Multimodal Assessment of Smoking cue Reactivity During a Smoking Cue Exposure Task

Background. Cue-reactivity as a characteristic symptom of substance use disorders (SUD) is highly context dependent. Paradigms with high context validity need to be established for the investigation of underlying neurobiological mechanisms. While craving can be assessed by self-report as one aspect of cue-reactivity (CR), the assessment of biological measures such as the autonomous response and EEG promises a holistic perspective including CR at an automatized level. In a multimodal approach, smoking cue exposure (CE) effects on heart rate variability (HRV), EEG frequency power, and craving as well as their interrelation were assessed. This pilot study focused on the validity of CR measurements in a naturalistic CE paradigm. Methods. EEG frequency power, HRV, and craving were assessed during resting state (RS) and smoking CE in smokers (n = 14) and nonsmoking controls (n = 10) to investigate the psychophysiological and subjective reactions to CE. Results. Increased beta power was found only in smokers during CE compared to the control condition. There was an inverse correlation of beta power and maximum craving. Likewise, HRV correlated negatively with maximum smoking urges in smokers immediately after the measurements, without differentiation between CE and control condition. Conclusion. The increased beta power in smokers during CE is discussed as increased inhibitory control related to reduced craving in smokers. Furthermore, increased craving during CE seems to be associated to decreased vagal activity. The multimodal measurements during the CE showed ecological validity to be fundamental for CE assessment in clinical populations to evaluate its predictive value.

Effects of physical activity on cognitive performance: a controlled clinical study in depressive patients

Physical activity is a common adjunctive therapy in psychiatric and psychosomatic hospitals. In the present study, we assessed the effects of an exercise program, integrated into routine inpatient treatment, on cognitive performance and subjective severity of depression in a sample of patients suffering from major depression. We randomized n = 38 patients with unipolar depression to either physical exercise (n = 18) or occupational therapy as an active control treatment (n = 20). Both treatments were delivered in group format over a period of 3-4 weeks. Data indicate that there were significant improvements of cognitive functions and depressive symptoms in both groups, with specific treatment effects in reaction time and in short-term verbal memory favoring the physical activity group. In conclusion, we found physical exercise to be a feasible, easy-to-implement add-on therapy for depressive patients with promising effects on cognitive performance. However, these results need to be replicated in larger samples with an extended follow-up.

Is prepulse modification altered by continuous theta burst stimulation? DAT1 genotype and motor threshold interact on prepulse modification following brain stimulation

Previous studies suggest an inhibitory top-down control of the amygdala by the prefrontal cortex (PFC). Both brain regions play a role in the modulation of prepulse modification (PPM) of the acoustic startle response by a pre-stimulus. Repetitive transcranial magnetic stimulation (rTMS) can modulate the activity of the PFC and might thus affect PPM. This study tested the effect of inhibitory rTMS on PPM accounting for a genetic variant of the dopamine transporter gene (DAT1). Healthy participants (N = 102) were stimulated with continuous theta burst stimulation (cTBS, an intense form of inhibitory rTMS) or sham treatment over the right PFC. Afterwards, during continuous presentation of a background white noise a louder noise burst was presented either alone (control startle) or preceded by a prepulse. Participants were genotyped for a DAT1 variable number tandem repeat (VNTR) polymorphism. Two succeeding sessions of cTBS over the right PFC (2 × 600 stimuli with a time lag of 15 min) attenuated averaged prepulse inhibition (PPI) in participants with a high resting motor threshold. An attenuation of PPI induced by prepulses with great distances to the pulse (480, 2000 ms) was observed following active cTBS in participants that were homozygous carriers of the 10-repeat-allele of the DAT1 genotype and had a high resting motor threshold. Our results confirm the importance of the prefrontal cortex for the modulation of PPM. The effects were observed in participants with a high resting motor threshold only, probably because they received a higher dose of cTBS. The effects in homozygous carriers of the DAT1 10-repeat allele confirm the relevance of dopamine for PPM. Conducting an exploratory study we decided against the use of a correction for multiple testing.

Influence of single-dose quetiapine on fear network activity - A pharmaco-imaging study

OBJECTIVE

Anxiety disorders are among the most frequent psychiatric disorders. Current treatment guidelines recommend antidepressants, the calcium modulator gabapentin, and benzodiazepines as pharmacological treatments. However, delayed onset of action precludes the use of antidepressants as an acute treatment, while benzodiazepines can be recommended only as an emergency treatment due to their inherent risk of dependence. Therefore, an alternative pharmacological agent with acute efficacy is needed. Preliminary evidence points towards possible anxiolytic properties of the atypical antipsychotic quetiapine. The goals of this study were to test the acute anxiolytic properties of quetiapine in patients suffering from arachnophobia in a challenge paradigm, and to assess the effects of quetiapine on the central nervous fear network.

METHODS

In a randomized, double-blind, placebo-controlled proof-of-concept study, n=58 arachnophobic patients underwent an fMRI scan while looking at phobia-related and neutral stimuli. Subjective anxiety was evaluated retrospectively in questionnaires.

