Clonal differentiation of uropathogenic Escherichia coli isolates of serotype O6:K5 by fimbrial antigen typing and DNA long-range mapping techniques

Escherichia coli isolates of serotype O6:K5 are the most common causative agents of cystitis and pyelonephritis in adults. To answer the question, as to whether strains of this particular serotype represent one special clonal group, out of a collection of 34 serotype O6:K5 isolates [Zingler et al. (1990) Zentralbl. Bakteriol Mikrobiol Hyg [A] 274:372–381] 15 strains were selected and analyzed in detail. The flagellar (H) antigen and the outer membrane protein (OMP) pattern were determined. Further serum resistance properties and the genetic presence and expression of other virulence factors, including hemolysin, aerobactin, P fimbriae, S/F1C fimbriae and type 1 fimbriae was evaluated. In addition the Xba-Imacrorestriction pattern of ten representative isolates was elaborated and the fimbrial (F) antigen type of the P fimbriae was determined, to obtain the complete O:K:H:F pattern. These analyses could clearly show that the O6:K5 isolates do not represent one clonal group. The XbaI-macrorestriction profiles were heterogeneous and marked differences in the hybridization patterns, using virulence-associated gene probes in Southern hybridization of long-range-separated genomic DNA, were observed among the strains. However, some of strains showed similarities in the genomic profiles, arguing for clonal groupings among the O6:K5 isolates. Interstingly the strains grouped together exhibited the same fimbrial F type that many indicate a coincidence of this phenotypic trait with clonality.In memoriam of Prof. G. Naumann     

Über Subarachnoidal-Blutungen

Zusammenfassung Es gibt zahlreiche Ursachen der Subarachnoidalblutungen. Naturgemäß müssen dieselben in Gefäßveränderungen gesucht werden.Eine sog. idiopathische, spontane, essentielle Blutung haben viele Autoren (insbesondereHess) dadurch begründet, daß jede erkennbare Gefäßveränderung oder sonstige äußere Beeinflussung in einer großen Anzahl von Fällen, besonders bei Jugendlichen, nicht nachgewiesen werden kann. Diese Fälle wurden mit einer angioneurotischen Diathese begründet.Sicher gibt es derartige Fälle; jedoch ist diese Krankheitsform mit großer Vorsicht und Kritik zu bewerten, da verborgene Ursachen verschiedener Art, besonders das Basalaneurysma, vorhanden sein können.D. 8.     

Blinded, Externally Controlled Multicenter Evaluation of Light Microscopy and PCR for Detection of Microsporidia in Stool Specimens

The quality parameters for the detection of microsporidia in identical sets of 50 stool samples were determined for six laboratories where technicians used light microscopy and for six laboratories where technicians used PCR. The average overall sensitivities were 67% (89% for patient samples only) for the PCR laboratories and 54% (80% for patient samples only) for the light microscopy laboratories. Specificities were 98 and 95%, respectively. Differences in results were most apparent between the individual laboratories rather than between the two major methods used.     

Activation of RhoA,B,C by Yersinia Cytotoxic Necrotizing Factor (CNFy) Induces Apoptosis in LNCaP Prostate Cancer Cells

Prostate cancer is the most common malignancy, accounting for about 25% of all incident cases among men in industrialized countries. The human androgen-dependent prostate cancer cell line LNCaP, which is derived from a metastatic lesion of human prostatic adenocarcinoma, is frequently used to study prostate cancer associated signaling pathways in vitro. Recently it was described that Rho GTPase activation in these cells leads to apoptotic responses. We used the bacterial toxins CNFy and CNF1, which specifically and directly activate Rho GTPases by deamidation of a single glutamine. We asked whether these Rho activators could induce apoptosis in LNCaP cells. Our results indicate that RhoA activation, induced by CNFy, does lead to intrinsic apoptosis of the cells. Analysis of the underlying signaling pathway reveals that apoptosis induction requires the activity of Rho kinase (ROCK) and myosin activation, an apoptotic pathway previously identified in cancer stem cells.     

