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Das Virus der Frühsommermeningoenzephalitis (FSME) und Borrelia burgdorferi als Erreger der Lyme-Borreliose sind die klinischbedeutsamsten durch Zecken übertragenen Infektionserreger in Europa. Der vorliegende Fall beschreibt eine serologisch gesicherte. Doppelinfektion mit dem FSME-Virus und Borellia burgdorferi bei einer 69jährigen deutschen Patientin nach einem Zeckenstich in einem österreichischen Endemiegebiet. Klinisch bestand zum Zeitpunkt der Krankenhausaufnahme eine ausgeprägte Somnolenz und ein hochgradiges Doppelbildsehen. Ein passive Immunisierung gegen FSME war postexpositionell erfolgt, konnte eine Infektion jedoch nicht verhindern. Eine Doppelinfektion durch beide Erreger wurde durch den serologischen Nachweis von spezifischen IgG und IgM Antikörpern gegen das FSME-Virus und im weiteren Verlauf auch gegen Borrelia burgdorferi im ELISA beziehungsweise im rekombinanten Immunoblot gesichert. Obwohl Doppelinfektionen durch die beiden genannten Erregerselten sind, sollten sie bei zeckenübertragenen Erkrankungen mit untypischem Verlauf in der Differentialdiagnose berücksichtigt werden.
Wir berichten über die Erfahrungen beim Aufbau einer Abteilung für die präoperative Eigenblutentnahme im Verantwortungsbereich des Institutes für Laboratoriumsmedizin der Städtischen Kliniken Frankfurt am Main-Höchst, einem Krankenhaus der Maximalversorgung mit 1150 Betten bzw. Tagesklinikplätzen. Die Herstellung von Eigenblutkonserven erfolgt nach § 13 des Arzneimittelgesetzes. Die Planung erfordert eine genaue Analyse des zu erwartenden Umfanges, der gegebenen Strukturen und betrieblichen Kapazitäten. Unsere Erfahrungen zeigen, daß mit der Entnahme von ca. 1200 autologen Blutkonserven pro Jahr und deren weiteren Bearbeitung eine Medizinisch-technische Assistentin ganztags und ein Arzt halbtags beschäftigt sind. Aus Gründen der Produktqualität und -Sicherheit sollte eine Trennung in die Komponenten Erythrozytenkonzentrat und Gefrorenes Frischplasma erfolgen und ein Qualitätssicherungssystem etabliert werden, das dem der Herstellung von homologen Blutkonserven entspricht. Dies bedeutet, bei jeder Entnahme die in den Richtlinien zur Blutgruppenbestimmung und Bluttransfusionen (Hämotherapie) in § 3.2.5 angegebenen Parameter zu testen (Glutamat-Pyruvattransaminase, Hepatitis B surfaceAntigen sowie Antikörper gegen Humanes Immundefizienz-Virus 1/2, Hepatitis-C-Virus und Treponema pallidum). Zusätzlich bestimmen wir C-reaktiyes Protein, ThromboplastinzeiL .Partielle Thromboplastinzeit, Leukozyten, Thrombozyten und Gesamteiweiß. Eine PC -gestützte Erfassung von Spender- und Spendedaten gewährleistet eine einfache statistische Auswertung der Entnahme Vorgänge. Die ebenfalls EDV-unterstützte Vergabe der Konservennummern und .BarcodeEtikettierung erleichtem es, die Eigenblutkonserven in der allgemeinen Blutbank-EDV zu verwalten. Durch eine fachübergreifende Zusammenarbeit, z.B. im Rahmen einer Transfusionskommission, müssen die Ablaufe aller fremdblutsparenden Maßnahmen vorgestellt und fortwährend optimiert werden, um Qualität, Akzeptanz und Wirtschaftlichkeit der autologen Blutentnahme zu erhalten.
