Mathias Berger
University of Freiburg
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Featured researches published by Mathias Berger.
FEBS Letters | 1991
Joachim Bauer; Sylvia Strauss; Ursula Schreiter-Gasser; Ursula Ganter; Petra Schlegel; Irene Witt; Benedikt Yolk; Mathias Berger
Recent studies indicated that the formation of a major constituent of Alzheimers disease (AD) senile plaques, called βA4‐peptide, does not result from normal processing of its precursor, amyloid precursor protein (APP). Since proteolytic cleavage of APP inside its βA4 sequence was found to be part of APP processing the formation of the βA4‐peptide seems to be prevented under normal conditions. We considered whether in AD one of the endogenous proteinase inhibitors might interfere with APP processing. After we had recently found that cultured human neuronal cells synthesize the most potent of the known human proteinase inhibitors, α‐2‐macroglobulin (α2M), upon stimulation with the inflammatory mediator interleukin‐6 (IL‐6) we now investigated whether α2M and IL‐6 could be detected in AD brains. Here we report that AD cortical senile plaques display strong α2M and IL‐6 immunoreactivity while no such immunoreactivity was found in age‐matched control brains. Strong perinuclear α2M immunoreactivity in hippocampal CAI neurons of Alzheimers disease brains indicates that neuronal cells are the site of α2M synthesis in AD brains. We did not detect elevated IL‐6 or α2M levels in the cerebrospinal fluid of AD patients. Our data indicate that a sequence of immunological events which seem to be restricted to the local cortical environment is part of AD pathology.
Biological Psychology | 2001
Dieter Riemann; Mathias Berger; Ulrich Voderholzer
Disturbances of sleep are typical for most depressed patients and belong to the core symptoms of the disorder. Polysomnographic sleep research has demonstrated that besides disturbances of sleep continuity, in depression sleep is characterized by a reduction of slow wave sleep and a disinhibition of REM sleep, with a shortening of REM latency, a prolongation of the first REM period and increased REM density. These findings have stimulated many sleep studies in depressive patients and patients with other psychiatric disorders. In the meantime, several theoretical models, originating from basic research, have been developed to explain sleep abnormalities of depression, like the two-process-model of sleep and sleep regulation, the GRF/CRF imbalance model and the reciprocal interaction model of non-REM and REM sleep regulation. Interestingly, most of the effective antidepressant agents suppress REM sleep. Furthermore, manipulations of the sleep-wake cycle, like sleep deprivation or a phase advance of the sleep period, alleviate depressive symptoms. These data indicate a strong bi-directional relationship between sleep, sleep alterations and depression.
European Archives of Psychiatry and Clinical Neuroscience | 1997
Ulrich Frommberger; Joachim Bauer; Peter Haselbauer; Andrea Fräulin; Dieter Riemann; Mathias Berger
The concentration of cytokines such as Interleukin-6 (IL-6) has been reported to be elevated in depressed and schizophrenic patients and, in healthy persons, upon stress. Interleukin-6 plasma levels were determined in depressed (n = 12) and schizophrenic (n = 32) patients during the acute state of illness and after remission at approximately 8 weeks after admission and were compared with healthy controls (n = 12). Patients were diagnosed according to DSM-III-R by the Structured Clinical Interview (SLID). Severity of illness was assessed for depression by the Montgomery Asberg Depression Rating Scale (MADRS) and for schizophrenia by the Brief Psychiatric Rating Scale (BPRS). Interleukin-6 plasma concentrations were elevated during the acute state either of depression or of schizophrenia if compared to controls. After remission, IL-6 concentrations in depressed and in schizophrenic patients had decreased and did not differ significantly from controls. We hypothesize that the elevated IL-6 levels during the acute state of depression or schizophrenia may reflect an unspecific stress response.
