Impact of Steroids on the Inflammatory Response after Ischemic Acute Kidney Injury in Rats.

Inflammation plays a crucial role in acute kidney injury (AKI). The current study was designed to analyze the influence of prednisolone treatment on the inflammatory reaction during the first 96 h after AKI induction in a rat model. AKI was induced by unilateral clipping of the renal vessels. The treatment group received prednisolone 5 mg/kg s.c. daily. Infiltration rates of macrophages, leukocytes, and T-cells (24, 96 h) as well as plasma concentrations of the inflammatory markers intercellular adhesion molecule, interleukin-1 beta (IL-1ß), IL-18, IL-6, and tumor necrosis factor-alpha (0, 6, 24, 96 h) were determined by fluorescence-activated cell sorting (FACS) analysis only. Ninety-six hours after AKI induction, the prednisolone group demonstrated significantly lower creatinine concentrations compared to the control group (P < 0.05). Twenty-four hours after induction of AKI, a significantly higher rate of infiltrating leukocytes was detectable with FACS analysis in the control group (P < 0.01) with a corresponding significantly higher rate of macrophages after 96 h (P < 0.01). IL-6 and IL-1ß demonstrated a peak after 6 h with a significantly higher release in the control group (IL-6: P < 0.01; IL-1ß: P < 0.05). In contrast to the control group, the prednisolone group demonstrated no further incline of IL-18 after 24 h. The results demonstrate the importance of stretching the observation period in an ischemia-reperfusion-induced AKI setting beyond the first 24 h. Despite the demonstrated protective effects of a continuous prednisolone application, it seems that this single anti-inflammatory agent will not be able to completely suppress the inflammatory response after an ischemia-reperfusion-induced AKI.

Role of p53 in aziridinylbenzoquinone-induced p21waf1 expression.

Quinones are the second largest family of anticancer drugs clinically used in the United States. However, their exact mode of action at the cellular and molecular level is not completely understood. We have shown earlier that the quinone 3,6-diaziridinyl-1,4-benzoquinone (DZQ) leads to the increased expression of p21waf1/cip1/sdi1 protein, an inhibitor of cyclin-dependent kinases. Because p21 has been established as an important negative regulator of the cell cycle, we further investigated the molecular basis of p21 induction by DZQ. Here we report that the induction of p21 by DZQ is regulated at the transcriptional level, and requires the activation of p53, a tumor suppressor protein. In cells that lack functional p53 protein, DZQ-mediated p21 induction is greatly diminished. However, the introduction of a wild type p53 gene into p53-negative cells restores the strong DZQ-inducibility of p21. Restoration of wild type p53 status in HL60 myeloid leukemia cells significantly increases the cells' sensitivity to the cytotoxic effects of DZQ. Thus, our results indicate that the p53-p21 pathway may play a central role in mediating the gene-regulatory and cytotoxic effects of aziridinylbenzoquinones.

Prospective multicentre study of the U-SENS test method for skin sensitization testing.

The U-SENS™ is a test method based on the human myeloid U937 cell line to assess the skin sensitisation potential of substances. To demonstrate its robustness, a multicentre validation study with four laboratories testing 24 coded substances has been conducted according to internationally agreed principles. The primary objective of the study was to enlarge the U-SENS™'s reproducibility database. Secondary objectives were to provide additional evidence on its transferability and its predictive capability. Reproducibility within laboratories was approximately 92%, while the reproducibility between laboratories was 87.5%. Predictivity for the 24 validation substances was high, with sensitivity, specificity and accuracy being on average at least 93.8%. Similar performances are obtained for 38 substances when combining the study results with those of an earlier multicentre study, as well as with an automated version of the U-SENS™. With reliability and relevance similar to comparable non-animal skin sensitisation test methods, which have achieved regulatory acceptance, it is concluded that the U-SENS™ is a well reproducible and predictive test method. This profiles the U-SENS™ as a valuable addition to the suite of non-animal testing methods for skin sensitisation with the potential to significantly contribute to the development of integrated testing strategies.

MR Imaging of Prostate Cancer: Diffusion Weighted Imaging and (3D) Hydrogen 1 (H) MR Spectroscopy in Comparison with Histology.

UNLABELLED: Purpose. To evaluate retrospectively the impact of diffusion weighted imaging (DWI) and (3D) hydrogen 1 ((1)H) MR-spectroscopy (MRS) on the detection of prostatic cancer in comparison to histological examinations. MATERIALS AND METHODS: 50 patients with suspicion of prostate cancer underwent a MRI examination at a 1.5T scanner. The prostate was divided into sextants. Regions of interest were placed in each sextant to evaluate the apparent diffusion coefficient (ADC)-values. The results of the DWI as well as MRS were compared retrospectively with the findings of the histological examination. Sensitivity and specificity of ADC and metabolic ratio (MET)-both separately and in combination-for identification of tumor tissue was computed for variable discrimination thresholds to evaluate its receiver operator characteristic (ROC). An association between ADC, MET and Gleason score was tested by the non-parametric Spearman ρ-test. Results. The average ADC-value was 1.65 ± 0.32mm(2)/s × 10(-3) in normal tissue and 0.96±0.24 mm(2)/s × 10(-3) in tumor tissue (mean ± 1 SD). MET was 0.418 ± 0.431 in normal tissue and 2.010 ± 1.649 in tumor tissue. The area under the ROC curve was 0.966 (95%-confidence interval 0.941-0.991) and 0.943 (0.918-0.968) for DWI and MRS, respectively. There was a highly significant negative correlation between ADC-value and the Gleason score in the tumor-positive tissue probes (n = 62, ρ = -0.405, P = .001). MRS did not show a significant correlation with the Gleason score (ρ = 0.117, P = .366). By using both the DWI and MRS, the regression model provided sensitivity and specificity for detection of tumor of 91.9% and 98.3%, respectively. Conclusion. The results of our study showed that both DWI and MRS should be considered as an additional and complementary tool to the T2-weighted MRI for detecting prostate cancer.

SNAP-29 is a promiscuous syntaxin-binding SNARE.

SNARE proteins are key regulators of membrane fusion and are proposed to dictate the specificity with which particular vesicles fuse with particular target organelles. On intracellular organelles that serve as targets for transport vesicles, organelle-specific syntaxins form heterodimers with either SNAP-23 or its recently described homolog SNAP-29. We have performed a variety of in vitro and in vivo binding assays in an attempt to determine whether SNAP-23 and SNAP-29 differ in their ability to form binary SNARE complexes with different intracellular syntaxins. While SNAP-23 preferentially binds to plasma membrane-localized syntaxins, SNAP-29 binds to both plasma membrane and intracellular syntaxins equally well. Furthermore, binding to SNAP-29 augments the ability of syntaxin to bind to vesicle-associated SNAREs and the presence of vesicle SNAREs dramatically increases SNAP-29 binding to syntaxin. These data suggest that SNAP-23 preferentially regulates plasma membrane-vesicle fusion events while SNAP-29 plays a role in the maintenance of various intracellular protein trafficking pathways.