RESULTS

The functional imaging data revealed that patients showed stronger amygdala activation to phobia-related than to neutral stimuli. However, no effect of quetiapine on fear network activity was detected. Further, on questionnaire measures, quetiapine significantly reduced somatic anxiety symptoms, but had no effect on general psychological anxiety.

CONCLUSION

Viewing phobic pictures resulted in a robust amygdala activation in arachnophobic patients. Quetiapine seems to have no influence on activation in anxiety-related brain areas but appears to reduce acute somatic anxiety symptoms in patients with specific phobia. The central nervous correlates of the anxiolytic effects of quetiapine remain to be clarified in future studies.

Spatial and temporal variability of source contributions to ambient PM10 during winter in Augsburg, Germany using organic and inorganic tracers

Daily PM10 samples were collected during a one-month sampling campaign from February 13 to March 12, 2008 at eight different sampling sites in Augsburg, Southern Germany. Source apportionment was performed to identify the main sources and related contributions by analysis of organic and inorganic tracers. Nine factors were separated comprising: solid fuel combustion, traffic-related emissions, secondary inorganics, and mixed sources. Spatiotemporal variation of the source contributions was evaluated using the Pearson correlation coefficient (r) and coefficient of divergence (COD). All factors (except hopanes and mixed sources) showed moderate to high (0.6<r>0.8) correlation coefficients between the eight sites and were distributed heterogeneously. Secondary sulfate and secondary nitrate factors were relatively more uniformly distributed (compared to other factors) with lower medians of COD value (0.47 and 0.56, respectively) and higher correlation values (r=0.97 and 0.85, respectively). The maximum daily average contribution for coal & wood combustion factor was observed at the LfU suburban site (4.0 μg m(-3)); wood combustion factor at the LSW residential site (5.1 μg m(-3)) ; diesel & fuel oil consumption factor at the Bifa suburban and BP urban sites (both 2.5 μg m(-3)); road dust & tram factor at the KP traffic site (16.2 μg m(-3)) and the BP urban site (6.6 μg m(-3)); hopanes factor at the BP urban and Bifa suburban sites (both 0.7 μg m(-3)); and de-icing NaCl factor at the KP traffic site (4.8 μg m(-3)). Secondary sulfate and secondary nitrate factors had approximately similar contributions (6.2 μg m(-3) and 4.3 μg m(-3), respectively) at all sites. Mixed sources factor had the highest daily average contribution to PM10 mass at the KP traffic site (7.0 μg m(-3)).

Flow Visualisation in Co-rotating Twin Screw Extruders: Positron Emission Particle Tracking and Numerical Particle Trajectories

Co-rotating twin-screw extruders are widely used compounding machines. They are mainly configured based on extensive experience and iterative approaches to optimise output and composite quality. The visualisation technology developed in the EU-project PEPTFlow allows visualisation of composite flow in twin-screw extruders under realistic processing conditions by tracking radioactive tracer particles in the polymer melt, using a specially developed camera system. This new approach allows polymer flow to be studied in different screw elements and screw configurations under realistic compounding conditions at normal temperatures and melt pressures. The paper presents the latest developments in the camera systems as well as the different ways to use and interpret the results. Detailed analysis of residence times and residence time distributions for standard compound screw elements, like kneading discs, conveying elements and reverse elements are presented. In addition for a better understanding of the flow field inside twin-screw extruders, numerical particle tracking is done. The Stokes equation, using XFEM method, are solved and the numerical RTD's (residence time distribution) are compared for various screw designs.

Comparison of combined psycho- and pharmacotherapy with monotherapy in anxiety disorders: controversial viewpoints and clinical perspectives

Anxiety disorders are among the most frequent psychiatric disorders. Experimental evidence supports both psychotherapy as well as pharmacotherapy as effective treatments. There is, however, a controversy concerning the efficacy of a combination of both approaches. While some studies suggest that combined treatment enhances efficacy, others report conflicting results. This article traces the positions in this debate. We present the results from two recent meta-analyses and discuss implications for clinical practice and further research. We suggest that a research strategy that strives to establish differential indications based on patient characteristics should be preferred over attempts to reach a global judgement of the question, which appears too simplistic given the complexity of the issue.

Contribution to the certification of B, Cd, Cu, Mg and Pb in a synthetic water sample, by use of isotope-dilution ICP-MS, for Comparison 12 of the International Measurement Evaluation Programme

The contribution of the Institute for Reference Materials and Measurements to the certification of the B, Cd, Cu, Mg, and Pb content of a synthetic water sample used in Comparison 12 of the International Measurement Evaluation Programme (IMEP-12) is described. The aim of the IMEP programme is to demonstrate objectively the degree of equivalence and quality of chemical measurements of individual laboratories on the international scene by comparing them with reference ranges traceable to the SI (Système International d'Unités). IMEP is organized in support of European Union policies and helps to improve the traceability of values produced by field chemical measurement laboratories. The analytical procedure used to establish the reference values for the B, Cd, Cu, Mg, and Pb content of the IMEP-12 sample is based on inductively coupled plasma-isotope-dilution mass spectrometry (ICP-IDMS) applied as a primary method of measurement. The measurements performed for the IMEP-12 study are described in detail. Focus is on the element boron, which is particularly difficult to analyze by ICP-MS because of potential problems of low sensitivity, high mass discrimination, memory effects, and abundance sensitivity. For each of the certified amount contents presented here a total uncertainty budget was calculated using the method of propagation of uncertainties according to ISO (International Organization for Standardization) and Eurachem guidelines. For all investigated elements with concentrations in the low micro g kg(-1) and mg kg(-1) range (corresponding to pmol kg(-1) to the high micro mol kg(-1) level), SI-traceable reference values with relative expanded uncertainties ( k=2) of less than 2 % were obtained.

