Culex torrentium mosquitoes from Germany are negative for Wolbachia

Wolbachia (Rickettsiales: Anaplasmataceae) infects a wide range of arthropods, including several mosquito species. The bacterium is known to induce a plethora of phenotypes in its host, examples being the reproductive phenotype cytoplasmic incompatibility or resistance against infection with arboviruses. The latter is especially relevant when assessing the vector competence of mosquito species for emerging arboviruses. Thus, knowledge of Wolbachia infection status is important for the assessment of vector competence. To facilitate Wolbachia screening in mosquito populations, a quantitative polymerase chain reaction (qPCR) assay was developed to enable high-throughput analysis of mosquito samples. Using this assay, the Wolbachia infection status of the two most common Culex mosquito species in Germany, Culex pipiens biotype pipiens Linnaeus (Diptera: Culicidae) and Culex torrentium Martini (Diptera: Culicidae), was assessed. About 93% of all tested C. pipiens biotype pipiens individuals were positive for Wolbachia, whereas none of the C. torrentium samples was found to be infected. Furthermore, other applications of the qPCR assay were explored by assessing a potential link between the levels of Wolbachia and West Nile virus (WNV) infections in German C. pipiens biotype pipiens mosquitoes. No relationship was found between the two variables, indicating that a Wolbachia-induced antiviral phenotype in this mosquito population is not exclusively attributable to the general level of bacterial infection.

[Quality of life after multiple trauma]

BACKGROUND

Multiple trauma is an independent injury pattern which, because of its complexity, is responsible for 25 % of the costs for the treatment of all injured patients. Because of the often long-lasting physical impairment and the high incidence of residual permanent handicaps, it is apparent that multiple trauma can lead to a reduction in patient quality of life.

OBJECTIVES

The aim of this study was to give an overview of the known data concerning the change in quality of life for multiple trauma patients. Furthermore, predictors for the reduction of quality of life after multiple trauma will be identified.

MATERIALS AND METHODS

A MedLine search was performed to identify studies dealing with the outcome after multiple trauma.

RESULTS

In addition to functional outcome parameters, the term quality of life has become more important in recent years when it comes to evaluating the outcome following injury. While the mortality after multiple trauma could be significantly reduced over the years, there is no comparable effect on the quality of life. Predictors for a worse quality of life after multiple trauma are female gender, high age, low social status, concomitant head injuries and injury to the lower extremities.

CONCLUSION

The fact that mortality after multiple trauma has decreased but not impairment of the quality of life makes it clear that in addition to the acute medical treatment, a follow-up treatment including not only physiotherapy but also psychotherapy is crucial for multiple trauma patients.

Increased exercise after stable closed fracture fixation does not affect fracture healing in mice

PURPOSE

The aim of the present study was to evaluate the systemic biological effect of increased exercise on bone repair after stable fracture fixation.

METHODS

Two groups of SKH-1h mice were studied. Animals of the first group (n=36) were housed in cages supplied with a running wheel, while mice of the second group (n=37) were housed in standard cages for control. Using a closed femur fracture model, bone repair was analysed by histomorphometry and biomechanical testing at 2 and 5 weeks. At 2 weeks, we additionally evaluated the expression of the proliferation marker PCNA (proliferating cell nuclear antigen) and the angiogenic and osteogenic growth factor VEGF (vascular endothelial growth factor). To standardise the mechanical conditions in the fracture gap, we used an intramedullary compression screw for stable fracture fixation.

RESULTS

Each mouse of the exercise group run a mean total distance of 23.5 km after 2 weeks and 104.3 km after 5 weeks. Histomorphometric analysis of the size and tissue composition of the callus could not reveal significant differences between mice undergoing exercise and controls. Accordingly, biomechanical testing showed a comparable torsional stiffness, peak rotation angle, and load at failure of the healing bones in the two groups. The expression of PCNA and VEGF did also not differ between mice of the exercise group and controls.

CONCLUSION

We conclude that increased exercise does not affect bone repair after stable fracture fixation.

