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IL-17 is a cytokine produced by a newly identified T-cell subpopulation (THl7/THIL-17). It is a central mediator in inflammatory processes that connects T-cell stimulation with neutrophil mobilization. The role of IL-17 in the immune dysfunction after polytrauma is still not clarified. In a retrospective study, the systemic concentration of IL-17 and IL-6 of 71 polytraumatized patients were analyzed daily by enzyme-linked immunosorbent assay. The patients' collective consist of 55 men and 16 women (43 +/- 16 years; injury severity score, 33 +/- 13). In only 6% of the patients, an increase in systemic IL-17 was detected. In most patients (94%), no systemic IL-17 was detectable or the IL-17 concentrations in plasma were in the range of the healthy donor group. To identify a possible role of systemic IL-17 in the posttraumatic phase, the patients were divided into two groups. Group A (47 men, 15 women) consists of patients with IL-17 concentrations in the range of normal healthy donors. Group B (8 men, 1 woman) consists of patients with elevated (>45 pg ml(-1) on at least 3 consecutive days) systemic IL-17 concentrations. Three patients in group B showed highly increased systemic IL-17 concentrations (median, >200 pg mL(-1)). These patients were male and showed all blunt chest and abdominal trauma with lung contusion and pneumohemothorax. However, there was no conformity in other injury patterns, injury severity score, age, outcome, intensive care period, or clinical complications. After a period of 4 years, we were able to obtain a new blood sample from one patient with high IL-17 level. The systemic IL-17 value of this former patient was now less than the detection limit. However, stimulation of peripheral blood mononuclear cells from thlise patient revealed elevated numbers of cells with the capacity to produce IL-17 as determined by enzyme-linked immuno spot assay and flow cytometry compared with peripheral blood mononuclear cells obtained from current polytrauma patients and healthy donors. In conclusion, IL-17 is not suitable as a pathophysiological or predictive marker after polytrauma. Whether highly increased systemic IL-17 concentrations detected in single patients are due to individually increased numbers of TH17 cells as we have demonstrated with one rerecruited patient has to be further analyzed.

Disks consisting of macroporous nickel-titanium alloy (NiTi, Nitinol, Actipore) are used as implants in clinical surgery, e.g. for fixation of spinal dysfunctions. The morphological properties were studied by scanning electron microscopy (SEM) and by synchrotron radiation-based microtomography (SRmuCT). The composition was studied by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and energy-dispersive X-ray spectroscopy (EDX). The mechanical properties were studied with temperature-dependent dynamical mechanical analysis (DMA). Studies on the biocompatibility were performed by co-incubation of porous NiTi samples with isolated peripheral blood leukocyte fractions (polymorphonuclear neutrophil granulocytes, PMN; peripheral blood mononuclear leukocytes, PBMC) in comparison with control cultures without NiTi samples. The cell adherence to the NiTi surface was analyzed by fluorescence microscopy and scanning electron microscopy. The activation of adherent leukocytes was analyzed by measurement of the released cytokines using enzyme-linked immunosorbent assay (ELISA). The cytokine response of PMN (analyzed by the release of IL-1ra and IL-8) was not significantly different between cell cultures with or without NiTi. There was a significant increase in the release of IL-1ra (p<0.001), IL-6 (p<0.05), and IL-8 (p<0.05) from PBMC in the presence of NiTi samples. In contrast, the release of TNF-alpha by PBMC was not significantly elevated in the presence of NiTi. IL-2 was released from PBMC only in the range of the lower detection limit in all cell cultures. The material, clearly macroporous with an interconnecting porosity, consists of NiTi (martensite; monoclinic, and austenite; cubic) with small impurities of NiTi2 and possibly NiC(x). The material is not superelastic upon manual compression and shows a good biocompatibility.

Nickel-titanium shape-memory alloys (NiTi-SMA) were coated with calcium phosphate by dipping in oversaturated calcium phosphate solution (CaP-coating). Polymorphonuclear neutrophil granulocytes (PMN) belong to the first cells which will adhere to implant materials. We analyzed the apoptosis of isolated human PMN after cell culture on non-coated and CaP-coated NiTi-SMA by light and scanning electron microscopy (cell morphology) and by flow cytometry (DNA-fragmentation). In contrast to PMN adherent to non-coated NiTi-SMA, the apoptosis of PMN adherent CaP-coated samples was inhibited. Cell culture media obtained from cultured leukocytes with CaP-coatings (conditioned media, CM) were able to transfer the apoptosis inhibiting activities to freshly isolated PMN. There was a significant (p<0.01) increase in GM-CSF, IL-8, IL-6, and TNF-alpha within CM obtained from coated versus non-coated NiTi-SMA as was determined by ELISA.

Nickel-titanium shape-memory alloys (NiTi-SMA) were coated with calcium phosphate by dipping in oversaturated calcium phosphate solution. The layer thickness (typically 5-20 micrometer) can be varied by choice of the immersion time. The porous nature of the layer of microcrystals makes it mechanically stable enough to withstand both the shape-memory transition upon cooling and heating and also strong bending of the material (superelastic effect). This layer may improve the biocompatibility of NiTi-SMA, particulary for osteosynthetic devices by creating a more physiological surface and by restricting a potential nickel release. The adherence of human leukocytes (peripheral blood mononuclear cells and polymorphonuclear neutrophil granulocytes) and platelets to the calcium phosphate layer was analyzed in vitro. In comparison to non-coated NiTi-SMA, leukocytes and platelets showed a significantly increased adhesion to the coated NiTi-SMA.