Der Nachweis von Chlamydia trachomatis Genomsequenzen ist seit einigen Jahren mit Hilfe kommerzieller Testkits, welche auf dem Prinzip der Polymerase-Ketten-Reaktion (PCR) oder Ligase-Kettenreaktion (LCR) beruhen, möglich. Vor kurzem wurde ein neues Verfahren, die Transcription Mediated Amplification (TMA), etabliert. In der vorliegenden Studie wurden drei Nukleinsäure Amplifikations-Techniken, die PCR, die LCR und die TMA für den Nachweis von Chlamydia trachomatis aus Urinproben miteinander bezüglich Sensitivität und Spezifität verglichen und einem Enzym-Immuno-Assay (EIA) zum C. trachomatis-Antigen-Nachweis aus endozervikalen Abstrichen gegenübergestellt. PCR, LCR und TMA zeigten eine vergleichbare Sensitivität und Spezifität. Diskrepante Ergebnisse ergaben sich im Vergleich mit dem C. trachomatis-Antigen-Nachweis. In 22 Abstrichen war Chlamydien-Antigen nachzuweisen. Nur bei 12 bzw. 11 der untersuchten Prostituierten konnten bei positivem zervikalen Abstrich Chlamydia trachomatis Genomsequenzen im Urin nachgewiesen werden. Bei 5 bzw. 4 Frauen wurde bei negativem Abstrichbefund C. trachomatis DNA bzw. RNA im Urin gefunden. Um bei Frauen eine hohe diagnostische Sensitivität zu erreichen, .sollten Urin und endozervikale Abstriche untersucht werden, da C. trachomatis nicht immer in beiden Probematerialien nachweisbar ist.
Die quantitative Bestimmung der Hepatitis B Virus (HBV) DNA mit Hilfe der Hybridisierung wird neben der klassischen Serologie zur Verlaufskontrolle der chronischen Hepatitis B seil längerer Zeit eingesetzt. Dagegen sind erst seit kurzem molekularbiologische Verfahren zur Quantifizierung der „Virus-Last bei der HIV- und Hepatitis C Virus (HCV) Infektion in Form kommerzieller Testkits verfügbar . Die HI V-1 RNA Kopienzahl stellt neben der CD4*-Zellzahl den zuverlässigsten prognostischen Marker, mit einer vergleichbar hohen Aussagekraft wie onkologische Stadieneinteilungen, dar. Dennoch bedürfen die aktuellen Testkits einiger Verbesserungen. Mangelhafte Reproduzierbarkeit im unteren Meßbereich, fehlende Standardisierung sowie eine schlechte Sensitivität für Non-B HIV-1 Subtypen stellen neben den hohen Reagenzienkosten die wichtigsten Nachteile der meisten zur Zeit verfügbaren Testkits dar. Bei der Verlaufskontrolle der chronischen Hepatitis B nimmt die Quantifizierung der HBV-DNA über Hybridisierung oder PCR nur eine untergeordnete Rolle ein. Der qualitative HBV-DNA-Nachweis wird bevorzugt zur Überprüfung der Infektiosität oder zur Abklärung ungewöhnlicher Serokonstellationen eingesetzt. Nach neueren Erkenntnissen wird der Verlauf der HCV-Infektion nicht oder nur unwesentlich vom Ausmaß der Viruslast beeinflußt. Als prognostische Faktoren spielen vor allem Alter, Geschlecht und Alkoholkonsum eine wesentliche Rolle. Dagegen scheint die Erfolgsaussicht der antiviralen Therapie mit der vor Behandlungsbeginn gemessenen Kopienzahl zu korrelieren.
Mutations in the clk-1 gene result in slower development and increased life span in Caenorhabditis elegans. The Saccharomyces cerevisiae homologue COQ7/CAT5 is essential for several metabolic pathways including ubiquinone biosynthesis, respiration, and gluconeogenic gene activation. We show here that Coq7p/Cat5p is a mitochondrial inner membrane protein directly involved in ubiquinone biosynthesis, and that the defect in gluconeogenic gene activation in coq7/cat5 null mutants is a general consequence of a defect in respiration. These results obtained in the yeast model suggest that the effects on development and life span in C. elegans clk-1 mutants may relate to changes in the amount of ubiquinone, an essential electron transport component and a lipid soluble antioxidant.
