Phenotype-Genotype Correlation Applying a Cocktail Approach and an Exome Chip Analysis Reveals Further Variants Contributing to Variation of Drug Metabolism

Although great progress has been made in the fine-tuning of diplotypes, there is still a need to further improve the predictability of individual phenotypes of pharmacogenetically relevant enzymes. The aim of this study was to analyze the additional contribution of sex and variants identified by exome chip analysis to the metabolic ratio of five probe drugs. A cocktail study applying dextromethorphan, losartan, omeprazole, midazolam, and caffeine was conducted on 200 healthy volunteers. CYP2D6, 2C9, 2C19, 3A4/5, and 1A2 genotypes were analyzed and correlated with metabolic ratios. In addition, an exome chip analysis was performed. These SNPs correlating with metabolic ratios were confirmed by individual genotyping. The contribution of various factors to metabolic ratios was assessed by multiple regression analysis. Genotypically predicted phenotypes defined by CPIC discriminated very well the log metabolic ratios with the exception of caffeine. There were minor sex differences in the activity of CYP2C9, 2C19, 1A2, and CYP3A4/5. For dextromethorphan (CYP2D6), IP6K2 (rs61740999) and TCF20 (rs5758651) affected metabolic ratios, but only IP6K2 remained significant after multiple regression analysis. For losartan (CYP2C9), FBXW12 (rs17080138), ZNF703 (rs79707182), and SLC17A4 (rs11754288) together with CYP diplotypes, and sex explained 50% of interindividual variability. For omeprazole (CYP2C19), no significant influence of CYP2C:TG haplotypes was observed, but CYP2C19 rs12777823 improved the predictability. The comprehensive genetic analysis and inclusion of sex in a multiple regression model significantly improved the explanation of variability of metabolic ratios, resulting in further improvement of algorithms for the prediction of individual phenotypes of drug-metabolizing enzymes.

Genome‑wide expression and methylation analyses reveal aberrant cell adhesion signaling in tyrosine kinase inhibitor‑resistant CML cells

Although chronic myeloid leukemia (CML) can be effectively treated using BCR-ABL1 kinase inhibitors, resistance due to kinase alterations or to BCR-ABL1 independent mechanisms remain a therapeutic challenge. For the latter, the underlying mechanisms are widely discussed; for instance, gene expression changes, epigenetic factors and alternative signaling pathway activation. In the present study, in vitro-CML cell models of resistance against the tyrosine kinase inhibitors (TKIs) imatinib (0.5 and 2 µM) and nilotinib (0.1 µM) with biological replicates were generated to identify novel mechanisms of resistance. Subsequently, genome-wide mRNA expression and DNA methylation were analyzed. While mRNA expression patterns differed largely between biological replicates, there was an overlap of 71 genes differentially expressed between cells resistant against imatinib or nilotinib. Moreover, all TKI resistant cell lines demonstrated a slight hypermethylation compared with native cells. In a combined analysis of 151 genes differentially expressed in the biological replicates of imatinib resistance, cell adhesion signaling, in particular the cellular matrix protein fibronectin 1 (FN1), was significantly dysregulated. This gene was also downregulated in nilotinib resistance. Further analyses showed significant FN1-downregulation in imatinib resistance on mRNA (P<0.001) and protein level (P<0.001). SiRNA-mediated FN1-knockdown in native cells reduced cell adhesion (P=0.02), decreased imatinib susceptibility visible by higher Ki-67 expression (1.5-fold, P=0.04) and increased cell number (1.5-fold, P=0.03). Vice versa, recovery of FN1-expression in imatinib resistant cells was sufficient to partially restore the response to imatinib. Overall, these results suggested a role of cell adhesion signaling and fibronectin 1 in TKI resistant CML and a potential target for novel strategies in treatment of resistant CML.

