[Clinical radiological evaluation of teeth-part 2 : Caries, inflammatory dental changes and important differential diagnoses]

Inflammatory diseases of the teeth and periodontium are widespread and are frequent secondary diagnoses in head and neck examinations. Periapical inflammation can be the cause of sinusitis or abscess formation in the oral and maxillofacial region. Early detection is important for the patient's course of treatment. For further diagnostics, a dental presentation should be carried out. Dental radiological examinations, such as panoramic radiographs and dental films are used for specific diagnostics. This article is intended to provide an overview of the different stages of caries, the most important inflammatory dental changes and their most frequent differential diagnoses.

[Clinical radiological evaluation of teeth-part 1 : Anatomy and anomalies]

Radiological assessment of the teeth and periodontium is often left to the dentist. Nevertheless, it is useful to know the anatomy and possible anomalies of the teeth in order to correctly assess pathological processes in both projection radiographic and slice imaging. Dental radiological examinations, such as panoramic slice imaging (PSA) and dental film are used for targeted diagnostics. In the case of incidental findings, a dental presentation should be made for further clarification. This article first provides an overview of the anatomy and anomalies of teeth.

[The effect of mobile air filter systems on aerosol concentrations in large volume scenarios against the background of the risk of infection of COVID-19. Can classroom teaching be resumed?]

BACKGROUND

As a consequence of the corona pandemic, universities nationwide had stopped classroom teaching by the start of the summer semester 2020. As part of the second lockdown, in many states schools and day care centers were also closed or reduced to a minimum. In this context the effect of room air filters has already been discussed multiple times; however, mobile devices for air filtration are currently not recommended by the German Federal Environment Agency. The following investigation shows the real effects of mobile air filters on aerosol concentrations when used in lecture theaters, canteens or school learning centers.

METHODS

The effects of a mobile air purifier (DEMA-airtech, Stuttgart, Germany) were measured in three large rooms (a lecture theater, a company canteen and a learning center of a grammar school). Aerosol and carbon dioxide concentrations were determined with devices from the company Palas (Karlsruhe, Germany).

RESULTS

All three scenarios showed a relevant and permanent decrease in aerosol concentrations through the use of air filters. The effect partly even surpassed the effectiveness of simple ventilation by opening the windows.

CONCLUSION

In addition to social distancing and wearing highly efficient face masks, the use air filters is recommended. This measure could enable classroom teaching to be resumed.

Forensic postmortem computed tomography in suspected unnatural adult deaths

PURPOSE

Our study sought to evaluate validity of forensic postmortem CT in establishing cause of death (COD) in suspected unnatural adult death based on the reference standard of autopsy.

METHODS

In our prospective, single-center study, 64 of 94 consecutive corpses (70.7 % male, mean age: 47.4 years) who underwent CT and autopsy between November 2013 and April 2019 were included in the analysis. Primary objective was agreement between CT and autopsy on primary COD using kappa statistics. Secondary objectives were competing COD and specific pathological findings.

RESULTS

Agreement on primary COD between forensic CT and autopsy without or in consideration of toxicological and histological findings was strong (85.9 % [55 of 64 corpses]; κ = 0.83 [95 %CI: 0.74 to 0.93] and 95.3 % [61 of 64 corpses]; κ = 0.94 [95 %CI: 0.84-1.04], respectively, McNemar p = 0.03). Sensitivity and specificity of CT in identification of acute heart failure, intracranial bleeding, burns and heat shocks, gunshot wounds, polytrauma, cranio-cerebral trauma, and strangulation or hanging was 100 %, each. Acute respiratory failure was detected with a sensitivity and specificity of 100 % and 96.8 %, cuts and stab wounds with 95.2 % and 100 %, and intoxication, pneumonia, or gastrointestinal bleeding with 60.0 % and 100 %, respectively. Agreement on competing COD was moderate (51.6 %, [33 of 64 corpses]; κ = 0.47 [95 %CI: 0.40 to 0.53], p < 0.001).

CONCLUSIONS

Forensic postmortem CT, complemented by external, toxicological, and histological examination was sufficiently valid to assess primary COD in the majority of suspected unnatural deaths with few restrictions.