Effectiveness of antiplatelet therapy in atherosclerotic disease: comparing the ASA low-response prevalence in CVD,CAD and PAD

Although acetylsalicylic acid (ASA, aspirin) reduces the risk of ischemic events in patients with atherosclerosis, a substantial number of incidents continue to occur. As only limited data exist we evaluated the antiplatelet effectiveness of ASA in patients with different manifestations of atherosclerosis as in cerebrovascular, coronary artery and peripheral arterial disease (CVD, CAD, PAD). For the evaluation of the antiplatelet effectiveness of ASA we used whole blood aggregometry (Chrono-log Model 590). The patients in the different subgroups received ASA 100, 200 or 500 mg daily. We analysed 737 consecutive patients: 47.5 % with CVD, 33.6 % with CAD, and 18.9 % with PAD. We identified 28.0 % of the CVD, 18.1 % of the CAD and 21.6 % of the PAD patients to be ASA low-responder (ALR). Comparing subgroups treated with 100 mg ASA, 36.4 % were ALR in the CVD group as were 13.1 % of the CAD and 21.6 % of the PAD patients. Multivariate regression analysis revealed an odds ratio for being ALR of 4.50 (95 % confidence interval (CI) 1.70–11.9) when 100 mg and of 2.97 (95 % CI 1.58–5.60) when 200 mg ASA was taken compared to a dose of 500 mg. Despite the proven benefits of antiplatelet therapy in the secondary prevention of atherosclerotic disease, current antiplatelet management is suboptimal as up to 36 % of patients failed to achieve an adequate platelet inhibitory effect. Our findings may explain, at least in part, the high rates of cardiovascular events observed in the course of atherothrombotic disease and support the need to improve antiplatelet therapy.     

Commentary: Dermal penetration of bisphenol A—Consequences for risk assessment

With this comment we would raise awareness for applying appropriate procedures in route-to-route extrapolation. The paper of Demierre et al. (2012) prompted us to comment on the simple approach for route-to-route extrapolation and to explain some short comings. For the risk assessment of exposures resulting from a non-oral route, route-to-route extrapolation is often done by correcting the non-oral route exposure by the route specific absorption into the systemic circulation and comparing the result with the (oral) threshold value. Making use of this procedure means that an internal dose obtained from the non-oral route is compared with an external dose of the oral route. This procedure would be appropriate only if the absorption on the oral route is 100%. If the absorption on the oral route is less than 100% the procedure may underestimate the risk of the exposure of the non-oral route. For some chemicals with a high first pass metabolism in the liver, e.g. BPA, the situation is even more complex and in addition, the target organ for toxicity has to be taken into consideration.     

Outcomes of ceftriaxone use compared to standard of therapy in methicillin susceptible staphylococcal aureus (MSSA) bloodstream infections

Background Standard of care therapy (SOCT) for the treatment of methicillin susceptible staphylococcal aureus (MSSA) infections requires multiple daily infusions. Despite questionable efficacy due to high protein binding, ceftriaxone (CTX) is frequently used for treatment of MSSA at Hines VA Hospital. Objective The objective of this study was to determine clinical and microbiological outcomes in patients with MSSA bacteremia treated with CTX compared to SOCT. Setting This retrospective study was conducted at the Edward Hines, Jr. VA Hospital which is a comprehensive health care center serving the veteran population of the greater metropolitan Chicago and northwest Indiana regions and is institutionally affiliated with the Loyola University Medical Center. The Hines VA provides medical care to over 56,000 veterans and operates approximately 500 hospital beds, including acute care and nursing home beds. Method We conducted a retrospective cohort study of patients with MSSA bacteremia treated at Hines VA Hospital between January 2000 and September 2009. Patients who received either SOCT or CTX for >50 % of the treatment course and for the appropriate duration were included. Patients who were on multiple antibiotics concurrently or who received <14 days of therapy were excluded. Main outcome measure The primary outcome of this study is to compare clinical outcomes of patients with MSSA bacteremia who were treated with CTX compared to those who received standard of care agents. Results Ninety-three patients with MSSA bacteremia were included in the analysis. Fifty-one were treated with SOCT and 42 with CTX. There were no differences in microbiological cure between SOCT (94.1 %) and CTX (95.2 %) (p = 0.812). Clinical cure was similar between groups (74.5 % for SOCT, 83.3 % for CTX) (p = 0.303). CTX was used more often to treat Staphylococcus aureus bacteremia associated with osteomyelitis whereas endocarditis and central line associated infections were treated more frequently with SOCT (p = 0.01). More patients treated with CTX were managed in the ambulatory setting (64 vs. 24 %; p = <0.001). There was a trend toward a longer hospital stay with SOCT. Conclusion Clinical outcomes for MSSA bacteremia did not differ significantly between patients treated with CTX and SOCT. Findings suggest that CTX may be an alternative for outpatient management of MSSA bacteremia.     

