Spectroscopy and Directed Transport of Topological Solitons in Crystals of Trapped Ions.

We study experimentally and theoretically discrete solitons in crystalline structures consisting of several tens of laser-cooled ions confined in a radio frequency trap. Resonantly exciting localized, spectrally gapped vibrational modes of the soliton, a nonlinear mechanism leads to a nonequilibrium steady state of the continuously cooled crystal. We find that the propagation and the escape of the soliton out of its quasi-one-dimensional channel can be described as a thermal activation mechanism. We control the effective temperature of the soliton's collective coordinate by the amplitude of the external excitation. Furthermore, the global trapping potential permits controlling the soliton dynamics and realizing directed transport depending on its topological charge.

Hepatic stellate cells display a functional vascular smooth muscle cell phenotype in a three-dimensional co-culture model with endothelial cells.

Hepatic stellate cells (HSCs) are pericytes of liver sinusoidal endothelial cells (LSECs) and activation of HSC into a myofibroblast-like phenotype (called transdifferentiation) is involved in several hepatic disease processes including neovascularization during liver metastasis, chronic and acute liver injury. While early smooth muscle cell (SMC) differentiation markers including SM alpha-actin and SM22alpha are expressed in a variety of non-SMC, expression of late-stage markers is far more restricted. Here, we found that in addition to early SMC markers, activated rat HSC express a large panel of characteristic late vascular SMC markers including SM myosin heavy chain, h1-calponin and h-caldesmon. Furthermore, myocardin, which is present exclusively in SMCs and cardiomyocytes and controls the transcription of a subset of early and late SMC markers, is highly expressed in activated HSC. We further studied activated HSC in a functional three-dimensional spheroidal co-culture system together with endothelial cells (EC). Co-culture spheroids of EC and SMC differentiate spontaneously and organize into a core of SMC and a surface layer of EC representing an inside-outside model of the physiological assembly of blood vessels. Replacing SMC by in vitro activated HSC resulted in a similar organized spheroid with differentiated, von-Willebrand factor producing, surface lining quiescent human umbilical vein endothelial cell and a core of HSC. In an in vitro angiogenesis assay, activated HSC induced quiescence in vascular EC-the hallmark of vascular SMC function. Co-spheroids of LSEC and activated HSC formed capillary-like sprouts in gel angiogenesis assays expressing the vascular EC marker VE-cadherin. Our findings indicate that activated HSC are capable to adapt a functional SMC phenotype and to induce formation of tubular sprouts by LSEC and vascular endothelial cells. Since tumors and tumor metastasis induce HSC activation, HSC may take part in tumor-induced neoangiogenesis by adapting SMC-like functions.

Stable and radioiodine concentrations in cow milk: dependence on iodine intake.

For testing the potential use of stable iodine as a countermeasure to reduce radioiodine transfer to milk, concentrations of stable iodine and radioiodine in the milk of dairy cows fed different amounts of stable iodine were measured. The results indicated that, compared to a normal average stable iodine intake of about 20 mg d(-1) for cows, low iodine dietary intake (<1.5 mg d(-1)) resulted in a reduced transfer of radioiodine to milk by 25%, varying stable iodine intakes in the range of 10-500 mg d(-1) did have no significant effect; at stable iodine intake rates above 1000 mg I d(-1), a reduction by a factor of approximately two was achieved. The high dietary iodine intakes--being about 100 times the normal iodine supply--required to reduce the radioiodine transfer significantly, will result in stable iodine concentrations in milk in excess of advised or legal limits for human consumption. Nevertheless, the provision of stable iodine via the milk pathway might be considered for emergency situations when stable iodine is used as a preventative measure for dose reduction to humans.

Fibroblast growth factor 16 and 18 are expressed in human cardiovascular tissues and induce on endothelial cells migration but not proliferation.

