Eliminating the effects of reporting bias on risk perception.

Taking the public discourse on health risks due to aluminum in antiperspirants as an example, we conducted a randomized controlled study with repeated measurements to research how selective reporting of risk information affects risk perception and trust in risk information. First, the study varied the information scope that the experimental subjects received (selective vs. complete information). Selective information highlighted that a health risk is given. Considering the full range of studies, complete information is indicated the opposite. A second variation referred to the facticity of the hazardous agent mentioned in the risk information (a reference to either an actual or fictitious agent). Moreover, the selectively informed subjects received the complete information after the effects of the selective information were measured. Four risk perceptions constructs were chosen as dependent variables, differing on two dimensions (affective vs. cognitive and personal risk vs. risk for others). In addition, subjects´ trust in the given risk information was measured. The study reveals that presenting selective information amplifies risk perceptions. The effect was observed, irrespective of whether the hazardous agent mentioned in the risk information was actual or fictitious. When subjects who first received the selective information obtained the complete information, indicating no elevated risk, risk perceptions decreased. However, the analysis also indicates that corrective information (indicating no risk) is less trusted than selective information that points to health risks. Furthermore, proper toxicological understanding, i.e., taking into account the dose-response relationship, supports the effect of corrective information on risk perceptions.

[Risk communication of the Federal Institute for Risk Assessment during a food-related outbreak]. / Risikokommunikation des Bundesinstituts für Risikobewertung bei einem lebensmittelbedingten Ausbruch.

Information about and explanation of risks as well as the initiation of behavioral changes and preventive actions are core tasks of risk communication. During the EHEC/HUS outbreak in spring 2011, the governmental agencies responsible for risk communication mainly focused on these tasks. In general, risk communication is understood as a continuous, long-term process that aims at an adequate handling of risks. In contrast, crisis communication is focused rather on an acute event and aims at timely information and behavioral measures. During the EHEC/HUS outbreak, risk communication partly changed over to crisis communication. The risk communication activities of the Federal Institute for Risk Assessment (Bundesinstitüt für Risikobewertung, BfR) during the EHEC/HUS outbreak are presented here. The results of a representative survey that was conducted in Germany shortly after the outbreak show details of the success of these risk communication activities. Finally, the necessity of communication about scientific uncertainty is addressed and new ways in risk communication with regard to new media are highlighted.

[Tasks and public perception of the Federal Institute for Risk Assessment]. / Aufgaben des Bundesinstituts für Risikobewertung und deren Wahrnehmung in der Bevölkerung.

The Federal Institute for Risk Assessment (BfR) was founded in 2002. On the basis of internationally accepted scientific criteria for risk assessment, the institute provides opinions and statements on the safety of food and feed, chemicals, commodities and on consumer health protection. In this regard, it gives advice to the Federal Government and other institutes and Stakeholder groups. BfR does its own research on subjects which are close to its remit on risk assessment. By means of its proactive and participative risk communication, the BfR renders science visible to and beneficial for society. The following overview presents the scientific remit of the BfR and the perception of consumer health protection by the public and by interest groups from the areas economics, politics, consumer associations, the media and science by means of a representative survey. Food risks are of high individual importance, especially for consumers. Here a target-specific use of social multipliers is important to interpret the differences between existing health risks and so called perceived risks.

Interleukin-1 signaling is dependent on free thiols.

Stimulation of the Interleukin-1 receptor type I (IL-1-RI) with IL-1 activates an associated serine/threonine kinase, IRAK, which phosphorylates downstream targets, resulting in NFkappaB activation. The signaling cascade is accompanied by oxidative processes and contains putative targets for redox regulation. Preincubation of the murine T cell line EL-4 and the human umbilical cord vein endothelial cell line ECV 304 with thiol modifying compounds like diamide, menadione or phenylarsine oxide inhibited the IL-1-induced phosphorylation of an endogenous substrate with a molecular mass of 60 kD. In the endothelial cell line, a second target of about 85 kD was phosphorylated after IL-1 stimulation, which was also inhibited by thiol modification. These data suggest that IL-1 signal transduction depends on free thiols which might be targets for redox regulation not only in lymphocytes, but also in endothelial cells.

Blood ethanol levels and adenylyl cyclase activity in lymphocytes of alcoholic patients.

BACKGROUND: The adenylyl cyclase (AC) signal transduction pathway is a target of acute and chronic ethanol actions. This study examined whether AC activity in lymphocyte membranes of male alcoholic patients correlated with blood concentrations of ethanol. METHODS: Patients (n = 13; mean age: 40 +/- 8 years) were studied on the day of admission (day 0) and 2 days later under detoxification. Moreover, 13 age-matched male healthy controls (mean age 40 +/- 9 years) were included. Lymphocyte membranes were prepared by differential centrifugation whereby blood ethanol was washed out. As a measure of AC activity the formation of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate was determined without (basal activity) and with stimulation of the second messenger system by the guanosine triphosphate (GTP) analogue GTP gamma S (20 mumol/L) via the G-protein or by forskolin (100 mumol/L) acting directly on the AC enzyme. RESULTS: On day 0, when ethanol blood concentrations were 38-100 mmol/L, we found a significant negative correlation between ethanol blood levels and stimulated AC activities. On day 2, the negative correlation with blood ethanol levels of day 0 had disappeared. CONCLUSIONS: The consumption of ethanol affects the AC system in lymphocytes of alcohol-dependent patients by a persistent effect on the cAMP forming enzyme.

Thiol modulation inhibits the interleukin (IL)-1-mediated activation of an IL-1 receptor-associated protein kinase and NF-kappa B.