[Chronic nonbacterial osteomyelitis : Imaging and differential diagnoses]

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease in childhood and adolescence with a preference for the female gender. It is manifested with multiple osseous lesions, with a predilection for the metaphyseal end zones of the long bones of the lower extremities. These bone lesions usually occur multifocally, can recur and develop a different appearance depending on the bone structure affected. Patients present with a longer disease history, changing clinical symptoms and unspecific paraclinical signs. Magnetic resonance imaging (MRI) is the imaging of choice and particularly as a whole body examination can speed up the diagnosis and is an important component of follow-up controls. Differential diagnoses include numerous inflammatory, benign and malignant bone diseases. Therefore, it is essential to know the diagnosis of CNO and to take it into consideration in cases of an unclear inflammatory bone process in young patients.

Extending the Construct Network of Trait Disinhibition to the Neuroimaging Domain: Validation of a Bridging Scale for Use in the European IMAGEN Project

Trait disinhibition, a clinical-liability construct, has well-established correlates in the diagnostic, self-rating, task-behavioral, and brain potential response domains. Recently, studies have begun to test for neuroimaging correlates of this liability factor, but more work of this type using larger data sets is needed to clarify its brain bases. The current study details the development and validation of a scale measure of trait disinhibition composed of questionnaire items available in the IMAGEN project, a large-scale longitudinal study of factors contributing to substance abuse that includes clinical interview, self-report personality, task-behavioral, neuroimaging, and genomic measures. Using a construct-rating and psychometric refinement approach, a scale was developed that evidenced: (a) positive relations with interview-assessed psychopathology in the IMAGEN sample, both concurrently and prospectively and (b) positive associations with scale measures of disinhibition and reported psychopathology, and a robust negative correlation with P3 brain response, in a separate adult sample ( M_age = 19.5). These findings demonstrate that a common scale measure can index this construct from adolescence through to early adulthood, and set the stage for systematic work directed at identifying neural and genetic biomarkers of this key liability construct using existing and future data from the IMAGEN project.

Identification of Key Items Regarding Personality, Environment, and Life Events to Assess Risk and Resilience Factors for Harmful Alcohol Drinking in Adolescents

AIMS

Alcohol misuse often develops during adolescence involving interacting factors deriving from personality, environment and life events that can be assessed with well-established instruments. However, for specific research purposes, involving the assessment of large data sets, it may be beneficial having a short tool of key items representing the most important risk factors.

METHODS

We identified a set of key items from standard questionnaires assessed in about 2000 adolescents. In our longitudinal study we identified important items on personality, environment, and life events explaining alcohol drinking behaviour at the age of 14 years and the increase of alcohol consumption 2 years later.

RESULTS

The key items explained 33.4% of variance in alcohol drinking behaviour (vs. 34.8% for original battery) and can be completed in six minutes.

CONCLUSIONS

Our item list represents a powerful easy-to-use tool for the examination of alcohol drinking behaviour in adolescents.

[Whole-body ferromagnetic detector systems in clinical MRI]

CLINICAL/METHODICAL ISSUE

In spite of technical and organizational measures, ferromagnetic objects still find their way into the magnetic resonance imaging (MRI) room and can cause severe injuries.

STANDARD RADIOLOGICAL METHODS

A detailed patient education and MRI safety training for personnel are necessary to avoid MRI incidents with ferromagnetic objects.

METHODICAL INNOVATIONS

Whole body ferromagnetic detection systems should increase patient safety and minimize risks for personnel and MRI equipment in the clinical routine.

PERFORMANCE

In a clinical MRI setting, a screener system used for outpatients and inpatients (n = 400) identified unknown ferrous objects in 2 % of the cases. In two of these cases patients were found to be in possession of unknown foreign ferrous objects. Furthermore, a door guard system only used for outpatients (n = 2500) detected unknown ferromagnetic objects in 0.3 % of the cases.

ACHIEVEMENTS

The number of ferrous objects that are unknowingly brought into the scanner room can be reduced with a whole body ferromagnetic detection system. For an optimal benefit of the system a ferrous-free environment and perfectly ferrous-free clothing for the medical personnel are necessary. In the clinical routine, the benefit of the system is limited particularly for immobile patients who have to remain in a horizontal position.

PRACTICAL RECOMMENDATIONS

A whole body ferromagnetic detection system can complement but not replace patient education and MRI safety training.