Endothelial cells line the blood vessel and precursor endothelial cells appear to have a pivotal effect on the organ formation of the heart, the embryonic development of the kidney, and the liver. Several growth factors including the fibroblast growth factors (FGF) seem to be involved in these processes. Ligands such as basic FGF produced and secreted by endothelial cells may also coordinate cellular migration, differentiation, and proliferation under pathological conditions including wound healing, tumorgenesis, and fibrogenesis in the adult. Recently we demonstrated the expression of two secreted FGFs, FGF16, and FGF18, in HUVEC and in rat aortic tissue. In the present report, we confirmed by RT-PCR analysis that FGF18 is wildly expressed in the cardiovascular tissue, while FGF16 showed a more restricted expression pattern. HUVEC clearly demonstrated chemotaxis towards FGF16 and FGF18. Both FGFs also enhanced cell migration in response to mechanical damage. However, recombinant FGF16 and FGF18 failed to induce endothelial cell proliferation or sprouting in a three-dimensional in vitro angiogenesis assay. Fgf18 expression was earlier reported in the liver, and we detected FGF18 expression in liver vascular and liver sinusoidal endothelial cells (LSECs), but not in hepatic parenchymal cells. Recombinant FGF18 stimulated DNA synthesis in primary hepatocytes, suggesting, that endothelial FGF18 might have a paracrine function in promoting growth of the parenchymal tissue. Interestingly, FGF2, which is mitogenic on endothelial cells and hepatocytes stimulates a sustained MAPK activation in both cell types, while FGF18 causes a short transient activation of the MAPK pathway in endothelial cells but a sustained activation in hepatocytes. Therefore, the difference in the time course of MAPK activation by the different FGFs appears to be the cause for the different cellular responses.

Upregulation of pleiotrophin expression in rat hepatic stellate cells by PDGF and hypoxia: implications for its role in experimental biliary liver fibrogenesis.

Pleiotrophin (PTN) is a secretory heparin binding protein with various biological activities including mitogenesis, angiogenesis, and tissue repair after injury. Recent studies have shown that PTN is a strong mitogen of hepatocytes and involved in liver regeneration. In adult liver cells Ptn gene is mainly expressed by quiescent hepatic stellate cells (HSCs). Although we have been able to demonstrate mRNA and protein expression of the anaplastic lymphoma kinase-the receptor tyrosine kinase for PTN-on HSCs, PTN did not act as a mitogen of HSCs in contrast to hepatocytes. PTN immunoreactivity was markedly increased in experimental fibrogenesis by common bile duct ligation and observed in sinusoidal HSCs. In primary HSC cultures, Ptn transcription was significantly increased by PDGF-BB, and under hypoxic atmosphere. Mechanistically, hypoxia and PDGF mediated induction of PTN expression in sinusoidal HSCs may provide a strong mitogenic signal for hepatocytes to limit the damage to the parenchymal cells in biliary-type liver fibrogenesis.

Identification of an unconventional nuclear localization signal in human ribosomal protein S2.

Ribosomal proteins must be imported into the nucleus after being synthesized in the cytoplasm. Since the rpS2 amino acid sequence does not contain a typical nuclear localization signal, we used deletion mutant analysis and rpS2-beta-galactosidase chimeric proteins to identify the nuclear targeting domains in rpS2. Nuclear rpS2 is strictly localized in the nucleoplasm and is not targeted to the nucleoli. Subcellular localization analysis of deletion mutants of rpS2-beta-galactosidase chimeras identified a central domain comprising 72 amino acids which is necessary and sufficient to target the chimeric beta-galactosidase to the nucleus. The nuclear targeting domain shares no significant similarity to already characterized nuclear localization signals in ribosomal proteins or other nuclear proteins. Although a Nup153 fragment containing the importinbeta binding site fused to VP22 blocks nuclear import of rpS2-beta-galactosidase fusion proteins, nuclear uptake of rpS2 could be mediated by several import receptors since it binds to importinalpha/beta and transportin.

Expression pattern of fibroblast growth factors (FGFs), their receptors and antagonists in primary endothelial cells and vascular smooth muscle cells.