Adjuvant Effect of Orally Applied Preparations Containing Non-Digestible Polysaccharides on Influenza Vaccination in Healthy Seniors: A Double-Blind, Randomised, Controlled Pilot Trial

Senior individuals can suffer from immunosenescence and novel strategies to bolster the immune response could contribute to healthy ageing. In this double-blind, randomised, controlled pilot trial, we investigated the ability of non-digestible polysaccharide (NPS) preparations to enhance the immune response in a human vaccination model. In total, 239 subjects (aged 50-79 years) were randomised to consume one of five different NPS (yeast β-glucan (YBG), shiitake β-glucan (SBG), oat β-glucan (OBG), arabinoxylan (AX), bacterial exopolysaccharide (EPS)) or control (CTRL) product daily for five weeks. After two weeks of intervention, subjects were vaccinated with seasonal influenza vaccine. The post-vaccination increases in haemagglutination inhibition antibody titres and seroprotection rate against the influenza strains were non-significantly enhanced in the NPS intervention groups compared to CTRL. Specifically, a trend towards a higher mean log2 fold increase was observed in the AX group (uncorrected p = 0.074) combined with a trend for an increased seroprotection rate, AX group (48.7%) compared to CTRL (25.6%) (uncorrected p = 0.057), for the influenza A H1N1 strain. Subjects consuming AX also had a reduced incidence of common colds compared to CTRL (1 vs. 8; p = 0.029 in Fisher exact test). No adverse effects of NPS consumption were reported. The findings of this pilot study warrant further research to study AX as an oral adjuvant to support vaccine efficacy.

High-dose spironolactone lacks effectiveness in treatment of fibromyalgia (RCT)

BACKGROUND

Spironolactone (SPL) is a reversible mineralocorticoid receptor (MR) and androgen receptor (AR) antagonist which attracts pharmacotherapeutic interest not only because of its beneficial effects in heart failure but also because of the pathogenetic roles of MR and AR activities in neuropsychiatric diseases. Recently, beneficial and rapid-onset effects of SPL have been documented in a case series of women with fibromyalgia syndrome (FMS). To reaffirm this observation, we performed a double-blind placebo-controlled randomized clinical trial (RCT).

METHODS

A total of 69 patients were screened, 56 patients were eligible and randomized to SPL or placebo (each n = 28). Forty-three patients completed the clinical trial to the last visit (n = 21 and n = 22). After a run-in phase of 50 and 100 mg/day, 200 mg/day SPL or placebo were applied between days 7 and 28. Primary outcome was the change in the FIQ-G score (Fibromyalgia Impact Questionnaire, German version). Secondary outcome parameters were the changes in pain (numeric rating scale, NRS), mood (ADS), quality of life (SF-36) and change in FIQ scores 14 days after the end of the medication.

RESULTS

SPL of 200 mg/day did not change significantly either the primary or the secondary end points. SPL evoked a transient rise in serum potassium and a transient fall in GFR maximal after 2 weeks, but without clinical relevance.

CONCLUSIONS

SPL at 200 mg/day does not improve symptoms in women with FMS, but was considered not to cause harm.

SIGNIFICANCE

The mineralocorticoid receptor and androgen receptor antagonist spironolactone is repeatedly tested for its therapeutic effectivity against neuropsychiatric disorders. The present RCT demonstrated that 200 mg spironolactone does not change the symptoms of the fibromyalgia syndrome (FMS) in adult women. Between 2 and 4 weeks, spironolactone evokes a transient decrease in GFR and increase in serum potassium. Spironolactone cannot be recommended for the treatment of FMS.

Gliflozins for the Treatment of Congestive Heart Failure and Renal Failure in Type 2 Diabetes

BACKGROUND

Gliflozins are effective drugs for the treatment of type 2 diabetes. They inhibit sodium glucose cotransporter 2 in the proximal renal tubule, leading to increased glucose excretion. On the basis of findings from relevant studies, gliflozins are also increasingly used in clinical practice to treat congestive heart failure and renal failure.

METHODS

This review is based on pertinent publications retrieved from a selective literature search in PubMed and GoogleScholar.

RESULTS

Cardiovascular safety studies revealed early on that gliflozins can lower the hospitalization rate of patients suffering from congestive heart failure with a reduced leftventricular ejection fraction (HFrEF). They also showed favorable effects on multiple renal endpoints. In recent years, studies such as DAPA-HF and CREDENCE have further documented the benefit of gliflozins in the treatment of congestive heart failure and renal failure in patients with type 2 diabetes, and gliflozins have accordingly been incorporated into the pertinent guidelines. In the recently published EMPEROR-Reduced trial, empagliflozin was found to significantly lower the frequency of a combined cardiovascular endpoint in patients with HFrEF (19.4 % versus 24.7%; hazard ratio [HR] 0.75; 95% confidence interval [0.65; 0.86]; number needed to treat [NNT] 19, p <0.001). In the DAPA-CKD trial, which was also recently published, dapagliflozin was found to significantly lower the frequency of a combined renal endpoint (9.2% versus 14.5%; HR 0.61 [0.51; 0.72]; NNT 19; p <0.001).

