Collection of evidence from the reverse side of self-adhesive stamps: A combined approach to obtain dactyloscopic and DNA evidence

The commonly applied method for the examination of self-adhesive stamps mainly focuses on DNA-profiling while neglecting potential fingerprint evidence. In our preliminary study it was shown that in an uncontrolled environment, fingerprints are transferred from the adhesive side of stamps onto the envelope within the first two days after application. Fingerprints can therefore be examined independently after the separation of the stamp from the envelope. The aim of this study was to develop a novel approach, which enables the combination of fingerprint development and the analysis of DNA traces originating from the same evidence, and to implement this into routine processes. Furthermore, this approach was compared with the edge fragment approach, the commonly applied standard method in our laboratory. The results showed that the novel approach is very beneficial for forensic examination of self-adhesive postage stamps on letters. Moreover, it enables parallel evaluation of dactyloscopic and DNA evidence without having an increased risk of contamination, PCR interference or altering of the fingerprint. The chance of obtaining useful forensic evidence for downstream database searching was increased from 50.0% to 83.3%. This novel method was shown to be valuable for the parallel evaluation of dactyloscopic and DNA trace material originating from the same evidence.

Streptococcal SpeB cleaved PAR-1 suppresses ERK phosphorylation and blunts thrombin-induced platelet aggregation

BACKGROUND

The family of 4 related protease-activated receptors (PAR-1, 2, 3 & 4) expressed by mammalian cells allow to sense for and react to extracellular proteolytic activity. Since major human bacterial pathogens secret a wide array of protease(-s) we investigated whether they interfere with human PAR function.

METHODOLOGY/PRINCIPAL FINDINGS

Supernatants from cultures of major human bacterial pathogens were assayed for the presence of protease(-s) capable to cleave overexpressed human PAR-1, 2, 3 and 4 reporter constructs. Group A streptococcus (GAS) was found to secret a PAR-1-cleaving protease. Experiments involving genetical and pharmacological gain and loss of function identified streptococcal pyrogenic exotoxin B SpeB as the protease responsible. On the host's side analysis of overexpressed PAR-1 carrying alanine substitutions and deletions showed the amino acid residue leucine44 on PAR-1's extracellular N-terminus to be the only cleavage site. Complementary studies on endogenously expressed PAR-1 using PAR-1 blocking antibodies further supported our conclusion. Through PAR-1 cleavage SpeB efficiently blunted thrombin-induced induction of the ERK-pathway in endothelial cells and prevented platelets aggregation in response to thrombin.

CONCLUSIONS/SIGNIFICANCE

Our results identify a novel function of the streptococcal virulence factor SpeB. By cleaving human PAR-1 at the N-terminal amino acid residue leucine44 SpeB rendered endothelial cells unresponsive to thrombin and prevented human platelets from thrombin-induced aggregation. These results suggest that by blunting PAR-1 signaling, SpeB modulates various innate host responses directed against invasive GAS potentially helping the invasive bacteria to escape. This may allow to tailor additional treatments in the future since upon invasion of the blood stream endothelial cells as well as platelets and mononuclear cells respond to PAR-1 agonists aiming to prevent further bacterial dissemination.

Osseofix® system for percutaneous stabilization of osteoporotic and tumorous vertebral compression fractures - clinical and radiological results after 12 months

PURPOSE

Determining whether implantation of an expandable titanium mesh cage (Osseofix® system) is a successful and safe minimally invasive therapy for osteoporotic and tumorous vertebral compression fractures (VCFs).

MATERIALS AND METHODS

32 patients (25 women, 7 men, mean age 71) with 46 osteoporotic or tumorous VCFs (T6 to L4) from June 2010 to January 2012 were included. All of them were stabilized with the Osseofix® system. Preinterventionally we performed X-ray, MRI, and bone density measurements (DXA). The clinical and radiological results were evaluated preop, postop and 12 months postop based on the visual analog scale (VAS) and the Oswestry Disability Index (ODI), X-ray (Beck Index, Cobb angle) and CT.

RESULTS

There was a significant improvement in pain intensity (VAS) (7.8 to 1.6) as well as a significant reduction in the mean ODI (71.36 % to 30.4 %) after 12 months. The mean kyphotic angle according to Cobb showed significant improvements (12.3° to 10.8°) after 12 months. Postinterventional imaging showed one case of loss of height in a stabilized lumbar vertebral body (2.2 %) in osteoporosis and one case with adjacent fracture (2.2 %) in osteoporosis. We saw no changes in the posterior vertebral wall. Except for one pronounced postoperative hematoma, we saw no surgical complications including no cement leakage.

CONCLUSION

The clinical mid-term results are good at a low complication rate. The stabilization of symptomatic osteoporotic and tumorous VCFs with the Osseofix® system is a safe and effective procedure, even in fractures with posterior wall involvement. The Osseofix® system is an interesting alternative to the established procedures of cement augmentation.

KEY POINTS

• The Osseofix® system is well suited for stabilizing osteoporotic and tumorous VCFs.• It is a safe and effective procedure without cement leakage and with a low complication rate.• The procedure is an interesting alternative to established cement augmentation procedures.

