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We report on an orbital and temperature dependent study of the onset of coherent quasiparticles in V

We studied the polaron conductivity in a field-effect transistor (FET) based on the doped oxide La 0.7 Sr 0.3 MnO 3 - δ , where the electric field penetration depth is enhanced due to suppression of metallic conduction by large oxygen deficiency δ , by mid-infrared microspectroscopy (wavelengths from 1.4 to 12 μ m ) on a 3 μ m wide active channel. Synchrotron radiation was used to obtain the mid-infrared response at the diffraction limit. We found that bound polarons, although clearly detected, play a minor role in the electric field-induced dc conductivity modulation, which may be then attributed to the accumulation/depletion of free carriers.

LPSs getting access to the circulation of mammalian organisms cause typical systemic inflammatory reactions with symptoms characteristic for acute sepsis. One possibility to attenuate LPS effects is to expose a host to a challenge with low LPS doses, which results in the establishment of "endotoxin tolerance" (ET). Because the microcirculation is of particular importance in LPS action, it seemed of interest to analyze leukocyte-endothelial interactions in the mesentery and liver once endotoxin tolerance has been established and are challenged with LPS. The mesenteric and hepatic microcirculation was investigated by intravital microscopy. After induction of ET LPS, shock was induced by i.v. injection of LPS, and microcirculation of the mesentery and liver was examined. Endotoxin tolerance resulted in reduced ex vivo TNF-alpha synthesis of whole blood. In vivo LPS caused no increase of body temperature. In sinusoids, LPS challenge increased adherence of leukocytes in naive rats, which was almost completely prevented by ET induction. In contrast, in postsinusoidal venules, leukocyte adherence was more intense after ET induction and subsequent to LPS application. Similarly, in postcapillary mesenteric venules, increased adherence of leukocytes after LPS challenge in the ET group was observed. After LPS injection, the endothelial barrier was more disturbed in the nontolerant group when compared with the ET group. Soluble L-selectin and intercellular adhesion molecule were elevated in both ET and untreated rats. Endotoxin tolerance influences leukocyte-endothelial interaction differentially depending on organ and vessel area.

[corrected] Severe injury leads to a severe deterioration of the patients' immune response. The changes of the immune response after severe injury include a broad range of immune functions and may result in a status of immunosuppression, which could favor infectious complications. Therefore, immunostimulating therapies have been introduced in the therapy for severely injured patients in clinical and experimental settings.The article summarizes actual immunomodulating approaches in the treatment of trauma patients and therapeutic strategies avoiding additional immune deteriorations.Examples for an immunostimulating approach in trauma patients are interferon gamma and the granulocyte macrophage-colony-stimulating factor (GM-CSF), which are summarized in this review in detail. However, the effect of such an interference in the patients' immune response with all its different cellular targets is not yet clearly understood, and most studies focus on the reaction of circulating monocytes. In addition, further immunomodulating strategies, including nutritional support, are addressed. However, clinically established therapeutic immunomodulating strategies in trauma care so far do not exist. The impact of the accidental and also an additional surgical trauma on the immune response has been clearly demonstrated. Therefore, the idea of a "damage control orthopedic surgery" (DCOS) is not only necessary to prevent further deterioration of the homeostasis of, e.g., the coagulating system, but is also desirable in terms of minimizing the burden on the immune system. In addition, also the timing of secondary surgical treatment in trauma patient care should include an evaluation of the immune response, although the most reliable markers still need to be identified.Immunomodulating therapies in trauma patients exist on an experimental level with inconsistent results. The general management of trauma patients includes strategies that have been developed also on the basis of immunological considerations.

Severe injury may lead to immunosuppression, multiple organ failure, and death. The aim of the study was to investigate the direct impact of soft tissue destruction on the development of trauma-associated immunomodulation. Hip surgery was considered to represent an isolated soft tissue trauma that allowed for the examination of changes taking place locally at the site of trauma or systemically with regard to monocyte function and leukocyte redistribution. Peripheral blood and wound fluid collected from the drains of 21 patients after hip surgery were analyzed to determine the cellular composition and/or the responsiveness of mononuclear cells (MNCs) to lipopolysaccharide (LPS). Different factors present in the wound fluids were tested for their capacity to modulate the MNC of healthy individuals with regard to cytokine and chemokine secretion. We found that various factors, including heat-shock protein (HSP) 60 and HSP70, were locally released at the site of soft tissue trauma and could be detected in wound fluids. The wound fluid-derived MNC (but not the peripheral blood-derived MNC) showed an impaired capacity to release TNF-alpha after LPS stimulation. Cell-free wound fluid suppressed in healthy individuals the LPS-induced TNF-alpha secretion by MNC. After surgery, granulocytosis was found in peripheral blood and in wound fluids, but monocytopenia was restricted to wound fluids. In parallel, wound fluids induced in healthy individuals the release by MNC of distinct chemokines specific for granulocytes and monocytes. These wound fluid-mediated effects of TNF-alpha suppression and chemokine induction could be mimicked by recombinant human HSP70 and, in part, by HSP60. Thus, tissue-derived factors, such as HSP70 released after injury, suppress monocyte function and, therefore, might favor the development of immunosuppression after severe injury.

Severe trauma leads to an increased vulnerability to bacterial sepsis. In the present study, we compared the immunostimulating potential of granulocyte-colony stimulating-factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma).Prospective clinical experimental study.University hospital intensive care unit and research facility.6 patients with an Injury Severity Score (ISS) of more than 25 points.Heparinized blood samples of severely injured patients and 12 healthy volunteers were incubated in vitro with 10 ng/ml GM-CSF, 10 ng/ml G-CSF or 10 ng/ml IFN-gamma for 6 h.Flow cytometry: HLA-DR expression on monocytes, B- and T-lymphocytes. ELISA: LPS-induced TNFalpha and IL-10 production.In all patients reduced cytokine production and HLA-DR expression on monocytes was established. After administration of GM-CSF and IFN-gamma it in vitro, the level of HLA-DR expression on monocytes and the it ex vivo TNFalpha-synthesis increased while only GM-CSF increased significantly IL-10-liberation after LPS-stimulation. However, only IFN-gamma had the capacity to enhance HLA-DR on B- and T-lymphocytes. G-CSF it in vitro had no significant effect on the measured parameter.These data suggest that GM-CSF and IFN-gamma may serve to support immune functions in severely injured patients.

