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Biomedical subjects

M J Schwarz

Publications and source records attributed to M J Schwarz.

At least 19 recordsLinked to original sources
PubMed2007

[Immunology in schizophrenic disorders].

This manuscript deals with whether immune-mediated mechanisms of inflammation contribute to the pathogenesis of schizophrenia. A model is presented which integrates psychoneuroimmunologic findings and actual results from pharmacological, neurochemical, and genetic studies in schizophrenia. A pivotal role in the neurobiology of schizophrenia is played by dopaminergic neurotransmission, which is modulated by influences of the glutamatergic system. The decreased function of the glutamate system described in schizophrenia seems primarily mediated by N-methyl-D-aspartate (NMDA) receptor antagonism. Kynurenine acid is the only known endogenous NMDA receptor antagonist. In higher concentrations it blocks the NMDA receptor, but in lower concentrations it blocks the nicotinergic acetylcholin receptor, which has a prominent role in cognitive functions. Therefore, higher levels of kynurenine acid may explain psychotic symptoms and cognitive dysfunction. Several findings point out that prenatal infection, associated with an early sensitisation of the immune system, may result in an imbalance of the immune response (type 1 vs type 2) in schizophrenia. This immune constellation leads to inhibition of the enzyme indoleamin dioxigenase (IDO). It and tryptophane 2,3-dioxygenase (TDO) both catalyse the degradation from tryptophan to kynurenine. Due to the inhibition of IDO, tryptophan is metabolised to kynurenine primarily by TDO. In the CNS, TDO is located only in astrocytes, which are in particular activated in schizophrenia and in which kynurenine acid is the final product and can not be further metabolised. Therefore kynurenine acid accumulates in the CNS of schizophrenics and - due to its NMDA-antagonistic properties - leads to cognitive dysfunction and psychotic symptoms. This model describes the pathway of immune-mediated glutamatergic-dopaminergic dysregulation, which may lead to the clinical symptoms of schizophrenia. Therapeutic consequences (e.g. cyclo-oxygenase-2 inhibitors) are discussed.

Brain↗
PubMed2006

The cyclooxygenase-2 inhibitor celecoxib has therapeutic effects in major depression: results of a double-blind, randomized, placebo controlled, add-on pilot study to reboxetine.

Signs of an inflammatory process, in particular increased pro-inflammatory cytokines and increased levels of prostaglandine E(2) (PGE(2)), have repeatedly been described in major depression (MD). As cyclooxygenase-2 (COX-2) inhibitors inhibit the PGE(2) production and the production of pro-inflammatory cytokines, we performed a therapeutic trial with the COX-2 inhibitor celecoxib. In a prospective, double-blind, add-on study, 40 patients suffering from an acute depressive episode were randomly assigned to either reboxetine and celecoxib or to reboxetine plus placebo. After a wash-out period, 20 patients received 4-10 mg reboxetine plus placebo and 20 received reboxetine plus 400 mg celecoxib for 6 weeks. The treatment effect was calculated by analysis of variance. There were no significant differences between groups in age, sex, duration or severity of disease or psychopathology, or reboxetine dose or plasma levels. Over 6 weeks, both groups of patients showed significant improvement in scores of the Hamilton Depression Scale. However, the celecoxib group showed significantly greater improvement compared to the reboxetine-alone group. Additional treatment with celecoxib has significant positive effects on the therapeutic action of reboxetine with regard to depressive symptomatology. Moreover, the fact that treatment with an anti-inflammatory drug showed beneficial effects on MD indicates that inflammation is related to the pathomechanism of the disorder, although the exact mechanisms remain to become elucidated.

Adrenergic Uptake Inhibitors↗
PubMed2004

Risperidone plasma levels, clinical response and side-effects.

