within the total Treg pool. WHAT IS KNOWN ALREADY: Immunosuppressive Tregs play a significant role in human reproduction and studies have shown that their number and function are reduced in reproductive failure and complications of pregnancy such as pre-eclampsia and preterm labor. However, no data exist concerning the importance of Tregs for a successful outcome following assisted reproduction technologies. STUDY DESIGN, SIZE, DURATION: Blood samples were obtained from 210 women undergoing IVF/ICSI treatment, where 14 patients were excluded due to biochemical pregnancy or missed abortion. Age control blood samples were collected from 20 neonates and 176 healthy female volunteers. The study was performed between October 2010 and March 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS: In this study, we determined prospectively the quantity and composition of the total CD4(+)CD127(low+/-)CD25(+)FoxP3(+)-Treg pool and three different Treg subsets (naïve CD45RA(+)-Tregs, HLA-DR(-)- and HLA-DR(+)-memory Tregs) in all women undergoing IVF/ICSI treatment. We examined whether there were differences between those who became pregnant (n = 36) and those who did not (n = 160). The blood samples were collected within 1 h before the embryo transfer and analyzed by six-color flow cytometry. In order to evaluate these results with regard to the normal age-related changes in composition of the total Treg pool, the same analysis was performed using samples of umbilical cord blood and from healthy female volunteers aged between 17 and 76 years. The composition of the total Treg pool was documented for successfully IVF/ICSI-treated women (n = 5) throughout their pregnancy and we assessed the suppressive activity of each Treg subset in pregnant (n = 10) compared with non-pregnant women (n = 10) using suppression assays. MAIN RESULTS AND ROLE OF CHANCE: The percentage of CD4(+)CD127(low+/-)CD25(+)FoxP3(+)-Tregs within the total CD4(+)-T cell pool did not change with age and did not differ between IVF/ICSI-treated women who did or did not become pregnant. For the total Treg pool, the percentage of the naïve CD45RA(+)-Tregs decreased continuously, while the percentage of HLA-DR(-)- and HLA-DR(+)-memory Tregs increased with aging. From the age of about 40 years, the increase in HLA-DR(+)-memory Tregs in particular became less pronounced, indicating that conversion of naïve CD45RA(+)Tregs into HLA-DR(+)-memory Tregs decreases with age. Women who did not achieve a pregnancy with IVF/ICSI were older than those who did (P < 0.01). However, multiple logistic regression analysis revealed that irrespective of age, the percentage of naïve CD45RA(+)-Tregs within the total Treg pool was decreased (P < 0.05), while the percentage of HLA-DR(-)-memory Tregs was increased (P < 0.01) in women who did not become pregnant compared with those who did. At the beginning of pregnancy, naïve CD45RA(+)-Tregs showed a major decrease but increased again during pregnancy and these cells showed a higher suppressive activity (P < 0.0001) in pregnant compared with non-pregnant women. LIMITATIONS, REASONS FOR CAUTION: There was a large variation in the percentages of the Treg subsets within the total Treg pool between successfully and non-successfully IVF/ICSI-treated women. Therefore, their determination would not allow us to predict the IVF/ICSI outcome with sufficient specificity and sensitivity. We did not examine the antigen specificity of the Treg subsets and therefore could not discern whether the naïve CD45RA(+)-Tregs recognized maternal or paternal antigens. WIDER IMPLICATIONS OF THE FINDINGS: Our findings suggest that Tregs, especially the naïve CD45RA(+)-Treg subset, may play a role in determining the probability of both becoming pregnant and maintenance of the pregnancy. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the German Research Council (DFG) grant STE 885/3-2 (to A.S.). All authors declare to have no conflict of interest.

Determination of optical parameters for light penetration in particulate materials and soils with diffuse reflectance (DR) spectroscopy.

The results of our investigations of particulate materials (aluminium oxide, quartz sand) and "real world" soils (a brown sand and a dark brown soil) using diffuse reflectance (DR) spectroscopy are presented. The findings are discussed within the framework of Kubelka-Munk (KM) theory as a simplified description of light propagation in highly turbid media. The relation between the KM and the Lambert-Beer (LB) treatment is outlined. The KM parameters determined were the scattering and absorption coefficients (S and K, respectively), and the light penetration depths, dp(KM). It was found that in the UV/VIS spectral range the scattering coefficients of the materials investigated vary by ca. one order of magnitude (S = 6-> 100 cm-1), whereas the absorption coefficients change by more than three orders of magnitude (K = < 1-> 1500 cm-1). The different absorption and scattering properties of the materials lead to strong variations in light penetration depths from the micron into the mm regime [dp(KM) = < 20-> 3500 microns].

Combination of laser-induced fluorescence and diffuse-reflectance spectroscopy for the in situ analysis of diesel-fuel-contaminated soils.

Results of our laser-induced fluorescence (LIF) and diffuse-reflectance investigations of quartz sand and different soils spiked with Diesel fuel are reported. The LIF calibration functions, which were found to be significantly different for the various matrices, and the limits of detection were determined. For excitation at lambda(ex) = 266 nm, the limits of detection obtained ranged from 7 parts in 10(6) for quartz sand to approximately 200 parts in 10(6) for dark sand with organic matter and for dark peat. Furthermore, the diffuse-reflectance spectra of the matrices in the ultraviolet-near-IR range were determined. An attempt to correlate the slopes of the LIF calibration functions with the reflectances of the matrices is presented. The obtained normalized calibration functions are well suited to take into account relevant optical soil parameters and to reduce the variability of the LIF calibration behavior significantly.