Haemorrhagic shock leads to decreased proinflammatory cytokine response which is associated with an increased susceptibility to bacterial infections. In the present study, the effect of GM-CSF on lipopolysaccharide (LPS)-induced TNF-alpha release and MAPkinase activation was analysed on the background of a possible immunostimulating activity of this substance. Male BALB/c mice were bled to a mean arterial blood pressure of 50 mmHg for 45 min followed by resuscitation. Peritoneal macrophages were isolated 20 h after haemorrhage and incubated with 10 ng/ml GM-CSF for 6h before LPS stimulation. TNF-alpha synthesis was studied in the culture supernatants using ELISA. Phosphorylation of ERK, p38MAPK and IkappaBalpha was detected by Western blotting. LPS-induced TNF-alpha production of peritoneal macrophages was significantly decreased 20 h after haemorrhage in comparison to the corresponding cells of sham-operated mice. In parallel the phosphorylation of IkappaBalpha was less in LPS-stimulated peritoneal macrophages from haemorrhagic mice. LPS-induced phosphorylation of ERK1/2 was also decreased in peritoneal macrophages isolated after haemorrhagic shock. In contrast, p38MAPK was phosphorylated more intensely after LPS-stimulation in macrophages collected from shocked mice. GM-CSF incubation elevated LPS-induced TNF-alpha response of macrophages from both sham-operated and shocked mice which was accompanied by an elevated IkappaB and ERK phosphorylation. In general, GM-CSF treatment in vitro enhanced peritoneal macrophages LPS-response both in terms of TNF-alpha synthesis and IkappaB and MAPK signalling, but the levels always stayed lower than those of GM-CSF-treated cells from sham-operated animals. In conclusion, GM-CSF preincubation could partly reactivate the depressed functions of peritoneal macrophages and may therefore exert immunostimulating properties after shock or trauma.

The ability to augment monocyte functions such as TNF-alpha-producing capacities confers a high immunostimulating potential to GM-CSF. In the present investigation, the mechanism of the GMCSF-mediated enhancement of monocyte cytokine production was analysed with regard to the involvement of intracellular signalling pathways. GM-CSF primes human monocytes dose- and time-dependently for enhanced LPS-stimulated TNF-alpha synthesis. Pre-incubation with 10 ng/ml GM-CSF for 6 h before LPS stimulation (10 ng/ml) caused a 3.4 +/- 1.9-fold increase in TNF-alpha release compared to unprimed controls. This was associated with increased phosphorylation of IkappaBalpha and elevated nuclear levels of the NF-kappaB components p50 and p65 and NF-kappaB binding to DNA. LPS-induced AP-1 binding to DNA was also enhanced in GM-CSF-pre-incubated cells. GMCSF treatment also caused a slight increase in TLR4 expression on monocytes while CD14 expression remained unchanged. GM-CSF-priming was unaffected by inhibitors of p38 MAPK (SB203580) and lipoxygenase (NDGA). In contrast, the broad-spectrum tyrosine kinase inhibitor genistein and the MEK-1 inhibitor (PD98059) abrogated GM-CSF priming of TNF-alpha release and activation of both NF-kappaB and AP-1. It is concluded that a tyrosine kinase of the GM-CSF-triggered ERK1/2 pathway augments the LPS-induced NF-kappaB and AP-1 activation.

Objective: Clinical complications arising from extracorporeal circulation (ECC) have been linked to disturbances in the microcirculation. Hyperoxia, a mainstay of supportive treatment, is clinically used for a variety of pathological states. In previous in vivo animal experiments we found increased leukocyte/endothelial (L/E) cell interaction following ECC due to oxygen derived free radicals. This study was carried out to investigate the link between arterial pO 2 during ECC and the potential damage to the microcirculation, supposedly caused by oxygen derived radicals. Methods: Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in Syrian golden hamsters. ECC was introduced via a micro-rollerpump (0.7 ml/min) and a 60 cm silicon tube (1 mm inner diameter) shunted between the carotid artery and the jugular vein after application of 300 IE Heparin/kg/bw. Experiments were performed in chronically instrumented, awake animals (age: 10-14 weeks, weight: 65-75 g). Control inspired room air, experimental group 1 inspired 100% oxygen, group 2 received 100% oxygen and 2000 IE of Heparin i.v. (n = 7/group), that releases endothelial bound superoxide dismutase, a natural scavenger of oxygen derived free radicals in the hamster. Results: Normobaric inhalation of 100% oxygen increased arterial pO 2 from 64 ± 8.1 mmHg to 512 ± 124 mmHg (P < 0.05 vs. baseline). ECC under 100% oxygen reduced functional capillary density (FCD) to 70% of baseline values 8 h after ECC (P < 0.05). Adherent leukocytes in postcapillary venules and arterioles increased significantly (P < 0.05). 2000 IE Heparin prevented the reduction in FCD and decreased the number of adherent leukocytes. Conclusions: Reduction in FCD, increased leukocyte adherence to the microvascular endothelium of postcapillary venules and arterioles under hyperoxia compared to ECC under room air conditions, demonstrates harmful effects of oxygen during ECC in vivo. A high dose of Heparin enhances functional capillary density, thus attenuating the microvascular dysfunction/damage in the period after ECC.

