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Biomedical subjects

A Heinz

Publications and source records attributed to A Heinz.

At least 19 recordsLinked to original sources
PubMed2007

Midbrain serotonin transporter binding potential measured with [11C]DASB is affected by serotonin transporter genotype.

BACKGROUND: Homozygote carriers of two long (L) alleles of the serotonin transporter (5-HTT) regulatory region displayed in vitro a twofold increase in 5-HTT expression compared with carriers of one or two short (S) alleles. However, in vivo imaging studies yielded contradictory results. Recently, an A > G exchange leading to differential transcriptional activation of 5-HTT mRNA in lymphobalstoid cell lines was discovered in the 5-HTT regulatory region. In vitro and in vivo evidence suggests that [(11)C]DASB, a new 5-HTT ligand offers some advantages over the ligands used in previous studies in measuring 5-HTT density independent of synaptic levels of serotonin. METHOD: We assessed 5-HTT binding potential (BP (2)) in the midbrain of 19 healthy subjects with positron emission tomography and [(11)C]DASB. Accounting for the hypothesized functional similarity of L (G) and S in driving 5-HTT transcription, we assessed whether L (A) L (A) homozygotes display increased midbrain BP (2) compared with carriers of at least one S allele. RESULTS: BP (2) in the midbrain was significantly increased in L (A) L (A) homozygotes compared with carriers of at least one S allele. Interestingly, the genotype effect on the midbrain was significantly different from that on the thalamus and the amygdala where no group differences were detected. CONCLUSIONS: This in vivo study provides further evidence that subjects homozygous for the L (A) allele display increased expression of 5-HTT in the midbrain, the origin of central serotonergic projections.

Adult↗
PubMed2007

Gene-gene effects on central processing of aversive stimuli.

Emotional reactivity and regulation are fundamental to human behavior. As inter-individual behavioral variation is affected by a multitude of different genes, there is intense interest to investigate gene-gene effects. Functional sequence variation at two genes has been associated with response and resiliency to emotionally unpleasant stimuli. These genes are the catechol-O-methyltransferase gene (COMT Val158Met) and the regulatory region (5-HTTLPR) of the serotonin transporter gene. Recently, it has been proposed that 5-HTT expression is not only affected by the common S/L variant of 5-HTTLPR but also by an A to G substitution. Using functional magnetic resonance imaging, we assessed the effects of COMT Val(158)Met and both 5-HTT genotypes on brain activation by standardized affective visual stimuli (unpleasant, pleasant, and neutral) in 48 healthy subjects. Based on previous studies, the analysis of genotype effects was restricted to limbic brain areas. To determine allele-dose effects, the number of COMT Met158 alleles (i.e., lower activity of COMT) and the number of 5-HTT low expressing alleles (S and G) was correlated with the blood oxygen level-dependent (BOLD) response to pleasant or unpleasant stimuli compared to neutral stimuli. We observed an additive effect of COMT and both 5-HTT polymorphisms, accounting for 40% of the inter-individual variance in the averaged BOLD response of amygdala, hippocampal and limbic cortical regions elicited by unpleasant stimuli. Effects of 5-HTT and COMT genotypes did not affect brain processing of pleasant stimuli. These data indicate that functional brain imaging may be used to assess the interaction of multiple genes on the function of neuronal networks.

Adult↗
PubMed2007

[Experience with new teaching methods and testing in psychiatric training].

In 1999, the Charité Medical University in Berlin, Germany, implemented a reformed medical study course (RMSC) along with traditional undergraduate medical education. The RMSC is characterized by problem-based learning (PBL), training in communication skills with "simulated patients", and interdisciplinary seminars. The curriculum is organized into blocks according to organ system and age (period od life). In a new intensive 4-week psychiatric block, 4th-year students get practical experience in psychiatric wards. Furthermore, PBL groups and workshops are offered that focus on frequent psychiatric disorders. By providing interactive courses with simulated patients, students are intensively trained in taking psychiatric histories and in generating psychopathological findings. Defined learning objectives are tested using multiple-choice items and objectively structured clinical examinations at semester end. First positive results indicate that this course represents an appropriate and practicable curriculum for teaching psychiatry in Germany.

Education, Medical↗
PubMed2007

[Alcohol-related disorders: etiopathology and therapeutic considerations].

