Tryptophan-enriched diet or 5-hydroxytryptophan supplementation given in a randomized controlled trial impacts social cognition on a neural and behavioral level

Understanding of emotions and intentions are key processes in social cognition at which serotonin is an important neuromodulator. Its precursor is the essential amino acid tryptophan (TRP). Reduced TRP availability leads to weaker impulse control ability and higher aggression, while TRP supplementation promotes confidence. In a double-blind placebo-controlled fMRI study with 77 healthy adults, we investigated the influence of a 4 week TRP enriched diet and an acute 5-hydroxytryptophan (5-HTP) intake on two social-cognitive tasks, a moral evaluation and an emotion recognition task. With 5-HTP, immoral behavior without negative consequences was rated as more reprehensible. Additionally, during story reading, activation in insula and supramarginal gyrus was increased after TRP intake. No significant effects of TRP on emotion recognition were identified for the whole sample. Importantly, emotion recognition ability decreased with age which was for positive emotions compensated by TRP. Since the supramarginal gyrus is associated with empathy, pain and related information integration results could be interpreted as reflecting stricter evaluation of negative behavior due to better integration of information. Improved recognition of positive emotions with TRP in older participants supports the use of a TRP-rich diet to compensate for age related decline in social-cognitive processes.

"Influence of diet on mood and social cognition: a pilot study"

Recently, a relationship has been observed between nutrition and social cognition. In this aspect, several dietary patterns, or even some probiotics, have been reported as social cognition modulators. However, to date, no studies have reported the effects of specific nutrients. Our aim was to evaluate the relationship between dietary macronutrients and the processing of social and affective information. Participants were undergraduates from the University of Extremadura (Badajoz, Spain) aged 21.3 ± 2.9 years., with a BMI of 22.8 ± 3.9 (kg m-2). The students' social cognition and diet were analysed through questionnaires and a dietary record. The diets were analysed with DIAL v.1.18® software (Alce Ingeniería®). The participants filled out the WHO-5 well-being index, Beck's anxiety inventory, Beck's depression inventory, ruminative response scale (RSS), Leiden index of depression sensitivity (LEIDS-r), empathy quotient (EQ), and interpersonal reactivity index (IRI). To analyse the data, nutrients were grouped through principal component analysis (PCA) into lipids, carbohydrates and proteins. Additionally, we assayed if these principal components were associated with psychological questionnaire scores using multiple linear regression analyses. The dietary pattern differed from the traditional Mediterranean diet due to high intake of proteins and saturated fatty acids. Regarding social cognition and macronutrients, we found a positive association between lipids, specifically cholesterol, and the Perspective-Taking Scale (an IRI component). Carbohydrates influenced the RSS, indicating that complex carbohydrates may be a risk factor for depression. Moreover, the brooding factor, a component of the RRS, was negatively affected by dietary carbohydrates and proteins, specifically by fiber and aspartate. Diet may influence several variables related to social cognition and mood. Particularly, a low-cholesterol diet rich in fiber, complex carbohydrates, and aspartate apparently provides benefits, improving the processing of social and affective information and psychic well-being.

Repetitive negative thinking in daily life and functional connectivity among default mode, fronto-parietal, and salience networks

Repetitive negative thinking (RNT) is a maladaptive response to sadness and a transdiagnostic risk-factor. A critical challenge hampering attempts to promote more adaptive responses to sadness is that the between-person characteristics associated with the tendency for RNT remain uncharacterized. From the perspective of the impaired disengagement hypothesis, we examine between-person differences in blood-oxygen-level-dependent (BOLD) functional networks underlying cognitive conflict signaling, self-referential thought, and cognitive flexibility, and the association between sadness and RNT in daily life. We pair functional magnetic resonance imaging with ambulatory assessments deployed 10 times per day over 4 consecutive days measuring momentary sadness and RNT from 58 participants (40 female, mean age = 36.69 years; 29 remitted from a lifetime episode of Major Depression) in a multilevel model. We show that RNT increases following sadness for participants with higher than average between-network connectivity of the default mode network and the fronto-parietal network. We also show that RNT increases following increases in sadness for participants with lower than average between-network connectivity of the fronto-parietal network and the salience network. We also find that flexibility of the salience network's pattern of connections with brain regions is protective against increases in RNT following sadness. Our findings highlight the importance of functional brain networks implicated in cognitive conflict signaling, self-referential thought, and cognitive flexibility for understanding maladaptive responses to sadness in daily life and provide support for the impaired disengagement hypothesis of RNT.

Gestörte Integration sozial-emotionaler Hinweisreize bei schizophrenen Patienten

Störungen sozialer Kognitionen wie der Theory of Mind (ToM) werden in den letzten Jahren verstärkt hinsichtlich ihrer Bedeutung für das Auftreten von Einschränkungen des sozialen Funktionsniveaus bei schizophrenen Erkrankungen diskutiert. ToM beschreibt die Fähigkeit, eigene und fremde Zustände mental zu repräsentieren, auf deren Basis, Annahmen über die Intentionen anderer zu machen. Sie bilden die Grundlage für adäquate soziale Interaktionen. Ziel der vorliegenden Studie war es, mit einem modifizierten Vertrauensspiel den Zusammenhang zwischen sozial-kognitiven Prozessen und ihre Umsetzung in Entscheidungen bei an Schizophrenie erkrankten Patienten zu untersuchen. Bei 19 Schizophrenie-Patienten und 19 gematchten Kontrollprobanden wurden in einem Computerspiel soziale Interaktionen simuliert. Die Probanden hatten die Aufgabe, mit vier virtuellen Mitspielern ihren Gewinn zu maximieren, indem sie jedem Mitspieler einen Teil eines Guthabens überschrieben. Je nach Fairness der Mitspieler wurde der Gewinn der Probanden vergrößert oder reduziert. Zwei Mitspieler verhielten sich fair, zwei unfair. Bei je einem fairen und einem unfairen Spieler ließ sich die Fairness anhand des Emotionsausdrucks vor hersagen. Trotz vergleichbarer Leistung in der Emotionserkennung passten die Patienten im Gegensatz zu den Kontrollen ihr Spielverhalten nicht an die Fairness des Spielpartners an. Dabei bewerteten sie die Fairness des Verhaltens ihres Spielpartners nach einem Spieldurchgang ebenso differenziert wie die Kontrollprobanden. Die Ergebnisse der Studie zeigen, dass eine Analyse von Interaktionsverhalten von an Schizophrenie erkrankten Patienten im Rahmen eines spieltheoretischen Ansatzes Defizite in sozialen Entscheidungsprozessen aufzeigen, die sich durch eine fehlende Fähigkeit der Patienten, vorhandene sozial-emotionale Hinweisreize in ihre Entscheidung einzubeziehen, erklären lassen.