Moraxella catarrhalis induces CEACAM3-Syk-CARD9-dependent activation of human granulocytes

The human restricted pathogen Moraxella catarrhalis is an important causal agent for exacerbations in chronic obstructive lung disease in adults. In such patients, increased numbers of granulocytes are present in the airways, which correlate with bacteria-induced exacerbations and severity of the disease. Our study investigated whether the interaction of M. catarrhalis with the human granulocyte-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM)-3 is linked to NF-κB activation, resulting in chemokine production. Granulocytes from healthy donors and NB4 cells were infected with M. catarrhalis in the presence of different inhibitors, blocking antibodies and siRNA. The supernatants were analysed by enzyme-linked immunosorbent assay for chemokines. NF-κB activation was determined using a luciferase reporter gene assay and chromatin-immunoprecipitation. We found evidence that the specific engagement of CEACAM3 by M. catarrhalis ubiquitous surface protein A1 (UspA1) results in the activation of pro-inflammatory events, such as degranulation of neutrophils, ROS production and chemokine secretion. The interaction of UspA1 with CEACAM3 induced the activation of the NF-κB pathway via Syk and the CARD9 pathway and was dependent on the phosphorylation of the CEACAM3 ITAM-like motif. These findings suggest that the CEACAM3 signalling in neutrophils is able to specifically modulate airway inflammation caused by infection with M. catarrhalis.

ATP-Evoked Intracellular Ca²⁺ Signaling of Different Supporting Cells in the Hearing Mouse Hemicochlea

Hearing and its protection is regulated by ATP-evoked Ca(2+) signaling in the supporting cells of the organ of Corti, however, the unique anatomy of the cochlea hampers observing these mechanisms. For the first time, we have performed functional ratiometric Ca(2+) imaging (fura-2) in three different supporting cell types in the hemicochlea preparation of hearing mice to measure purinergic receptor-mediated Ca(2+) signaling in pillar, Deiters' and Hensen's cells. Their resting [Ca(2+)]i was determined and compared in the same type of preparation. ATP evoked reversible, repeatable and dose-dependent Ca(2+) transients in all three cell types, showing desensitization. Inhibiting the Ca(2+) signaling of the ionotropic P2X (omission of extracellular Ca(2+)) and metabotropic P2Y purinergic receptors (depletion of intracellular Ca(2+) stores) revealed the involvement of both receptor types. Detection of P2X2,3,4,6,7 and P2Y1,2,6,12,14 receptor mRNAs by RT-PCR supported this finding and antagonism by PPADS suggested different functional purinergic receptor population in pillar versus Deiters' and Hensen's cells. The sum of the extra- and intracellular Ca(2+)-dependent components of the response was about equal with the control ATP response (linear additivity) in pillar cells, and showed supralinearity in Deiters' and Hensen's cells. Calcium-induced calcium release might explain this synergistic interaction. The more pronounced Ca(2+) leak from the endoplasmic reticulum in Deiters' and Hensen's cells, unmasked by cyclopiazonic acid, may also suggests the higher activity of the internal stores in Ca(2+) signaling in these cells. Differences in Ca(2+) homeostasis and ATP-induced Ca(2+) signaling might reflect the distinct roles these cells play in cochlear function and pathophysiology.

The role of the cannabinoid receptor in adolescents' processing of facial expressions

The processing of emotional faces is an important prerequisite for adequate social interactions in daily life, and might thus specifically be altered in adolescence, a period marked by significant changes in social emotional processing. Previous research has shown that the cannabinoid receptor CB1R is associated with longer gaze duration and increased brain responses in the striatum to happy faces in adults, yet, for adolescents, it is not clear whether an association between CBR1 and face processing exists. In the present study we investigated genetic effects of the two CB1R polymorphisms, rs1049353 and rs806377, on the processing of emotional faces in healthy adolescents. They participated in functional magnetic resonance imaging during a Faces Task, watching blocks of video clips with angry and neutral facial expressions, and completed a Morphed Faces Task in the laboratory where they looked at different facial expressions that switched from anger to fear or sadness or from happiness to fear or sadness, and labelled them according to these four emotional expressions. A-allele versus GG-carriers in rs1049353 displayed earlier recognition of facial expressions changing from anger to sadness or fear, but not for expressions changing from happiness to sadness or fear, and higher brain responses to angry, but not neutral, faces in the amygdala and insula. For rs806377 no significant effects emerged. This suggests that rs1049353 is involved in the processing of negative facial expressions with relation to anger in adolescence. These findings add to our understanding of social emotion-related mechanisms in this life period.