Erythropoietin stimulates bone formation, cell proliferation, and angiogenesis in a femoral segmental defect model in mice

The glycoprotein erythropoietin (EPO) has been demonstrated to stimulate fracture healing. The aim of the present study was to investigate the effect of EPO treatment on bone repair in a femoral segmental defect model. Bone repair was analyzed in mice which were treated by EPO (500IE/kg/d intraperitoneally; n=38) and in mice which received the vehicle for control (n=40). Two and 10 weeks after creating a 1.8mm femoral segmental defect, bone repair was studied by micro-CT, histology, and Western blot analysis. At 10 weeks, micro-CT and histomorphometric analyses showed a significantly higher bridging rate of the bone defects in EPO-treated animals than in controls. This was associated by a significantly higher bone volume within the segmental defects of the EPO-treated animals. At 2 weeks, Western blot analyses revealed a significantly higher expression of vascular endothelial growth factor (VEGF) in EPO-treated animals compared to controls. Accordingly, the number of blood vessels was significantly increased in the EPO group at 2 weeks. At 10 weeks, we found a significantly higher expression of proliferating cell nuclear antigen (PCNA) in EPO-treated animals when compared to controls. Western blot analyses showed no significant differences between the groups in the expression of the endothelial and inducible nitric oxide synthases (eNOS and iNOS) and the angiopoietin receptor Tie-2. Immunohistochemistry confirmed the results of the Western blot analyses, demonstrating a significantly higher number of VEGF- and PCNA-positive cells in EPO-treated animals than in controls at 2 and 10 weeks, respectively. We conclude that EPO is capable of stimulating bone formation, cell proliferation and VEGF-mediated angiogenesis in a femoral segmental defect model.

Intravital microscopic studies of angiogenesis during bone defect healing in mice calvaria

PURPOSE

Due to the great availability of specific antibodies, gene-targeted animals and knockout strains, mouse models came into the focus of musculoskeletal research. Herein, we introduce a calvarian defect model in mice that allows the repetitive analysis of blood vessel formation during bone repair by intravital microscopy.

METHODS

The right parietal calvaria of 20 adult CD-1 mice were exposed by skin excision. Under continuous irrigation, a circular defect (Ø0.75 mm) was drilled into the calvarium without penetrating the inner cortical shell. A circular glass (Ø12 mm; thickness 0.15 mm) was fixed by two microscrews (M1; length 2mm) to cover the bone defect. Angiogenesis was analysed by intravital microscopy at days 0, 3, 6, 9, 12, 15, 18 and 21. In addition, bone repair was evaluated by histomorphometry at days 3, 6, 9 and 15. Immunohistochemical stainings for the angiogenic growth factor vascular endothelial growth factor (VEGF) and the cell proliferation marker proliferating cell nuclear antigen (PCNA) were performed to assess angiogenic and proliferative activity during healing of the calvarian defect.

RESULTS

Histomorphometry showed a typical pattern of intramembranous bone repair. Osseous bridging of the defect was observed at day 9. This was associated with the formation of a neo-periosteum, which covered the new woven bone and contained a dense network of newly formed blood vessels. At day 9, particularly cells of the neo-periosteum showed intense staining for VEGF, whilst PCNA-positive staining was found mainly in osteoblasts. At day 15, the major fraction of fibrous tissue was replaced by bone undergoing extensive remodelling. Intravital microscopy revealed an increase of vascular density between days 3 and 15. Blood vessel diameters showed an increase between days 3 and 9 and a subsequent decrease between days 9 and 21.

CONCLUSIONS

The present calvarian defect model provides a powerful tool to evaluate the process of angiogenesis during intramembranous bone repair in mice.

Transcranial doppler monitoring of intracranial pressure therapy with mannitol, sorbitol and glycerol in patients with acute stroke

INTRODUCTION

The noninvasive management of the conservative therapy for intracranial pressure (ICP) with hyperosmolar substances is a central problem in the treatment of brain edema. Using transcranial Doppler (TCD), a continuous monitoring of ICP is now possible, because the TCD pulsatility index (PI) intraindividually closely correlates with the level of ICP.

PATIENTS AND METHODS

We administered an ICP-lowering treatment 113 times in 10 patients with intracranial bleeding or ischemic stroke who also had signs of elevated ICP in the computer tomogram. The treatment was carried out over a period of 9 days, using 50 g each of intravenous sorbitol (n = 38) and mannitol (n = 32) or oral glycerol (n = 43).

RESULTS

PI was significantly lowered between 20.0 and 23.9% (p < 0.01) by all substances in the affected and unaffected sides. The differences between the three substances and the differences between the affected and unaffected sides were not significant. The duration of the therapeutic effect of glycerol (190 +/- 41 min) was significantly longer (p < 0.01) than that of sorbitol (150 +/- 28 min) or mannitol (130 +/- 20 min). The duration of the therapeutic effect was also significantly shorter (p < 0.01) in patients with a high PI (> 1.5). All three substances led to a significant increase (p < 0.01) in minimal (= diastolic) flow velocity (Vmin). The increase was highest for glycerol (56.3 +/-72.6%).

SUMMARY

The decrease in PI under therapy was caused by an increase in Vmin. This indicates that ICP therapy with hyperosmolar substances improves brain edema and does not suggest a therapy-induced vasoconstriction.