Fibroblast growth factors (FGFs) are important angiogenic growth factors. While basic FGF (FGF2) is well established as a potent inducer of angiogenesis much less is known about other FGFs possibly expressed by EC. We investigated the expression of all known FGFs, their main tyrosine kinase receptors and antagonists by RT-PCR analysis in human umbilical vascular endothelial cells (HUVECs) to obtain a complete expression profile of this important growth factor system in model endothelial cells (EC). In addition to FGFR1IIIc, which is considered as the major FGF receptor in EC, HUVECs express similar levels of FGFR3IIIc, detectable amounts of FGFR2IIIc and a new FGF receptor without an intracellular kinase domain (FGFR5). HUVECs express several secreted FGFs, including FGF5, 7, 8, 16 and 18 and two members of the fibroblast growth factor homologous factors (FHFs), not yet reported to be expressed in EC. The expression panel was compared with that obtained from human vascular smooth muscle cells (VSMCs) and human aortic tissue. Human umbilical artery smooth muscle cells (HUASMCs) and HUVECs express the identical FGF receptor and ligand panel implicating that both cell types act, according the FGF signals more as an entity than as individual cell types. Expression of Fgf1, 2, 7, 16 and 18 and the antagonists Sprouty 2,3 and 4 was demonstrated for all analysed cDNAs. The IIIc isoforms of FGFR1 and 2 and the novel FGFR5 were expressed in the aorta, but expression of the FGF receptor 3 was not detected in cDNAs derived from aortic tissue. In the VSMC of rat aortic tissue and in HUASM cultured cells we could demonstrate FGF18 immunoreactivity in the nucleus of the cells. The expression of several secreted FGFs by EC may focus the view more on their paracrine effects on neighbouring cells during tissue regeneration or tumor formation.

In situ gamma-ray spectrometry in forests: determination of kerma rate in air from 137Cs.

A method is presented to determine the kerma rate in air from 137Cs due to Chernobyl fallout in forests. In situ gamma-ray spectra from several forest sites in Russia, in the Ukraine and in Southern Germany are evaluated with the aim of deducing the ratio of primary and forward scattered photons for 137Cs. With this ratio and the results of Monte-Carlo simulations of photon transport the contribution of scattered photons to the total kerma is assessed successfully. Scattered photons contribute between 42% and 50% to the total kerma rate from radiocesium, which is less than according values for grassland areas. The contribution of radiocesium to the total kerma rate varies between 40% and 90%. whereas radiocesium stored in the forest biomass contributes only a few percent. The mean mass depth of radiocesium ranges from 2.6 to 6.4 g cm(-2) in the forest soils.

Influence of glucose, fructose and sucrose as carbon sources on kinetics and stoichiometry of lysine production by Corynebacterium glutamicum.

Batch cultivations of l-lysine-producing Corynebacterium glutamicum ATCC 21253 were carried out on the different carbon sources, glucose, sucrose and fructose. The time profiles of substrate and product concentrations were evaluated to compare kinetics and stoichiometry of lysine production. The lysine yield (mol C/mol C) on glucose was 8% higher than on sucrose and 30% higher than on fructose. The highest final biomass concentration of 5.0 g/l was obtained on glucose, whereas fructose and sucrose yielded 20% less biomass. Compared to glucose, fructose resulted in significantly higher respiration rates, a higher substrate uptake rate but a lower lysine production rate during the cultivation process. This was probably due to a higher tricarboxylic cycle activity combined with a lower activity of the pentose phosphate pathway. On sucrose, specific rates and yields differed significantly from those on fructose and glucose. Transport and metabolism of sucrose, therefore, are not a simple superposition of its building blocks, glucose and fructose.

[Motor function during patient-controlled analgesia via a lumbar epidural catheter after major abdominal surgery. Ropivacaine-sufentanil vs. bupivacaine-sufentanil]. / Motorische Blockade während einer patientenkontrollierten lumbalen Epiduralanalgesie nach abdominellen Eingriffen - Ein Vergleich zwischen Ropivacain-Sufentanil und Bupivacain-Sufentanil.