Predictors of changes in daily alcohol consumption in the aftermath of military deployment

BACKGROUND

Several studies have documented factors related to increase in alcohol consumption in the context of stressful experiences. However, little is known about predictors of different courses of alcohol use in this context. This study aims to investigate diverse predictors and correlates of increase and decrease of average daily alcohol consumption (aDAC) in the aftermath of military deployment taking into account a variety of potentially relevant factors.

METHODS

N=358 soldiers were examined before (T1) and 12 months after return from deployment (T2) using standardized interviews. Change in aDAC was categorized into decreased (n=72), stable (n=215) and increased (n=71) aDAC.

RESULTS

Overall, aDAC did not change significantly between T1 and T2 (median change=0.0 g, inter quartile range=11.3g). Compared to stable aDAC, increase was characterized by a lower proportion of high-educated individuals (OR: 0.3 (0.1-0.7), p=0.008), lower rank (marginally significant: OR: 2.0 (1.0-4.1), p=0.050), and less acceptance (trend: MR: 0.97 (0.93-1.00), p=0.053). Correlates of increased aDAC were less social support (MR: 0.84 (0.71-0.99), p=0.043), more sleeping problems (MR: 1.15 (1.00-1.31), p=0.045) and more negative post-event cognitions following deployment (MR: 2.32 (1.28-4.21), p=0.006). Decrease in aDAC was predicted by lower PTSD symptom severity before deployment (MR: 0.34 (0.16-0.72), p=0.005) and less childhood emotional neglect (marginally significant: MR: 0.78 (0.60-1.00), p=0.050).

CONCLUSIONS

Increase and decrease in alcohol use after stressful experiences might have differential risk factors and correlates. Findings might stimulate future research that could result in improved measures to prevent increases as well as in interventions that could foster decreases in alcohol consumption in the context of stressful experiences.

The role of stimulus complexity, spectral overlap, and pitch for gap-detection thresholds in young and old listeners

Thresholds for detecting a gap between two complex tones were determined for young listeners with normal hearing and old listeners with mild age-related hearing loss. The leading tonal marker was always a 20-ms, 250-Hz complex tone with energy at 250, 500, 750, and 1000 Hz. The lagging marker, also tonal, could differ from the leading marker with respect to fundamental frequency (f0), the presence versus absence of energy at f0, and the degree to which it overlapped spectrally with the leading marker. All stimuli were presented with steeper (1 ms) and less steep (4 ms) envelope rise and fall times. F0 differences, decreases in the degree of spectral overlap between the markers, and shallower envelope shape all contributed to increases in gap-detection thresholds. Age differences for gap detection of complex sounds were generally small and constant when gap-detection thresholds were measured on a log scale. When comparing the results for complex sounds to thresholds obtained for pure-tones in a previous study by Heinrich and Schneider [(2006). J. Acoust. Soc. Am. 119, 2316-2326], thresholds increased in an orderly fashion from markers with identical (within-channel) pure tones to different (between-channel) pure tones to complex sounds. This pattern of results was true for listeners of both ages although younger listeners had smaller thresholds overall.

Darstellung und Schwingungsspektren von Alkyl-und Rhodanohydrohexaboraten / Preparation and Vibrational Spectra of Alkyl and Rhodano Hydrohexaborates

Treatment of B6H6 2- with iodoalkanes and (SCN)2 in organic solvents affords the monosubstituted protonated hexaborates RB6H6 -, R = CH3, C2H5< C3H7, C4H9, C8H17 and SCN, respectively. The acidity constants of these weak Brönsted acids range for the alkylated species from 8.8 to 9.6, and for R = SCN the pka value is ~5. From basic solutions the salts Cs2RB6H5 can be precipitated, which show band patterns in the IR and Raman spectra typical for monosubstituted hydrohexaborates. The protonated compounds RB6H6 - are distinguished from the corresponding Brönsted bases RB6H5 2- by a high frequency shift of the BH stretching vibrations in the order of 100 cm-1. For Cs2(SCN)B6H5, S coordination of SCN- is supposed because of the high frequency of νCN: 2144 cm-1.