Neural reward processing in individuals remitted from major depression

BACKGROUND

Dysfunctional behavioural and neural processing of reward has been found in currently depressed individuals. However, little is known about altered reward processing in remitted depressed individuals.

METHOD

A total of 23 medication-free individuals with remitted major depressive disorder (rMDD) and 23 matched healthy controls (HCs) performed a reward task during functional magnetic resonance imaging. We also investigated reward dependence, novelty seeking and harm avoidance using the Tridimensional Personality Questionnaire and their association with neural responses of reward processing.

RESULTS

Compared to HCs, individuals with rMDD exhibited enhanced responses to reward-predicting cues in the hippocampus, amygdala and superior frontal gyrus. When reward was delivered, rMDD subjects did not significantly differ from HCs. In both groups neural activity during reward anticipation was negatively correlated with harm avoidance.

CONCLUSIONS

Our results show that rMDD is characterized by hyperactivation in fronto-limbic regions during reward anticipation. Alterations in neural activation during reward processing might reflect an increased effort in remitted depressed individuals to allocate neural activity for executive and evaluative processes during anticipatory reward processing.

Investigation of metamemory functioning in the at-risk mental state for psychosis

BACKGROUND

Metamemory describes the monitoring and knowledge about one's memory capabilities. Patients with schizophrenia have been found to be less able in differentiating between correct and false answers (smaller confidence gap) when asked to provide retrospective confidence ratings in previous studies. Furthermore, higher proportions of very-high-confident but false responses have been found in this patient group (high knowledge corruption). Whether and how these biases contribute to the early pathogenesis of psychosis is yet unclear. This study thus aimed at investigating metamemory function in the early course of psychosis.

METHOD

Patients in an at-risk mental state for psychosis (ARMS, n = 34), patients with a first episode of psychosis (FEP, n = 21) and healthy controls (HCs, n = 38) were compared on a verbal recognition task combined with retrospective confidence-level ratings.

RESULTS

FEP patients showed the smallest confidence gap, followed by ARMS patients, followed by HCs. All groups differed significantly from each other. Regarding knowledge corruption, FEP patients differed significantly from HCs, whereas a statistical trend was revealed in comparison of ARMS and FEP groups. Correlations were revealed between metamemory, measures of positive symptoms and working memory performance.

CONCLUSIONS

These data underline the presence of a metamemory bias in ARMS patients which is even more pronounced in FEP patients. The bias might represent an early cognitive marker of the beginning psychotic state. Longitudinal studies are needed to unravel whether metacognitive deficits predict the transition to psychosis and to evaluate therapeutic interventions.

Orientation of colonized sand flies Phlebotomus papatasi, P. duboscqi, and Lutzomyia longipalpis (Diptera: Psychodidae) to diverse honeys using a 3-chamber in-line olfactometer

A 3-chamber in-line olfactometer designed for use with sand flies is described and tested as a high-throughput method to screen honeys for attractiveness to Phlebotomus papatasi (four geographic isolates), P. duboscqi (two geographic isolates), and Lutzomyia longipalpis maintained in colonies at the Walter Reed Army Institute of Research. A diversity of unifloral honey odors were evaluated as a proxy for the natural floral odors that sand flies may use in orientation to floral sugar sources in the field. In the 3-chamber in-line olfactometer, the choice modules come directly off both sides of the release area instead of angling away as in the Y-tube olfactometer. Of the 25 honeys tested, five had a significant attraction for one or more of the sand fly isolates tested. This olfactometer and high-throughput method has utility for evaluating a diversity of natural materials with unknown complex odor blends that can then be down-selected for further evaluation in wind tunnels and/or field scenarios.

Multi-site reproducibility of prefrontal-hippocampal connectivity estimates by stochastic DCM

This study examined the reproducibility of prefrontal-hippocampal connectivity estimates obtained by stochastic dynamic causal modeling (sDCM). 180 healthy subjects were measured by functional magnetic resonance imaging (fMRI) during a standard working memory N-Back task at three different sites (Mannheim, Bonn, Berlin; each with 60 participants). The reproducibility of regional activations in key regions for working memory (dorsolateral prefrontal cortex, DLPFC; hippocampal formation, HF) was evaluated using conjunction analyses across locations. These analyses showed consistent activation of right DLPFC and deactivation of left HF across all three different sites. The effective connectivity between DLPFC and HF was analyzed using a simple two-region sDCM. For each subject, we evaluated sixty-seven alternative sDCMs and compared their relative plausibility using Bayesian model selection (BMS). Across all locations, BMS consistently revealed the same winning model, with the 2-Back working memory condition as driving input to both DLPFC and HF and with a connection from DLPFC to HF. Statistical tests on the sDCM parameter estimates did not show any significant differences across the three sites. The consistency of both the BMS results and model parameter estimates indicates the reliability of sDCM in our paradigm. This provides a basis for future genetic and clinical studies using this approach.