INTRODUCTION: The aim of the present study was to investigate postoperative motoric impairment during patient-controlled analgesia after major abdominal surgery with ropivacaine-sufentanil and bupivacaine-sufentanil via a lumbar epidural catheter. METHODS: After approval of the local ethics committee, 40 patients scheduled for major lower abdominal surgery were randomly allocated to receive bupivacaine 0.25 % or ropivacaine 0.2 %, both with sufentanil 2 microgram/ml in a double blind manner. General anaesthesia (midazolam, etomidate, fentanyl, vecuronium, and desflurane in N2O/O2) and postoperative management of the patients were standardised. Postoperatively, the motoric function and ability for active early mobilisation was examined clinically (application of the Bromage scale, ability to leave the bed and ability to walk). Reduction of muscular force of the legs was measured postoperatively using a scale and compared with preoperative baseline values. To ensure a similar level of analgesia, a 10-cm visual analogue scale was applied at rest and while coughing. RESULTS: The two groups did not differ with respect to the demographic data and postoperative levels of analgesia. Less reduction of motoric function at rest was observed in the ropivacaine group (p = 0,044). However, this did not lead to an increased ability to get up from bed (p = 0,57) or to walk around (p = 0,17). A high number of patients did not meet the requirements for early ambulation. Almost half of the patients of both groups were unable to leave their beds in the morning of the first postoperative day. On the second postoperative day about 25 - 30 % of the patients could not walk even when support was applied. Furthermore, median reduction (10th/90th percentile) of muscular strength was reduced to 50 % (37 %/76 %) in the ropivacaine group and to 48 % (31 %/61 %) in the bupivacaine group compared with preoperative values. DISCUSSION: While quality of analgesia was similar, mobility of the legs at rest is better preserved with ropivacaine 0.2 % than with bupivacaine 0.25 %. However, despite the fact that high dose sufentanil was added to both local anaesthetics, there was marked motoric impairment in both groups probably due to the lumbar site of the epidural catheter. This was associated with an unacceptable high incidence of patients unsuitable for early postoperative mobilisation.

Hepato-splanchnic metabolic effects of the stable prostacyclin analogue iloprost in patients with septic shock.

OBJECTIVE: To evaluate the effects of the stable prostacyclin analogue iloprost on hepato-splanchnic blood flow, oxygen exchange and metabolism in patients with septic shock. DESIGN: Prospective clinical study. SETTING: Intensive care unit in a university clinic. PATIENTS: Eleven patients with septic shock requiring norepinephrine to maintain mean arterial pressure above 70 mmHg. INTERVENTIONS: Iloprost was incrementally infused to increase cardiac index by 15%. MEASUREMENTS AND MAIN RESULTS: Splanchnic blood flow (Qspl) was measured using the steady-state indocyanine-green infusion technique and endogenous glucose production rate (EGP) using a stable isotope approach. Systemic and splanchnic oxygen consumption (VO2), the hepato-splanchnic uptake rates of the glucose precursors lactate, pyruvate, alanine and glutamine, the hepatic venous redox state and gastric mucosal-arterial PCO2 gradients were determined. After a baseline measurement, iloprost infusion was started. After 90 min all measurements were repeated and a third measurement was obtained after another 90 min following iloprost withdrawal. Qspl (baseline I: 0.82/0.75-1.08 l x min x m2; iloprost: 0.94/0.88-1.29 l x min x m2; baseline II: 0.87/0.74-1.09 l x min x m2) and splanchnic oxygen delivery (baseline I: 122/103-166 ml x min x m2; iloprost: 134/117-203 ml x min x m2; baseline II: 130/98-158 ml x min x m2) significantly increased. While systemic VO2 significantly increased (baseline I: 139/131-142 ml x min x m2; iloprost: 147/136-164 ml x min x m2; baseline II: 143/133-154 ml x min x m2) splanchnic VO2 increased in 9 of 11 patients which, however, did not reach statistical significance. EGP significantly decreased (baseline I: 23/16-26 micromol x kg x min; iloprost: 16/14-21 micromol x kg x min; baseline II: 18/12-20 micromol x kg x min), whereas all other parameters of energy metabolism remained unchanged. CONCLUSION: In patients with septic shock an iloprost-induced increase in cardiac index increased splanchnic blood flow and shifted oxygen utilization from the energy requiring de novo glucose production rate to other oxygen-demanding metabolic pathways.

Influence of prone position on gastric mucosal-arterial PCO2 gradients.

