Legionella pneumophila serogroup Lansing 3 isolated from a patient with fatal pneumonia, and descriptions of L. pneumophila subsp. pneumophila subsp. nov., L. pneumophila subsp. fraseri subsp. nov., and L. pneumophila subsp. pascullei subsp. nov

Previous DNA relatedness and enzyme electrophoretic mobility studies indicated heterogeneity among strains of Legionella pneumophila serogroups 1, 4, 5, and Lansing 3 (a new, as yet unnumbered serogroup). In this study 60 L. pneumophila strains were studied by DNA hybridization (hydroxyapatite method) to assess their genomic relatedness. These strains were also studied biochemically and serologically to determine whether they formed one or more phenotypic groups. DNA relatedness studies identified three groups. DNA group 1 contained the type strain Philadelphia 1 and strains from serogroups 1 through 14 of L. pneumophila. The average relatedness of DNA group 1 strains was 88% at 60 degrees C with 1.1% divergence in related sequences and 85% at 75 degrees C. DNA group 2 contained strain Los Angeles 1, the reference strain of serogroup 4, and strains of serogroups 1, 4, 5, and Lansing 3, an unnumbered serogroup. Average relatedness of DNA group 2 strains was 84% at 60 degrees C with 0.7% divergence and 87% at 75 degrees C. Reciprocal relatedness of DNA groups 1 and 2 was approximately 67% at 60 degrees C with 6.0% divergence and 48% at 75 degrees C. DNA group 3 strains were in serogroup 5. They were 98% related at 60 degrees C with 0.5% divergence and 97% related at 75 degrees C. Reciprocal relatedness of DNA group 3 and DNA group 1 was approximately 74% at 60 degrees C with 5.3% divergence and 43% at 75 degrees C, and reciprocal relatedness of DNA groups 3 and 2 was 66% at 60 degrees C with 5.7% divergence and 55% at 75 degrees C. The DNA groups could not be separated biochemically or serologically or by cell wall fatty acid and isoprenoid quinone composition. Three subspecies of L. pneumophila are proposed to accommodate the three DNA groups: L. pneumophila subsp. pneumophila subsp. nov. for DNA group 1, L. pneumophila subsp. fraseri subsp. nov. for DNA group 2, and pneumophila subsp. pascullei subsp. nov. for DNA group 3.     

The serology of hepatitis C virus (HCV) infection: antibody crossreaction in the hypervariable region 1

Summary We determined the NS1/E2 N-terminal sequence including the hypervariable region 1 (HVR1) from five individuals chronically infected with HCV: two from the Czech Republic and three from Germany. From each sequence, six 12-mer overlapping peptides were synthesized and used in a peptide scan to evaluate seroreactivity of each of those patients, as well as three anti-HCV positive blood donors to the different isolates. We could show the general presence of antibodies to multiple HVR1 specific sequences reflecting the existence of multiple variants in infected persons. Finally, we observed the persistance of HCV infections in all individuals despite an active humoral response directed against the virus.     

Quantitative gas chromatography-mass spectrometry determination of pentaerythrityl tetranitrate metabolites pentaerythrityl trinitrate, pentaerythrityl dinitrate and pentaerythrityl in human plasma

Assay methods based on gas chromatography/mass spectroscopy (GC-MS) may be used to measure PE1N (pentaerithrityl mononitrate, CAS 1607-00-7), PE2N (pentaerithrityl dinitrate, CAS 1607-01-8) and intermediate pentaerithrityltrinitrate (PE3N, CAS 1607-17-6) in human plasma. Based on this method a simplified method to quantify the metabolites of PETN (pentaerithrityl tetranitrate, CAS 78-11-5, Pentalong) is described. In the present study a consistent method to extract the metabolites of human plasma and following derivatisation is described. Since PE1N can be quantified up to 150 ng/ml, PE2N and PE3N up to 30 ng/ml in human plasma, a dilution of the plasma samples can be avoided. The mean recovery rate is not so high as in other described methods, and inaccuracy is about 10%. Therefore a calibration range between 0.2-30 ng/ml of PE2N and 1-150 ng/ml of PE1N has to be considered. The described method offers an alternative and applicable option to quantify the PETN-metabolites and elucidate their part as NO-donors.     

Can a threshold for 11‐nor‐9‐carboxy‐Δ9 ‐tetrahydrocannabinol in hair be derived when its respective concentration in blood serum indicates regular use?