Intravenous immunglobulin binds beta amyloid and modifies its aggregation, neurotoxicity and microglial phagocytosis in vitro

Intravenous Immunoglobulin (IVIG) has been proposed as a potential therapeutic for Alzheimer's disease (AD) and its efficacy is currently being tested in mild-to-moderate AD. Earlier studies reported the presence of anti-amyloid beta (Aβ) antibodies in IVIG. These observations led to clinical studies investigating the potential role of IVIG as a therapeutic agent in AD. Also, IVIG is known to mediate beneficial effects in chronic inflammatory and autoimmune conditions by interfering with various pathological processes. Therefore, we investigated the effects of IVIG and purified polyclonal Aβ -specific antibodies (pAbs-Aβ) on aggregation, toxicity and phagocytosis of Aβ in vitro, thus elucidating some of the potential mechanisms of action of IVIG in AD patients. We report that both IVIG and pAbs-Aβ specifically bound to Aβ and inhibited its aggregation in a dose-dependent manner as measured by Thioflavin T assay. Additionally, IVIG and the purified pAbs-Aβ inhibited Aβ-induced neurotoxicity in the SH-SY5Y human neuroblastoma cell line and prevented Aβ binding to rat primary cortical neurons. Interestingly, IVIG and pAbs-Aβ also increased the number of phagocytosing cells as well as the amount of phagocytosed fibrillar Aβ by BV-2 microglia. Phagocytosis of Aβ depended on receptor-mediated endocytosis and was accompanied by upregulation of CD11b expression. Importantly, we could also show that Privigen dose-dependently reversed Aβ-mediated LTP inhibition in mouse hippocampal slices. Therefore, our in vitro results suggest that IVIG may have an impact on different processes involved in AD pathogenesis, thereby promoting further understanding of the effects of IVIG observed in clinical studies.

Protease-activated receptor-1 cleaved at R46 mediates cytoprotective effects

BACKGROUND

Activated protein C (aPC) mediates powerful cytoprotective effects through the protease-activated receptor-1 (PAR1) that translate into reduced harm in mouse injury models. However, it remains elusive how aPC-activated PAR1 can mediate cytoprotective effects whereas thrombin activation does the opposite.

OBJECTIVES

We hypothesized that aPC and thrombin might induce distinct active conformations in PAR1 causing opposing effects.

METHODS

We analyzed antibody binding to, and cleavage and signalling of PAR1 in either endogenously expressing endothelial or overexpressing 293T cells.

RESULTS

In thrombin-cleaved PAR1 neither the tethered ligand nor the hirudin-like domain were available for anti-PAR1 ATAP2 and WEDE15 binding unless the tethered ligand was quenched. In contrast, aPC irreversibly prevented ATAP2 binding while not affecting WEDE15 binding. Reporter constructs with selective glutamine substitutions confirmed R41 as the only thrombin cleavage site in PAR1, whereas aPC preferentially cleaved at R46. Similarly, we report distinct cleavage sites on PAR3, K38 for thrombin and R41 for aPC. A soluble peptide corresponding to R46-cleaved PAR1 enhanced the endothelial barrier function and reduced staurosporine toxicity in endothelial as well as in 293T cells if PAR1 was expressed. Overexpression of PAR1 variants demonstrated that cleavage at R46 but not R41 is required for cytoprotective aPC signaling.

CONCLUSIONS

We provide a novel concept on how aPC and thrombin mediate distinct effects. We propose that the enzyme-specific cleavage sites induce specific conformations which mediate divergent downstream effects. This unexpected model of PAR1 signaling might lead to novel therapeutic options for the treatment of inflammatory diseases.

[Amputation of the leg with impaired circulation. The orthopaedic surgeon's view]

Despite therapeutic improvements in the treatment of arterial circulatory problems of the leg, several tens of thousands of amputations are performed every year. The amputation is not the end of the treatment but is the beginning of the rehabilitation. Decisive criteria for a successful rehabilitation are the quality of the leg-stump, the immediate and early care, and an adequate artificial leg.

A novel DNA-binding protein modulating methicillin resistance in Staphylococcus aureus

Background

Methicillin resistance in Staphylococcus aureus is conferred by the mecA-encoded penicillin-binding protein PBP2a. Additional genomic factors are also known to influence resistance levels in strain specific ways, although little is known about their contribution to resistance phenotypes in clinical isolates. Here we searched for novel proteins binding to the mec operator, in an attempt to identify new factor(s) controlling methicillin resistance phenotypes.

Results

Analysis of proteins binding to a DNA fragment containing the mec operator region identified a novel, putative helix-turn-helix DNA-binding protein, SA1665. Nonpolar deletion of SA1665, in heterogeneously methicillin resistant S. aureus (MRSA) of different genetic backgrounds, increased methicillin resistance levels in a strain dependent manner. This phenotype could be fully complemented by reintroducing SA1665 in trans. Northern and Western blot analyses, however, revealed that SA1665 had no visible influence on mecA transcription or amounts of PBP2a produced.