CONCLUSION

On the basis of findings from specific studies, gliflozins will henceforth be a major class of drug for the treatment of HFrEF and renal failure, independently of the presence of type 2 diabetes.

Alternative Polyadenylation of ABC Transporters of the C-Family (ABCC1, ABCC2, ABCC3) and Implications on Posttranscriptional Micro-RNA Regulation

ATP-binding cassette (ABC) transporters represent a large group of efflux pumps that are strongly involved in the pharmacokinetics of various drugs and nutrient distribution. It was recently shown that micro-RNAs (miRNAs) may significantly alter their expression as proven, e.g., for miR-379 and ABCC2 However, alternative mRNA polyadenylation may result in expression of 3'-untranslated regions (3'-UTRs) with varying lengths. Thus, length variants may result in presence or absence of miRNA binding sites for regulatory miRNAs with consequences on posttranscriptional control. In the present study, we report on 3'-UTR variants of ABCC1, ABCC2, and ABCC3 mRNA. Applying in vitro luciferase reporter gene assays, we show that expression of short ABCC2 3'-UTR variants leads to a significant loss of miR-379/ABCC2 interaction and subsequent upregulation of ABCC2 expression. Furthermore, we show that expression of ABCC2 3'-UTR lengths varies significantly between human healthy tissues but is not directly correlated to the respective protein level in vivo. In conclusion, the presence of altered 3'-UTR lengths in ABC transporters could lead to functional consequences regarding posttranscriptional gene expression, potentially regulated by alternative polyadenylation. Hence, 3'-UTR length variability may be considered as a further mechanism contributing to variability of ABCC transporter expression and subsequent drug variation in drug response. SIGNIFICANCE STATEMENT: micro-RNA (miRNA) binding to 3'-untranslated region (3'-UTR) plays an important role in the control of ATP-binding cassette (ABC)-transporter mRNA degradation and translation into proteins. We disclosed various 3'-UTR length variants of ABCC1, C2, and C3 mRNA, with loss of mRNA seed regions partly leading to varying and tissue-dependent interaction with miRNAs, as proven by reporter gene assays. Alternative 3'-UTR lengths may contribute to variable ABCC transporter expression and potentially explains inconsistent findings in miRNA studies.

New Insight in the Q^{2} Dependence of Proton Generalized Polarizabilities

Virtual Compton scattering on the proton has been investigated at three yet unexplored values of the four-momentum transfer Q^{2}: 0.10, 0.20, and 0.45  GeV^{2}, at the Mainz Microtron. Fits performed using either the low-energy theorem or dispersion relations allowed the extraction of the structure functions P_{LL}-P_{TT}/ε and P_{LT}, as well as the electric and magnetic generalized polarizabilities α_{E1}(Q^{2}) and β_{M1}(Q^{2}). These new results show a smooth and rapid falloff of α_{E1}(Q^{2}), in contrast to previous measurements at Q^{2}=0.33  GeV^{2}, and provide for the first time a precise mapping of β_{M1}(Q^{2}) in the low-Q^{2} region.

Drug Hypersensitivity

BACKGROUND

Adverse drug reactions (ADRs) can be divided into pharmacological ADRs (type A) and hypersensitivity reactions (type B). Type B reactions can be further subdivided into immediate (<1 h, urticaria, anaphylaxis) and delayed reactions (>1 h, variable manifestation like exanthema, hepatitis, cytopenias). Prevention of hypersensitivity is often still a challenge.

METHODS

Selective literature search in Medline and Google Scholar as well as research in ADR databases like OpenVigil or SIDER.

RESULTS

Laboratory tests ([specific] IgE, lymphocyte transformation test), histological examination, dermatological tests (prick tests, epicutaneous testing) and-under certain circumstances-provocation tests can be used for diagnostics. There are only a few pharmacogenetic biomarkers to predict hypersensitivity reactions. Currently, testing for defined HLA genes is mandatory before prescription of abacavir and before the use of carbamazepine in Han Chinese or Thai patients. Immediate discontinuation of the trigger is essential in all allergic hypersensitivity reactions. Immediate reactions are treated with antihistamines, glucocorticoids and occasionally with epinephrine. Delayed reactions are usually treated with glucocorticoids.

