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Biomedical subjects

Marcus Koch

Publications and source records attributed to Marcus Koch.

13 recordsLinked to original sources
PubMed2006

Plasma S100beta and NSE levels and progression in multiple sclerosis.

Plasma levels of the glial cell marker S100beta and the neuronal marker neuron-specific enolase (NSE) are elevated in various conditions of central nervous system damage. In this study we investigated whether plasma levels of S100beta and NSE are related to disease progression in multiple sclerosis (MS). Plasma levels of S100beta and NSE were measured in 25 patients with relapsing remitting MS (RRMS), 23 with secondary progressive MS (SPMS) and 16 with primary progressive MS (PPMS). All MS patients were in a clinically stable phase. Progression and disability were evaluated during a follow-up period of five years. We found that plasma NSE levels were lower in patients with clinically relevant worsening on the Expanded Disability Status Scale (EDSS), defined as 1 point increase from EDSS <6.0 or 0.5 point increase from EDSS> or =6 after five years (p=0.042), and in patients with a progressive disease course (p=0.01). There was a significant negative correlation between plasma NSE levels and both EDSS and Multiple Sclerosis Severity Status (MSSS) scores at baseline and after five years of follow-up (r=-0.33 and -0.38, p=0.027 and 0.003). There were no significant differences between patient groups in plasma S100beta levels. Plasma NSE levels appear inversely related to disease progression in MS.

Adult↗
PubMed2006

Brassicaceae contain nortropane alkaloids.

The report of cochlearine, the 3-hydroxybenzoate ester of tropine found in Cochlearia officinalis, Brassicaceae, initiated a screening for tropane alkaloids in Cochlearia species and for calystegines in further Brassicaceae. All ten Cochlearia species investigated contained cochlearine, tropine, and pseudotropine. Calystegines, nortropane alkaloids deriving from pseudotropine, were also identified in all Cochlearia species and accumulated up to 0.5% dry mass in leaves. Brassicaceae species of all major lineages of the family were analysed for calystegines. Of the 43 species included in the study, 18 accumulated calystegines of various structures. This is the first screening of Brassicaceae for products of the tropane alkaloid pathway, which is known as characteristic for plants of Solanaceae family. The identification of calystegines in all branches of the Brassicaceae family including Aethionema, a species at the basis of the family, suggests tropane alkaloids as secondary compound typical for Brassicaceae.

Alkaloids↗
PubMed2006

Erythrocyte membrane fatty acids in benign and progressive forms of multiple sclerosis.

BACKGROUND: There is no good explanation why a proportion of patients with multiple sclerosis (MS) have a relatively benign form of the disease. An imbalance between saturated and unsaturated fatty acids (FA) might influence the disease course of MS. AIM: To assess whether the erythrocyte membrane fatty acid composition, which is a biological marker of long term dietary FA consumption, is different between patients with benign and progressive MS. METHODS: The erythrocyte membrane FA composition was measured by gas chromatography in 23 healthy controls, 27 patients with benign MS, 32 patients with secondary progressive MS and 23 patients with primary progressive MS. None of the patients was following a special diet. RESULTS: No significant differences in levels of saturated and unsaturated FA or in omega-3- and omega-6-polyunsaturated FA were found between controls and patients with the different subtypes of MS. CONCLUSION: Our data suggest that factors other than dietary fatty acid consumption are responsible for the different disease courses of MS.

Adult↗
PubMed2006

A cold-loving crenarchaeon is a substantial part of a novel microbial community in cold sulphidic marsh water.

In this paper, we report the identification and first characterization of a novel, cold-loving, prokaryotic community thriving among white-greenish 'streamers' in the cold (c. 10 degrees C) sulphurous water of the marsh Sippenauer Moor near Regensburg, Bavaria, Germany. It consists of the bacterial genus Thiothrix, the bacterium 'Sip100' and one archaeal representative, forming together a unique association structure with a distinct life cycle. Fluorescence in situ hybridization studies have revealed that the archaeal member can be affiliated to the crenarchaeal kingdom ('Cre1'). This crenarchaeon was always observed attached to the bacterial community member 'Sip100'. Extended fluorescence in situ hybridization studies showed that this crenarchaeon was not detected in a free-living form, raising the idea of a probable host-dependent relationship. In line with our fluorescence in situ hybridization studies, novel crenarchaeal 16S rRNA gene sequences were identified in these samples. The design and application of a new in situ cultivation method in the sulphurous water of the marsh allowed first insights into the cohesion mechanisms, lifestyle and chronology of the microbes involved in this prokaryotic community in nature. Our results suggest that hitherto unknown Crenarchaeota thrive in cold sulphidic water and are a substantial part of a synchronized microbial community.