To study whether a treatment with the hematopoietic growth factor GM-CSF restores the attenuated ex-vivo cytokine-producing capacity of macrophages after sublethal hemorrhagic shock.Male Sprague-Dawley rats.20 microg/animal of recombinant murine GM-CSF after shock via arterial line.Hemorrhagic shock was established by pressure-controlled bleeding to a mean arterial pressure of 50 mm Hg for 35-40 min and consecutive resuscitation. 24 h after hemorrhage, lipopolysaccharide (LPS)-induced cytokine production of isolated macrophages derived from different compartments was measured.A significant reduction of LPS-induced TNFalpha production was found in whole blood cultures (1.0 +/- 0.7 ng/ml after sham vs. 0.23 +/- 0.08 ng/ml after shock operation), macrophages derived from spleen (0.88 +/- 0.23 ng/ml after sham vs. 0.03 +/- 0.1 ng/ml after shock operation), peritoneum (2.2 +/- 0.7 ng/ml after sham vs. 0.29 +/- 0.4 ng/ml after shock operation) and bronchoalveolar fluid (0.65 +/- 0.13 ng/ml after sham vs. 0.003 +/- 0.027 ng/ml after shock operation, mean +/- S.D.). In cells from animals treated with GM-CSF a significantly enhanced LPS-induced TNFalpha production in splenic, alveolar and peritoneal macrophages was found after shock compared to the cells derived from untreated animals (peritoneum: 289 +/- 366 ng/ml TNFalpha after shock vs. 2066 +/- 94 ng/ml TNFalpha after shock and GM-CSF; lung: 9 +/- 12 ng/ml TNFalpha after shock vs. 64 +/- 17 ng/ml TNFalpha after shock and GM-CSF; spleen: 58 +/- 96 ng/ml TNFalpha after shock vs. 548 +/- 47 ng/ml TNFalpha after shock and GM-CSF). Blood cultures collected from rats after hemorrhagic shock did not show a significant increase of TNFalpha-production after GM-CSF treatment.Hemorrhagic shock caused a depression of the TNFalphaa response to LPS which was partly counteracted by treatment with GM-CSF. Therefore, GM-CSF represents a promising approach to normalise trauma- and shock-induced immune dysfunction.

Primary events such as severe injury and elective surgery cause a deterioration of the immune response measurable by reduction of expression of HLA-DR on monocytes or ex vivo LPS-induced TNFalpha production. The further influence of secondary surgery after severe injury on the immune response remains unresolved.Prospective observation study.Surgical intensive care unit of an university hospital.Sixteen severely injured patients with an ISS25 points.On day 1 after trauma and immediately before secondary surgery, mean fluorescence intensity (MFI) of HLA-DR expression on monocytes and TNFalpha ex vivo synthesis was significantly reduced compared to healthy donors. Overall, surgical intervention during the second week after trauma caused no further reduction of HLA-DR expression on monocytes and of the ex vivo TNFalpha-synthesis. However, major surgery such as intramedullary nailing or pelvic osteosynthesis caused reduction of the HLA-DR expression and TNFalpha-synthesis, whereas, minor surgical interventions such as osteosynthesis on peripheral joints exhibited no significant effects on the immune response. Surgical intervention performed to clear septic foci normalised immune response by elevating HLA-DR expression on monocytes and ex vivo TNFalpha synthesis. Severe injury caused elevated serum IL-10 levels, whereas secondary surgery did not induce a further increase in serum IL-10 levels.This study shows that initial trauma as well as major secondary surgery causes a suppression of immune functions, whereas minor secondary surgery does not cause significant immune disturbance.

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

Objective It is known that endotoxin tolerance prevents lethality after ischemia/reperfusion injuries (e.g., myocardial infarction) in laboratory animals. We used a rat model of partial hepatic ischemia/reperfusion to investigate whether endotoxin tolerance prevents associated lethality and disorders of liver function. Design Prospective animal study. Setting University research facility. Subjects Male Sprague-Dawley rats. Interventions Hepatic ischemia was initiated by atraumatic clipping across the portal venous and hepatic arterial blood supply to the left lateral lobe for 90 mins. The common bile duct was canalized, and in a second set of experiments the bile duct of the left lateral lobe was canalized selectively. Bile flow, bile acids, and transaminases were determined during ischemia and 300 mins of reperfusion in endotoxin-tolerant and -nontolerant rats. Measurements and main results Endotoxin-nontolerant animals showed a 50% lethality after hepatic ischemia/reperfusion injuries. All endotoxin-tolerant rats survived and did not react with any change in bile flow, showing a constant flow. The amount of bile acids in the common bile duct was reduced during ischemia and regained the concentrations of sham-operated animals 60 mins after reperfusion. From 180 mins after reperfusion, the difference between endotoxin-tolerant and -nontolerant animals was statistically significant. When bile acid concentration was determined in the ischemic left lateral lobe, ischemia/reperfusion was found to significantly decrease in endotoxin-nontolerant rats 60 mins after reperfusion. In contrast, endotoxin-tolerant rats produced normal amounts of bile acids 60 mins after reperfusion. At 120 mins after reperfusion, the amount of bile acids in the formerly ischemic left lateral lobe was more than normal. Conclusions In this model of partial hepatic ischemia/reperfusion, endotoxin tolerance prevents ischemia/reperfusion injury-associated lethality and local disorders of liver function. This phenomenon induced by endotoxin tolerance may be useful in liver surgery to prevent ischemia/reperfusion injury.

The ubiquitin-proteasome pathway is regarded as playing a crucial role in protein breakdown in inflammation and sepsis as well as in the regulation of inflammatory cell responses. In this pathway, ubiquitylation of target proteins is believed to act as a recognition signal for degradation by the 26S proteasome. As yet neither the ubiquitylation rate of cytosolic proteins, as a result of the total ubiquitin-protein ligase (tUbPL) activity, nor the specific ubiquitylation of calmodulin (ubiquitin-calmodulin ligase, uCaM-synthetase) has been determined in human mononuclear cells. Therefore, we studied cytosolic protein ubiquitylation in normal and in endotoxin (LPS)-stimulated human peripheral blood mononuclear cells (PBMNCs). PBMNCs from healthy volunteers were incubated with 0 or 100 ng/ml LPS for 18 h. Cytosolic extracts were obtained by hypotonic lysis and ultracentrifugation. TUbPL was measured as [125I]-[CT]-ubiquitin incorporation into the sum of cytosolic proteins. UCaM-synthetase activity was quantified with the fluphenazine (FP)-Sepharose affinity adsorption test. Endotoxin stimulation appears to inhibit tUbPL 3.7 ± 2.7-fold to 48 ± 43 fkat/mg (n = 6). UCaM-synthetase in cultures (n = 5) without endotoxin was determined to be 91 ± 32 fkat/mg +Ca2+ and 29 ± 23 fkat/mg —Ca2+. With endotoxin uCaM-synthetase was 138 ± 73 fkat/mg +Ca2+ and 14 ± 22 fkat/mg —Ca 2+. Ca2+-specificity (ratio ± Ca2+) of uCaM-synthetase increases from 3.1 without LPS to 10 after LPS stimulation, which was caused by a 2-fold decrease in minus Ca2+ activity and a 1.5-fold increase in plus Ca2+ activity. The data indicate specific regulatory effects of endotoxin on the cytosolic ubiquitylation systems in human PBMNCs.