INTRODUCTION: Assessment of the relation between oral risperidone dose, serum drug levels and clinical response may provide important information for rational treatment decisions. Inter-individual differences in the liver cytochrome P450 system, especially in the CYP2D6 subsystem, which account for a significant portion of risperidone metabolism, may also influence plasma drug levels and alter clinical response parameters. We thus prospectively investigated risperidone serum concentrations in relation to clinical efficacy and side-effects and genotyped major CYP2D6 polymorphisms to determine their effect upon these parameters. METHODS: Neuroleptic monotherapy with risperidone was administered to schizophrenia patients in a 6-week open dose clinical trial. Weekly assessments including CGI and PANSS ratings to assess psychopathology; SAS to assess medication side effects; and blood draws to quantify steady state plasma levels of risperidone and 9-OH-risperidone were carried out. In addition, major CYP2D6 polymorphisms including alleles *4, *6 and *14 were genotyped. RESULTS: Eighty-two patients were recruited. Mean oral dose of risperidone was 4.3 +/- 0.9 mg. Mean plasma level of both risperidone and 9-OH-risperidone together ("active moiety") was 41.6 +/- 26.6 ng/ml. Significant improvements in PANSS scales and the various subscales ensued. There was a positive linear correlation between active moiety plasma levels and dose (r = 0.291, p = 0.015) and between risperidone and 9-OH-risperidone levels (r = 0.262; p = 0.016). Nonresponders to pharmacotherapy (PANSS-Improvement < 30%) showed significantly higher active moiety plasma levels (49.9 +/- 30.7 ng/ml) than responders (38.2 +/- 17.0 ng/ml; p = 0.045) without significantly higher oral doses (p = 0.601). Patients with longer illness duration (> or = 3 years) had significantly higher plasma drug levels than those with a shorter course (< 3 years; p = 0.039). Extrapyramidal side effects (EPS) and plasma levels were not correlated (r = 0.028; p = 0.843), but higher plasma levels at week 2 predicted an incidence for EPS (p < 0.050). Accordingly, patients initially receiving higher oral doses of risperidone were significantly more likely to respond with EPS in the trial course. Eight patients (9.8%) were heterozygous carriers of the CYP2D6 allele *4. CYP2D6 polymorphisms did not predict clinical response, but predicted a tendential increase in the plasma risperidone to 9-OH-risperidone ratio (0.5 +/- 0.6 vs. 1.9 +/- 1.8; p = 0.120). DISCUSSION: The major finding was that responders to risperidone treatment had significantly lower blood levels of risperidone and 9-OH risperidone than patients who did not respond to the treatment despite administration of similar oral doses. The observed CYP2D6 polymorphisms did not contribute to altered clinical efficacy, but affected risperidone to 9-OH-risperidone ratios. Increased plasma levels of the active moiety in patients with longer illness may represent general aging effects. Conversely, the observed higher plasma levels in nonresponders may derive from unaccounted genetic metabolism abnormalities or Phase II metabolism disturbances. Patients initially receiving higher oral risperidone doses were more likely to respond with extrapyramidal side effects which reaffirms the need for careful titration. The high inter-individual variability in risperidone and 9-OH-risperidone metabolization and the relationship between clinical outcome and plasma levels warrants regular plasma level monitoring of both compounds to assess for the clinically relevant active moiety.

Adolescent↗
PubMed2004

Psychotropic effects of COX-2 inhibitors--a possible new approach for the treatment of psychiatric disorders.

Cyclooxygenase-2 (COX-2)--constitutively expressed in the CNS--is suggested to have an important functional role in the CNS. COX-2 interacts with neurotransmitters such as acetylcholine, serotonin, and glutamate, but is also involved in the regulation of immune system and in inflammation in the central nervous system (CNS) via effects of prostaglandins, in particular prostaglandin E (2). Recently, a role for the new generation of selective COX-2 inhibitors in the treatment of psychiatric disorders is discussed. Until now, COX-2 inhibitors have failed to show therapeutic effects in Alzheimer's disease, but studies from basic research point to a possible effect on cognition. A clinical effect of the COX-2 inhibitor celecoxib on cognition was observed in schizophrenic patients. The therapeutic effect of celecoxib add-on treatment to the atypical antipsychotic risperidone, however, is not restricted to cognition. A general effect on symptoms of schizophrenia was observed, which supports the view that an immunological/inflammatory process is involved in the pathogenesis of schizophrenia. In depression, however, signs of inflammation have been described since many years. Although results of clinical studies with COX-2 inhibitors in depression are still lacking, clinical improvement of a depressive syndrome has been observed in patients, who have been treated with rofecoxib due to other indications. These preliminary clinical data are encouraging for therapeutic effects of the selective COX-2 inhibitors in psychiatric disorders, although these effects have to be confirmed in bigger clinical studies.