The scientific understanding of the neurobiological priniciples of alcoholism has made significant progress in recent years. Especially the effects of ethanol on the neurotransmitter-systems are well studied. Dopaminergic and GABAergic facilitation contribute to the stimulating effects of low doses of alcohol while many of its adverse effects are mediated by glutamatergic inhibition at higher doses. A reduced serotonine-metabolism was shown to be a risk factor for the development of an alcohol dependence. The historic success of absinthe is discussed in this context. Absinthe is a mixture of ethanol and thujone, a substance that leads to a GABAergic inhibition as well as a reduced serotonergic responsiveness. Many studies substantiate the role of cannabinoid as well as striatal opiate-receptors in alcohol-related disorders. Neuroimaging studies could prove the important role of the reward system in this connection. Genetic factors were shown to be predisposing, however biological and environmental factors have a regulatory effect on the gene expression. Disturbances of the hpa-axis (hypothalamus-pituitary gland-adrenal cortex) were also shown to play a role in alcohol dependence. The understanding of these neurobiological principles of alcohol-related disorders should contribute to enhance and improve their therapeutic options.

Alcohol-Related Disorders↗
PubMed2006

K isomers in 254No: probing single-particle energies and pairing strengths in the heaviest nuclei.

We have identified two isomers in 254No, built on two- and four-quasiparticle excitations, with quantum numbers K pi = 8- and (14+), as well as a low-energy 2-quasiparticle Kpi = 3+ state. The occurrence of isomers establishes that K is a good quantum number and therefore that the nucleus has an axial prolate shape. The 2-quasiparticle states probe the energies of the proton levels that govern the stability of superheavy nuclei, test 2-quasiparticle energies from theory, and thereby check their predictions of magic gaps.

Journal Article↗
PubMed2006

Hippocampal glutamate concentration predicts cerebral theta oscillations during cognitive processing.

RATIONALE: Brain waves reflect collective behavior of neurons and provide insight into distributed network processing. Frontal and hippocampal theta oscillations (4-7 Hz) were linked to cognitive tasks and animal studies have suggested an involvement of glutamatergic neurotransmission in integrative frontal-hippocampal processing. Human evidence for such relationships is lacking. METHODS: Here, we studied the associations between glutamate concentrations in the hippocampal region, measured by a 3-T proton magnetic resonance spectroscopy (1H-MRS), and EEG theta activity during an auditory target detection paradigm. RESULTS: A robust relationship between hippocampal glutamate and frontal theta activity during stimulus processing was found. Moreover, frontal theta oscillations were related to response speed. CONCLUSION: The results suggest a functional coupling between the frontal cortex and hippocampal region during stimulus processing and support the idea of the hippocampus as a neural rhythm generator driven by glutamatergic neurotransmission. These preliminary data show, for the first time, a relationship between in vivo measured glutamate and basic cerebral information processing in humans.

Adult↗
PubMed2006

40Ca(alpha, gamma)44Ti reaction in the energy regime of supernova nucleosynthesis.

The 44Ti(t1/2=59 yr) nuclide, an important signature of supernova nucleosynthesis, has recently been observed as live radioactivity by gamma-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction 40Ca(alpha, gamma)44Ti (Ec.m. approximately 0.6-1.2 MeV/u by direct off-line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor approximately 2 over previous estimates and bringing it closer to Cas A observations.

Journal Article↗
PubMed2006

Breakdown of K selection in 178Hf.

Coulomb activation of the four quasiparticle Kpi=16+ 178Hf isomer (t1/2=31 y) has led to the measurement of a set of Elamda matrix elements coupling the isomer band to the ground band. The present data combined with earlier 178 Hf Coulomb excitation data have probed the components in the wave functions and revealed the onset and saturation of K mixing in low-K bands, whereas the mixing is negligible in the high-K bands. The implications can be applied to other quadrupole-deformed nuclei.

Journal Article↗
PubMed2006

[Cue-induced alcohol craving. Neurobiological correlates and clinical relevance].

If there is no further intervention, relapse rates in detoxified alcoholics are high, up to 85%, even after complete remission of bodily withdrawal symptoms. It has been suggested that one relevant mechanism contributing to the relapse risk is the exposure to stimuli (cues) that have regularly been associated with alcohol intake. Such stimuli can become conditioned cues that elicit alcohol craving and intake as conditioned responses. Current brain imaging studies indicate that dysfunction of dopaminergic, glutamatergic, and opioidergic neurotransmission in the brain reward system (ventral striatum including the nucleus accumbens) is associated with alcohol craving and brain activation elicited by alcohol-associated pictures. These findings point to specific indications for psychotherapeutic and additive pharmacological treatment options.

Alcoholism↗
PubMed2006

The impact of cognitions on the development of panic and somatoform disorders: a prospective study in patients with vestibular neuritis.