A 100 μg/L or higher concentration of 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol (THC‐COOH) in blood serum is generally assumed to be associated with regular and/or heavy use of cannabis. At present, determination of the extent of cannabis use by means of the concentration of THC‐COOH in hair has not been assessed. Therefore, we aimed at establishing a threshold for THC‐COOH concentrations in hair to prove frequent consumption by comparing THC‐COOH concentrations in 129 corresponding serum and hair samples, respectively. The concentration of THC‐COOH in the serum was analyzed by gas chromatography–mass spectrometry and in the hair by liquid chromatography–tandem mass spectrometry. Data were statistically evaluated using receiver operating characteristic curves and contingency tables. Our results suggest that a THC‐COOH concentration of ≥4.2 pg/mg in hair was always accompanied by a THC‐COOH concentration of at least 100 μg/L in blood serum. Should this be confirmed by further studies of a larger study population, a hair concentration of 4.2 pg/mg THC‐COOH can be set as a threshold to predict regular and/or heavy consumption of cannabis even if no corresponding blood sample is available for analysis.     

Molekulare Diagnostik der infektiösen Gastroenteritis

Die Gastroenterologie - Die infektiöse Gastroenteritis gehört zu den häufigsten Erkrankungen überhaupt. Leitsymptom ist die akute Diarrhö mit oder ohne Erbrechen. Aufgrund...     

Mechanically stable implants of synthetic bone mineral by cold isostatic pressing

A calcium phosphate phase that is equivalent in composition (carbonate content) and crystallinity (nanocrystals) to the mineral phase of bone was prepared by a continuous precipitation method. The powder was compacted by cold isostatic pressing into desired shapes with high compressive strength (range of 20-50 MPa, depending on the geometry). It is concluded that such implant materials can be prepared with a fine-tuned biodegradability in combination with a high mechanical strength. The high mechanical strength of the objects also permits further mechanical shaping procedures like drilling or cutting.     

Insulin-like growth factor-I affects amino compounds in the fluids of the chicken embryo

The concentration differences of more than 40 amino acids and related compounds in the amniotic fluid, allantoic fluid, and plasma of the chicken embryo are maintained by specific barriers. Since the amniotic and allantoic membranes are not innervated, we proposed that these barriers are controlled by hormones. Specific effects of insulin and prolactin on the amino compounds in the three fluids confirmed this hypothesis and raised the question of the possible role of growth factors. Application of insulin-like growth factor-I (IGF-I) to the chorioallantoic membrane of day 13 chicken embryos caused the following concentration changes in 41 amino compounds measured 1 and 2 h later: (1) in the amniotic fluid, an increase of 40 compounds, regardless of the presence or absence of a concomitant stress effect on these compounds; only NH3 was not affected; (2) in the allantoic fluid, a decrease of reduced glutathione (GSH) and anserine, and an increase of NH3; (3) in the plasma, a decrease of 24 compounds. Within the same time frame, stress caused in the amniotic fluid a drop of the concentration of 29, and an increase of 5, amino compounds; IGF-I reversed the stress effect on all 29 compounds the concentrations of which had dropped and enhanced the stress-induced increase of the other 5 compounds. In the allantoic fluid, stress induced an increase of GSH; IGF-I reversed this effect. In the plasma, stress caused an increase of 9 compounds; IGF-I counteracted the increase in 7 cases. These findings indicate new and unexpected roles of IGF-I in the prenatal regulation of amino compounds.     

Stimulation of plasminogen activation by recombinant cellular prion protein is conserved in the NH2-terminal fragment PrP23-110

The cellular prion protein (PrP(c)), tissue-type plasminogen activator (t-PA) and plasminogen are expressed in synaptic membranes in vivo. In the central nervous system the fibrinolytic system is associated with excitotoxin-mediated neurotoxicity and Alzheimer's disease. Recently binding of the disease associated isoform of the prion protein (PrP(Sc)) to plasminogen and stimulation of t-PA activity have been reported. In this study the interaction of PrP(c) and plasminogen was investigated using chromogenic assays in vitro. We found that plasmin is able to cleave recombinant PrP(c) at lysine residue 110 generating an NH(2)-terminal truncated molecule that has previously been described as a major product of PrP(c) metabolism. We further characterized the proteolytic fragments with respect to their ability to stimulate plasminogen activation in vitro. Our results show that the NH(2)-terminal part of PrP(c) spanning amino acids 23-110 (PrP23-110) together with low molecular weight heparin stimulates t-PA mediated plasminogen activation in vitro. The apparent rate constant was increased 57 fold in the presence of 800 nM PrP23-110. Furthermore, we compared the stimulation of t-PA activity by PrP(c) and beta-amyloid peptide (1-42). While the activity of the beta-amyloid was independent of low molecular weight heparin, PrP23-110 was approximately 4- and 37 fold more active than beta-amyloid in the absence or presence of low molecular weight heparin. In summary, plasmin cleaves PrP(c) in vitro and the liberated NH(2)-terminal fragment accelerates plasminogen activation. Cleavage of PrP c has previously been reported. Thus cleavage of PrP(c) enhancing plasminogen activation at the cell surface could constitute a regulatory mechanism of pericellular proteolysis.