Sequential analyses of neurobiochemical markers of cerebral damage in cerebrospinal fluid and serum in CNS infections.

OBJECTIVE: To elucidate the relation between release patterns and cerebrospinal fluid/serum concentrations of neurobiochemical markers of cerebral damage and their potential value as monitoring parameters in central nervous system infections. METHODS: We investigated protein S-100B and neuron-specific enolase (NSE) in 102 sequential cerebrospinal fluid (CSF)-serum-pairs in patients with bacterial (n = 11) or viral (n = 13) meningitis/meningoencephalitis and neuroborreliosis (n = 8) in comparison with controls (n = 13). RESULTS: Highest S-100B values in CSF and serum were found on admission and showed a significant decrease afterwards. Comparison between disease groups revealed significant differences between bacterial and viral meningitis and neuroborreliosis for S-100B and also when compared with controls. NSE was not significantly elevated. CONCLUSIONS: S-100B is altered in CNS infection but does not provide additional benefit in the differential diagnosis when compared with standard CSF parameters. Nevertheless, S-100B values might be used as an additional monitoring parameter especially when sequential lumbar punctures are contraindicated.

Re-evaluation of the dysfunction of mitochondrial respiratory chain in skeletal muscle of patients with Parkinson's disease.

The origin and tissue distribution of the mitochondrial dysfunction in Parkinson's disease (PD) remains still a matter of controversy. To re-evaluate a probably free radical-born, generalized mitochondrial impairment in PD, we applied optimized enzymatic assays, high resolution oxygraphic measurements of permeabilized muscle fibers, and application of metabolic control analysis to skeletal muscle samples of 19 PD patients and 36 age-matched controls. We detected decreased activities of respiratory chain complexes I and IV being accompanied by increased flux control coefficients of complexes I and IV on oxygen consumption of muscle fibers. We further investigated if randomly distributed point mutations in two discrete regions of the mitochondrial DNA are increased in PD muscle, and if they could contribute to the mitochondrial impairment. Our data confirm the previously debated presence of a mild mitochondrial defect in skeletal muscle of patients with PD which is accompanied with an about 1.5 to 2-fold increase of point mutated mtDNA.

Sudden progression of a glioblastoma in partial remission?

There are only sparse data on viral CNS infections in patients with malignant glioma. We report a case of fatal herpes encephalitis in a patient with glioblastoma in partial remission and provide a short review of the literature.

Immunoreactivities of amyloid beta peptide((1-42)) and total tau protein in lumbar cerebrospinal fluid of patients with normal pressure hydrocephalus.

Immunoreactivities of amyloid beta peptide((1-42)) (Abeta42-IR) and total tau protein (TTIR) were measured in lumbar cerebrospinal fluid of 48 patients (12 patients in each group) with normal pressure hydrocephalus (NPH), vascular dementia (VD), Alzheimer's disease (AD), Parkinson's disease without dementia (PD) and 24 controls (CON) using sensitive and specific enzyme immunoassays. TTIR in NPH was not significantly changed compared with VD, PD and CON, while NPH-Abeta42-IR was significantly decreased compared with PD and CON. In AD, significant increases of TTIR and significant decreases of Abeta42-IR were found. Using a TTIR by Abeta42 plot, all NPH, PD, and CON samples were within the non-AD plot region. 92% of AD and VD samples were within the AD and non-AD area, respectively. We conclude that combined measurement of Abeta42-IR and TTIR contributes to the differential diagnosis of NPH vs. AD and of AD vs. VD, respectively.

Spatial and temporal disease progression of adult-onset subacute sclerosing panencephalitis.

An adult-onset case of subacute sclerosing panencephalitis with occipitofrontal spread of the infection documented clinically and by MRI is reported. Autopsy revealed numerous intranuclear viral inclusions and widespread demyelination in both frontal lobes. In the occipital lobes where the disease started 5 years previously, inclusions were rare, but degenerative tissue changes were prominent. This case underlines the importance of measles virus migration for the progression of this fatal disorder.

Detection of mitochondrial defects by laser fluorimetry.

The mitochondrial function in skeletal muscle biopsies of three patients with chronic progressive external ophthalmoplegia, having deletions of the mitochondrial DNA, was studied by laser-excited fluorescence measurements of NAD(P)H and flavoproteins in saponin-skinned fibers. We detected substantially elevated steady state redox states of the mitochondrial NAD-system in the muscle fibers of these patients. Moreover, the respiratory chain-linked autofluorescence changes in the muscle fibers of these patients were larger in comparison to controls indicating substantial alterations of the mitochondrial content. These results are in line with the presence of elevated numbers of partially respiratory chain inhibited mitochondria in the skeletal muscle of chronic progressive external ophthalmoplegia patients.

Application of inhibitor titrations for the detection of oxidative phosphorylation defects in saponin-skinned muscle fibers of patients with mitochondrial diseases.