11B-NMR-Spektren von Alkyl-, Halogeno- und Rhodanohydrohexaboraten / 11B NMR Spectra of Alkyl-, Halogeno- and Rhodanohydrohexaborates

The temperature dependence of the 11B NMR spectra of the monosubstituted and protonated c/oso-hexaborates RB6H6 -, R=CH3, C2H5, C3H7, C4H9 C8H17, (SCN)B6H6 - and XB6H6 X = Cl. Br. I, has been determined in the range 180-300 K. The extra proton migrates at higher temperatures intramolecularly, probably across the edges of the B6 core. The extra proton is fixed to a facet of the octahedron below the coalescence temperatures 240 K (RB6H6 -) and 210 K (XB6H6 -) as recognized by the splitting of the signal of the equatorial B atoms due to the lowering of the symmetry from C4v to Cs . From the spin-spin coupling it can be deduced that the proton prefers with the softer Brönsted acids RB6H6 - facets adjacent to the substituent, while with the stronger Brönsted acids XB6H6 - facets including the antipodal B atom are occupied.

Oxidationsreaktionen an ΧnB6Η6-n 2-, Χ = Cl, Br, I; n = 1-6 und Kristallstrukturen von [(n-C4H9)4N]B6I6 und [(n-C4H9)4N]2B6I6 / Oxidation Reactions on XnB6H6-n 2-, X = Cl, Br, I; n = 1-6, and Crystal Structures of [(n-C4H9)4N]B6I6 and [(n-C4H9)4N],B6I6

By cyclic voltammetry investigations in acetonitrile solution it has been shown, that the halogenohydrohexaborates X„B6H6-n 2-, X = Cl, Br, I; n = 1-6, undergo a one-electron oxidation to form the corresponding radical anions. The reactions are completely reversible only for the perhalogenated ions B6X6 2- and for trans-Br4Β6Η2 2-. The oxidation by Ce(IV) in CH3CN yields deep blue B6I6, orange B6Br6- and yellow green B6Cl6-, characterized by their UV-VIS, IR/Raman spectra and by magnetic measurements. The crystal structures of the paramagnetic, air-stable, blue-black [(n-C4H9)4N]B6I6 (I) and the diamagnetic, colourless [(n-C4H9)4N]2B6I6 (II) were determined from single crystal X-ray diffraction analyses. I is monoclinic, space group P21/c, with a = 14.398(7), b = 14.638(3), c = 16.511(6) Å, β = 109.24(1)° (at —50°C), containing two crystallographically independent centrosymmetric B6 entities, which are strongly distorted with B— B bond lengths between 1.63 and 1.91 and I— I between 2.02 and 2.22 A. II is monoclinic, space group P21, with a = 11.246(3), b = 15.576(4), c = 14.900(4) Å, β = 92.10(1)° (at 23 °C) and contains nearly regular octahedral anions with bond lengths B—B 1.64-1.68 and B—I 2.17-2.21 A.

Higher precision level at individual laying performance tests in noncage housing systems

With the Weihenstephan funnel nest box, 12 laying hen flocks were tested for their individual laying performance, egg quality, and nesting behavior in a noncage environment. During the whole observation period of 8 yr, a transponder-based data recording system was continuously improved and resulted in a recording accuracy of 97%. At peak production, heritabilities for the number of eggs laid are in some flocks higher than expected. With improved data accuracy, heritability estimates on individual egg weights are more stable. Heritabilities for nesting behavior traits range between a low to moderate level, providing very useful information for laying hen selection to help improve traits that cannot be recorded in cages. Over the years, the benefits of the Weihenstephan funnel nest box for laying hen breeders have grown. This is due to higher data recording accuracies and extended testing capacities, which result in more reliable genetic parameters.

Longer telomere length in patients with schizophrenia

Previous studies have reported an association between shorter leukocyte telomere length and schizophrenia (SCZ). The aim of the present study was to replicate this finding in a large sample of SCZ patients (n=539) and population-based controls (n=519). In addition, the possible influence of SCZ severity on telomere length - as measured by age of onset, mode of onset, and course of the disorder - was investigated. Telomere length was negatively associated with age in both patients and controls. This is a consistently reported phenomenon, related to the problem of DNA end-replication. However, in contrast to previous findings, SCZ patients displayed longer telomeres compared to controls (p=0.015). No association was found with any SCZ-severity subphenotype. Interestingly, recent studies have reported associations between longer leukocyte telomere length and both smaller hippocampal volume, and poorer episodic memory performance. Both phenotypes are common in patients with SCZ. Further studies are warranted to investigate whether the present association between SCZ and increased telomere length was driven by such associations, or rather by association with the clinical disease per se or other associated phenotypes, endophenotypes or lifestyle factors.