CONCLUSION

Careful, structured diagnostics in case of suspected hypersensitivity together with adequate documentation (allergy passport) is necessary in order to avoid incidents in patients receiving subsequent treatment. Consistent use of existing resources (diagnostics and documentation) can help to avoid hypersensitivity reactions or to rapidly recognize and treat them, respectively.

Mapping Medication Metadata from the ABDA Data Model to an OpenEHR Medication Archetype: A Qualitative Analysis

Integrating data from various source systems to gain knowledge and meaningful data about patients for care and research is challenging. This work demonstrates how medication knowledge data from the database of the Federal Union of German Associations of Pharmacists (ABDA) can be used for storing and annotating medicinal products in an openEHR medication archetype.

Linking pre-existing biorepositories for medical research: the PopGen 2.0 Network

The significance of human biorepositories for modern medical research, particularly for comprehensive population-based genetic analyses, is constantly growing. While large and centralized institutions are usually considered best suited to meet the increasing demand for high-quality “biobanks,” most medical research institutions still host rather heterogeneous and fragmented biobanking activities, undertaken by clinical departments with oftentimes rather different scientific scope. Undoubtedly, most clinicians and medical researchers would appreciate infrastructural support in terms of the storage and handling of their biosamples, but they are also likely to expect access to their samples avoiding extensive formal requirements. We report on the establishment of the PopGen 2.0 Network (P2N), an overarching alliance of initially seven biobanks from Northern Germany which adopted a joint but lean governance structure and use-and-access policy for their samples and data. In addition, the members of P2N have pursued an intense collaboration on ethical, legal and social issues and maintain a common IT infrastructure. The implementation of P2N has substantially improved the prospects of biobank-based research at the participating institutions. The network may thus serve as a role model for similar initiatives geared at linking pre-existing biorepositories for the benefit of research quality, efficiency, and transparency.

Beam-Recoil Polarization Measurement of π^{0} Electroproduction on the Proton in the Region of the Roper Resonance

The helicity-dependent recoil proton polarizations P_{x}^{'} and P_{z}^{'} as well as the helicity-independent component P_{y} have been measured in the p(e[over →],e^{'}p[over →])π^{0} reaction at four-momentum transfer Q^{2}≃0.1  GeV^{2}, center-of-mass proton emission angle θ_{p}^{*}≃90°, and invariant mass W≃1440  MeV. This first precise measurement of double-polarization observables in the energy domain of the Roper resonance P_{11}(1440) by exploiting recoil polarimetry has allowed for the extraction of its scalar electroexcitation amplitude at an unprecedentedly low value of Q^{2}, establishing a powerful instrument for probing the interplay of quark and meson degrees of freedom in the nucleon.

Pharmacogenetics and Predictive Testing of Drug Hypersensitivity Reactions

Adverse drug reactions adverse drug reaction (ADR) occur in approximately 17% of patients. Avoiding ADR is thus mandatory from both an ethical and an economic point of view. Whereas, pharmacogenetics changes of the pharmacokinetics may contribute to the explanation of some type A reactions, strong relationships of genetic markers has also been shown for drug hypersensitivity belonging to type B reactions. We present the classifications of ADR, discuss genetic influences and focus on delayed-onset hypersensitivity reactions, i.e., drug-induced liver injury, drug-induced agranulocytosis, and severe cutaneous ADR. A guidance how to read and interpret the contingency table is provided as well as an algorithm whether and how a test for a pharmacogenetic biomarker should be conducted.

A European Spectrum of Pharmacogenomic Biomarkers: Implications for Clinical Pharmacogenomics

Pharmacogenomics aims to correlate inter-individual differences of drug efficacy and/or toxicity with the underlying genetic composition, particularly in genes encoding for protein factors and enzymes involved in drug metabolism and transport. In several European populations, particularly in countries with lower income, information related to the prevalence of pharmacogenomic biomarkers is incomplete or lacking. Here, we have implemented the microattribution approach to assess the pharmacogenomic biomarkers allelic spectrum in 18 European populations, mostly from developing European countries, by analyzing 1,931 pharmacogenomics biomarkers in 231 genes. Our data show significant inter-population pharmacogenomic biomarker allele frequency differences, particularly in 7 clinically actionable pharmacogenomic biomarkers in 7 European populations, affecting drug efficacy and/or toxicity of 51 medication treatment modalities. These data also reflect on the differences observed in the prevalence of high-risk genotypes in these populations, as far as common markers in the CYP2C9, CYP2C19, CYP3A5, VKORC1, SLCO1B1 and TPMT pharmacogenes are concerned. Also, our data demonstrate notable differences in predicted genotype-based warfarin dosing among these populations. Our findings can be exploited not only to develop guidelines for medical prioritization, but most importantly to facilitate integration of pharmacogenomics and to support pre-emptive pharmacogenomic testing. This may subsequently contribute towards significant cost-savings in the overall healthcare expenditure in the participating countries, where pharmacogenomics implementation proves to be cost-effective.