Biofilms↗
PubMed2006

Uric acid in multiple sclerosis.

Peroxynitrite, a reactive oxidant formed by the reaction of nitric oxide with superoxide at sites of inflammation in multiple sclerosis (MS), is capable of damaging tissues and cells. Uric acid, a natural scavenger of peroxynitrite, reduces inflammatory demyelination in experimental allergic encephalomyelitis. Some studies reported lower serum levels of uric acid in MS patients compared with controls, whereas other studies found no difference. A critical appraisal of these studies favors the view that reduced uric acid in MS is secondary to its peroxynitrite scavenging activity during inflammatory disease activity, rather than a primary deficiency. Serum uric acid levels could be used as a biomarker for monitoring disease activity in MS. Therapeutic strategies aimed at raising serum uric acid levels may have a glial/neuroprotective effect on MS patients.

Animals↗
PubMed2005

Oxidative stress in serum and peripheral blood leukocytes in patients with different disease courses of multiple sclerosis.

BACKGROUND: The role of oxidative stress in patients with multiple sclerosis (MS) is poorly understood. OBJECTIVE: To investigate oxidative stress in serum and peripheral blood leukocytes in patients with different disease courses of MS. METHODS: Diene conjugate (DC) levels (a measure of lipid peroxidation), total antioxidative activity (AOA) and total antiradical activity (ARA) were measured in serum and peripheral blood leukocytes from 30 patients with benign relapsing remitting MS (BMS), 27 with secondary progressive MS (SPMS), 29 with primary progressive MS (PPMS), and 30 healthy controls. All MS patients were in a clinically stable phase. RESULTS: Serum DC levels were elevated in patients with BMS (p <0.05), SPMS (p <0.01) and PPMS (p <0.001). Serum total AOA and ARA were not different between MS patients and controls. Compared to controls, leukocyte DC levels were not different in each MS subgroup, but total ARA was elevated. There was a strong correlation, both in controls and MS patients, between leukocyte DC levels and leukocyte total ARA (p <0.0001) and leukocyte total AOA (p <0.0001). CONCLUSION: Oxidative stress occurs in progressive as well as benign MS. The finding that cells withstand oxidative stress, due to upregulated cellular antioxidant defence mechanisms, suggests that reactive oxygen species (ROS) formation in MS is not necessarily deleterious.

Adult↗
PubMed2005

Transmission of Chlamydia pneumoniae infection from blood monocytes to vascular cells in a novel transendothelial migration model.

Chlamydia pneumoniae uses blood monocytes (PBMC) for systemic dissemination, persists in atherosclerotic lesions, and has been implicated in the pathogenesis of atherosclerosis. During transmigration in a newly developed transendothelial migration model (TEM) C. pneumoniae-infected PBMC spread their infection to endothelial cells. Transmigrated PBMC retained their infectivity and transmitted the pathogen to smooth muscle cells in the lower chamber of the TEM. Detection of chlamydial HSP60 mRNA proved pathogen viability and virulence. We conclude that PBMC can spread chlamydial infection to vascular wall cells and we suggest the TEM as a novel tool to analyze host-pathogen interactions in vascular chlamydial infections.

Arteriosclerosis↗
PubMed2004

Comparing the linkage maps of the close relatives Arabidopsis lyrata and A. thaliana.