Association between genetic variation in a region on chromosome 11 and schizophrenia in large samples from Europe

Recent molecular studies have implicated common alleles of small to moderate effect and rare alleles with larger effect sizes in the genetic architecture of schizophrenia (SCZ). It is expected that the reliable detection of risk variants with very small effect sizes can only be achieved through the recruitment of very large samples of patients and controls (that is tens of thousands), or large, potentially more homogeneous samples that have been recruited from confined geographical areas using identical diagnostic criteria. Applying the latter strategy, we performed a genome-wide association study (GWAS) of 1169 clinically well characterized and ethnically homogeneous SCZ patients from a confined area of Western Europe (464 from Germany, 705 from The Netherlands) and 3714 ethnically matched controls (1272 and 2442, respectively). In a subsequent follow-up study of our top GWAS results, we included an additional 2569 SCZ patients and 4088 controls (from Germany, The Netherlands and Denmark). Genetic variation in a region on chromosome 11 that contains the candidate genes AMBRA1, DGKZ, CHRM4 and MDK was significantly associated with SCZ in the combined sample (n=11 540; P=3.89 × 10(-9), odds ratio (OR)=1.25). This finding was replicated in 23 206 independent samples of European ancestry (P=0.0029, OR=1.11). In a subsequent imaging genetics study, healthy carriers of the risk allele exhibited altered activation in the cingulate cortex during a cognitive control task. The area of interest is a critical interface between emotion regulation and cognition that is structurally and functionally abnormal in SCZ and bipolar disorder.

Comparison of three carbon dioxide sources on phlebotomine sand fly capture in Egypt

Lighted Centers for Disease Control and Prevention (CDC) light traps were baited with carbon dioxide (CO2) produced from three different sources to compare the efficacy of each in collecting phlebotomine sand flies in Bahrif village, Aswan Governorate, Egypt. Treatments consisted of compressed CO2 gas released at a rate of 250 ml/min, 1.5 kg of dry ice (replaced daily) sublimating from an insulated plastic container, CO2 gas produced from a prototype FASTGAS (FG) CO2 generator system (APTIV Inc., Portland, OR), and a CDC light trap without a CO2 source. Carbon dioxide was released above each treatment trap's catch opening. Traps were placed in a 4 x 4 Latin square designed study with three replications completed after four consecutive nights in August 2007. During the study, 1,842 phlebotomine sand flies were collected from two genera and five species. Traps collected 1,739 (94.4%) Phlebotomus papatasi (Scopoli), 19 (1.0%) Phlebotomus sergenti, 64 (3.5%) Sergentomyia schwetzi, 16 (0.9%) Sergentomyia palestinensis, and four (0.2%) Sergentomyia tiberiadis. Overall treatment results were dry ice (541) > FG (504) > compressed gas (454) > no CO2 (343). Total catches of P. papatasi were not significantly different between treatments, although CO2-baited traps collected 23-34% more sand flies than the unbaited (control) trap. Results indicate that the traps baited with a prototype CO2 generator were as attractive as traps supplied with CO2 sources traditionally used in sand fly surveillance efforts. Field-deployable CO2 generators are particularly advantageous in remote areas where dry ice or compressed gas is difficult to obtain.

Neuronal correlates of affective theory of mind in schizophrenia out-patients: evidence for a baseline deficit

BACKGROUND

Schizophrenia out-patients have deficits in affective theory of mind (ToM) but also on more basal levels of social cognition, such as the processing of neutral and emotional expressions. These deficits are associated with changes in brain activation in the amygdala and the superior temporal sulcus (STS). However, until now there have been no studies that examined these different levels of social cognition and their neurobiological underpinnings in patients within one design.

METHOD

Sixteen medicated schizophrenia out-patients and 16 matched healthy controls were studied with functional magnetic resonance imaging (fMRI) during a social cognition task that allows the investigation of affective ToM (aToM), emotion recognition and the processing of neutral facial expressions.

RESULTS

Patients showed a deficit in emotion recognition and a more prominent deficit in aToM. The performance in aToM and in emotion recognition was correlated in the control group but not in the schizophrenia group. Region-of-interest analysis of functional brain imaging data revealed no difference between groups during aToM, but a hyperactivation in the schizophrenia group in the left amygdala and right STS during emotion recognition and the processing of neutral facial expressions.

CONCLUSIONS

The results indicate that schizophrenia out-patients have deficits at several levels of social cognition and provide the first evidence that deficits on higher-order social cognitive processes in schizophrenia may be traced back to an aberrant processing of faces per se.

Objective measurement of motor activity during cognitive performance in adults with attention-deficit/hyperactivity disorder

OBJECTIVE

This study investigates whether hyperactivity, i.e. an increased level of motor activity, can be observed in adults with attention-deficit/hyperactivity disorder (ADHD).

METHOD

An infrared motion-tracking system was used to measure motor activity in 20 unmedicated adults with ADHD and 20 matched healthy controls (HC) during a 1-back working memory task.

RESULTS

Motor activity was higher in ADHD. It increased with the duration of testing and co-varied with cognitive performance in ADHD only. Subjective and objective measurements of motor activity were related in HC, but not in ADHD.

CONCLUSION

Higher levels of motor activity in ADHD are objectively measurable not only in children, but in adults as well. It is linked to cognitive performance arguing against distinguishable diagnostic subtypes. The objective measurement of motor activity seems to extend the description of ADHD symptoms derived from rating scales and might thus help to bridge the gap between psychopathological symptom description and neurobiological alterations.