OpenVigil FDA - Inspection of U.S. American Adverse Drug Events Pharmacovigilance Data and Novel Clinical Applications

Pharmacovigilance contributes to health care. However, direct access to the underlying data for academic institutions and individual physicians or pharmacists is intricate, and easily employable analysis modes for everyday clinical situations are missing. This underlines the need for a tool to bring pharmacovigilance to the clinics. To address these issues, we have developed OpenVigil FDA, a novel web-based pharmacovigilance analysis tool which uses the openFDA online interface of the Food and Drug Administration (FDA) to access U.S. American and international pharmacovigilance data from the Adverse Event Reporting System (AERS). OpenVigil FDA provides disproportionality analyses to (i) identify the drug most likely evoking a new adverse event, (ii) compare two drugs concerning their safety profile, (iii) check arbitrary combinations of two drugs for unknown drug-drug interactions and (iv) enhance the relevance of results by identifying confounding factors and eliminating them using background correction. We present examples for these applications and discuss the promises and limits of pharmacovigilance, openFDA and OpenVigil FDA. OpenVigil FDA is the first public available tool to apply pharmacovigilance findings directly to real-life clinical problems. OpenVigil FDA does not require special licenses or statistical programs.

[Propranolol therapy for periocular and orbital infantile haemangiomas]

In spite of the self-limiting natural course of infantile haemangiomas of the eyelids and orbit, the effects of amblyopia, compression of the optic nerve, and impairment of the aesthetic appearance may develop. Since the serendipitous discovery of the effects of propranolol, a non-selective beta-blocker, on infantile haemangioma in 2008, it has largely replaced the former standard treatments with corticosteroids, laser or surgical procedures. This review discusses the pathogenesis, classification, indication for treatment, and treatment options for infantile haemangiomas. In addition, the results of patients with infantile haemangiomas of the eyelids and orbit treated with systemic propranolol are shown. With additional confirmation of data, including a positive effect-risk-analysis, propranolol will potentially replace high-dose corticosteroids and surgery in the treatment of infantile haemangiomas in the eyelids and orbit. Further clinical studies are necessary to optimise the dosage, treatment period, and application modalities (oral or topical). In the future, propranolol accompanied with paediatric-cardiological monitoring should emerge as the first-line therapy for problematic infantile haemangiomas.

Use of threshold-specific energy model for the prediction of effects of smoking and radon exposure on the risk of lung cancer

Lung cancer is the leading cause of cancer death in both men and women. Smoking causes 80-90% of cases of lung cancer. In this study, an attempt was made to assess the impact of cigarette smoking on the risk of lung cancer by the so-called threshold-specific energy model. This model allows to analyse the biological effects of radon daughter products on the lung tissue, and is based on the assumption that the biological effect (i.e. cell inactivation) will manifest itself after the threshold-specific energy z0 deposited in the sensitive volume of the cell is exceeded. Cigarette smoking causes, among others, an increase in the synthesis of the survivin protein that protects cells from apoptosis and thereby reduces their radiosensitivity. Based on these facts, an attempt was made to estimate the shape of the curves describing the increase in the oncological effect of radiation as a function of daily cigarette consumption.

Search at the Mainz Microtron for light massive gauge bosons relevant for the muon g-2 anomaly

A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model of particle physics. In this Letter, the search for the signal of such a U(1) gauge boson in electron-positron pair production at the spectrometer setup of the A1 Collaboration at the Mainz Microtron is described. Exclusion limits in the mass range of 40  MeV/c^{2} to 300  MeV/c^{2}, with a sensitivity in the squared mixing parameter of as little as ε^{2}=8×10^{-7} are presented. A large fraction of the parameter space has been excluded where the discrepancy of the measured anomalous magnetic moment of the muon with theory might be explained by an additional U(1) gauge boson.