We have constructed a genetic map of Arabidopsis lyrata, a self-incompatible relative of the plant model species A. thaliana. A. lyrata is a diploid (n = 8) species that diverged from A. thaliana (n = 5) approximately 5 MYA. Mapping was conducted in a full-sib progeny of two unrelated F(1) hybrids between two European populations of A. lyrata ssp. petraea. We used the least-squares method of the Joinmap program for map construction. The gross chromosomal differences between the two species were most parsimoniously explained with three fusions, two reciprocal translocations, and one inversion. The total map length was 515 cM, and the distances were 12% larger than those between corresponding markers in the linkage map of A. thaliana. The 72 markers, consisting of microsatellites and gene-based markers, were spaced on average every 8 cM. Transmission ratio distortion was extensive, and most distortions were specific to each reciprocal cross, suggesting cytoplasmic interactions. We estimate locations and most probable genotype frequencies of transmission ratio distorting loci (TRDL) with a Bayesian method and discuss the possible reasons for the observed distortions.

Arabidopsis↗
PubMed2003

In situ growth of the novel SM1 euryarchaeon from a string-of-pearls-like microbial community in its cold biotope, its physical separation and insights into its structure and physiology.

Recently, a unique archaeal/bacterial community that grows in a macroscopically visible string-of-pearls-like structure in cold (~10 degrees C), sulfurous marsh water was discovered. Here, a new technique is described that allows the fast and reliable growth of these string-of-pearls-like microbial communities in larger quantities on polyethylene nets in nature. The microbial net population, estimated to consist of about 10,000 single pearls, can be harvested once a week and the archaeal cells selectively separated by density gradient centrifugation. As in native pearls, the archaeal cell fraction obtained consisted of a single type of coccoid cells only, 0.6 micro m in diameter. This novel type of euryarchaea has been tentatively named SM1 euryarchaeon. Electron microscopy and immuno-fluorescence in situ hybridization (immuno-FISH) revealed that about 100 pili-like fibers, up to 3 micro m in length, emanate radially from the surface of each cell. The SM1 euryarchaeal cells exhibited a viability of about 90%. The optimal conditions for viability were temperatures between -2 degrees C and 20 degrees C, pH 5-9, and low salt conditions; cell viability was independent of oxygen partial pressures. The cultures stained gram-positive, the cell wall was sensitive to SDS, EDTA and Proteinase K treatment. The cells did not exhibit the typical fluorescence for methanogens and did not contain coenzyme F(420). The G+C-content was 34.5 mol%.

Archaea↗
PubMed2002

Prokaryotic phylogenetic diversity and corresponding geochemical data of the brine-seawater interface of the Shaban Deep, Red Sea.

The interface between the hypersaline brine and the overlying sea-water (brine-seawater interface) of the Shaban Deep, northern Red Sea was investigated for the presence of microorganisms using the 16S rRNA gene as a molecular marker. Samples of the south and east basin (depth: 1331 m and 1332 m respectively) were selected to ascertain the microbial diversity of this extreme and, so far, unexplored environment. Phylogenetic analysis revealed novel lineages within the Bacteria, the Crenarchaeota and the Euryarchaeota. Novel representatives of the KB1 sequence group (Eder et al., 1999 Arch Microbiol 172: 213-218) were detected indicating a widespread distribution of the corresponding Bacteria in Deep Sea brine pools. Our results contribute to the understanding of the hitherto unknown microbial diversity at the chemical gradient of the Shaban Deep, and suggest the presence of novel Bacteria and Archaea thriving under extreme environmental conditions.

Archaea↗
PubMedDate not supplied

Irreversible neurological worsening following high-dose corticosteroids in advanced progressive multiple sclerosis.

BACKGROUND: A course of high-dose corticosteroids has been shown to hasten recovery from a relapse of multiple sclerosis (MS). Some patients with progressive MS ask for a course with corticosteroids outside a relapse, hoping to gain some functional improvement. OBJECTIVE: To describe 4 patients with advanced progressive MS who experienced worsening of disability after treatment with high-dose corticosteroids. RESULTS: All 4 patients had moderate to severe disability and asked for corticosteroid treatment because they were slowly progressing. None of them had a relapse. All experienced improvement by the end of the treatment course. One or 2 days after discontinuation of treatment, however, they deteriorated clinically and became more disabled than before treatment. CONCLUSION: The use of high-dose corticosteroid therapy in progressive forms of MS outside relapses can be detrimental and worsen disability.

Adrenal Cortex Hormones↗