European Archives of Psychiatry and Clinical Neuroscience | 1993
Fritz Hohagen; K. Rink; Christoph Käppler; Elisabeth Schramm; Dieter Riemann; S. Weyerer; Mathias Berger
SummaryThe aim of the study was to assess prevalence and treatment modalities of insomnia in general practice. To investigate the course of insomnia, a longitudinal study design was adopted. Two thousand five hundred and twelve patients (age 18–65 years) were investigated with a questionnaire in general practice (T1). Four months later (T2) and again 2 years later (T3) a questionnaire was sent to all patients who had complained about severe insomnia at the time of the first inquiry. To assess insomnia, operationalized diagnostic criteria were applied (DSM-III-R). Eighteen point seven percent suffered from severe, 12.2% suffered from moderate and 15% suffered from mild insomnia. In the course of 2 years insomnia appeared as a chronic health problem. A high comorbidity of severe insomnia was found with chronic somatic and psychiatric disorders, especially with depression. Of the severely insomniac patients, 23.9% used prescribed hypnotics habitually, mainly benzodiazepines. The use of prescribed hypnotics remained rather stable during the whole study period. More than half of the patients reported a daily use of the hypnotics for 1–5 years or longer, but only 22% of the severely insomniac patients reported at the time of the third inquiry a significant improvement of insomnia due to the administration of sleeping pills. Thus, the long-term administration of benzodiazepine hypnotics seems to be an inadequate treatment strategy in chronic insomnia. Whether the occurrence of rebound insomnia after benzodiazepine withdrawal may be one of the main factors for chronic hypnotic use requires discussion. Although insomnia may be an important symptom of many somatic and psychiatric disorders, the general practitioner was unaware in more than half of the cases that the patients suffered from a sleep problem. Severe insomniac patients displayed a higher mean number of medical consultations compared with good sleepers or patients with mild insomnia, indicating that insomnia constitutes a significant burden for the primary care physicians.
Biological Psychiatry | 1991
Christoph J. Lauer; Dieter Riemann; M. Wiegand; Mathias Berger
In order to evaluate the impact of aging on EEG sleep patterns we investigated the polysomnograms of 74 patients with major depression and 51 healthy volunteers aged 18-65 years. In most of the EEG sleep parameters, age-related changes were obvious in both the depressives and the normals. In the patients, some of these alterations occurred earlier and were more pronounced. The amount of slow-wave sleep decreased with age, but no differences were found between the depressives and the healthy volunteers at any particular age. Rapid-eye-movement (REM) latency was clearly affected by age, but there were no significant differences between patients and controls until the middle of the fourth decade of life. On the other hand, REM density measures did not vary with age and were increased in the depressives. Therefore, REM density appears to be a more likely candidate for a biologic marker for major depression than is REM latency.
Glia | 1996
Bernd L. Fiebich; Knut Biber; Klaus Lieb; Dietrich van Calker; Mathias Berger; Joachim Bauer; Peter J. Gebicke-Haerter
We investigated the regulation of COX‐2 expression and activity by adenosine receptors in rat microglial cells. The selective adenosine A2a‐receptor agonist CGS21680 and the non‐selective adenosine A1‐ and A2‐receptor agonist 5′‐N‐ethylcarboxi‐amidoadenosine (NECA) induced an increase in COX‐2 mRNA levels and the synthesis of prostaglandin E2 (PGE2). The adenosine A1‐receptor agonist cyclopentyladenosine (CPA) was less potent, and the adenosine A3‐receptor‐specific agonist N6‐2‐(‐aminophenylo)ethyladenosine (APNEA) showed only marginal effects. Microglia expressed adenosine A1‐, A2a‐, and A3‐, but not A2b‐receptor mRNAs, whereas astroglial cells expressed adenosine A2b‐ but not A2a‐receptor mRNA. The adenosine A2a‐receptor selective antagonist (E)‐8‐(3,4‐dimethoxystyryl)‐1,3‐dipropyl‐7‐methylxanthine (KF17837) inhibited both CGS21680‐induced COX‐2 expression and PGE2 release. CGS21680‐increased PGE2 levels were inhibited by dexamethasone, by the nonsteroidal antiinflammatory drug meloxicam, and by the adenylyl cyclase inhibitor 9‐(tetrahydro‐2‐furanyl)‐9H‐purine‐6‐amine (SQ22536). CGS21680 and NECA both increased intracellular cAMP levels in microglial cells. Dibutyryl cAMP as well as forskolin induced the release of PGE2. The results strongly suggest that adenosine A2a‐receptor‐induced intracellular signaling events cause an up‐regulation of the COX‐2 gene and the release of PGE2. Apparently, the cAMP second messenger system plays a crucial role in COX‐2 gene regulation in rat microglial cells. The results are discussed with respect to neurodegenerative disorders of the CNS such as Alzheimers disease, in which activated microglia are critically involved and COX inhibitors may be of therapeutic benefit.
