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Andreas Reif

Publications and source records attributed to Andreas Reif.

28 records · Page 2Linked to original sources
PubMed2004

Encephalopathy and myoclonus triggered by valproic acid.

In recent years, the use of valproic acid (VPA) as a mood-stabilizing agent has continuously increased. Although VPA usually is well tolerated, its use in combination with other psychotropic compounds might bear an elevated risk of adverse reactions. Here, we present the case of a 42-year-old male suffering from treatment-resistant psychotic depression, who was prescribed VPA additionally to lithium, clomipramine, flupentixol and risperidone. By doing so, he developed myoclonus, tremor and encephalopathy with sedation and marked EEG background slowing. Most notably, these side effects occurred in the presence of normal VPA and ammonia serum concentrations. On VPA discontinuation, all symptoms vanished and EEG normalized. We thus suggest that direct VPA-induced encephalopathy in the absence of ammonemia does exist, in this case probably facilitated by psychotropic polypharmacy.

Adult↗
PubMed2004

Differential effect of endothelial nitric oxide synthase (NOS-III) on the regulation of adult neurogenesis and behaviour.

Although it has been postulated that adult neurogenesis, i.e. the generation of functional neurons from progenitor cells in the mammalian brain, is involved in both the pathogenesis of depressive disorders and the therapeutic effect of antidepressant drugs, its regulation is still poorly understood. Nitric oxide, a gaseous messenger molecule, represents a possible modulating agent as it is involved in learning and memory formation as well as synapto- and morphogenesis. Here we investigated whether adult neurogenesis is altered in mice lacking endothelial nitric oxide synthase (NOS-III). Compared to wild-type littermates, NOS-III-deficient mice showed a significant reduction in neuronal progenitor cell proliferation in the dentate gyrus, suggesting a role for NOS-III in the stimulation of neuroneogenesis. NeuN, beta-III-tubulin and GFAP double-immunolabelling demonstrated that proliferating progenitor cells differentiate preferentially into neurons but not into astrocytes. However, when the survival rate of newly formed cells was examined no difference between wild-type and NOS-III knockout mice was found, suggesting that NOS-III selectively exerts its effects on the proliferation of progenitor cells. This might be mediated by a decrease in vascular endothelial growth factor (VEGF) transcripts in the hippocampus of knockout animals. At the behavioural level, while NOS-III knockout mice displayed better and faster learning in a learned helplessness paradigm, no depression-like behaviours were observed. In conclusion, our results indicated that NOS-III is involved in the proliferation of neuronal progenitor cells, although behavioural analysis does not provide evidence for a pro-depressive effect of reduced neuroneogenesis.

Animals↗
PubMed2003

Anxiety-related traits in mice with modified genes of the serotonergic pathway.

The neurobiology of anxiety is complex, reflecting the cumulative physiological effects of multiple genes. These genes are interactive with each other and with the environment in which they are expressed. Variation in genes coding for proteins that control serotonin (5-HT) system development and plasticity, establish 5-HT neuron identity, and modulate 5-HT receptor-mediated signal transduction and cellular pathways have been implicated in the genetics of anxiety and related disorders. Here, we selected anxiety and avoidance as paradigmatic traits and behavior and cover both traditional studies with inbred murine strains and selected lines which have been modified by gene knockout technologies. The design of a mouse model partially or completely lacking a gene of interest during all stages of development (constitutive knockout) or in a spatio-temporal context (conditional knockout) is among the prime strategies directed at elucidating the role of genetic factors in fear and anxiety. In many cases, knockout mice have been able to confirm what has already been anticipated based on pharmacological studies. In other instances, knockout studies have changed views of the relevance of 5-HT homeostasis in brain development and plasticity as well as processes underlying emotional behavior. In this review, we discuss the pertinent literature regarding phenotypic changes in mice bearing inactivation mutations of 5-HT receptors, 5-HT transporter, monoamine oxidase A and other components of the serotonergic pathway. Finally, we attempt to identify future directions of genetic manipulation in animal models to advance our understanding of brain dysregulation characteristic of anxiety disorders.

Animals↗
PubMed2003

NADPH-diaphorase staining reveals new types of interneurons in human putamen.

Neurons in the human striatum have been divided into five or seven different types, respectively. To further characterize these interneurons, we investigated the putamen of five brains by means of NADPH-diaphorase staining and compared our results to previous classifications in man. The NADPH-diaphorase method is selective for nitric oxide synthase (NOS); in the human striatum, predominantly interneurons were stained. NADPH-diaphorase positive neurons were then further examined. They showed clear morphological differences and could be classified into 12 different types, which only partially corresponded to previously described neuron types. Thus, we suggest at least three novel types of neostriatal interneurons. Furthermore, a special class of large neurons thought to be efferent in nature, stained NOS-positive.

Adult↗
PubMed2003

Toward a molecular architecture of personality.

Epidemiological studies provided a large body of evidence that personality dimensions are influenced by genetic factors and that the genetic component is highly complex, polygenic, and epistatic. However, consistent findings on the genetic basis of personality have yet remained sparse. In recent years, molecular genetics has begun to identify specific genes coding in particular for components of the serotonergic and dopaminergic neurotransmitter systems representing quantitative trait loci (QTLs) for behavioral traits. The QTL concept suggests that complex traits are not attributable to single genes. According to this polygenic model, the genetic basis of personality and behavior and its pathological variations thus results from additive or nonadditive interactions of various genes. As the number of suitable candidate genes constantly increases, the QTL model provides a reasonable explanation for the genetic basis of personality and its disorders. In this review, the current knowledge on the impact of a large number of candidate gene polymorphisms (e.g. variations in serotonin and dopamine receptor and serotonin transporter genes) on personality and temperament is summarized. Additionally, investigations of gene-gene and gene-environment interactions in humans and animals, which currently intensify the identification of genes that underlie behavioral variations, are examined. The findings converge on the notion that a probabilistic rather than deterministic impact of genes on the expression of behavior will contribute to the demystification of behavioral disorders.

Animals↗
PubMedDate not supplied

Folie a deux versus genetically driven delusional disorder: case reports and nosological considerations.

Folie a deux is thought to occur in persons who live close together, so that delusions of the primarily ill patient are adopted by the partner. Alternatively, if both patients are related, they may share the same genetically driven psychiatric illness. We present the cases of two psychotic couples (monozygotic twins and a mother and daughter pair, respectively), in which both subjects featured an almost identical psychopathological syndrome with the same delusional content and thus fulfilled the diagnostic criteria of folie a deux. When Leonhard's diagnostic system was applied, all four patients were found to suffer from affect-laden paraphrenia, arguing against the presence of folie a deux in those dyads. Thus, thorough psychopathological examination in suspected folie a deux settings can help to obtain valid diagnoses.

Female↗
PubMedDate not supplied

Delusional paralysis: an unusual variant of Cotard's syndrome.

Cotard's syndrome, a highly impressive psychopathological condition, occurs mainly in depressive disorders and entails nihilistic delusions concerning the body and the non-existing of the self as outstanding features, accompanied by hypochondriacal delusions and ideas of guilt as well as immortality. We here report on a female patient presenting with an unusual variant of the syndrome: most prominently, she had the delusion to be paralysed, although displaying psychomotor agitation, and that neuroleptic agents had devoured her nerve ganglia. Upon ECT, symptoms rapidly improved. Psychopathological implications and the nosological position of Cotard's syndrome are discussed.

Aged↗