BACKGROUND: There is a high incidence of panic and somatoform disorders after vestibular neuritis. However, the occurrence of psychiatric disorders has been shown to be unrelated to persistent functional vestibular impairment. The aim of the present study was to examine the role played by cognitions in the development of panic and somatoform disorders. METHOD: In a 2-year prospective study, cognitions were recorded at various stages using the Agoraphobic Cognitions Questionnaire and Body Sensations Questionnaire. Our analysis focused on whether body-related anxiety or panic-related thoughts can predict the development of a panic or somatoform disorder. RESULTS: Fear arising on the first day of an acute vestibular episode did not predict the development of panic or somatoform disorders. One week after the dysfunction, however, the fear of vertigo was a significant predictor, explaining 20% of the variance in the development of either disorder. After 6 weeks, persistent fear of vertigo or vomiting predicted approximately 30% of the variance, and after 6 months panic-related thoughts predicted 40% of the variance and, with the inclusion of body-related fears, as much as 60% of the variance in the development of panic or somatoform disorders. CONCLUSION: Our data confirm prospectively a number of fundamental assumptions of cognitive theory concerning the development of anxiety disorders. Subjects who experience vertigo as particularly alarming focus more intensely than other patients on the negative symptoms they perceive as being related to the disorder. Patients with panic-related cognitions were prone to develop panic or somatoform disorders.

Acute Disease↗
PubMed2006

Genetic association of the human corticotropin releasing hormone receptor 1 (CRHR1) with binge drinking and alcohol intake patterns in two independent samples.

To investigate the role of the corticotropin releasing hormone receptor 1 (CRHR1) in patterns of human alcohol drinking and its potential contribution to alcohol dependence, we analysed two independent samples: a sample of adolescents, which consisted of individuals from the 'Mannheim Study of Risk Children' (MARC), who had little previous exposure to alcohol, and a sample of alcohol-dependent adults, who met DSM-IV criteria of alcohol dependence. Following determination of allelic frequencies of 14 polymorphisms of the CRHR1 gene, two haplotype tagging (ht)SNPs discriminating between haplotypes with a frequency of > or =0.7% were identified. Both samples were genotyped and systematically examined for association with the htSNPs of CRHR1. In the adolescent sample, significant group differences between genotypes were observed in binge drinking, lifetime prevalence of alcohol intake and lifetime prevalence of drunkenness. The sample of adult alcohol-dependent patients showed association of CRHR1 with high amount of drinking. This is the first time that an association of CRHR1 with specific patterns of alcohol consumption has been reported. Our findings support results from animal models, suggesting an importance of CRHR1 in integrating gene-environment effects in alcohol use disorders.

Adolescent↗
PubMed2006

Combination of multimodal imaging and molecular genetic information to investigate complex psychiatric disorders.

Multimodal imaging, the combination of several brain imaging techniques in one subject, provides a wealth of parameters and favours the interpretation of complex models in schizophrenia research. Moreover, new imaging tools allow the investigation of distinct neurotransmitter systems and their modulation by pharmacological intervention. An important feature of multimodal imaging is the possibility to characterize the activation dependencies of different neurotransmitters and provide the experimental tool to test system models of brain function and dysfunction. The combination of measurement techniques with high temporal resolution (e. g. MEG, EEG) and high spatial resolution (e. g. fMRI) facilitate the understanding of local and global systems as well as time characteristics. Moreover, the association of imaging parameters with genetic variations of neurotransmitter systems allows the investigation of neurotransmitter activity and its role in the pathophysiology of schizophrenia. To overcome the limitations of standard statistical methods, new approaches in machine learning have to be adapted to handle multiple parameters obtained from brain imaging and genetic measurements.

Brain↗
PubMed2006

Dopamine and the diseased brain.

Dysfunction of central dopaminergic neurotransmission has been implicated in a series of neuropsychiatric disorders, including Tourette's syndrome, schizophrenia, and drug and alcohol dependence. The behavioral and psychopathological manifestations of central dopaminergic dysfunction differ depending on the site of their neurobiological correlate. These sites may be found in the dorsal or ventral striatum, but also in cortical regions such as the limbic and prefrontal cortex, among other locations. A low basic dopamine turnover and an increase in the availability of dopamine D2 receptors in the caudate body have been associated with the severity of motor tics in Tourette's syndrome. In the ventral striatum and particularly in the nucleus accumbens, different drugs of abuse stimulate dopamine release and thus reinforce drug consumption. The downregulation of dopamine D2 receptors in this area of the brain has been associated with alcohol craving and an increase in the processing of alcohol-related stimuli in the medial prefrontal cortex. Brain imaging studies in which intrasynaptic dopamine release is manipulated in vivo have shown that increased subcortical dopamine release is associated with the pathogenesis of positive symptoms in schizophrenia. This review discusses a broad range of brain imaging and neuroendocrinological studies on dopaminergic dysfunction in neuropsychiatric disorders, including relevant findings on the basis of primate studies. In addition, the hypothesis is examined that phasic dopamine release is associated with salience attribution to external stimuli, insofar as it mediates reward anticipation in the ventral striatum and limbic cortex, habit formation in the dorsal striatum, and working memory function in the prefrontal cortex.