Attraction of Triatoma dimidiata and Rhodnius prolixus (Hemiptera: Reduviidae) to combinations of host cues tested at two distances

The "kissing bugs," Triatoma dimidiata (Latreille) and Rhodnius prolixus (Stål) (Reduviidae: Triatominae) are major vectors of Chagas disease in Central and South America. To further uncover the attraction to certain host cues by these vectors at long and short distances from their host, the behavioral responses of two life stages (fifth-instar nymphs and adult males) of these two species to different known or suspected attractants, alone or in combination, were investigated. Tests were done using short- and long-range environments, namely, a four-port olfactometer and a long-range artificial chamber designed to mimic the insect's natural habitats. In single-attractant trials, heat alone and CO2 alone were found to be more attractive than selected chemicals. In multiple-attractant trials, both species and life stages were attracted at short distances, and a statistically significant synergistic increase in attraction was observed in long-distance multimodal tests. Lures containing CO2 were the most effective attractants at both long and short distances. R. prolixus adult males were significantly less attracted to several lure combinations than the nymphs of either species, perhaps because adults were more motivated to seek mates than feed. Our findings suggest that although the triatomine bugs may be capable of detecting odorants and heat sources at short distances, their ability to locate a host over a long distance is best aided by the presence of a CO2 plume.

Gene polymorphisms of renin angiotensin system and serotonin transporter gene in patients with vasovagal syncope

Objective of this study was to compare the distribution frequencies of gene polymorphisms of renin-angiotensin and serotonin system in patients with positive and negative head- up tilt test (HUT).

METHODS

DNA from 191 patients (mean age 44+ 18 years, 61 men) was collected. HUT was positive in 117 and negative in 74 patients. Following gene polymorphisms were determined by the PCR method: ACE insertion/deletion (I/D ACE), angiotensinogen (AGT) (M 235), angiotensin II receptor (ATR1) (A 1166C) and serotonin transporter (SERT) polymorphism (5HTTLPR).

RESULTS

No significant differences in the distribution of gene polymorphisms between syncopal patients with positive and negative HUT were dectected. Distribution of polymorphisms included: I/D ACE: II 19 vs 20%, ID 55 vs 52%, DD 26 vs 28%. Angiotensinogen gene polymorphism MM 27% vs 30%, MT 48% vs 46%, TT 25% vs 24%. ATR1 polymorphism AA 44 vs 32%, AC50 vs 60%, CC 6 vs 8%, 5HTTLPR serotonin transporter gene polymorphism LL 42 vs 43%, SL 41 vs 39%, SS 17 vs 18%.

CONCLUSIONS

An association between polymorphisms of ACE, AGT, ATR1 and SERT gene, and predisposition to VVS was not proven by the present study (Tab. 2, Ref. 22). Full Text (Free, PDF) www.bmj.sk.

Synthesis and analytical follow-up of the mineralization of a new fluorosurfactant prototype

Fluorinated surfactants have become essential in numerous technical applications due to their unparalleled effectiveness and efficiency. The environmental persistence of the non-biodegradable perfluorinated alkyl moiety has become a matter of concern. Therefore, it was searched for new molecules with chemically stable fluorinated end groups which can be microbially transformed into labile fluorinated substances. One prototype substance, 10-(trifluoromethoxy)decane-1-sulfonate, has shown biomineralization. Monitoring the formation of metabolites over time elucidated the mechanism of biotransformation. Analysis was performed utilizing liquid chromatography-single quadrupole mass spectrometry (LC-MS) and quadrupole-time of flight tandem mass spectrometry (QqTOF-MS). It was possible to distinguish between two major degradation pathways of the fluorinated alkylsulfonate derivative: (i) a desulfonation and subsequent oxidation and degradation of the alkyl chain being predominant and (ii) an insertion of oxygen with a subsequent cleavage and degradation of the molecule. The utilized trifluoromethoxy-endgroup resulted in instable trifluoromethanol after degradation of the alkyl chain, which led to a high degree of mineralization of the molecule.

A functional variant of the tryptophan hydroxylase 2 gene impacts working memory: a genetic imaging study

Imaging studies have demonstrated that prefrontal and parietal regions are activated during working memory (WM) tasks. Recently some molecular genetic studies reported associations between a functional promoter polymorphism of the tryptophan hydroxylase 2 gene (TPH2), that regulates the synthesis of serotonin, and attention. In 49 healthy Caucasian subjects the role of the TPH2 -703 G/T polymorphism for WM was tested by means of an imaging genomics approach in an n-back task. fMRI data showed an increased activation for the 2-back as compared to the 0-back condition for a large network in prefrontal and parietal areas. Although behavioural data showed no performance differences between the genotype groups of the -703 G/T a significantly stronger activation of the TT genotype carriers in BA 6, BA 46, and BA 40 was visible in contrast to the GT and GG groups. Present findings in congruence with previous findings support the hypothesis that TT carriers compensate deficits in executive control functions by increased brain activity.

The influence of antipsychotic treatment on brain reward system reactivity in schizophrenia patients

INTRODUCTION

Neuroleptic dysphoria is discussed as a serious side effect of antipsychotic medication. One aspect of this condition, a reduced motivation to reach potential rewards, might be induced by a blockade of striatal D2 receptors resulting in a reduced reactivity of the brain reward system. However, since this D2 antagonistic effect is higher for typical than atypical antipsychotics, typical antipsychotics should induce a stronger dampening of brain reward system activation. This hypothesis was tested in an event related functional magnetic resonance imaging study.

METHODS

A monetary reward paradigm was presented to 30 schizophrenia patients, who were treated with typical or atypical antipsychotics or a combination of both. Hemodynamic responses were analyzed during the anticipation and the reception of the reward.

RESULTS

Activation of the right ventral striatum, a core region of the brain reward system, was lower in patients treated with typical antipsychotics but only during the anticipation and not the delivery of a monetary reward.

DISCUSSION

This result indicates that a D2 associated reduction of brain reward system reactivity might be the neurobiological correlate of reduced motivation observed in the context of neuroleptic dysphoria. Using typical antipsychotics might worsen this effect, increasing the negative symptomatology of schizophrenia patients.

[Diagnostic benefit of the use of implanted loop recorder (Reveal Plus) for patients with syncope with unclear aetiology]

The objective of the study was to evaluate the diagnostic yield of a loop recorder (Reveal Plus, Medtronic) in the diagnosis of syncope conditions whose aetiology remains unclear despite the performance of a full diagnostic procedure.