The risk variant in ODZ4 for bipolar disorder impacts on amygdala activation during reward processing

OBJECTIVES

Bipolar disorder is a severe mood disorder, which normally begins during adolescence or early adulthood and has a heritability of up to 80%. The largest genome-wide association analysis of bipolar disorder recently identified a new genome-wide associated variant in OZD4 (rs12576775). The aim of the present study was to further elucidate the role of this risk variant in the disease process using an imaging genetics approach. As increased amygdala and striatal responses during the processing of reward and emotion are characteristic for bipolar disorder patients, it was tested whether the risk variant has an influence on this endophenotype in healthy adolescents.

METHODS

We examined the impact of the risk variant rs12576775 on functional magnetic resonance imaging data in an adolescent sample (N = 485). Differential activation between carriers of the risk allele (G-allele) and homozygous A-allele carriers in the amygdala and the striatum during a modification of the monetary incentive delay task (examining reward) and a face task (examining emotion) was analyzed.

RESULTS

Carriers of the risk allele showed an increased blood oxygen level-dependent response in the amygdala during reward sensitivity (p = 0.05) and reward expectation (p < 0.05) but not during the face task. No significant group differences were found in the striatum during both reward and emotion processing.

CONCLUSION

Our results indicate that the ODZ4 risk variant influences reward processing in the amygdala. Alterations in the processing of emotion may have different underlying mechanisms and need to be further examined.

Event-related potentials indicating impaired emotional attention in cerebellar stroke--a case study

The cerebellum has been implicated in affective and attentional processes, but little is known about corresponding neural signatures. We investigated early and late components of event-related potentials (ERPs) to emotionally arousing pictures, with and without competing attentional tasks, in a patient with an ischemic right posterior cerebellar infarction, at two months post infarct and two year follow-up. The early posterior negativity (EPN) response to highly arousing emotional cues in the competing visual attention condition revealed that the augmentation over occipital areas, as typically seen in normals, was absent post-infarct but was restored after two years. The late positive potentials (LPP) response to highly arousing emotional cues showed augmentation over frontal areas post-infarct, and over centro-parietal regions after two years. These ERP findings suggest a specific pattern of disruption of neural function associated with emotional-behavioral disturbances following cerebellar lesions, which can revert to normal with long term recovery.

From gene to brain to behavior: schizophrenia-associated variation in AMBRA1 alters impulsivity-related traits

Recently, genome-wide association between schizophrenia and an intronic variant in AMBRA1 (rs11819869) was reported. Additionally, in a reverse genetic approach in adult healthy subjects, risk allele carriers showed a higher medial prefrontal cortex blood oxygen level-dependent (BOLD) response during a flanker task examining motor inhibition as an aspect of impulsivity. To test whether this finding can be expanded to further aspects of impulsivity, we analysed the effects of the rs11819869 genotype on impulsivity-related traits on a behavioral, temperament and neural level in a large sample of healthy adolescents. We consider this reverse genetic approach specifically suited for use in a healthy adolescent sample, as these individuals comprise those who will eventually develop mental disorders in which impulsivity is implicated. Healthy adolescents from the IMAGEN study were included in the neuropsychological analysis (n = 848) and a functional magnetic resonance imaging (fMRI) task (n = 512). Various aspects of impulsivity were assessed using the Temperament and Character Inventory-Revised, the Substance Use Risk Profile Scale, the Cambridge Cognition Neuropsychological Test Automated Battery, and the Stop Signal Task (SST) in the fMRI paradigm. On a behavioral level, increased delay aversion was observed in risk allele carriers. Furthermore, risk allele carriers showed a higher BOLD response in an orbito-frontal target region during the SST, which declined to trend status after Family Wise Error correction. Our findings support the hypothesis that the schizophrenia-related risk variant of rs11819869 is involved in various aspects of impulsivity, and that this involvement occurs on a behavioral as well as an imaging genetics level.

K+ depolarization evokes ATP, adenosine and glutamate release from glia in rat hippocampus: a microelectrode biosensor study

BACKGROUND AND PURPOSE

This study was undertaken to characterize the ATP, adenosine and glutamate outflow evoked by depolarization with high K(+) concentrations, in slices of rat hippocampus.