Conclusion

SA1665 is a new chromosomal factor which influences methicillin resistance in MRSA. Although SA1665 bound to the mecA promoter region, it had no apparent influence on mecA transcription or translation, suggesting that this predicted DNA-binding protein modulates resistance indirectly, most likely through the control of other genomic factors which contribute to resistance.

Impact of mecA promoter mutations on mecA expression and beta-lactam resistance levels

The reason for the extremely low-level oxacillin resistance in a so-called 'drug clone', a methicillin-resistant Staphylococcus aureus circulating among injection drug users in Zurich, Switzerland, could be traced back to the mecA promoter sequence and particularly to the strain's genetic background. Sequencing of its mec complex identified a point mutation (TATACT to TATATT), creating a perfect palindrome in the -10 region of the mecA promoter/operator region containing the binding sites for the mecA repressors MecI and BlaI. Two strains with vastly different beta-lactam resistance phenotypes, the low-level resistant drug clone type strain CHE482 and the highly homogeneously resistant strain COLn, were cured of their SCCmec elements and subsequently transformed with plasmids containing mecA under the control of either the wild-type or mutant promoter. Expression studies showed that this mutation had significant effects on both mecA transcription and corresponding PBP2a production, but only small effects on beta-lactam resistance levels within a given genetic background. A further mutation in the mecA ribosomal binding site (GGAGG to GGAGT), common to SCCmec type IV strains, was found to have no discernable effect on mecA transcription and PBP2a content, and only minimal effects on beta-lactam resistance. Factors associated with the genetic backgrounds into which these differently controlled mecA genes were introduced had a much higher impact on beta-lactam resistance levels than the rates of mecA transcription. The tight repression of mecA expression in this drug clone in the absence of beta-lactams could contribute to the apparent fitness of this fast growing strain.

Fitness cost of staphylococcal cassette chromosome mec in methicillin-resistant Staphylococcus aureus by way of continuous culture

We examined the effect of introducing type I or IV staphylococcal cassette chromosome mec (SCCmec) elements on the growth yield of Staphylococcus aureus in glucose-limited continuous culture. Type I showed increased glucose consumption and ATP demand per gram of cells synthesized and decreased cell yield compared to those of the parent strain. In contrast, type IV SCCmec elements had no adverse energetic effect.

Mosaic staphylococcal cassette chromosome mec containing two recombinase loci and a new mec complex, B2

A novel staphylococcal cassette chromosome (SCC) mec from a clinical methicillin-resistant Staphylococcus aureus isolate (ST100/CC5) had a mosaic structure, composed of SCC DNA from several different backgrounds. It harbored two complete ccr loci and a new variant of mec complex B, with DeltamecR1 interrupted by the aminoglycoside resistance transposon Tn4001.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Zurich, Switzerland (2003): prevalence of type IV SCCmec and a new SCCmec element associated with isolates from intravenous drug users

The majority of methicillin-resistant Staphylococcus aureus (MRSA) isolates, recovered in 2003 at the Department of Medical Microbiology in Zürich, Switzerland, belonged to major clones that are circulating worldwide. Staphylococcal cassette chromosome mec type IV (SCCmec-IV), harbored by half of the isolates, was found in sequence type 217 (ST 217), which is an allelic variant of epidemic MRSA-15 (designated EMRSA-15), in a new local ST 617 descending from clonal complex CC 8 and in low-level oxacillin-resistant strains of multiple genetic lineages characteristic of community-onset MRSA. SCCmec-I, SCCmec-II, and SCCmec-III were in the minority, and four MRSA isolates had complex, rearranged SCCmec elements. A novel SCCmec-N1 of approximately 30 kb, associated with a dfrA gene and a ccr 4-related recombinase complex, was identified in a large number of low-level oxacillin-resistant isolates, which descended from the successful clonal complex CC 45 and are spreading among intraveneous drug users. In contrast, the SCCmec types of oxacillin-resistant coagulase-negative staphylococci (MRCNS) were of completely different composition. SCCmec type I (SCCmec-I) and SCCmec-II were more frequent than in the MRSA, while fewer contained SCCmec-IV. The other MRCNS displayed 11 different, complex patterns, suggesting frequent recombination between different SCCmec elements. With one ccr-negative exception, these strains amplified between one and three different ccr products, indicating either new varied complexes or multiple ccr loci. This suggests the presence of novel SCCmec types in MRCNS and no extensive interspecies SCCmec transfer between MRSA and MRCNS.

Fitness cost of SCCmec and methicillin resistance levels in Staphylococcus aureus

Transformation of a type I SCCmec element into Staphylococcus aureus yielded highly oxacillin-resistant transformants with a reduced growth rate. Faster-growing variants could again be selected at the cost of reduced resistance levels, demonstrating an inverse correlation between oxacillin resistance levels and growth rate.

[Experience with the management of fresh cruciate ligament rupture in athletes]

Since 1984 we have done over the top repair of the acutely torn anterior cruciate ligament combined with augmentation by McIntosh lateral-substitution over the top procedure with iliotibial band in view of frequent instabilities following simple reconstruction. After treatment by continuous passive motion and early weight bearing is possible. The results at review were good. This method is recommended to avoid the risk of rerupture.