PATIENTS AND METHOD

Loop recorders were implanted in 25 patients with recurrent syncope (9 men, 16 women, average age 59 +/- 14 years), who reported 4 +/- 2.7 episodes of syncope (2-10 episodes). A complete diagnostic algorithm was performed for all patients before implantation including the head-up tilt test, an invasive electrophysiological examination and a neurological examination. The aetiology of the syncope was not established by these examinations.

RESULTS

During an average monitoring period of 13 +/- 8 months (1-24 months) 10 patients experiences recidivating syncope, 7 patients experienced pre-syncope and 1 patient experienced palpitations. 7 were asymptomatic during monitoring. Symptomatic arrhythmia was detected in 10 patients (40%). The most frequent finding was bradyarrhythmia (6 patients--sinus arrest in 3 patients, serious bradycardia in 2 patients, AV block in 1 patient). Tachyarrhythmia was the cause of symptoms in 4 patients (supraventricular tachycardia in 3 patients, ventricular bigeminy in 1 patient). In the case of 5 patients (20%) syncope (pre-syncope) took place in the absence of a serious arrhythmia and was classified as vasovagal syncope.

CONCLUSION

The implantable loop recorder established a diagnosis in 15 of 25 patients (60%) with syncope that was not diagnosed by conventional tests and it is a highly beneficial method for diagnosing syncope.

Diagnostic yield of adenosine and nitroglycerine stimulated tilt test in patients with unexplained syncope

OBJECTIVES

We aimed to compare diagnostic yield of adenosine tilt test (A-HUT) with nitroglycerine tilt test (NTG-HUT) in patients with unexplained syncope and to assess the use of adenosine tilt test as an alternative to routine tilt testing.

BACKGROUND

Adenosine could provoke a vasovagal response in susceptible patients. Adenosine stimulated tilt testing is less time consuming than conventional tilt testing.

METHODS

Forty-one consecutive patients with unexplained syncope were tested (29 females /12 males; mean age 44 +/- 20 years). As a part of standard diagnostic testing they undewent both adenosine and nitroglycerin stimulated tilt testing in random fashion.

RESULTS

NTG-HUT was positive in 28 patients (68%). Six patients (14.6 %) developed a vasovagal response after adenosine stimulated head-up tilt test (A-HUT). All patiens with positive A-HUT showed also the positivity of NTG-HUT. No patient from with negative NTG-HUT developed a vasovagal response after adenosine induction. The diagnostic yield of NTG-HUT was significantly higher than yield of A-HUT (p < 0.001). The diagnostic yield of A-HUT was significantly affected by age. Subjects with a positive adenosine tilt test were younger than those with a negative tilt (29 +/- 10 vs. 46 +/- 20 years, p = 0.016). Five of six positive patients were <30 years of age. Diagnostic yield in those patients was 31%, whereas in patients >30 years of age was significantly lower (4%, p = 0.007).

CONCLUSION

Diagnostic yield of the adenosine stimulated tilt testing is significantly lower than diagnostic yield of nitroglycerine stimulated tilt testing. Given the very short time needed for performing adenosine stimulated HUT, it may be useful in patiens <30 years of age. In this group of patiens positive adenosine-stimulated HUT may obviate need for the time consuming nitroglycerine-stimulated HUT (Tab. 1, Fig. 3, Ref. 17).

[The importance of anamnesis in differential diagnosis of reflex and cardiogenic syncope]

The aim of the study was to establish the difference in the anamnestic data in cardiogenic and reflex syncope during a systematic gathering of data using a structured questionnaire and to measure the benefits of structured clinical history in differential diagnosis of syncope.

METHODOLOGY

70 patients with syncope of undetermined etiology (average age 51 years, 26 men and 44 women) underwent a standard diagnostic protocol procedure. Cardiogenic syncope was diagnosed in 16 patients (23%), vasovagal syncope in 34 patients (49%), in 20 patients (28%) the cause of the syncope remained uncertain. Anamnestic data was collected through a structured questionnaire which contained 70 points.

OUTCOME

Patients with cardiogenic syncope, as opposed to those with vasovagal syncope, tended to show higher age (68 vs. 43 years, p < 0.001), higher occurrence of IHD (75% vs. 35%, p = 0.008) and hypertension (62% vs. 29%, p = 0.02). Cardiogenic syncope in the prodromal phase exhibited a more frequent feeling of weakness (43% vs. 14%, p = 0.02), absence of the typical provoking factor (56% vs. 15%, p < 0.001), unspecific occurrence during the day (81% vs. 41%, p = 0.008), and weak pulse according to witness report (50% vs. 8%, p = 0.01). There was a significantly higher incidence of visual disturbances in vasovagal syncope in the prodromal phase (47% vs. 19%, p = 0.05) and sweating (29% vs. 6%, p = 0.05), provoking factors often involved long standing on feet (66% vs. 25%, p = 0.01) and hunger (29% vs. 0%, p = 0.01), and paleness was often reported by witnesses as opposed to vasovagal syncope (91% vs. 31%, p = 0.04). The rate of occurrence of palpitation and nausea in the prodromal phase was identical in both types of syncope.

CONCLUSION

There exists a significant difference in anamnestic data of patients with cardiogenic syncope and those with vasovagal syncope. Derailed clinical history is a useful method in differential diagnosis of syncope.