Animals↗
PubMed2005

Postgraduate training for young psychiatrists--experience of the Berlin Summer School.

BACKGROUND: Growing professional exchange between Eastern and Western European countries increases the possibilities for international postgraduate training courses and by that satisfying the need for rapid and facilitation of travel and migration in the enlarged European Union increase achieving high standards. The purpose of this study was to evaluate a summer school program that trained young Eastern European psychiatrists and to assess the impact of the program on their professional development and future activities. METHOD: We evaluated the training effect of the first 3 years of the Berlin Summer School with respect to (1) the participants' satisfaction with the topics, quality and originality of the presentations, and (2) long-term effects and implications for their professional career. All participants (N=43) filled out anonymously the evaluation form at the end of each summer school. An evaluation of long-term effects was carried out 2 years later with a questionnaire that was sent via e-mail to all former participants. RESULTS: Participants were most satisfied with practical topics such as "how to prepare a paper", "how to evaluate a paper", or "how to participate in a congress." The appreciation of the presented topics and the appreciation of courses increased in each consecutive summer school. All summer school participants reported that the course had some influence on their future career, and one fifth of the participants felt that their professional development was influenced "a lot". CONCLUSIONS: Although limited to 1 week of intensive training, a summer school program can have a longer lasting positive influence on the professional development of the participants. Participants felt that particularly the training of practical skills improved their research performance. Former participants founded an independent multicentric and multinational research group and supported national courses that were organized similar to the Berlin Summer School.

Analysis of Variance↗
PubMed2005

Structure of the odd-A, shell-stabilized nucleus 253/102No.

In-beam gamma-ray spectroscopic measurements have been made on 253/102No. A single rotational band was identified up to a probable spin of 39/2planck, which is assigned to the 7/2(+)[624] Nilsson configuration. The bandhead energy and the moment of inertia provide discriminating tests of contemporary models of the heaviest nuclei. Novel methods were required to interpret the sparse data set associated with cross sections of around 50 nb. These methods included comparisons of experimental and simulated spectra, as well as testing for evidence of a rotational band in the gammagamma matrix.

Journal Article↗
PubMed2005

[The NMDA receptor system: genetic risk factor for alcoholism].

Alcohol dependence is one of the most common addictive diseases and known to be in part genetically transmitted, based on an oligogenic background in which each gene involved contributes only little to the resulting phenotype. Besides influencing other signal transduction mechanisms, alcohol specifically inhibits the NMDA signaling cascade, which mediates the excitatory effects of glutamate in the brain. Target molecules, sensitive to ethanol, include the NMDA receptors as well as downstream molecules of the glutamatergic system, glutamate transporters, and associated regulatory proteins. Adaptive processes of the glutamatergic system during chronic alcohol consumption may play a major role for later development of reward symptoms. Candidate gene studies, including association studies and animal models, are powerful and sensitive for detecting oligogenic effects and thus important to alcoholism research.

Alcoholism↗
PubMed2005

Mental health care in Berlin.

AIM: To provide information on the mental health care system in Berlin, Germany. METHOD: Using available data we report on the spectrum of mental health care services provided in Berlin, the number of professionals working in these sectors, funding arrangements, pathways into care, and user/carer involvement. RESULTS: The health care system in Berlin consists of a network of inpatient, outpatient, ancillary, and rehabilitative facilities, all of which are meant to work in a synergistic fashion. However, although the individual treatment options are generally well-planned, there is still a lack of co-ordination between them. Currently, the entire network is threatened by cuts in state funding for ancillary and rehabilitative services, by further reductions in the number of hospital beds, and by insurance company cuts in prescription drug budgets, such as those used for atypical antipsychotics in outpatient care. DISCUSSION: Despite many similarities with the situation in other European capitals, the system of mental health care in Berlin suffers from a variety of problems related to co-ordination and costs that are unique to the German capital.

Berlin↗