Accidental as well as surgical trauma has been reported to cause reduced endotoxin responsiveness of blood in terms of cytokine production. In this study, the effect of interferon-gamma (IFN-gamma) on tumour necrosis factor-alpha (TNF-alpha)-producing capacity of whole blood after severe trauma and cardiac surgery was investigated. Blood samples of severely injured patients were collected at the first day after trauma and of cardiac surgery patients before, 4 h and 2 days after cardiopulmonary bypass (CPB). The blood samples were incubated with INF-gamma (0-100 U/ml) for 20 h and subsequently lipopolysaccharide (LPS)-induced TNF-alpha production was determined. Compared to healthy donors, LPS-induced TNF-alpha production was significantly reduced in blood cultures of trauma patients on day 1 after trauma and 4 h after CPB. Pre-incubation with IFN-gamma in vitro increased endotoxin-induced TNF-alpha production in volunteers' and all patients' blood specimens in a dose-dependent manner. IFN-gamma prompted an elevation of cytokine synthesis in CPB patients' blood which equalled that of volunteers, whereas it caused a lower rise in TNF-alpha production in blood of multiply injured patients, reaching levels of untreated donors only after incubation with 100 U/ml IFN-gamma. These experiments show that hyporesponsiveness of whole blood induced by trauma or cardiac surgery with CPB is not irreversible, but can be counteracted by the immunostimulant IFN-gamma. IFN-gamma, therefore, could be applied clinically in trauma patients or after cardiac surgery to prevent or to resolve infection complications.

In einer Ubersichtsarbeit von Abraham & Marshall (1999) wurde dargelegt, dass samtliche, an uber 15.000 Patienten durchgefuhrten Studien mit dem Ziel der Beeinflussung der dysregulierten, inflammatorischen Reaktion bei Sepsis und Multiorganversagen enttauschende Ergebnisse aufwiesen. Ursache hierfur liegt vorrangig in dem theoretischen Konzept einer isolierten,uberschiesenden Bildung endogener proinflammatorischer Mediatoren ( z.B. TNF, Interleukine, PAF), welche durch Autodestruktion zur Entwicklung eines septischen Multiorganversagens fuhren.Untersuchungen der letzten Jahre zeigen jedoch, dass eine inflammatorische Reaktion nicht mit einer isolierten Ausschuttung proinflammatorischer Mediatoren einhergeht, sondern gleichzeitig eine erhebliche antiinflammatorische Reaktion nachweisbar ist, die proinflammatorische Reaktion eine essentielle Komponente einer adaquaten Wirtsreaktion darstellt und aufgrund der hohen Redundanz des Zytokinnetzwerkes der therapeutische Ansatz einer Neutralisation eines einzelnen Mediators nicht mehr gerechtfertigt ist. Zukunftige mediatormodulatorische Therapieansatze setzten neben einer Charakterisierung moglicher individueller inflammatorischer Reaktionsformen und der Identifizierung klinisch relevanter immunologischer Parameter ein engmaschiges immunologisches Monitoring voraus, wodurch eine individuell adaptierte Mediatormodulation ermoglicht wird.

The aim of the present study was to investigate a systemic induction of bone formation in rats by immunosuppression with FK506 (1 mg/kg body weight intraperitoneally [ip]) in a model of osteoinduction of isogeneic and xenogeneic demineralized bone matrix (DBM) for a period of 28 days. In particular, alterations of in vitro cytokine synthesis and changes of lymphocyte subsets were studied. DBM was implanted intramuscularly in the abdominal wall of Lewis rats (seven per group). Blood was sampled on days -7, 0, 7, and 28 for determination of in vitro tumor necrosis factor a (TNF-alpha) synthesis and lymphocyte subsets by flow cytometry (CD3+, CD4+, CD8+, CD45+, ED9+, and Ia+ antibodies). Ossicles of de novo formed bone and the tibias were removed on day 28 after double tetracycline labeling for histomorphometric analysis. Immunosuppression with FK506 significantly decreased lipopolysaccharide (LPS)-stimulated in vitro cytokine synthesis after 7 days and 28 days (p0.05). Compared with control animals FK506 treatment significantly increased the volume of induced bone in isogeneic (2.1 +/- 0.3 mm3 vs. 10.8 +/- 0.9 mm3) and xenogeneic (O mm3 vs. 4.7 +/- 0.8 mm3) DBM. Bone histomorphometry of the tibias revealed that immunosuppression increased both bone formation and bone resorption, accompanied by a significant reduction in the relative trabecular area (Tb.Ar). FK506 caused a decrease in the counts of CD8+ T cells probably because of destruction or dislocation of these cells. This suggests that the amount of CD8+ cells and the degree of T cell activation in terms of mean fluorescence intensity (MFI) may be associated with bone metabolism. In support of this, statistical analysis revealed a significant positive correlation between parameters of bone formation as well as bone resorption and the CD4+/CD8+ ratio. There was a significant negative correlation between parameters of remodeling of the metaphysis of the tibia and induced bone volume (BV), respectively, and MFI values of CD3+/Ia+ cells. These findings suggest an important role of T lymphocytes in bone formation and bone resorption in vivo. FK506 caused a marked increase of bone formation in DBM. However, the conclusion that immunosuppression increases fracture healing warrants further investigation.