Viral myocarditis and coagulopathy: increased tissue factor expression and plasma thrombogenicity

We investigated the effects of viral infection on Tissue Factor (TF) expression and activity in mice within the myocardium to understand increased thrombosis during myocarditis. Mice were infected with coxsackie virus B3 (CVB3) and the hearts were collected at day 4, 8 and 28 post infection (p.i.). Myocardial TF expression and cellular activity as well as plasma activity were analyzed from CVB3 infected mice by Western blot, chromogenic Factor Xa generation assay, in situ staining for active TF and immunohistochemistry. In addition to TF expression, hemodynamic parameters were measured during the time course of infection. Furthermore, we analyzed myocardial tissues from patients with suspected inflammatory cardiomyopathy. TF protein expression was maximally 5-fold elevated 8 days p.i. in mice and remained increased on day 28 p.i. (P < 0.001 vs. non-infected controls). Alterations in TF expression were associated with fibrin deposits within the myocardium. The TF pathway inhibitor protein expression in the myocardium was not altered during myocarditis. Active cellular TF co-localized with CD3 positive cells and VCAM-1 positive endothelial cells in the myocardium. The TF expression was positively correlated with the amount of infiltrating CD3 and Mac3 positive cells (Spearman-Rho ρ = 0.749 P < 0.0001 for CD3⁺ and ρ = 0.775 P < 0.0001 for Mac3⁺; N = 35). Increased myocardial TF expression was associated with a 2-fold elevated plasma activity (P < 0.05 vs. non-infected controls). In the human hearts, the TF expression correlated postively with an endothelial cell activation marker (ρ = 0.523 P < 0.0001 for CD62E; N = 54). Viral myocarditis is a hypercoagulative state which is associated with increased myocardial TF expression and activity. Upregulation of TF contributes to a systemic activation of the coagulation cascade.     

Calcium lability of cytoplasmic microtubules and its modulation by microtubule-associated proteins

Detergent-extracted BSC-1 monkey cells have been used as a model system to study the Ca²⁺ sensitivity of in vivo polymerized microtubules under in vitro conditions. The effects of various experimental treatments were observed by immunofluorescence microscopy. Whereas microtubules are completely stable at Ca²⁺ concentrations below 1 μM, Ca²⁺ at greater than 1-4 μM induces microtubule disassembly that begins in the cell periphery and proceeds towards the cell center. At concentrations of up to 500 μM, both the pattern and time course of disassembly are not markedly altered, suggesting that, within this concentration range, Ca²⁺ effects are catalytic rather than stoichiometric. Higher (millimolar) Ca²⁺ concentration results in rapid destruction of microtubules. Of other divalent cations, only Sr²⁺ has a slight depolymerizing effect, whereas millimolar Ba²⁺, Mg²⁺, or Mn²⁺ is ineffective. Disassembly induced by micromolar Ca²⁺ is inhibited by pharmacological agents known to bind to calmodulin and inhibit its function, suggesting that calmodulin mediates Ca²⁺ effects. Both the addition of exogenous brain microtubule-associated proteins (MAPs) after lysis and the retention of endogenous cellular MAPs normally extracted during the lysis step stabilize microtubules against the depolymerizing effect of micromolar Ca²⁺. The results indicate that, in this model system, microtubules are sensitive to physiological Ca²⁺ concentrations and that this sensitivity may be conferred by calmodulin associated with the microtubules. MAPs appear to have a modulating effect on microtubular Ca²⁺ sensitivity and thus may function as a discriminating factor in cellular functions performed by calmodulin. It is hypothesized that Ca²⁺-stimulated microtubule disassembly depends on the relative amount of MAPs.