Vacuolar proton-translocating ATPase (holoATPase and free membrane sector) was isolated from bovine chromaffin granules by blue native polyacrylamide gel electrophoresis. A 5-fold excess of membrane sector over holoenzyme was determined in isolated chromaffin granule membranes. M9.2, a novel extremely hydrophobic 9.2-kDa protein comprising 80 amino acids, was detected in the membrane sector. It shows sequence and structural similarity to Vma21p, a yeast protein required for assembly of vacuolar ATPase. A second membrane sector-associated protein (M8-9) was identified and characterized by amino-terminal protein sequencing.
The 2[4Fe-4S] ferredoxin from Chromatium vinosum arises as one prominent member of a recently defined family of proteins found in very diverse bacteria. The potentiometric circular dichroism titrations of the protein and of several molecular variants generated by site-directed mutagenesis have established that the reduction potentials of the two clusters differ widely by almost 200 mV. This large difference has been confirmed by electrochemical methods, and each redox transition has been assigned to one of the clusters. The unusually low potential center is surprisingly the one that displays a conventional CX1X2CX3X4C (Xn, variable amino acid) binding motif and a structural environment similar to that of clusters having less negative potentials. A comparison with other ferredoxins has highlighted factors contributing to the reduction potential of [4Fe-4S] clusters in proteins. (i) The loop between the coordinating cysteines 40 and 49 and the C terminus alpha-helix of C. vinosum ferredoxin cause a negative, but relatively moderate, shift of approximately 60 mV for the nearby cluster. (ii) Very negative potentials, below -600 mV, correlate with the presence of a bulky side chain in position X4 of the coordinating triad of cysteines. These findings set the framework in which previous observations on ferredoxins can be better understood. They also shed light onto the possible occurrence and properties of very low potential [4Fe-4S] clusters in less well characterized proteins.
The crystal structure of the bovine Rieske iron-sulfur protein indicates a sulfur atom (S-1) of the iron-sulfur cluster and the sulfur atom (Sgamma) of a cysteine residue that coordinates one of the iron atoms form hydrogen bonds with the hydroxyl groups of Ser-163 and Tyr-165, respectively. We have altered the equivalent Ser-183 and Tyr-185 in the Saccharomyces cerevisiae Rieske iron-sulfur protein by site-directed mutagenesis of the iron-sulfur protein gene to examine how these hydrogen bonds affect the midpoint potential of the iron-sulfur cluster and how changes in the midpoint potential affect the activity of the enzyme. Eliminating the hydrogen bond from the hydroxyl group of Ser-183 to S-1 of the cluster lowers the midpoint potential of the cluster by 130 mV, and eliminating the hydrogen bond from the hydroxyl group of Tyr-185 to Sgamma of Cys-159 lowers the midpoint potential by 65 mV. Eliminating both hydrogen bonds has an approximately additive effect, lowering the midpoint potential by 180 mV. Thus, these hydrogen bonds contribute significantly to the positive midpoint potential of the cluster but are not essential for its assembly. The activity of the bc1 complex decreases with the decrease in midpoint potential, confirming that oxidation of ubiquinol by the iron-sulfur protein is the rate-limiting partial reaction in the bc1 complex, and that the rate of this reaction is extensively influenced by the midpoint potential of the iron-sulfur cluster.