Liver surgery and liver transplantation as well as circulatory shock are often associated with hepatic ischemia/reperfusion (I/R) injury. Recent evidence suggests that TNF-alpha plays a central role in I/R injury and, therefore, down-regulation of TNF-alpha seems to be a promising way to protect against the deleterious consequences of I/R. Endotoxin tolerance represents a state of unresponsiveness to endotoxin and is associated with diminished TNF-alpha production. Thus, the effect of endotoxin tolerance on hepatic I/R injury of the liver was investigated in a rat model. I/R injury was induced by temporary ischemia of the left lateral liver lobe for 90 min followed by a 3 h observation period of reperfusion. I/R injury resulted in functional hepatic disorder characterized by a decrease both in bile flow and bile acid concentration and 50% mortality. This was prevented by induction of endotoxin tolerance. Hepatic TNF-alpha mRNA expression after I/R of the liver was determined by RT-PCR. In untreated rats, TNF-alpha mRNA was induced in the liver 60 min after reperfusion and further increased until 3 h after reperfusion. In contrast, in endotoxin-tolerant rats, no increases in TNF-alpha mRNA expression were detected. This suggests that induction of endotoxin tolerance protects against hepatic I/R injury possibly via down-regulation of intra-organ TNF-alpha expression.

In experimental trauma-hemorrhage and sepsis, a sexual dimorphism of cell-mediated immune functions has been described, which has been related to higher susceptibility to and mortality from sepsis in males. Therefore, in the present study, sex differences with regard to cytokine release of endotoxin stimulated whole blood and its relation to the development of severe posttraumatic sepsis were investigated in blunt trauma patients with multiple injuries.Eighty-four patients (25 female; 59 male) sustaining blunt injuries with an Injury Severity Score16 were enrolled in the study. Whole blood and serum were obtained during a 14-day period of hospitalization. The capacity of peripheral blood mononuclear cells to produce cytokines (tumor necrosis factor-alpha, interleukin [IL]-6, IL-8) was tested by using a whole blood assay. Serum samples were assayed for anti-inflammatory cytokines (IL-4, IL-10, and transforming growth factor beta1) and sex hormones (testosterone, estradiol, progesterone). Patients were monitored daily for sepsis criteria according to the ACCP/ SCCM consensus conference 1992.Within the entire patient population, sex differences in posttraumatic cytokine release were not detectable. Male trauma patients developing severe sepsis (n = 16) presented with a significantly increased cytokine producing capacity in the early posttraumatic period (or = 24 hours after admission to the emergency room) when compared with males with an uncomplicated recovery. In females, differences between the subgroups of patients with (n = 7) and without development of severe sepsis were not detectable. There were no differences in systemic levels of anti-inflammatory cytokines within the early posttraumatic period between the subgroups of male and female patients with and without development of severe sepsis. In females, differences in sex hormone levels were not detectable, whereas in males, development of severe sepsis later was found to coincide with significantly decreased testosterone and increased estradiol serum levels.The present study demonstrates a sex-specific regulation of leukocyte function in patients with multiple injuries within the early posttraumatic period. In male patients with multiple injuries, increased cytokine-producing capacities may correspond to enhanced inflammatory responses, which increase susceptibility to sepsis, whereas in female patients, other regulatory mechanisms may be involved.

In experimental models, the synthesis of heat shock protein 70 (HSP 70) has been recognized as an intracellular response to ischemia and reperfusion, insults inherent to transplantation. In this study, the HSP response in early stages of human liver transplantation was investigated. HSP 70 mRNA expression was detected by means of reverse transcriptase (RT)-PCR in liver biopsies (n = 28) and in cells obtained from the organ perfusate (n = 14) following cold preservation. The expression of HSP 70 differed substantially between individuals. Retrospective analysis revealed a close correlation of the amount of HSP 70 mRNA in perfusate cells and biopsies with the onset of organ dysfunction due to early graft rejection. Patients with early graft rejection had a significantly lower amount of HSP 70 mRNA than patients without rejection. These results suggest a protective role of HSP 70 expression. Low levels of HSP 70 may, therefore, represent a prognostic marker for early graft rejection.

It has been shown that induction of endotoxin tolerance results in a decreased potential to produce pro-inflammatory cytokines such as TNF or IL-1. The present study was carried out to examine the capacity of peripheral blood mononuclear cells (PBMC) from endotoxin tolerant humans to synthesize the anti-inflammatory cytokines IL-10 and TGFβ in response to endotoxin. Four individuals were rendered endotoxin tolerant by daily i.v. injections of endotoxin. PBMC were isolated before tolerance induction and on day 4 after the last endotoxin treatment. The cells were stimulated with endotoxin ex vivo and cytokines in culture supernatants were determined. PBMC isolated on day 4 of all of the volunteers showed decreased TNFα, IL-6 and IL-10 synthesis upon endotoxin treatment in vitro compared to pretolerant cells, while no differences occurred with regard to the amount of TGFβ formed by PBMC before and after tolerance induction. Furthermore, no changes were found in the expression of HLA-DR on PBMC after tolerance induction.

In pancreatic lesions of non-obese diabetic (NOD) mice the expression of inducible nitric oxide synthase (iNOS) and of the cytokines interferon-gamma and interleukin-4 were studied. Strong iNOS expression as determined at the level of transcription, translation and of enzyme activity was associated with destructive insulitis as seen 8-10 days after cyclophosphamide treatment of 70- to 80-day-old female NOD mice. Immunohistochemistry showed iNOS associated with infiltrating macrophages but not in endocrine cells. The enhancement of iNOS after cyclophosphamide correlated with an increase of T-helper type 1 (Th1) associated interferon-gamma expression while T-helper type 2 (Th2) associated interleukin-4 was the dominant cytokine prior to cyclophosphamide and after diabetes onset. We conclude that insulitis in young NOD mice is carried by Th2 cells while cyclophosphamide enhanced insulitis is determined by Th1 cells. Macrophages show two different functional states in insulitis; strong iNOS expression in macrophages is associated with destructive insulitis.