Antipsychotic Agents↗
PubMed2003

Activities of extract and constituents of Banisteriopsis caapi relevant to parkinsonism.

Dopamine deficiency is characteristic of Parkinson's disease (PD) and treatments aim at elevating levels by administration of its precursor L-dihydroxyphenylalanine (L-DOPA), or inhibiting monoamine oxidases (MAOs), thus preventing its breakdown. Reports of improvements in PD patients treated with Banisteriopsis caapi extracts stimulated investigation of B. caapi stem extract and its two ingredients, harmine and harmaline for these activities. Tests for MAO inhibition using liver homogenate showed that extract and harmaline showed a concentration-dependent inhibition of MAO A (IC(50) 1.24 microg/ml and IC(50) 4.54 nM, respectively) but had little effect on MAO B activity. The extract at 2.5 mg/ml caused a highly significant increase in release of [3H]dopamine from rat striatal slices, as did 200 microM harmine and 6 microM harmaline. In both these experiments, the amount of harmine present could not account for the total activity of the extract. The ability of harmine and harmaline to stimulate dopamine release is a novel finding. These results give some basis to the reputed usefulness of B. caapi stem extract in the treatment of PD.

Animals↗
PubMed2002

Evidence for an altered tryptophan metabolism in fibromyalgia.

Fibromyalgia (FM) is a prevalent syndrome with chronic pain and a hypothesized underlying disturbance of the tryptophan (TRP) metabolism. We performed a tryptophan depletion (TD) test in 17 FM patients and 17 controls. TRP, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), and interleukin-6 (IL-6) were measured. Additionally pain perception was monitored in the FM patients. FM patients and controls exhibited a decrease of TRP and KYN during TD. 5-HIAA levels also decreased in all controls and in 11 FM patients, but showed a marked increase in 6 FM patients. IL-6 significantly increased during TD in the patients, but not in the controls. Pain perception was not affected in the FM patients. These data demonstrate an altered TRP metabolism in a subgroup of FM patients, where the TD seems to activate 5-HT metabolism. Our findings may have diagnostic as well as therapeutic implications in the field of fibromyalgia.

Adult↗
PubMed2001

No association between anti-myelin oligodendrocyte glycoprotein antibodies and serum/cerebrospinal fluid levels of the soluble interleukin-6 receptor complex in multiple sclerosis.

Myelin-oligodendrocyte glycoprotein (MOG) specific antibodies (abs) are involved in autoantibody-mediated demyelination possibly contributing to lesion development in multiple sclerosis (MS). Interleukin-6 (IL-6) has been reported to play a crucial role for the pathogenesis of a MOG-induced animal model of MS. To investigate the link between anti-MOG abs production and IL-6 up-regulation in MS we determined the presence of anti-MOG abs and measured concentrations of IL-6 and its soluble receptors (sIL-6RC) in paired serum and cerebrospinal fluid (CSF) samples of MS patients and serum samples of age-matched healthy controls (HC). Anti-MOG abs were detected in 75% of MS sera, 57% of MS CSF samples and 20% of HC sera. There was no difference in IL-6 and sIL-6RC levels between anti-MOG abs positive and negative samples. Thus, no association between the presence of anti-MOG abs and serum/CSF levels of IL-6/sIL-6RC was found.

Adult↗
PubMed2001

Serotonin-2A-receptor and -transporter polymorphisms: lack of association in patients with major depression.

Disturbances in serotonergic neurotransmission system have been implicated in the etiology of mood disorders. As the importance of genetic factors is well established, genes encoding for proteins of the serotonergic pathway are important candidates to unravel the underlying genetic contribution. We examined two polymorphisms in the serotonin-2A-receptor gene (5-HT2A; T102C and His452Tyr) and the insertion/deletion polymorphism in the promoter region of the serotonin transporter (5-HTTLPR) in a sample of 173 patients with major depression and 121 healthy controls. No statistical significant differences between patients and controls were found for any of the three investigated polymorphisms, neither in the distribution of the genotypes nor in allele frequencies. However, concerning the 5-HTTLPR polymorphism, the frequency of S/S (short allele) homozygotes was higher (23.1%) than in the control group (14.0%), but this failed to reach significance. Moreover we observed a different treatment response in patients with one or two C-alleles of the T102C polymorphism, with a significantly higher decrease in HAMD-17 (ANOVA: d.f. = 1, F = 5,288, P = 0.023) after 4 weeks of antidepressant treatment. Overall our results suggest that the investigated 5-HT2A and 5-HTTLPR polymorphisms are not major susceptibility factors in the etiology of major depression. However, subtypes might be identified at least on a basis of differential treatment response.