EXPERIMENTAL APPROACH

We utilized the microelectrode biosensor technique and extracellular electrophysiological recording for the real-time monitoring of the efflux of ATP, adenosine and glutamate.

KEY RESULTS

ATP, adenosine and glutamate sensors exhibited transient and reversible current during depolarization with 25 mM K(+) , with distinct kinetics. The ecto-ATPase inhibitor ARL67156 enhanced the extracellular level of ATP and inhibited the prolonged adenosine efflux, suggesting that generation of adenosine may derive from the extracellular breakdown of ATP. Stimulation-evoked ATP, adenosine and glutamate efflux was inhibited by tetrodotoxin, while exposure to Ca(2+) -free medium abolished ATP and adenosine efflux from hippocampal slices. Extracellular elevation of ATP and adenosine were decreased in the presence of NMDA receptor antagonists, D-AP-5 and ifenprodil, whereas non-NMDA receptor blockade by CNQX inhibited glutamate but not ATP and adenosine efflux. The gliotoxin fluoroacetate and P2X7 receptor antagonists inhibited the K(+) -evoked ATP, adenosine and glutamate efflux, while carbenoxolone in low concentration and probenecid decreased only the adenosine efflux.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrated activity-dependent gliotransmitter release in the hippocampus in response to ongoing neuronal activity. ATP and glutamate were released by P2X7 receptor activation into extracellular space. Although the increased extracellular levels of adenosine did derive from released ATP, adenosine might also be released directly via pannexin hemichannels.

A cross-over study of effects on the hypothalamus-pituitary-adrenal (HPA) axis and the sympathoadrenergic system in magnetic field strength exposure from 0 to 7 T

The concept of stress is relevant to magnetic resonance imaging (MRI) examination in various ways. First, levels of stress to staff and patients have not been quantified in ultra-high magnetic fields. Second, research is increasingly interested in experimentally defining regional brain activity during stress. It is therefore important to know whether exposure to the ultra-high static magnetic fields per se might also lead to neurohormonal responses in the hypothalamus-pituitary-adrenal axis and the sympathoadrenal systems. In the present blinded case cross-over study with 41 healthy participants, we measured cortisol not only before and after but also during static magnetic field exposure in MRI scanners. Measures of catecholamines before and after exposure were also part of the study protocol. Using three different field strengths (1.5, 3 and 7 T) and a mock scanner (0 T), we examined whether not only the MRI procedure but also the static magnetic field per se has an influence on the neuroendocrine responses. We found no significant differences in the course of cortisol or catecholamine concentrations between the different static magnetic fields. Our study suggests that the results of MRI studies using stress-paradigms are not influenced by the static magnetic field itself.

Cognition and sensation in very high static magnetic fields: a randomized case-crossover study with different field strengths

PURPOSE

To establish the extent to which representative cognitive functions in subjects undergoing magnetic resonance (MR) imaging are acutely impaired by static magnetic fields of varying field strengths.

MATERIALS AND METHODS

This study was approved by the local ethics committee, and informed consent was obtained from all subjects. In this single-blind case-crossover study, 41 healthy subjects underwent an extensive neuropsychologic examination while in MR units of differing field strengths (1.5, 3.0, and 7.0 T), including a mock imager with no magnetic field as a control condition. Subjects were blinded to field strength. Tests were performed while subjects were lying still in the MR unit and while the examination table was moved. The tests covered a representative set of cognitive functions, such as memory, eye-hand coordination, attention, reaction time, and visual discrimination. Subjective sensory perceptions were also assessed. Effects were analyzed with a repeated-measures analysis of variance; the within-subject factors were field strength (0, 1.5, 3.0, and 7.0 T) and state (static, dynamic).

RESULTS

Static magnetic fields were not found to have a significant effect on cognitive function at any field strength. However, sensory perceptions did vary according to field strength. Dizziness, nystagmus, phosphenes, and head ringing were related to the strength of the static magnetic field.

CONCLUSION

Static magnetic fields as high as 7.0 T did not have a significant effect on cognition.