Coulomb-mediated interactions between intersubband excitations of electrons in GaAs/AlGaAs double quantum wells and longitudinal optical phonons are studied by two-dimensional spectroscopy in the terahertz frequency range. The multitude of diagonal and off-diagonal peaks in the 2D spectrum gives evidence of strong polaronic signatures in the nonlinear response. A quantitative theoretical analysis reveals a dipole coupling of electrons to the polar lattice that is much stronger than in bulk GaAs, due to a dynamic localization of the electron wave function by scattering processes.

A mutant cell line (J7.DEF.3) derived from murine macrophage-like J774.1 cells, was isolated on the basis of defective specific 125I-labeled LPS-binding in the presence of serum. Although J7.DEF.3 cells still respond to LPS in inducing TNF-alpha release and nitric oxide (NO) formation, these cells nevertheless showed significantly decreased responsiveness to LPS relative to the J774.1 parent. Under serum-free conditions, no differences between J774.1 and J7.DEF.3 cells in response to LPS were observed. The time kinetics of responsiveness to LPS also showed a delay in the onset of TNF-alpha release and NO formation in the mutant cells relative to parent cells. Importantly, this decrease in responsiveness to LPS relative to parental cells was dependent on the length of the polysaccharide portion of LPS. The defect in the mutant cells has been shown to be specific for LPS, in that these cells respond to heat-killed Listeria monocytogenes and to zymosan to a similar extent as do the parental cells. Collectively these results suggest that the defect in the J7.DEF.3 mutant cells may be related to a cellular LPS-binding molecule that, in turn, may depend upon an LPS-binding serum component.

We have previously shown that the synthetic tetraacyl precursor Ia (compound 406, LA-14-PP, or lipid IVa) was not able to induce the production of tumor necrosis factor, interleukin-1, and interleukin-6 in human monocytes but strongly antagonized lipopolysaccharide (LPS)-induced formation of these monokines. This inhibition was detectable at the level of mRNA production. To achieve a better understanding of molecular basis of this inhibition, we investigated whether lipid A precursor Ia (LA-14-PP), Escherichia coli-type lipid A (LA-15-PP), Chromobacterium violaceum-type lipid A (LA-22-PP), and synthetic lipid A partial structures and analogs (LA-23-PP, LA-24-PP, and PE-4) were able to influence the binding of 125I-LPS to human monocytes and compared this inhibitory activity with the agonistic and antagonistic action in the induction of monokines in human monocytes. 125I-LPS (20 ng per well) was added to human monocytes in the presence or absence of unlabeled rough Re mutant-derived LPS (Re-LPS) or lipid A compounds, and specific LPS binding was determined after 7 h. This binding was found to be dependent on CD14 as shown by the use of an anti-CD14 monoclonal antibody. Compound LA-14-PP was found to inhibit the binding of 125I-LPS to the cells in a similar dose-response to that of unlabeled LPS. This shows that the inhibitory capacity on LPS binding does not correlate with the monokine-inducing capacity because Re-LPS is active in inducing tumor necrosis factor, interleukin-1, and interleukin-6, while LA-14-PP is not. The strong capacity of LA-14-PP to inhibit 125I-LPS binding, however, correlates with the strong inhibitory capacity of this compound on LPS-induced monokine production. Compounds LA-15-PP, LA-23-PP, and LA-24-PP were active in the inhibition of 125I-LPS binding but were 5- to 10-fold weaker than Re-LPS and LA-14-PP. Of all lipid A structures tested, compound LA-22-PP expressed the weakest inhibitory capacity on LPS binding. These compounds showed again that the activity of binding inhibition does not correlate with the monokine-inducing capacity. We assume that the inhibitory effects of lipid A partial structures on LPS-induced monokine production have their origin in a competitive inhibition between LPS and the lipid A partial structures for the same binding site on the cell membrane.

Mycoplasma fermentans-derived high-molecular-weight material (MDHM) was originally discovered because of its capacity to generate, through the induction of monokine synthesis, cytolytic T lymphocytes in concanavalin A-stimulated thymocyte cultures. This study shows that MDHM-activated macrophages not only released interleukin-6 (IL-6) but also exhibited increased synthesis of cell-associated IL-1 as well as liberation of tumor necrosis factor and prostaglandin. We determined 6-keto prostaglandin F1 alpha since it is the stable metabolite of the bioactive prostacyclin. MDHM appeared to be as potent as lipopolysaccharide in inducing the synthesis of these mediators. Priming with gamma interferon further increased MDHM-mediated IL-6 release. Since monokines can be pyrogenic, we tested the effects of an intravenous injection of MDHM on rectal temperatures and leukocyte counts in rabbits. At 1 h after a bolus injection of MDHM, leukocyte counts dropped to about 35% of the initial values, reflecting a decrease in both lymphocytes and granulocytes. At 4 to 6 h after injection, granulocyte counts began to increase again, whereas lymphocyte counts remained low. No leukocytosis was noted during this time. The lack of leukocytosis can be explained by the failure of MDHM-stimulated macrophages to release IL-1. The property of MDHM to cause IL-6 release from macrophages and the IL-6 growth dependency of the 7TD1 hybridoma cell line were made use of in a coculture assay system to quantitate the activity of MDHM. With this method and macrophages from C3H/HeJ lipopolysaccharide-nonresponder mice, MDHM activity was found to be equally distributed in the mycoplasma growth medium and the sedimented mycoplasmas after sonication.