Adult↗
PubMed2001

Increased titers of antibodies against streptococcal M12 and M19 proteins in patients with Tourette's syndrome.

It has been suggested that a post-streptococcal autoimmune process may be involved in the pathogenesis of a subgroup of children with tics and obsessive-compulsive symptoms (PANDAS). Elevated antibody titers against streptococcal antigens have also been described in adult patients suffering from Tourette's syndrome (TS). In order to characterise further streptococcal antigens, we focussed on M proteins. M proteins are a major virulence factor of group A streptococci and known to evoke an immunologic cross-reaction with diverse epitopes of human tissue including brain tissue. Therefore, antibodies against M proteins may play a role in the pathophysiology of at least a subgroup of TS patients. Antibodies against M proteins were studied in 25 adult patients suffering from TS and 25 healthy controls after careful medical examination. The antibody titers against the peptides M1, M4, M6, M12 and M19 were estimated by ELISA. Our results show increased titers of antibodies against the streptococcal M12 and M19 proteins in TS patients as compared with controls, while antibody titers against M1, M4 and M6 did not differ between the TS and control groups. Elevated serum titers of antibodies against M12 and M19 proteins support the view that a streptococcus-induced autoimmune process may be involved in TS. The finding of a possible autoimmune origin of TS has implications for both pathophysiology and future therapeutic strategies.

Adolescent↗
PubMed2001

T-helper-1 and T-helper-2 responses in psychiatric disorders.

The expanding field of psychoneuroimmunology has markedly increased knowledge about the interference of the central nervous system and the immune system. Immunological abnormalities in psychiatric patients have been repeatedly described in the last century. Modern concepts of immunology and the growing knowledge of psychoneuroimmunology may help in understanding the distinct immunological mechanisms in psychiatric disorders. One of these concepts regarding the adaptive immune system is the discrimination between Th1-like cell-mediated and Th2-like antibody-related immune responses. This article systematically describes alterations of Th1- or Th2-specific parameters in the major psychiatric disorders schizophrenia, major depression, and Alzheimer's disease. There are several hints of associations of these two distinct arms of immune response with subgroups of schizophrenia and major depression. The immunological research in Alzheimer's disease has already led to a preclinical model of immunotherapy. Categorization of immune parameters may also help to identify a possible immune-related pathophysiology in psychotic and affective disorders, resulting in specific treatment strategies.

Humans↗
PubMed2001

The Th2-hypothesis of schizophrenia: a strategy to identify a subgroup of schizophrenia caused by immune mechanisms.

Immunologic findings in schizophrenia have been described for decades, but it was not possible to identify a pathogen until now. Most of these studies report immune abnormalities in a group of the investigated patients, but a distinct subgroup of schizophrenia with immune-related pathology has still not been characterized. In this paper we have integrated the most important immunologic data in schizophrenia research and hypothesize a shift to Th2-like immune reactivity in a subgroup of schizophrenic patients. Besides the immunological abnormalities, this subgroup is further characterized by more pronounced negative symptoms and poor therapy outcome. There is evidence that this subgroup might be caused by a prenatal viral infection.

Humans↗
PubMed2000

Decreased levels of soluble intercellular adhesion molecule-1 (sICAM-1) in unmedicated and medicated schizophrenic patients.

BACKGROUND: The soluble intercellular adhesion molecule-1 (sICAM-1) is a marker for the activation of the cellular immune system. Since an activation of the immune system has been observed in a part of the schizophrenic patients, we measured the serum levels of soluble ICAM-1 (sICAM-1) in schizophrenic patients and correlated them to the patient's psychopathology. METHODS: To monitor a possible effect of antipsychotic therapy, 36 schizophrenic patients were examined twice: first without antipsychotic medication immediately after admission to the hospital and then, after clinical improvement before discharge. The results were compared with those of 36 age- and gender-related healthy individuals. RESULTS: The schizophrenic patients showed significantly decreased serum levels of sICAM-1 at the first examination (248 +/- 95 ng/mL) and at re-examination (266 +/- 95 ng/mL) compared with the comparison group (323 +/- 74 ng/mL). Patients with more pronounced negative symptoms showed higher levels of sICAM-1 at the first examination. CONCLUSIONS: We conclude that reduced sICAM-1 levels in schizophrenia indicate a reduced activity of the cellular immune system in at least a subgroup of schizophrenic patients.