The biocompatibility of nickel-titanium alloys was investigated by single-culture experiments on functionally graded samples with a stepwise change in composition from pure nickel to pure titanium, including an Ni-Ti shape memory alloy for a 50:50 mixture. This approach permitted a considerable decrease of experimental resources by simultaneously studying a full variation of composition. The results indicate a good biocompatibility for a nickel content up to about 50%. The cells used in the biocompatibility studies comprised osteoblast-like osteosarcoma cells (SAOS-2, MG-63), primary human osteoblasts (HOB), and murine fibroblasts (3T3).

The biocompatibility of nickel-titanium alloys was investigated by single-culture experiments on functionally graded samples with a stepwise change in composition from nickel to titanium, including NiTi shape memory alloy of a 50:50 mixture. This approach permitted a considerable decrease of experimental resources by simultaneously studying a full variation of composition. The results indicate a good biocompatibility for a nickel content up to about 50%. The cells used in the biocompatibility studies comprised human osteoblast-like osteosarcoma cells (SAOS-2, MG-63), primary human osteoblasts (HOB), and murine fibroblasts (3T3).

In a low-sodium, choline+ (Ch+) medium, rat heart slices, that were labelled in vivo with [3H]norepinephrine, exhibited a delayed Ca2+-dependent release of radioactivity, these radioactive compounds consisted of both amines and deaminated metabolites. The Ca2+-dependent release of radioactivity was largely blocked by cocaine suggesting that the release may represent an outward transport of [3H]amines. Reserpine, which is known to inhibit binding of norepinephrine to synaptic vesicles, stimulated the release of deaminated metabolites and some amines from the slices. Cocaine increased the release of [3H]amines in monoamine oxidase inhibited, reserpinized slices in the control medium. When Ch+-Ca2+ and reserpine stimulation were combined, the effects of Ch+-Ca2+ predominated. These effects were blocked by cocaine, which then permitted the response to reserpine to become established. The conclusion derived from the above experiments is that norepinephrine coming from synaptic vesicles brought in close proximity to the plasma membrane by a Ca2+-dependent system can be transported outwardly to the extraneuronal space by a cocaine-sensitive mechanism.

Reports from this laboratory have suggested that the secretion of norepinephrine (NE) in slices of ventricle from the rat heart, incubated in a medium of choline and Ca2+ (Ch+-Ca2+) deprived of Na+, is mediated by the outward transport of NE (blocked by cocaine) from synaptic vesicles fused or attached to the axolemma. Lithium (and reserpine), block the Mg2+-ATP-stimulated uptake of NE by isolated synaptic vesicles (Slotkin, Seidler, Whitmore, Salvaggio, and Lau, 1978). Hence, a hypothesis to be tested was that lithium ions would increase secretion of NE stimulated by Ch+-Ca2+. By contrast, amines mobilized by lithium ions (or reserpine) in control nerves would be deaminated. Experiments showed that lithium-Krebs increased the excretion of [3H]deaminated metabolites of [3H]NE. A much smaller quantity of [3H]NE was released by a process that was independent of Ca2+ and weakly inhibited by cocaine. When combined with Ch+Ca2+, lithium ions, in concentrations that were known to block uptake in isolated vesicles, induced a Ca2+-dependent secretion of [3H]amines. A small quantity of [3H]deaminated metabolites was excreted. Both processes were strongly inhibited by both cocaine and desipramine. Both reserpine (Bogdanski, 1982) and lithium ions blocked the inhibitory effect of exogenous ATP (2 mM) on secretion induced by Ch+-Ca2+. This effect indicated a proximity of vesicles to the axolemma. The effects of lithium ions could be explained by the hypothesis if lithium prevented storage of [3H]NE in vesicles by blocking the Mg2+ + ATP-dependent amine pump in vesicle membranes.

Rat hearts were labelled with [3H]norepinephrine in vivo. Slices of ventricles were prepared, preincubated in Krebs-HCO3 medium (KRB), and then incubated in a Na+-deficient, choline+-Krebs HCO3 (Ch+-Ca2+). The choline+-Krebs HCO3 medium induced a delayed neurosecretion which could be inhibited by either one of the blockers of the uptake of NE, cocaine or desipramine, when included in both the Krebs and the Ch+-Ca2+. When either desipramine or cocaine was present in the Na+-rich preincubation medium only, the duration of action of desipramine was more prolonged than that of cocaine. When desipramine was first added to the Ch+-Ca2+ medium at various times after incubation, the inhibitory response became smaller as the duration of preliminary Na+-deprivation was increased. After incubation for 80 min neither desipramine nor cocaine inhibited secretion. Sodium (added to Ch+-Ca2+ medium or in a Krebs replacement medium) then slowed the rate of release stimulated by Ch+-Ca2+ and facilitated an inhibitory action for both inhibitors. The inhibition did not require the continued presence of Na+. Depolarizing concentrations of K+ in the Ch+-Ca2+ medium with Na+ and either one of the inhibitors, prevented the inhibition of neurosecretion. However, K+ which was added to the preincubation medium with either inhibitor did not prevent the prolonged inhibition of neurosecretion. By contrast with the secretory response to Ch+-Ca2+, the secretory response to K+ in Na+-enriched Ch+-Ca2+ medium was weakly inhibited by the inhibitors of transport.