A study was carried out on 29 patients to investigate the amount of histamine liberation and release of platelet-activating factor and 6-keto-prostaglandin F1α from gastric mucosa and whole blood or mononuclear cells by sodium benzoate. The patients suffered from asthma (10), atopic dermatitis (7) and chronic urticaria (4). 8 patients with unrelated, non-immunologic diseases served as controls. In the oral provocation test (OPT) 3 patients experienced a recurrence of their original disease, whilst 1 asthmatic patient reacted with abdominal disorder. The release of histamine and prostaglandin from mucosa was significantly increased by sodium benzoate in comparison to the spontaneous release observed in patients. The mucosa of the control persons did not react to sodium benzoate. Furthermore, there was a significant difference in prostaglandin release between patients with positive OPT and the control persons. No difference could be found between patients with negative OPT and those with positive OPT. Additionally, in the mediator release from whole blood or mononuclear cells there was no obvious difference apparent. These results suggest a possible involvement of prostacyclin and histamine in adverse reactions to benzoate. Due to the sensitivity of the method, a mediator release from mucosa can already be demonstrated in a preclinical state of the pseudoallergic reaction in the absence of clinical symptoms.

Cardiopulmonary bypass (CPB) impairs monocyte and neutrophil proliferation, cytokine synthesis, and antigen presentation. This study compares in vivo data with results from an extracorporeal circulation (ECC) model, distinguishing direct effects on cytokine synthesis from regulatory mechanisms.Whole blood from 18 patients prior to, during and after CPB was stimulated with lipopolysaccharide (LPS). Tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8 levels were measured. Additionally, blood from 4 volunteers was circulated in an ECC model. Cytokine levels were measured before and during mock ECC.LPS-induced cytokine synthesis was reduced after CPB (TNF-alpha: 11 %; IL-6: 29 %; IL-8: 48 % of preoperative values, all p0.001). In mock ECC, cytokine production (except IL-8) was suppressed: TNF-alpha production was lowest 60 min after starting ECC, IL-6 synthesis was lowest at 90 min (33 % and 15 % vs. pre-ECC levels; both p0.001). Patient sera contained cytokine-inhibitory activity after CPB, an activity not found in mock ECC.(1) In patients, CPB induces early transient LPS hyporesponsiveness; (2) blood contact with foreign surfaces induces LPS hyporesponsiveness; (3) serum cytokine-inhibitory activities are released after CPB, but not in mock ECC. Impaired leukocyte function may explain increased susceptibility to infections after CPB.

Many attempts have been made to introduce THz detection systems for security inspection at check points. For all approaches the spectral characteristics of the most common materials of investigation are required both in reflectance and transmittance. We investigated a broad variety of materials, including explosives, polymers and drugs by using Fourier-Transform Spectroscopy and synchrotron radiation as a broadband THz source. The spectral properties are discussed with respect to the material density, thickness, grain size, and measurement geometry. We found strong dependence on the aforementioned parameters which have to be considered for time-domain and other laser-based detection systems.

The reflectivity R of ab-oriented Mg1xAlxB1yCy2 single crystals has been measured by means of infrared microspectroscopy for 130017 000 cm 1 . An increase with doping of the scattering rates in the and bands is observed, being more pronounced in the C-doped crystals. The band plasma frequency also changes with doping due to the electron doping, while the band one is almost unchanged. Moreover, a → interband excitation, predicted by theory, is observed at IB0.47 eV in the undoped sample, and shifts to lower energies with doping. By performing theoretical calculation of the doping dependence IB, the experimental observations can be explained with the increase with electron doping of the Fermi energy of the holes in the band. On the other hand, the band density of states seems not to change substantially, suggesting that a relevant role, for what regards the reduction of Tc, can be played also by the disorder, at least for the doping level studied here. The superconducting state has been also probed by infrared synchrotron radiation for 30150 cm 1 in one pure and one C-doped sample. In the undoped sample Tc=38.5 K a signature of the gap only is observed. At y=0.08 Tc=31.9 K, the presence of the contribution of the gap indicates dirty-limit superconductivity in both bands.

Optical spectra of a double-layered perovskite ruthenate Ca3Ru2O7 show a pseudogap opening around 200 cm(-1) below 50 K, which is attributable to the partial k-space gap opening due to the density wave instability. Unlike most other density wave materials, Ca3Ru2O7 has spectral weight redistributions, not near the energy gap region, but at a much higher energy region around 800 cm(-1). As a possible origin of these intriguing features, we discuss the orbital flip excitation in the density wave ground state.

Die ET zeichnet sich neben der bekannten Suppression proinflammatorischer Zytokine auch durch eine Verringerung der Storung der Gefaspermeabilitat und der Leukozytenadhasion in der sinusoidalen Endstrombahn der Leber aus. Offensichtlich kontrare Regulationsmechanismen scheinen bei der Leukozyten-Endothelinteraktion in den postkapillaren Venolen sowohl der Leber als auch des Mesenteriums vorzuliegen, da hier genau umgekehrte Phanomene auftauchen. Da zumindest fur die Leber bei der ET eine verminderte Organschadigung in der Literatur beschrieben ist, bewirken die adharierenden Leukozyten in den postkapillaren Venolen offensichtlich keinen relevanten Gewebeschaden. Unterschiedliche Leukozytenpopulation sowie eine Modulation der transmigrierenden Leukozyten konnten dieses Phanomen erklaren.

Die Fahigkeit der Vorlaufer-DZ im Knochenmark zur Proliferation und Differenzierung in DZ scheint wahrend einer Sepsis nicht beeintrachtigt zu sein. Wahrend einer Sepsis kommt es jedoch zu einer Modulation der Vorlaufer-DZ bezuglich der Zytokinsekretion. Dieser Defekt wird wahrend der in vitro 7 Tage dauernden Phase der Proliferation und Differenzierung auf die Tochterzellen uber tragen, die mit einer verstarkten Ausschuttung von IL-10 auf bakterielle Stimuli reagieren. Die unterschiedliche Reaktivitat auf bakterielle Bestandteile beruht nicht auf einer veranderten Expression von TLR4. Weiterhin zeigen die aus KMZ von septischen Tieren generierten DZ eine reduzierte Fahigkeit zur T-Zell Aktivierung. Die wahrend einer Sepsis stattfindende Immunmodulation von DZ scheint nicht auf bereits differenzierte DZ in den lymphoiden Organen beschrankt zu sein. Auch die Vorlauferzellen der DZ im Knochenmark sind betroffen und differenzieren zu DZ, die aufgrund einer vermehrten IL-10 Produktion der Ausbildung einer effektiven Immunantwort entgegenwirken. Daher postulieren wir, dass aus dem Knochenmark differenzierte DZ bei einer nachfolgenden Besiedelung der lymphoiden Organe die bereits bestehende Immunsuppression wahrend einer Sepsis weiter vertiefen.