Inferring candidate genes for attention deficit hyperactivity disorder (ADHD) assessed by the World Health Organization Adult ADHD Self-Report Scale (ASRS)

The present study tests the psychometric properties and validity of the German version of the World Health Organization Adult Attention Deficit Hyperactivity Disorder (ADHD) Self-Report Scale (ASRS), which is a short screening instrument for use in the general population. Furthermore, two candidate genes for ADHD, the COMT VAL158MET and the 5-HT2a T102C polymorphisms, were tested for associations with the ASRS subscales inattention and hyperactivity/impulsivity in N = 203 healthy subjects. The ordinal CFA yielded a two-factorial model corroborating the structure of the official English WHO version. Genetic analysis revealed an association between the VAL allele of COMT and the inattention scale (F(1, 201) = 7.20, p = 0.008), the hyperactivity/impulsivity scale (F(1, 201) = 4.30, p = 0.039), and the total ASRS scale (F(2, 201) = 7.64, p = 0.006) with highest scores in carriers of the MET/MET genotype. The C-allele of 5-HT2a was significantly associated with the hyperactivity/impulsivity scale (F(1, 201) = 5.52, p = 0.020) and the total ASRS scale (F(1, 201) = 4.21, p = 0.042) with highest scores in carriers of the TT genotype. The data provide evidence for the structural as well as for the external validity of the ASRS.

Differential activation of pre-SMA and SMA proper during action observation: Effects of instructions

Many neurophysiological studies give evidence for a matching system between action observation and imitation. We used functional MRI to investigate the effects of different instructions for observing identical stimuli of whole-body gymnastics movements. The imitative-like observation mode asked normal human participants to observe the sequence containing repetitive parts and to subsequently imagine the observed movements in the first-person perspective. The evaluative observation mode asked the participants to carefully observe and judge movement accuracy and consistency in the repetitive sequence. We hypothesized that the supplementary motor area would be specifically involved in performing the observational tasks. Results indicate that the SMA proper is generally activated during observation of whole-body gymnastic movements and shows pronounced activation in imitative-like observation mode. Pre-SMA activity can be differentially modulated by instructions related to the observation task.

Personality and Emotion: Test of Gray's Personality Theory by Means of an fMRI Study

Although it is known that there are fundamental personality differences in the behavioral responses to emotional stimuli, traits have scarcely been investigated in this context by means of functional imaging studies. To maximize the variance with respect to personality, the authors tested 12 control subjects and 12 subjects who had sadomasochistic experiences with respect to the relationship between J. A. Gray's (1970) personality dimensions, the behavioral approach system (BAS) and the behavioral inhibition system (BIS), and brain activity in regions of interest. The BIS was associated with activity in numerous brain areas in response to fear, disgust, and erotic visual stimuli, whereas few associations could he detected between the BAS and brain activity in response to disgust and erotic stimuli.

The insula is not specifically involved in disgust processing: an fMRI study

fMRI studies have shown that the perception of facial disgust expressions specifically activates the insula. The present fMRI study investigated whether this structure is also involved in the processing of visual stimuli depicting non-mimic disgust elicitors compared to fear-inducing and neutral scenes. Twelve female subjects were scanned while viewing alternating blocks of 40 disgust-inducing, 40 fear-inducing and 40 affectively neutral pictures, shown for 1.5 s each. Afterwards, affective ratings were assessed. The disgust pictures, rated as highly repulsive, induced activation in the insula, the amygdala, the orbitofrontal and occipito-temporal cortex. Since during the fear condition the insula was also involved, our findings do not fit the idea of the insula as a specific disgust processor.

Latent inhibition and schizophrenia: Pavlovian conditioning of autonomic responses

Latent inhibition (LI) is an important model for understanding cognitive deficits in schizophrenia. Disruption of LI is thought to result from an inability to ignore irrelevant stimuli. The study investigated LI in schizophrenic patients by using Pavlovian conditioning of electrodermal responses in a complete within-subject design. Thirty-two schizophrenic patients (16 acute, unmedicated and 16 medicated patients) and 16 healthy control subjects (matched with respect to age and gender) participated in the study. The experiment consisted of two stages: preexposure and conditioning. During preexposure two visual stimuli were presented. one of which served as the to-be-conditioned stimulus (CSp + ) and the other one was the not-to-be-conditioned stimulus (CSp - ) during the following conditioning ( = acquisition). During acquisition, two novel visual stimuli(CSn + and CSn - ) were introduced. A reaction time task was used as the unconditioned stimulus (US). LI was defined as the difference in response differentiation observed between preexposed and non-preexposed sets of CS + and CS - . During preexposure, the schizophrenic patients did not differ in electrodermal responding from the control subjects, neither concerning the extent of orienting nor the course of habituation. The exposure to novel stimuli at the beginning of the acquisition elicited reduced orienting responses in unmedicated patients compared to medicated patients and control subjects. LI was observed in medicated schizophrenic patients and healthy controls, but not in acute unmedicated patients. Furthermore LI was found to be correlated with the duration of illness: it was attenuated in patients who had suffered their first psychotic episode.

Nematic liquid crystals with a tetrafluoroethylene bridge in the mesogenic core structure

A dramatic increase of the clearing temperatures of liquid crystals based on bis(cyclohexyl)ethane 1 by 50 to 70 K can be achieved by the perfluorination of the central ethylene link. Conformational analysis indicates that this effect is due to the increased rigidity of the mesogenic core structure and to the suppression of conformers with a bent shape. Materials based on bis(cylohexyl)tetrafluoroethane 2 might play a crucial role as materials for the next generation of active matrix LCDs with reduced power consumption.

Patterns of recovery of autonomic dysfunctions and neurocognitive deficits in schizophrenics after acute psychotic episodes

In this study, the authors aimed to identify patterns of autonomic dysfunction and neurocognitive deficit recovery. The authors performed laboratory assessments on 66 patients with schizophrenia immediately after an acute psychotic episode and 6, 12, and 18 months later. Shortly after the psychotic episode, the patients displayed cardiovascular hyperarousal at rest, cardiovascular and electrodermal hyporeactivity during 2 Continuous Performance Tasks (CPTs) and deficits in 2 behavioral CPT measures (i.e., reaction time and omission error rate) compared with 29 normal controls. In the subsequent postpsychotic course, changes indicative of a process of recovery occurred in all measurement areas, although with regard to autonomic hyporeactivity amelioration was limited to a subgroup of schizophrenics with complete and persistent symptomatic remission. Neurocognitive improvement in CPTs did not appear to depend on unimpaired autonomic reactivity mechanisms.