Controlled intra- and transdermal protein delivery using a minimally invasive Erbium:YAG fractional laser ablation technology

The aim of the study was (i) to investigate the feasibility of using fractional laser ablation to create micropore arrays in order to deliver proteins into and across the skin and (ii) to demonstrate how transport rates could be controlled by variation of poration and formulation conditions. Four proteins with very different structures and properties were investigated - equine heart cytochrome c (Cyt c; 12.4 kDa), recombinant human growth hormone expressed in Escherichia coli (hGH; 22 kDa), urinary follicle stimulating hormone (FSH; 30 kDa) and FITC-labelled bovine serum albumin (FITC-BSA; 70 kDa). The transport experiments were performed using a scanning Er:YAG diode pumped laser (P.L.E.A.S.E.®; Precise Laser Epidermal System). The distribution of FITC-BSA in the micropores following P.L.E.A.S.E.® poration was visualised by using confocal laser scanning microscopy (CLSM). Porcine skin was used for the device parameter and CLSM studies; its validity as a model was confirmed by subsequent comparison with transport of Cyt c and FITC-BSA across P.L.E.A.S.E.® porated human skin. No protein transport (deposition or permeation) was observed across intact skin; however, P.L.E.A.S.E.® poration enabled total delivery after 24h of 48.2±8.9, 8.1±4.2, 0.2±0.1 and 273.3±30.6 μg/cm(2) for Cyt c, hGH, FSH and FITC-BSA, respectively, using 900 pores/135.9 cm(2). Calculation of permeability coefficients showed that there was no linear dependence of transport on molecular weight ((1.6±0.3), (0.1±0.05), (0.08±0.03) and (0.9±0.1)×10(-3) cm/h, for Cyt c, hGH, FSH and FITC-BSA, respectively); indeed, a U-shaped curve was observed. This suggested that molecular weight was not a sufficiently sensitive descriptor and that transport was more likely to be determined by the surface properties of the respective proteins since these would govern interactions with the local microenvironment. Increasing pore density (i.e. the number of micropores per unit area) had a statistically significant effect on the cumulative permeation of both Cyt c (at 100, 150, 300 and 600 pores/cm(2), permeation was 11.2±2.4, 15.3±11.8, 33.8±10.5 and 51.2±15.8 4 μg/cm(2), respectively) and FITC-BSA (at 50, 100, 150 and 300 pores/cm(2), it was 58.5±15.3, 132.6±40.0, 192.7±24.4, 293.3±76.5 μg/cm(2), respectively). Linear relationships were established in both cases. However, only the delivery of FITC-BSA was improved upon increasing fluence (53.3±22.5, 293.3±76.5, 329.6±11.5 and 222.1±29.4 μg/cm(2) at 22.65, 45.3, 90.6 and 135.9 J/cm(2), respectively). The impact of fluence - and hence pore depth - on transport will depend on the relative diffusivities of the protein in the micropore and in the 'bulk' epidermis/dermis. Experiments with Cyt c and FSH confirmed that delivery was dependent upon concentration, and it was shown that therapeutic delivery of the latter was feasible. Cumulative permeation of Cyt c and FITC-BSA was also shown to be statistically equivalent across porcine and human skin. In conclusion, it was demonstrated that laser microporation enabled protein delivery into and across the skin and that this could be modulated via the poration parameters and was also dependent upon the concentration gradient in the pore. However, the role of protein physicochemical properties and their influence on transport rates remains to be elucidated and will be explored in future studies.

Magnetic resonance imaging of the active second stage of labour: proof of principle

OBJECTIVE

To prove that magnetic resonance imaging of foetal anatomy during the active second stage of vaginal delivery is feasible.

MATERIALS AND METHODS

Initially, five pregnant volunteers around the 30th week of gestation were examined in an open MRI. Based on the findings, one vaginal delivery was acquired under real-time imaging. To monitor the birth status during image acquisition, an MR-compatible wireless cardiotocography (CTG) system was built. Single-shot sequence parameters were optimised to compensate motion artefacts during labour.

RESULTS

Safety requirements to monitor the birth process under real-time MR imaging were met. High-resolution MR images were acquired immediately before and after delivery. In one patient, TSE single-shot cinematic sequences of the active second stage of labour were obtained. All sequences were adapted to tolerate movement of the mother and infant, as well as residual noise from the CTG. Furthermore, the MR imaging during labour showed only minor image artefacts.

CONCLUSION

CTG-monitored acquisition of MRI series during the active second stage of delivery is feasible. Image quality should allow various further studies to improve models for birth simulation as well as potential investigation of obstructed labour and obstetric complications.