The initial pro-inflammatory phase during sepsis is followed by an anti-inflammatory response resulting in immune suppression associated with T cell anergy/depletion. Since dendritic cells (DC) are potent antigen-presenting cells and play a key role in inducing the appropriate T cell response e. g. upon infection, we tested the hypothesis that DC are involved in sepsis-mediated immune suppression using a mouse cecal ligation and puncture (CLP) model which resembles human polymicrobial sepsis. DC from spleen and peripheral lymph nodes (LN) were characterized in terms of expression of co-stimulatory molecules and cytokine synthesis by means of FACS analyses at various time points after CLP or control operation. Additionally, allogenic T cell activation was assessed. Within 6 to 15 h after CLP, splenic DC were found to express high levels of CD86, CD40, and MHC class II molecules. The expression of these markers further increased until 36 h after CLP. At that time point increased levels of co-stimulatory molecules were also found in the LN. Thirty-six h after CLP, a marked loss of DC in the spleen particularly from the CD4+CD8- subpopulation was observed. The remaining DC were unresponsive to bacterial components in terms of interleukin (IL) 12 synthesis and further upregulation of co-stimulatory molecules. Additionally, splenic DC from septic mice showed reduced capacity to stimulate allogenic T cell proliferation in comparison to DC from healthy controls. In summary, systemic infection during sepsis results in sequential upregulation of co-stimulatory molecules involved in T cell activation first in the spleen and later in the LN and is associated with unresponsiveness to bacterial components. Thus, suppression of DC number and function may be a key to impaired immune activation during sepsis.

Terahertz scanning near-field infrared microscopy (SNIM) below 1 THz is demonstrated. The near-field technique benefits from the broadband and highly brilliant coherent synchrotron radiation (CSR) from an electron storage ring and from a detection method based on locking on to the intrinsic time structure of the synchrotron radiation. The scanning microscope utilizes conical waveguides as near-field probes with apertures smaller than the wavelength. Different cone approaches have been investigated to obtain maximum transmittance. Together with a Martin-Puplett spectrometer the set-up enables spectroscopic mapping of the transmittance of samples well below the diffraction limit. Spatial resolution down to about λ/40 at 2 wavenumbers (0.06 THz) is derived from the transmittance spectra of the near-field probes. The potential of the technique is exemplified by imaging biological samples. Strongly absorbing living leaves have been imaged in transmittance with a spatial resolution of 130 μm at about 12 wavenumbers (0.36 THz). The THz near-field images reveal distinct structural differences of leaves from different plants investigated. The technique presented also allows spectral imaging of bulky organic tissues. Human teeth samples of various thicknesses have been imaged between 2 and 20 wavenumbers (between 0.06 and 0.6 THz). Regions of enamel and dentin within tooth samples are spatially and spectrally resolved, and buried caries lesions are imaged through both the outer enamel and into the underlying dentin.

Infrared (IR) spectroscopy has been employed to investigate the c axis reflectivity of Bi2Sr2CaCu2O8 in the sub-THz frequency region.In order to reach this challenging frequency range a synchrotron source has been employed. Working in a special low-momentum compaction mode of operation where the electron bunch shape is significantly shortened and distorted, stable broadband coherent (super radiant) very far-infrared radiation is produced with orders of magnitude more intensity than conventional thermal and synchrotron sources. Using this source for reflectivity measurements we have been able to observe the Josephs on plasma resonance (JPR) in optimally doped Bi2Sr2CaCu2O8. Evidence is found for an in homogeneous distribution of superfluid density within the sample. This source allows us to investigate charge dynamics in this extremely anisotropic superconductor, and opens up the possibility to study other highly correlated systems in this critical low-energy region.

Clinical complications arising from extracorporeal circulation (ECC) have been linked to disturbances in the microcirculation. Hyperoxia, a mainstay of supportive treatment, is clinically used for a variety of pathological states. In previous in vivo animal experiments we found increased leukocyte/endothelial (L/E) cell interaction following ECC due to oxygen derived free radicals. This study was carried out to investigate the link between arterial pO2 during ECC and the potential damage to the microcirculation, supposedly caused by oxygen derived radicals.Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in syrian golden hamsters. ECC was introduced via a micro-rollerpump (0.7 ml/min) and a 60 cm silicon tube (1 mm inner diameter) shunted between the carotid artery and the jugular vein after application of 300 IE Heparin/kg/bw. Experiments were performed in chronically instrumented, awake animals (age: 10-14 weeks, weight: 65-75 g). Control inspired room air, experimental group 1 inspired 100% oxygen, group 2 received 100% oxygen and 2000 IE of Heparin i.v. (n=7/group), that releases endothelial bound superoxide dismutase, a natural scavenger of oxygen derived free radicals in the hamster.Normobaric inhalation of 100% oxygen increased arterial pO2 from 64+/-8.1 mmHg to 512+/-124 mmHg (P0.05 vs. baseline). ECC under 100% oxygen reduced functional capillary density (FCD) to 70% of baseline values 8 h after ECC (P0.05). Adherent leukocytes in postcapillary venules and arterioles increased significantly (P0.05). 2000 IE Heparin prevented the reduction in FCD and decreased the number of adherent leukocytes.Reduction in FCD, increased leukocyte adherence to the microvascular endothelium of postcapillary venules and arterioles under hyperoxia compared to ECC under room air conditions, demonstrates harmful effects of oxygen during ECC in vivo. A high dose of Heparin enhances functional capillary density, thus attenuating the microvascular dysfunction/damage in the period after ECC.