Psychological Medicine | 2005
Anna Wirz-Justice; Francesco Benedetti; Mathias Berger; Raymond W. Lam; Klaus Martiny; Michael Terman; Joseph C. Wu
The Committee on Chronotherapeutics, delegated by the International Society for Affective Disorders (ISAD), makes the following recommendations after reviewing the evidence as of November 2004. (1) Wake therapy is the most rapid antidepressant available today: approximately 60% of patients, independent of diagnostic subtype, respond with marked improvement within hours. Treatment can be a single or repeated sleep deprivation, total (all night) or partial (second half of the night). Relapse can be prevented by daily light therapy, concomitant administration of SSRIs, lithium (for bipolar patients), or a short phase advance of sleep over 3 days following a single night of wake therapy. Combinations of these interventions show great promise. (2) Light therapy is effective for major depression--not only for the seasonal subtype. As an adjuvant to conventional antidepressants in unipolar patients, or lithium in bipolar patients, morning light hastens and potentiates the antidepressant response. Light therapy shows benefit even for patients with chronic depression of 2 years or more, outperforming their weak response to drugs. This method provides a viable alternative for patients who refuse, resist or cannot tolerate medication, or for whom drugs may be contraindicated, as in antepartum depression. (3) Given the urgent need for new strategies to treat patients with residual depressive symptoms, clinical trials of wake therapy and/or adjuvant light therapy, coupled with follow-up studies of long-term recurrence, are a high priority.
Acta Neuropathologica | 1995
Michael Huell; Sylvia Strauss; Benedikt Volk; Mathias Berger; Joachim Bauer
Interleukin-6 (IL-6) immunoreactivity has previously been shown in plaques in Alzheimers disease (AD) and elevated IL-6 concentrations have been measured biochemically in brains of AD patients. In this study, we investigated the appearance of IL-6 immunoreactivity in AD plaques according to the stage of plaque formation. Using the Bielschowsky silver-staining method, we were able to differentiate between four types of plaques described earlier: diffuse, primitive, classic and compact. While diffuse plaques represent the early stage of plaque formation, primitive and classic plaques are thought to represent later stages of plaque development. We investigated serial sections of paraffin-embedded cortices of ten clinically diagnosed and histopathologically confirmed AD patients and ten patients with no clinical history of dementia. We found plaques in the brains of both nondemented and demented persons using the silver staining method or immunohistochemistry with antibodies against the amyloid precursor protein. In the group of clinically nondemented persons, diffuse plaques were the predominant plaque type, whereas primitive plaques formed the larger portion of lesions in the group of AD brains. IL-6 could not be detected in plaques of patients without dementia. Many IL-6-positive plaques were found in six of the AD brains and to a smaller extent in the other four AD cases. In the six cases with a large number of IL-6-positive plaques, IL-6 was found in a significantly higher ratio of diffuse plaques than expected from a random distribution of IL-6 in all plaque types. We conclude from these findings that IL-6 immunoreactivity correlates with clinical dementia and that in AD patients, an IL-6-related immunological event may contribute to plaque formation. IL-6 might be involved both in the transformation from diffuse to primitive plaques in AD as well as in the development of dementia.
Psychiatry Research-neuroimaging | 1997
Dieter Ebert; Oliver Speck; Almuth König; Mathias Berger; Jürgen Hennig; Fritz Hohagen
We compared 12 patients with obsessive-compulsive disorder (OCD) and six control subjects by 1H-magnetic resonance spectroscopy. Significantly lower relative N-acetyl-aspartate (NAA) levels were found in the right striatum of OCD patients, as well as a decrease of anterior cingulate NAA that correlated with severity of illness. Age and sex were correlated to striatal NAA levels.
Acta Psychiatrica Scandinavica | 1994
Fritz Hohagen; Christoph Käppler; Elisabeth Schramm; K. Rink; S. Weyerer; Dieter Riemann; Mathias Berger
This study aimed to assess the prevalence and treatment modalities of elderly practice attenders. A total of 330 patients aged over 65 years were investigated with a questionnaire in general practice. To assess insomnia, operationalized diagnostic criteria according to DSM‐III‐R were applied. Twenty‐three percent of the elderly patients suffered from severe, 17% from moderate and 17% from mild insomnia. More than 80% of the patients reported suffering from insomnia for 1–5 years or longer, which indicates a chronic course. Elderly patients showed unrealistic expectations concerning duration of sleep and spend more time in bed than they realistically can expect to sleep. More than half of the elderly patients reported habitual daytime napping. Sleep‐disturbed elderly patients did not differ significantly from good sleepers in their habit of taking daytime naps, but even when taking daytime naps, good sleepers slept significantly longer than the sleep‐disturbed patients. A significant association was found between insomnia and mental disorders, i.e., depression and organic brain syndrome according to the diagnosis of the general physician. In about half of the cases the primary care physician was not aware that the elderly patient suffered from severe insomnia. More than half of the elderly severe insomniacs took prescribed hypnotics habitually, mainly benzodiazepines.