Mitochondrial gene polymorphisms that protect mice from colitis

BACKGROUND & AIMS

Dysregulated energy homeostasis in the intestinal mucosa frequently is observed in patients with ulcerative colitis (UC). Intestinal tissues from these patients have reduced activity of the mitochondrial oxidative phosphorylation (OXPHOS) complex, so mitochondrial dysfunction could contribute to the pathogenesis of UC. However, little is known about the mechanisms by which OXPHOS activity could be altered. We used conplastic mice, which have identical nuclear but different mitochondrial genomes, to investigate activities of the OXPHOS complex.

METHODS

Colitis was induced in C57BL/6J wild-type (B6.B6) and 3 strains of conplastic mice (B6.NZB, B6.NOD, and B6.AKR) by administration of dextran sodium sulfate or rectal application of trinitrobenzene sulfonate. Colon tissues were collected and analyzed by histopathology, immunohistochemical analysis, and immunoblot analysis; we also measured mucosal levels of adenosine triphosphate (ATP) and reactive oxygen species, OXPHOS complex activity, and epithelial cell proliferation and apoptosis.

RESULTS

We identified mice with increased mucosal OXPHOS complex activities and levels of ATP. These mice developed less-severe colitis after administration of dextran sodium sulfate or trinitrobenzene sulfonate than mice with lower mucosal levels of ATP. Colon tissues from these mice also had increased enterocyte proliferation and transcription factor nuclear factor-κB activity, which have been shown to protect the mucosal barrier-defects in these processes have been associated with inflammatory bowel disease.

CONCLUSIONS

Variants in mitochondrial DNA that increase mucosal levels of ATP protect mice from colitis. Increasing mitochondrial ATP synthesis in intestinal epithelial cells could be a therapeutic approach for UC.

Measurement of the neutron electric to magnetic form factor ratio at Q2=1.58 GeV2 using the reaction 3He[over →](e[over →],e'n)pp

A measurement of beam helicity asymmetries in the reaction 3He[over →](e[over →],e'n)pp is performed at the Mainz Microtron in quasielastic kinematics to determine the electric to magnetic form factor ratio of the neutron GEn/GMn at a four-momentum transfer Q2=1.58  GeV2. Longitudinally polarized electrons are scattered on a highly polarized 3He gas target. The scattered electrons are detected with a high-resolution magnetic spectrometer, and the ejected neutrons are detected with a dedicated neutron detector composed of scintillator bars. To reduce systematic errors, data are taken for four different target polarization orientations allowing the determination of GEn/GMn from a double ratio. We find μnGEn/GMn=0.250±0.058(stat)±0.017(syst).

The shaker potassium channel is no target for xenon anesthesia in short-sleeping Drosophila melanogaster mutants

Background. Xenon seems to be an ideal anesthetic drug. To explore if next to the antagonism at the NMDA-receptor other molecular targets are involved, we tested the xenon requirement in short sleeping Drosophila shaker mutants and in na[har³⁸]. Methods. The Drosophila melanogaster strains wildtype Canton-S, na[har³⁸], sh¹⁰² and sh^mns, were raised and sleep was measured. Based on the response of the flies at different xenon concentrations, logEC50 values were calculated. Results. The logEC50-values for WT Canton-S were 1.671 (1.601–1.742 95%-confidence intervall; n = 238; P versus sh¹⁰² > 0,05), for sh^mns 1.711 (1.650–1.773; n = 242; P versus WT Canton-S > 0,05). The logEC50-value for sh¹⁰² was 1.594 (1.493–1.694; n = 261; P versus sh^mns > 0.05). The logEC-value of na[har³⁸] was 2.076 (1.619–2.532; n = 207; P versus sh^mns < 0.05, versus sh¹⁰² < 0.05, versus WT Canton-S < 0.05). P values for all shaker mutants were P > 0.05, while na[har³⁸] was found to be hyposensitive compared to wildtype (P < 0.05). Conclusions. The xenon requirement in Drosophila melanogaster is not influenced by a single gene mutation at the shaker locus, whereas a reduced expression of a nonselective cation channel leads to an increased xenon requirement. This supports the thesis that xenon mediates its effects not only via an antagonism at the NMDA-receptor.