Patterns of recovery of autonomic dysfunctions and neurocognitive deficits in schizophrenics after acute psychotic episodes

In this study, the authors aimed to identify patterns of autonomic dysfunction and neurocognitive deficit recovery. The authors performed laboratory assessments on 66 patients with schizophrenia immediately after an acute psychotic episode and 6, 12, and 18 months later. Shortly after the psychotic episode, the patients displayed cardiovascular hyperarousal at rest, cardiovascular and electrodermal hyporeactivity during 2 Continuous Performance Tasks (CPTs) and deficits in 2 behavioral CPT measures (i.e., reaction time and omission error rate) compared with 29 normal controls. In the subsequent postpsychotic course, changes indicative of a process of recovery occurred in all measurement areas, although with regard to autonomic hyporeactivity amelioration was limited to a subgroup of schizophrenics with complete and persistent symptomatic remission. Neurocognitive improvement in CPTs did not appear to depend on unimpaired autonomic reactivity mechanisms.

The dimensional complexity of the EEG during cognitive tasks reflects the impaired information processing in schizophrenic patients

The aim of the present study was to investigate whether schizophrenic patients show a different change of the dimensional complexity of the EEG, as represented by the Grassberger-Procaccia correlation dimension D(2,) under cognitive challenge compared to normal control subjects. With respect to results reported in the literature, it was expected that the complexity of the signal under cognitive challenge is higher in schizophrenic patients than in normal control subjects reflecting the impaired information processing abilities of the patients. Eighty-seven schizophrenic and 30 matched control subjects performed two different types of the continuous performance task. The results revealed differences between schizophrenic patients and control subjects for the performance as well as the complexity measures. Schizophrenic patients produced more omission errors than normal subjects did. For the EEG complexity measure no differences occurred under the baseline condition. In contrast, during the first minute under task conditions the control subjects showed a decrease of the dimension while no changes were found for the schizophrenic group. These results occurred for both types of the cognitive task but they reached clear significance only in one of them. The results are interpreted as reflecting the ability of normal subjects to adapt their information processing system to the cognitive challenge and to focus their attention on the task while schizophrenic subjects do not show this adaptation to the task.

Construction of spectral sensitivity function using polychromatic UV sources

A procedure is presented for constructing the spectral sensitivity functions of biological dosimeters, using five polychromatic UV sources possessing different emission spectra. Phage T7 and uracil biological dosimeters have been used for measuring the dose rates of the lamps. Their spectral sensitivity functions consisting of two exponential terms have been constructed. The parameters of the spectral sensitivity functions have been determined by comparing the directly measured and calculated dose-rate values. The parameters of the sensitivity function are accepted as correct values when the deviation of the measured and calculated values is a minimum. Based on the deviations between the constructed and the experimentally determined spectral sensitivities with monochromatic sources, the differences between the measured and calculated results are interpreted. The importance of the correct spectral sensitivity data is demonstrated through the effectiveness spectra of a TL 01 lamp for phage T7 killing, uracil dimerization and erythema induction.

[Feelings without speech or speech without feelings? Further evidence for the decoupling hypothesis of alexithymia]

The theoretical background of the present investigation was the decoupling hypothesis of alexithymia, which presumes for alexithymic individuals a dissociation of psychophysiological indicators of emotion from verbal cognitive awareness of one's emotional state. To study alterations in reactivity to emotionally distressing stimuli in alexithymic individuals, 12 high-alexithymic and 14 low-alexithymic subjects (separated by TAS) out of a general sample of 54 were investigated. All subjects were exposed to cognitive (CPT) and affect inductive (film sequences) distress. During stimulus exposition electrodermal activity (spontaneous fluctuations) was recorded. After stimulus exposition the subjects assessed their emotional reaction towards the film sequences (DAS). Concerning electrodermal activity no differences were found between high and low alexithymics under cognitive distress. In any case a significant autonomous arousal was registered. However, only the low alexithymic subjects but not the high alexithymics showed a significant increase of spontaneous fluctuations as expression of autonomous arousal during presentation of affect inductive stimuli. The altered psychophysiological reactivity found in high alexithymics in contrast to low alexithymic subjects was revealed specifically for the processing of emotional qualified stimuli. However, there was no difference between the groups in cognitive self assessment of emotional response towards the film sequences. The findings are discussed with reference to neurophysiological and psychodynamic models and the decoupling hypothesis of alexithymia.

Classical conditioning and information processing: different mechanism for prepared and unprepared stimuli?

Although learning without awareness conflicts with recent theories of classical human Pavlovian conditioning, there is at least one type of conditioning in which CS-US contingency is processed without awareness--the so-called prepared conditioning. Therefore, presenting a secondary reaction time probe to measure the amount of information processing capacity required should produce interference with the secondary task in unprepared, but not in prepared conditioning, since in the latter information should be processed in parallel. In a previous study, the authors could not find differences between both types of conditioning, neither in reaction time nor in electrodermal indicators of information processing. The present study was conducted to replicate and extend these findings, using a differential autonomic conditioning paradigm. One half of 42 subjects received spider and snake slides as prepared stimuli, while the other half received flower slides as unprepared stimuli. Both kinds of stimuli were used as CS+ and as CS-. An electric shock served as unconditioned stimulus. During 24 acquisition and 24 extinction trials, electrodermal and heart rate responses, as well as reaction times to probe stimulus were recorded. The results revealed significant conditioning effects in terms of CS-/CS+ differences. However, no differences were found between prepared and unprepared stimuli, neither in autonomic measures nor in reaction time. Again, our results are in favor of serial information processing in both prepared and unprepared stimuli, suggesting that the so-called prepared conditioning may be treated as a subclass of classical autonomic conditioning instead of forming a specific class of learning.

