A synthetic tumor necrosis factor-alpha agonist peptide enhances human polymorphonuclear leukocyte-mediated killing of Plasmodium falciparum in vitro and suppresses Plasmodium chabaudi infection in mice.

A peptide corresponding to residues 70-80 of the TNF-alpha polypeptide was synthesized and shown to enhance human PMN-mediated killing of Plasmodium falciparum in vitro and reduced the Plasmodium chabaudi parasitemia in mice. Studies of the mechanism of action showed that the peptide, TNF(70-80), stimulated and primed PMN for an increased respiratory burst and release of granule constituents in response to a second agonist. The PMN-stimulatory activity of the peptide was inhibited by mAbs against the p55 and p75 TNF receptors and a TNF-neutralizing mAb. Analysis of PMN receptor expression showed that CR3 (CD18/CD11b) and Fc gamma RIII were upregulated by TNF(70-80), which was consistent with the peptide's ability to enhance parasite killing by PMN. The peptide, unlike TNF, did not increase the expression of adhesion molecules on endothelial cells and failed to promote binding of P. falciparum-infected erythrocytes to endothelial cells. TNF(70-80) also inhibited the TNF-induced increase in adhesion of P. falciparum-infected erythrocytes to endothelial cells. The results demonstrate that the host-protective effects of TNF can be retained while toxic effects are eliminated using a selected, characterized subunit of the cytokine.     

The impact of the CCD-angle on range of motion and cup positioning in total hip arthroplasty

BACKGROUND: Biomechanical analysis and clinical experience reveal that offset total hip stems increase soft tissue tension and reduce the risk for dislocation in total hip arthroplasty. Most of these stems have a smaller neck-shaft-angle to increase the offset. This study investigates if changing the neck-shaft-angle has an impact on how cup and stem should be positioned with regard to range of motion. METHODS: A mathematical model of a total hip arthroplasty was developed to analyze range of motion until impingement between cup and neck. Range of motion was determined for each combination of neck-shaft-angles and additional parameters like cup inclination, cup anteversion, stem antetorsion, head/neck ratio and design of the cup opening. RESULTS: A maximized range of motion is achieved for neck-shaft-angles between 125 degrees and 131 degrees . Reducing the neck-shaft-angle by one degree requires reducing the cup anteversion by about 2 degrees and increasing the cup inclination by 0.45 degrees . Stems with neck-shaft-angles more than 135 degrees are not recommended when the head/neck ratio is 2.3 or less. INTERPRETATION: Stems with a reduced neck-shaft-angle for an increased offset should be coupled with cups that are inclined slightly higher and less anteverted as compared to a standard stem. Precise recommendations for optimal component positioning can only be given for a specific prosthesis system regarding all parameters.     

Nonviral glial cell-derived neurotrophic factor gene transfer enhances survival of cultured dopaminergic neurons and improves their function after transplantation in a rat model of Parkinson's disease

Transplantation of dopaminergic fetal mesencephalic tissue into the striatum is currently being developed for treatment of patients with advanced Parkinson's disease. Ethical concerns regarding the use of human fetal tissue, and the limited availability as well as poor survival and differentiation of dopaminergic neurons after transplantation have reduced the extent and outcome of this approach so far. With the purpose of finding means to increase the yield of dopaminergic neurons in transplants, and to reduce the amount of fetal tissue needed for each transplanted patient, we transfected rat fetal ventral mesencephalic (VM) tissue grown as organotypic free-floating roller tube (FFRT) cultures with a vector encoding human glial cell-derived neurotrophic factor (hGDNF). For transfer of an episomal expression vector (pRep7-GDNF8) a nonviral, nonliposomal cationic transfection technique was applied and optimized. Recombinant hGDNF expression resulted in a higher number of TH-positive neurons in the cultures as measured 6 days after transfection. Ventral mesencephalic cultures expressing hGDNF were then grafted into the striatum of unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. Grafting of genetically modified VM cultures resulted in earlier functional recovery compared with grafting nontransfected cultures. We conclude that organotypic free-floating roller tube cultures can be successfully transfected to produce hGDNF with effects on TH-expressing neurons in vitro and functional effects after grafting in a rat Parkinson's disease model.     

Central venous catheter-associated bloodstream infection and colonisation of insertion site and catheter tip. What are the rates and risk factors in haematology patients?

Skin colonisation is an important source for central venous catheter (CVC) colonisation and infection. This study intended to identify risk factors for skin colonisation prior to CVC placement (baseline colonisation) and within 10 days after CVC insertion (subsequent colonisation), for CVC-tip colonisation and for bloodstream infection (BSI). Within a randomised clinical trial, data of 219 patients with haematological malignancies and inserted CVC (with a total of 5,501 CVC-days and 4,275 days at risk) in two university hospitals were analysed. Quantitative skin cultures were obtained from the insertion site before CVC placement and at regular intervals afterwards. CVC-tip cultures were taken on CVC removal and data collection was performed. Statistical analysis included linear and logistic regression models. Age was an independent risk factor for colonisation prior to CVC placement (baseline colonisation). Independent risk factors for subsequent colonisation were baseline colonisation and male gender. High level of subsequent skin colonisation at the insertion site was a predictor of CVC-tip colonisation, and a predictor of BSI. High level of skin colonisation predicts catheter tip colonisation and possibly subsequent infection. Sustained reduction of bacterial growth at the CVC insertion site is therefore indispensable. Male patients are at particular risk for skin colonisation and may be a target population for additional insertion-site care before and during catheterisation.     

Phenotypic characterization and functional analysis of human tumor immune infiltration after mechanical and enzymatic disaggregation

Multi-parametric flow cytometry analysis is a reliable method for phenotypic and functional characterization of tumor infiltrating immune cells (TIIC). The isolation of infiltrating leukocytes from solid tumors can be achieved through various methods which can be both enzymatic and mechanical; however, these methods may alter cell biology. The aim of this study was to compare the effects of three tissue disaggregation techniques on TIIC biology in breast, kidney and lung tumor specimens. We therefore compared two enzymatic treatments using either collagenase type IA alone or in combination with collagenase type IV and DNase I type II, and one mechanical system (Medimachine?). We evaluated the impact of treatments on cell viability, surface marker integrity and proliferative capacity. We show that cell viability was not significantly altered by treatments. However, enzymatic treatments decreased cell proliferation; specifically collagenases and DNase provoked a significant decrease in detection of surface markers such as CD4, CD8, CD45RA and CD14, indicating that results of phenotypic studies employing these techniques could be affected. In conclusion, mechanical tissue disaggregation by Medimachine? appears to be optimal to maintain phenotypic and functional TIIC features.