[Poster-Abstract] Formel zur Beurteilung der Blut-Liquor-Schrankenfunktion bei älteren Patienten
(1998)
The iron-sulfur proteins of the cytochrome bc1 complexes of Schizosaccharomyces pombe and Saccharomyces cerevisiae contain the three amino acid motif RX( downward arrow)(F/L/I)XX(T/S/G)XXXX (downward arrow) that is typical for proteins that are cleaved sequentially in two steps by matrix processing peptidase (MPP) and mitochondrial intermediate peptidase (MIP). Despite the presence of this recognition sequence the S. pombe iron-sulfur protein is processed only once during import into mitochondria, whereas the S. cerevisiae protein is processed in two steps. Import of S. pombe iron-sulfur protein in which the putative MIP or MPP recognition sites are eliminated by site-directed mutagenesis and import of iron-sulfur protein into mitochondria from yeast mutants that lack MIP activity indicate that one step processing of the S. pombe iron-sulfur protein is independent of those sites and of MIP activity. Sequencing of the mature protein obtained after import in vitro and of the endogenous iron-sulfur protein isolated from mitochondrial membranes by preparative 2D-electrophoresis shows that MPP recognizes a second site in the presequence and processing occurs between residues 43 and 44. If proline-20 of the S. pombe presequence is changed into a serine, a second cleavage step is induced. Conversely, if serine-24 of the S. cerevisiae presequence is changed to a proline, the first cleavage step that is normally catalyzed by MPP is blocked, causing precursor iron-sulfur protein to accumulate. Together these results indicate that a single amino acid change in the presequence is responsible for one-step processing in S. pombe versus two-step processing in S. cerevisiae.
In Saccharomyces cerevisiae, the NDI1 gene encodes a mitochondrial NADH dehydrogenase, the catalytic side of which projects to the matrix side of the inner mitochondrial membrane. In addition to this NADH dehydrogenase, S. cerevisiae exhibits another mitochondrial NADH-dehydrogenase activity, which oxidizes NADH at the cytosolic side of the inner membrane. To investigate whether open reading frames YMR145c/NDE1 and YDL 085w/NDE2, which exhibit sequence similarity with NDI1, encode the latter enzyme, NADH-dependent mitochondrial respiration was assayed in wild-type S. cerevisiae and nde deletion mutants. Mitochondria were isolated from aerobic, glucose-limited chemostat cultures grown at a dilution rate (D) of 0. 10 h-1, in which reoxidation of cytosolic NADH by wild-type cells occurred exclusively by respiration. Compared with the wild type, rates of mitochondrial NADH oxidation were about 3-fold reduced in an nde1Delta mutant and unaffected in an nde2Delta mutant. NADH-dependent mitochondrial respiration was completely abolished in an nde1Delta nde2Delta double mutant. Mitochondrial respiration of substrates other than NADH was not affected in nde mutants. In shake flasks, an nde1Delta nde2Delta mutant exhibited reduced specific growth rates on ethanol and galactose but not on glucose. Glucose metabolism in aerobic, glucose-limited chemostat cultures (D = 0.10 h-1) of an nde1Delta nde2Delta mutant was essentially respiratory. Apparently, under these conditions alternative systems for reoxidation of cytosolic NADH could replace the role of Nde1p and Nde2p in S. cerevisiae.
Using apoE phenotyping by immunoblotting and apoE genotyping we identified four heterozygous carriers of a rare apolipoprotein (apo) E2 variant, apoE2 (Arg136 → Cys). ApoE2 (Arg136 → Cys) was not distinct from apoE2 (Arg158 → Cys) by phenotyping, but produced a unique pattern of bands on CfoI restriction typing of a 244 bp apoE gene fragment. Two of the four apoE2 (Arg136 → Cys)/3 heterozygotes had elevated triglycerides, two were normolipidemic. The composition of very low density lipoproteins (VLDL) was normal in each of the four apoE2 (Arg136 → Cys) carriers, regardless of the triglyceride concentrations. None of the apoE2 (Arg136 → Cys) carriers displayed a broad β-band and none revealed β-migrating particles in the VLDL. The two hypertriglyceridemic carriers of apoE2 (Arg136 → Cys) were, therefore, classified as having type IV rather than type III hyperlipoproteinemia. LDL receptor binding activities were studied using recombinant apoE loaded to dimyristoylphosphatidylcholine (DMPC) vesicles and to VLDL and from an apoE-deficient individual. LDL receptor binding of apoE2 (Arg136 → Cys) was 14% of apoE3 and was thus higher than that of apoE2 (Arg158 → Cys). Both apoE2 (Arg136 → Cys) and apoE2 (Arg158 → Cys) displayed substantial heparin binding (61 and 53% of apoE3, respectively). As the dominant apoE variants known so far are characterized by more pronounced reductions of heparin binding, we suggest that apoE2 (Arg136 → Cys) is not associated with dominant expression of type III hyperlipoproteinemia. These findings lend support to the concept that apoE variants predisposing to dominant type III hyperlipoproteinemia differ from recessive mutations by a more severe defect in heparin binding.—März, W., M. M. Hoffmann, H. Scharnagl, E. Fisher, M. Chen, M. Nauck, G. Feussner, and H. Wieland. Apolipoprotein E2 (Arg136 → Cys) mutation in the receptor binding domain of apoE is not associated with dominant type III hyperlipoproteinemia.