Search for light gauge bosons of the dark sector at the Mainz Microtron

A new exclusion limit for the electromagnetic production of a light U(1) gauge boson γ' decaying to e + e- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the standard model and are also discussed as candidates for the interaction of dark matter with standard model matter. In electron scattering from a heavy nucleus, the existing limits for a narrow state coupling to e + e- were reduced by nearly an order of magnitude in the range of the lepton pair mass of 210 MeV/c2}<me +}e-<300 MeV/c2. This experiment demonstrates the potential of high current and high resolution fixed target experiments for the search for physics beyond the standard model.

Development of a longterm dataset of solid/liquid precipitation

Abstract. Solid precipitation (mainly snow, but snow and ice pellets or hail as well), is an important parameter for climate studies. But as this parameter usually is not available operationally before the second part of the 20th century and nowadays is not reported by automatic stations, information usable for long term climate studies is rare. Therefore a proxy for the fraction of solid precipitation based on a nonlinear relationship between the percentage of solid precipitation and monthly mean temperature was developed for the Greater Alpine Region of Europe and applied to the existing longterm high resolution temperature and precipitation grids (5 arcmin). In this paper the method is introduced and some examples of the resulting datasets available at monthly resolution for 1800–2003 are given.

Multi-methodical realisation of Austrian climate maps for 1971–2000

Abstract. Constantly changing climate, the availability of a higher resolved digital elevation model and further development of geostatistical interpolation methods gave reason for updating the most frequently demanded climate maps out of the Austrian digital climate atlas from 1961–1990 to 1971–2000. To achieve a station density as high as possible, data from eleven national and foreign institutes were collected and gap-filled. According to the climate parameter, different geostatistical interpolation methods (including regionalised multilinear regressions, geographically weighted regressions and curve fitting to base parameter) were applied. The resultant 17 grids concern 30-year-means of air temperature, precipitation and snow parameters as well as derived indices. They are now available for a variety of scientific and planning purposes.

High-precision determination of the electric and magnetic form factors of the proton

New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q² = 1 (GeV/c)² with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted by fits of a large variety of form factor models directly to the cross sections. The form factors show some features at the scale of the pion cloud. The charge and magnetic radii are determined to be <r²E>½ = 0.879(5)stat(4)syst(2)model(4)group fm and <r²M>½ = 0.777(13)stat(9)syst(5)model(2)group fm.

Interaction of morphine but not fentanyl with cerebral α2-adrenoceptors in α2-adrenoceptor knockout mice

Objectives

α2-Adrenergic and μ-opioid receptors belong to the rhodopsin family of G-protein coupled receptors and mediate antinociceptive effects via similar signal transduction pathways. Previous studies have revealed direct functional interactions between both receptor systems including synergistic and additive effects. To evaluate underlying mechanisms, we have studied whether morphine and fentanyl interacted with α2-adrenoceptor-subtypes in mice lacking one individual α2-adrenoceptor-subtype (α2-adrenoceptor knockout).

Methods

Opioid interaction with α2-adrenoceptors was investigated by quantitative receptor autoradiography in brain slices of α2A-, α2B- or α2C-adrenoceptor deficient mice. Displacement of the radiolabelled α2-adrenoceptor agonist [125I]paraiodoclonidine from α2-adrenoceptors in different brain regions by increasing concentrations of morphine, fentanyl and naloxone was analysed. The binding affinity of both opioids to α2-adrenoceptor subtypes in different brain regions was quantified.

Key findings

Morphine but not fentanyl or naloxone provoked dose-dependent displacement of [125I]paraiodoclonidine from all α2-adrenoceptor subtypes in the brain regions analysed. Binding affinity was highest in cortex, medulla oblongata and pons of α2A-adrenoceptor knockout mice.

Conclusions

Our results indicated that morphine interacted with α2-adrenoceptors showing higher affinity for the α2B and α2C than for the α2A subtype. In contrast, fentanyl and naloxone did not show any relevant affinity to α2-adrenoceptors. This effect may have an impact on the pharmacological actions of morphine.

[Hypoglycemic risk of insulinotropic drugs]

Orally available insulinotropics that directly close K(ATP)-channels, such as sulfonylureas and glinides, differ in their pharmacokinetics and -dynamics (PK/PD). This results in different risks for their incidence of hypoglycemic episodes. Glibenclamide (USAN: glyburide) has the highest risk, followed by glimepiride. Glinides reveal a low risk of hypoglycemia due to their short duration of drug effect. Apart from PK/PD, clinically more relevant factors determine incidences of hypoglycemia. Adequate supervision at initial prescription or switch of insulinotropic drugs, comedication and patient compliance superimpose these pharmacological differences.