Inhibitor titrations were applied to characterize functional changes in mitochondrial energy metabolism in the skeletal muscle of patients with mitochondrial diseases. For this we titrated the maximal mitochondrial respiration rate of saponin-skinned muscle fibers isolated from the skeletal muscle biopsy with the specific inhibitors of mitochondrial oxidative phosphorylation complexes I, IV and V-rotenone, azide and oligomycin. For three patients with deletions of mitochondrial DNA and one patient with a complex I deficiency the titrations revealed at rather normal respiration activities of saponin-skinned fibers significant differences to healthy controls: (i) The inhibitor titration curves of the affected enzyme were much steeper and (ii) for almost complete inhibition of respiration a smaller amount of the inhibitor is necessary. The detailed analysis of the titration curves within the framework of metabolic control theory indicated elevated flux control coefficients of the respective complex of respiratory chain. On the other hand, for one patient with a mitochondrial DNA depletion syndrome, decreased respiration activities of skinned fibers but no redistribution of flux control was observed. We conclude, therefore, that application of inhibitor titrations and the quantitative description of the titration curve can be a valuable approach to elucidate functional defects of mitochondrial oxidative phosphorylation.

Flow cytometric detection of mitochondrial dysfunction in subpopulations of human mononuclear cells.

At 488 nm argon-ion laser excitation human mononuclear cells emit flavoprotein-related autofluorescence signals. Approximately 60% of these are caused by the mitochondrial flavoproteins alpha-lipoamide dehydrogenase and electron transfer flavoprotein, having differences in their fluorescence emission spectra. At the emission wavelength of 530 nm the redox changes of alpha-lipoamide dehydrogenase fluorescence in human mononuclear cells can be monitored by flow cytometry. This allows the estimation of the steady-state reduction level of this flavoprotein being in redox equilibrium with the mitochondrial NAD-system. We applied this method to elucidate the possible impairment of mitochondrial function in subpopulations of mononuclear cells of patients harboring deletions of the mitochondrial DNA in skeletal muscle. In the monocyte fraction of three patients and in the lymphocyte fraction of one patient we observed in the presence of the mitochondrial substrate octanoate elevated steady-state reduction levels of alpha-lipoamide dehydrogenase. This is an indication for the presence of respiratory chain-inhibited mitochondria in mononuclear cell subpopulations of the described patients. These data were confirmed by conventional determinations of maximal oxygen consumption rates of digitonin-permeabilized cells. Therefore, the flow cytometric determination of flavoprotein-caused autofluorescence changes is a useful and sensitive method for the detection of an impairment of mitochondrial respiratory chain in subpopulations of heterogeneous cell suspensions.

Laser-excited fluorescence studies of mitochondrial function in saponin-skinned skeletal muscle fibers of patients with chronic progressive external ophthalmoplegia.

The functional behavior of mitochondria in skeletal muscle of patients with chronic progressive external ophthalmoplegia was studied by laser-excited fluorescence measurements of NAD(P)H and flavoproteins in saponin-skinned fibers. Variations in the mitochondrial content and the presence of partially respiratory chain-inhibited mitochondria can be detected using this novel method.

Antigen presentation in the central nervous system. The inhibitory effect of IL-10 on MHC class II expression and production of cytokines depends on the inducing signals and the type of cell analyzed.

Cells of the macrophage lineage are required to cope with bacterial infection and to serve as APC for T lymphocytes. Among the regulatory factors limiting the macrophage response to infection and the expansion of Ag-specific T cells, IL-10 has received recent attention. On monocytes/macrophages, IL-10 has been shown to inhibit the intracellular killing of bacteria, the secretion of cytokines, and the expression of MHC molecules. In the present study we have examined the effect of IL-10 on different APC obtained from the central nervous system. Both, astrocytes and microglial cells are in a resting state and require activation signals to express MHC class II and cytokine genes. Whereas IL-10 profoundly inhibits the IFN-gamma-induced expression of MHC class II Ag on microglial cells, it had no such effects on astrocytes. Nevertheless, IL-10 suppressed the MHC class II- and Ag-dependent proliferative response of T cells in the presence of both types of APC. As shown by the use of anti-IL-10 Abs, endogenously produced IL-10 influenced the function of microglia but not of astrocytes to serve as APC. IL-10 significantly inhibited the LPS-induced production of granulocyte-macrophage-CSF, macrophage-CSF, and IL-6 by both astrocytes and microglial cells. In contrast, the secretion of these cytokines by the two glial cell population was not altered by IL-10 when IL-1 beta, TNF-alpha, or viruses were used as stimuli.

Production and function of IL-10 in the central nervous system.

Our data suggest an important regulatory role for IL-10 within the central nervous system by a) reducing the antigenpresenting capacity of astro- and microglia and thereby lowering or preventing, antigen-specific proliferative T cell responses, and b) inhibition of inflammatory cytokine production by the resident parenchymal cells as well as from infiltrating monocytes/macrophages. In the latter instance the signals triggering cytokine production are crucial since IL-10 interferes with bacterial but not viral or cytokine-induced activation of expression of cytokine genes.