Inhibition of human glutathione reductase by 10-arylisoalloxazines: crystalline, kinetic, and electrochemical studies

A series of newly synthesized N(10)-arylisoalloxazines--some of which are known to be antimalarial agents--were studied as inhibitors of human glutathione reductase (GR;NADPH + GSSG + H(+) <==> NADP(+) + 2GSH). The flavoenzyme was inhibited with IC(50) values between </- 1 and 100 microM in the presence of 100 microM NADPH. The isoalloxazines and N(3)-methylisoalloxazines with a 4'-chlorophenyl or a 3',5'-dichlorophenyl group at N10 were found to be the most promising inhibitors of GR, although even the bulkier 10-naphthyl and -anthryl derivatives were also effective inhibitors. In contrast, at position N3 of the isoalloxazine ring, the size of the substituent was found to strongly influence the inhibitory effect. Introduction of a carboxymethyl group at N3--which markedly increased the solubility of the derivative in aqueous solutions-- caused a rise in the IC(50) values by 1 order of magnitude. 8-Fluoro- and 8-azido-10-arylisoalloxazines were potent inhibitors of GR; consequently position C8 of the benzenoid subnucleus instead of N3 should be considered for introducing substituents. No correlation was observed between the inhibitory strength of several isoalloxazines and their redox potential as measured by cyclovoltammetry. The crystallographic analysis of GR complexed with 10-(4'-chlorophenyl)-3-(carboxymethyl)isoalloxazine and 10-(3',5'-dichlorophenyl)-3-(carboxymethyl)isoalloxazine, respectively, revealed the presence of one inhibitor molecule bound at the 2-fold axis of the homodimeric protein. This location is consistent with fluorescence titration measurements and enzyme kinetic studies in solution which gave no indication for binding at the substrate sites.

Synthesis of N-acetylglucosaminyl asparagine-substituted puromycin analogues

As part of our project aimed to introduce specifically glycosylated amino acids into proteins, new glycosylated puromycin analogues were chemically synthesized. Introduction of a free N-acetylglucosaminyl asparaginyl side chain abolished the activity of puromycin completely, but when the sugar OH groups were rendered increasingly hydrophobic by acetylation or benzylation, up to 8% of the activity was recovered. The results of our preliminary inhibition tests suggest that the interaction of puromycin analogues and therefore also of glycosylated aminoacyl tRNA, with the ribosomal A site increase with hydrophobicity of the modifying protecting groups.

Autonomic indicators of information processing related to conditioning

The aim of the present study was to quantitatively investigate the role of information processing in conditioning using stimuli with varying amounts of information content. A letter reproduction task varying in complexity served as the unconditioned stimulus. In the first experiment, we tested the indicator function of electrodermal and cardiovascular variables. The amount of information processing resources required emerged most clearly in electrodermal reactions (EDRs), showing an increase with increasing stimulus information content. A second experiment was performed using the same design to confirm the role of processing resources allocation during conditioning by means of an independent indicator. A reaction time task was introduced as a measure of information processing resources utilized. The results paralleled the dependence of EDRs on stimulus information content, as was found in the first experiment.

Electrodermal Pavlovian conditioning with prepared and unprepared stimuli

One-trial learning referred to by Guthrie has been suggested to occur in autonomic conditioning, if the conditional stimuli (CSs) are so-called prepared ones. To test this idea, half of 28 subjects were given spider or snake slides as "prepared" CSs, while the remainder were given neutral slides as "unprepared" CSs. A shock was employed as the unconditional stimulus (UCS), with a CS-UCS interval of 8 seconds. Electrodermal activity and probe reaction times were the dependent measures of conditioning, conceived in cognitive, information-processing terms as the learning of the CS/UCS contingency. Evidence for the usual CS/UCS contingency learning emerged in both indicators, and during both acquisition and extinction, but none for one-trial learning, perhaps because the UCS was insufficiently aversive.

Electrodermal activity as an indicator of information processing in a nonaversive differential classical conditioning paradigm

Most investigations of information processing in human Pavlovian autonomic conditioning focussed on the role of awareness of the contingency of the conditioned stimulus (CS) and the unconditioned stimulus (UCS). While in these studies only the qualitative information of the CS (UCS occurring vs not occurring) was varied, the present experiment was designed to vary the quantitative information of the CS. In a differential conditioning paradigm, using a letter reproduction task as nonaversive UCS, electrodermal responses to different degrees of CS information content were investigated. Twenty subjects experienced two different conditions in a within subject design. In one condition only the number of letters used in the following UCS was presented as CS+, while in the other condition the CS already contained the whole UCS information. Both conditions led to significant differences in magnitudes of electrodermal responding.

Transdermal monotherapy with mepindolol BIO TSD in patients with stable angina pectoris. Placebo-controlled, crossover investigation of a new therapeutic concept with 12-hours overnight application

10 patients (6 females and 4 males with an average age of 75 years) with stable angina pectoris were treated transdermally with mepindolol in a balanced, randomized, controlled, crossover study to compare the anti-ischemic effects of 12-hour overnight, and 24-hour applications. The number of angina pectoris attacks, the oral nitrate consumption and the ischemic parameters in 24-hour ECG, i.e. episodes of manifest (MMI) and silent (SMI) myocardial ischemia, the total duration of ischemia and 24-hour heart rate profiles were investigated. Both application schemes showed typical systemic beta blocker effects in all patients and significant clinical efficacy. A dose/effect relationship and a time/effect relationship between the two different application schemes were demonstrated across all the parameters investigated. Systemic and local tolerance of the therapy was good. 2 patients showed transient, mild skin irritation, but only during one phase of the study. Premature discontinuation was not necessary in any cases. There were no relevant changes in the clinical-chemistry. The new therapeutic concept of 24-hour treatment for a. pectoris with 12-hour overnight transdermal applications showed both good clinical efficacy and a good safety profile.