SI-traceable certification of the amount content of cadium below the ng g(-1) level in blood samples by isotope dilution ICP-MS applied as a primary method of measurement

The development and implementation of a method for the certification of cadmium in blood samples at low ng g(-1) and sub ng g(-1) levels is described. The analytical procedure is based on inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) applied as a primary method of measurement. Two different sample digestion methods, an optimized microwave digestion procedure using HNO3 and H2O2 as oxidizing agents and a high-pressure asher digestion procedure, were developed and compared. The very high salt content of the digests and the high molybdenum content, which can cause oxide-based interferences with the Cd isotopes, were reduced by a chromatographic matrix separation step using an anion-exchange resin. All isotope ratio measurements were performed by a quadrupole ICP-MS equipped with an ultrasonic nebulizer with membrane desolvator. This sample introduction set-up was used to increase sensitivity and minimize the formation of oxides (less MoO+ interference with the Cd isotopes). Because of the very low Cd concentrations in the samples and the resulting need to minimize the procedural blank as much as possible, all sample-processing steps were performed in a clean room environment. Detection limits of 0.005 ng g(-1) Cd were achieved using sample weights of 2.7 g. The method described was used to recertify the cadmium content of three different blood reference materials from the Community Bureau of Reference (BCR) of the European Commission (BCR-194, BCR-195, BCR- 196). Cadmium concentrations ranged between approximately 0.2 ng g(-1) and approximately 12 ng g(-1). For these materials, SI-traceable certified values including total uncertainty budgets according to ISO and Eurachem guidelines were established.

Development of an ICP-IDMS method for accurate routine analyses of toxic heavy metals in polyolefins and comparison with results by TI-IDMS

An inductively coupled plasma isotope dilution mass spectrometric (ICP-IDMS) method was developed as a suitable method - with respect to its sensitivity, precision, accuracy, and time-consumption - for the analysis of toxic heavy metal traces (Pb, Cd, Cr, and Hg) in polyolefins. Results for Pb, Cd, and Cr were compared with those obtained by thermal ionization isotope dilution mass spectrometry (TI-IDMS), which was used as a reference method. Because of its high first ionization potential and its high volatility mercury could not be determined by TI-IDMS. A multi-element spike solution, containing isotopically enriched 206Pb, 116Cd, 53Cr, and 201Hg, was used for the isotope dilution step. Decomposition of the polyolefin samples was carried out with concentrated HNO3 at temperatures of about 300 degrees C in a high pressure asher (HPA). This procedure decomposes polyolefins completely and allows isotopic equilibration between sample and spike isotopes. Detection limits of 16 ng/g, 5 ng/g, 164 ng/g, and 9 ng/g were obtained for Pb, Cd, Cr, and Hg by ICP-IDMS using only sample weights of 0.25 g. In different commercially available polyethylene samples heavy metal concentrations in the range of < 5 ng/g to 4 x 10(3) ng/g were analyzed. Both mass spectrometric methods were applied within the EU project "Polymeric Elemental Reference Material (PERM)" for the certification of two polyethylene reference materials. The ICP-IDMS results agreed very well with those of TI-IDMS which demonstrates the accuracy of the ICP-IDMS method also suitable for routine analyses.

Should the exit of the artificial abutment tooth be positioned in the region of the attached gingiva?

The necessity of an area of attached gingiva around penetrating implants was examined in 26 patients. It was demonstrated that plaque corneal in the major factor in avoiding inflammatory reactions.

END GROUP AND SEDIMENTATION DATA ON FRAGMENTED HIGH MOLECULAR WEIGHT RIBONUCLEATES

A method for end group analysis of ribonucleate preparations using purified snake venom phosphodiesterase is described. Unusual difficulties encountered with the method are discussed. The technique is useful for detection of end groups resulting from enzymic and chemical fragmentation of high molecular weight ribonucleates. Preliminary studies indicate that the method has limited usefulness because of a spontaneous hydrolysis of ribonucleates which occurs under the conditions which are optimal for hydrolysis with snake venom phosphodiesterase (pH 9, in the presence of magnesium). Physicochemical studies have shown that the pronounced dependence of sedimentation coefficient on ionic strength which has been reported by other investigators is also observed with fragmented high molecular weight ribonucleates and with 16S + 24S ribonucleates of Ehrlich ascites cells. The changes of sedimentation rate are associated with configurational and aggregation effects.