The interleukin-1 receptor type I (IL-1RI) is associated with other proteins thus forming a complex system by which IL-1 exerts its various signals. The initiating event is still uncertain, but activation of a recently described receptor-associated protein kinase is one of the earliest events detectable (Martin et al., Eur. J. Immunol. 1994. 24: 1566). IL-1 signaling is commonly accompanied by oxidative processes and is thought to be subject to redox regulation. We therefore investigated whether the activation of the IL-1RI-associated protein kinase could be a target for redox regulation and whether an altered activity of the kinase could influence IL-1-mediated NF-kappa B activation. A murine T cell line, EL4, was stimulated with IL-1 with and without pretreatment with different compounds known to influence the cellular redox status. Thiol modifying agents like diamide, menadione, pyrrolidine dithiocarbamate (PDTC), diethyl dithiocarbamate or phenylarsine oxide inhibited the IL-1-induced activation of the IL-1RI-associated protein kinase. N-Acetylcysteine, alpha,alpha'-dipyridyl, aminotriazole or nitrofurantoin did not show any effect. The inhibition by PDTC was reversible unless glutathione synthesis was blocked by buthionine sulfoximine. The described conditions which inhibited or prevented the activation of the IL-1RI-associated kinase similarly impaired the activation of NF-kappa B in EL4 cells. From these observations we conclude that free thiols in the IL-1RI complex are essential for the activation of the IL-1RI-associated protein kinase and that this process is mandatory for IL-1 signaling leading to NF-kappa B activation.

Adenylyl cyclase type II is stimulated by PKC via C-terminal phosphorylation.

Adenylyl cyclases of the type II family differ from other subforms in that they are conditionally stimulated via alpha(s)/betagamma subunits and regulated by PKC mediated phosphorylation. AC II, stably expressed in HEK 239 cells, was incubated with the PKC activator tetradecanoylphorbol acetate (TPA). Using cells metabolically labeled with [32P]phosphate, TPA caused concerted stimulation of basal and forskolin activated adenylyl cyclase together with incorporation of [32P]phosphate into AC II protein. Enhanced phosphorylation was also indicated by a monoclonal anti-phosphothreonine antibody. Assignment of TPA-induced [32P]phosphate-incorporation to specific sites was achieved by a combination of chemical and immunochemical methods. Three out of five [32P]labeled peptides that were generated by fragmentation with N-chlorosuccinimide were also recognized by the monoclonal antibody BBC-4 [S. Mollner, T. Pfeuffer, Eur. J. Biochem. 171 (1988) 265-271] directed against an epitope 8 kDa from the extreme C-terminus. These findings suggested Ser-871 (consensus sequence ARSLK) and Thr-1057 (CTCR) as acceptor candidates of phorbolester induced phosphoryl transfer.

Phorbol ester-induced sensitisation of adenylyl cyclase type II is related to phosphorylation of threonine 1057.

Following up the results from previous studies on chemical fragmentation of TPA-treated, [32P]phosphate labeled adenylyl cyclase type II (AC II) (Böl, G. F., Hülster, A., and Pfeuffer, T. in press) we have replaced serine 871 or threonine 1057 by alanine using site directed mutagenesis. Both mutants had unimpaired catalytic activity, however enhancement by phorbolester TPA was reduced by 60-80 % in the T1057A mutant, but not in the S871A mutant. The stimulation of adenylyl cyclase type II by betagamma subunits of heterotrimeric G-pro teins and that by PKC have been previously shown to be mutually exclusive (Zimmermann and Taussig (1996), J. Biol. Chem. 271, 27161-27166). This is in line with the present findings that AC II expressed in COS-1 cells was only barely stimulated (10%) by coexpressed betagamma-subunits in presence of TPA. Mutation of threonine 1057 to alanine however caused partial regain of betagamma-stimulation in the presence of TPA by 40%, as compared to that of WT adenylyl cyclase type II which was 70% in the absence of TPA. These data strongly implicate the importance of threonine 1057 as phosphate acceptor following PKC-mediated sensitisation of adenylyl cyclase type II.

Interleukin-1-induced activation of a protein kinase co-precipitating with the type I interleukin-1 receptor in T cells.

We have investigated the possibility of a protein kinase participating in the signal transduction mechanisms of the interleukin-1 (IL-1) type I receptor (IL-1RI). Our data show that a protein kinase was co-precipitated with the IL-1RI from the two murine T helper cell lines D10N and EL-4. The kinase activity was detected in an in vitro kinase assay performed with the immuno beads in the presence of exogenous substrates. IL-1 treatment of the cells resulted in a rapid activation of this protein kinase in a concentration-dependent manner. Both forms of IL-1, IL-1 alpha and IL-1 beta, induced this kinase activity, whereas the IL-1 receptor antagonist (IL-1ra) was inactive. In excess IL-1ra competitively antagonized IL-1 stimulation. In the in vitro kinase assay the exogenous substrates myelin basic protein and histone H1 were phosphorylated, whereas casein or heat-shock protein HSP27 were not accepted, reflecting a certain selectivity of this protein kinase. The IL-1RI co-precipitable protein kinase showed a serine/threonine specificity and was inhibited by staurosporine, but not by inhibitors specific for protein tyrosine kinase or protein kinase C. These results show that a serine/threonine protein kinase directly interacts with the IL-1RI at the plasma membrane level of T helper cells forming a novel type of IL-1 inducible signaling complex. This protein kinase may resemble the link coupling the plasma membrane IL-1 receptor to cytosolic downstream elements in the IL-1 signaling pathway.