A detailed analysis of the chemical constituents of a Caribbean specimen of Aiolochroia crassa was performed. Five brominated products (1 -5) were isolated and one of these was a new bromotyrosine metabolite. The structure of the new compound 1 has been established from spectral studies. Compounds 1 and 2, which are the major brominated metabolites and have not been previously identified in any Aiolochroia species, could be usefully employed as chemotaxonomic markers.
A gene trap strategy has been used to identify genes that are repressed in cells transformed by an activated epidermal growth factor (EGF)/EGF receptor signal transduction pathway. EGF receptor-expressing NIH3T3 cells (HER1 cells) were infected with a retrovirus containing coding sequences for the human CD2 antigen and for secreted alkaline phosphatase in the U3 region. By selecting for and against CD2 expression, we obtained clones in which the gene trap had integrated into genes selectively repressed by EGF. Two of these clones encoded for the secreted extracellular matrix proteins TIMP3 and COL1A2. We show here that both genes are downstream targets of RAS and are specifically repressed by EGF-induced transformation. Moreover, this strategy tags tumor suppressor genes in their normal chromosomal location, thereby improving target-specific screens for antineoplastic drugs.
To investigate the contribution of hydrophobic residues to the molecular recognition of cytochrome c with cytochrome oxidase, we mutated several hydrophobic amino acids exposed on subunit II of the Paracoccus denitrificans oxidase. KM and kcat values and the bimolecular rate constant were determined under steady- or presteady-state conditions, respectively. We present evidence that Trp-121 which is surrounded by a hydrophobic patch is the electron entry site to oxidase. Mutations in this cluster do not affect the binding of cytochrome c as the KM remains largely unchanged. Rather, the kcat is reduced, proposing that these hydrophobic residues are required for a fine tuning of the redox partners in the initial collisional complex to obtain a configuration optimal for electron transfer.
The human hemopoietic cell kinase (HCK) is a member of the src family of protein tyrosine kinases specifically expressed in myeloid cells and to a minor extent in B-lymphoid cells. HCK expression is up-regulated at the transcriptional level during myeloid differentiation of hematopoietic cells. To elucidate the molecular basis of the differential HCK gene expression, the genomic region containing the HCK promoter was isolated and functionally characterized. A DNA fragment containing 101 base pairs of the 5′-flanking sequence showed strong promoter activity in the macrophage cell line RAW264 but was inactive in the non-monocytic cell lines HUT-78 and NIH-3T3. Site-directed mutagenesis of the proximal promoter region showed that two GC-rich sequence elements are essential for transcriptional activity in myeloid cells. Electrophoretic mobility shift analysis using nuclear extracts obtained from RAW264 cells and from the promonocytic cell line U-937 revealed the formation of at least three distinct protein-DNA complexes at each of these sites, one of which was found to contain the transcription factor Sp1. Expression of a reporter gene linked to the −101HCK promoter region was up-regulated by Sp1, but not by other members of the Sp1 family of transcription factors, in Drosophila Schneider cells. A synergistic effect onHCK promoter activity was observed at high concentrations of Sp1. Our results show that Sp1 plays an essential role in the regulation of the differential gene expression of the HCKgene.
Romantik
(1998)