Acute Disease↗
PubMed2000

The immune system and schizophrenia. An integrative view.

Immune alterations in schizophrenia have been described for decades. Modern immunological methods and new insights into the highly developed and functionally differentiated immune system allow an integrative view of both the older and the recent findings of immunological abnormalities in schizophrenia. Both the unspecific and the specific arms of the immune system seem to be involved in the dysfunction of the immune system in schizophrenia. The unspecific, "innate" immune system shows signs of overactivation in unmedicated schizophrenic patients, as indicated by increased monocytes and gamma delta-cells. Increased levels of interleukin-6 (IL-6) and the activation of the IL-6 system in schizophrenia might be the result of the activation of monocytes/macrophages, too. On the other hand, several parameters of the specific cellular immune system are blunted, such as, for example, the decreased T helper-1 (TH-1)-related immune parameters in schizophrenic patients both in vitro and in vivo. It seems that a TH-1-TH-2 imbalance with a shift to the TH-2 system is associated with schizophrenia. During antipsychotic therapy with neuroleptics, the specific TH-1-related immune answer becomes activated, but in addition the B cell system and antibody production increase.

Humans↗
PubMed2000

TGF-beta(1) genotype and accelerated decline in lung function of patients with cystic fibrosis.

BACKGROUND: Polymorphisms in transforming growth factor (TGF)-beta(1) associated with variations in cytokine levels are linked to fibrosis in a number of tissues. However, the contribution of this cytokine to organ fibrosis in patients with cystic fibrosis is presently unclear. This study was undertaken to examine the association between TGF-beta(1) gene polymorphisms and the development of pulmonary dysfunction in patients with cystic fibrosis. METHODS: Polymorphisms in the TGF-beta(1) gene defining amino acids of codons 10 and 25 were determined by ARMS-PCR using DNA stored on 171 Caucasian patients who were homozygous for the DeltaF508 mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Clinical information on the patients was obtained from medical records. RESULTS: Patients with cystic fibrosis of a TGF-beta(1) high producer genotype for codon 10 had more rapid deterioration in lung function than those with a TGF-beta(1) low producer genotype. The relative risk of accelerated decline in forced expiratory volume in one second (FEV(1)) to 50% predicted and forced vital capacity (FVC) to 70% predicted of patients with a high producer genotype was 1.74 (95% CI 1.11 to 2. 73) compared with 1.95 (95% CI 1.24 to 3.06) for those with a low producer genotype. DISCUSSION: TGF-beta(1) genotypes may have a role in mediating pulmonary dysfunction in patients with cystic fibrosis. Further work is required to determine whether inhibition of TGF-beta(1) activity in these patients may slow disease progression.

Adolescent↗
PubMed2000

Cellular and humoral immune system in schizophrenia: a conceptual re-evaluation.

Immune alterations in schizophrenia have been described for decades. However, modern immunological methods and new insights into the highly developed and functionally differentiated immune system allow an integrative view of both the older and also more recent findings of immunological abnormalities in schizophrenia. The conceptual advances in immunology require the re-evaluation of elder immunological findings in schizophrenia. In this overview, recent advances in immunological research regarding the differentiation between T-Helper-1 and T-Helper-2 cells and between the so-called specific and unspecific arms of the immune system are discussed. The unspecific "innate" immune system shows signs of an over-activation in unmedicated schizophrenic patients, as increased monocytes and gamma delta-cells point to. Increased levels of Interleukin-6 (IL-6) and the activation of the IL-6 system in schizophrenia might be the result of the activation of monocytes/macrophages, too. In contrast, several parameters of the specific cellular immune system are blunted, e.g. the decreased T-helper-1 (TH-1) related immune parameters in schizophrenic patients, both in vitro and in vivo. It seems that a TH-1-TH-2 imbalance with a shift to the TH-2 system is associated with schizophrenia. During therapy with antipsychotics, the specific TH-1 related immune answer becomes activated, but the B-cell system and the antibody production become activated too.

Antibody Formation↗