OBJECTIVE: To evaluate the effects of mechanical ventilation in the prone position on gastric mucosal-arterial PCO2 gradients. DESIGN: Prospective clinical study. SETTING: Intensive care unit in a university clinic. PATIENTS: Twenty-five patients requiring mechanical ventilation. The physician in charge indicated the turning manoeuver for the individual patient. MEASUREMENTS/RESULTS: In addition to routine measurements of global hemodynamics and gas exchange we determined: 1) intragastric pressure; and 2) gastric mucosal-arterial PCO2 difference. After a baseline measurement in the supine position patients were turned to the prone position. After 60', 120', a median of 6.5 h (2-10 h) in the prone position, and again after 60' in the supine position, all measurements were repeated. Global hemodynamics remained unaltered throughout the study. While gastric mucosal-arterial PCO2 gradients did not change significantly during the first 60 min in the prone position, they significantly increased during the following 60 min [median/percentile: baseline: 6 (1 to -3); 60': 7 (15-5); 120': 13 (20-8) mmHg]. The median intragastric pressure was not significantly affected [baseline: 10 (13-5); 60': 12 (16-8); 120': 11 (13-7) mmHg], but 9 of the 11 patients in whom intragastric pressure increased during the first 60 min in the prone position also showed significantly increased PCO2 gradients (P < 0.01). CONCLUSION: Mechanical ventilation in the prone position may be affiliated with increased tonometric gastric mucosal-arterial PCO2 gradients depending on the effect on intraabdominal pressure. Measuring intraabdominal pressure and/or gastric mucosal PCO2 via a nasogastric tube therefore may help to detect adverse effects of this ventilatory strategy.

NoBP, a nuclear fibroblast growth factor 3 binding protein, is cell cycle regulated and promotes cell growth.

Secreted and nuclear forms of fibroblast growth factor 3 (FGF3) have opposing effects on cells. The secreted form stimulates cell growth and transformation, while the nuclear form inhibits DNA synthesis and cell proliferation. By using the yeast two-hybrid system we have identified a nucleolar FGF3 binding protein (NoBP) which coimmunoprecipitated and colocalized with FGF3 in transfected COS-1 cells. Characterization of the NoBP binding domain of FGF3 exactly matched the sequence requirements of FGF3 for its translocation into the nucleoli, suggesting that NoBP might be the nucleolar binding partner of FGF3 essential for its nucleolus localization. Carboxyl-terminal domains of NoBP contain linear nuclear and nucleolar targeting motifs which are capable of directing a heterologous protein beta-galactosidase to the nucleus and the nucleoli. While NoBP expression was detected in all analyzed proliferating established cell lines, NoBP transcription was rapidly downregulated in the promyelocytic leukemia cell line HL60 when induced to differentiate. Analysis on the expression pattern of NoBP mRNA throughout the cell cycle in HeLa cells synchronized by lovastatin demonstrated a substantial upregulation during the late G(1)/early S phase. NoBP overexpression conferred a proliferating effect onto NIH 3T3 cells and can counteract the inhibitory effect of nuclear FGF3, suggesting a role of NoBP in controlling proliferation in cells. We propose that NoBP is the functional target of nuclear FGF3 action.

Effect of an acute increase in PCO2 on splanchnic perfusion and metabolism.

OBJECTIVES: To evaluate the acute effects of an increase in PCO2 on splanchnic tissue perfusion and metabolism. DESIGN: Clinical prospective study in the intensive care unit in a university clinic. PATIENTS: Six patients with severe acute lung injury requiring mechanical ventilation. All patients had bilateral infiltrates on chest radiography, a PaO2/FIO2 ratio less than 200 mmHg, and stable hemodynamics without vasoactive drugs. INTERVENTIONS: PCO2 was increased 5-20% by an added dead space from baseline, followed by a return to baseline. MEASUREMENTS AND RESULTS: Splanchnic blood flow was measured using primed continuous infusion of indocyanine green dye with hepatic venous sampling and systemic hemodynamics by routine monitoring; we also determined the gastric mucosal-arterial PCO2 difference and splanchnic lactate/pyruvate exchange. PCO2 was increased by an added dead space; after 60 min all measurements were repeated; after return to baseline a third measurement followed. The increase in PCO2 had no significant effect on splanchnic blood flow or indices of perfusion and metabolism. CONCLUSION: Our results suggest that acute moderate changes in PCO2 have no major effect on splanchnic perfusion and metabolism.

Effect of dopexamine on hepatic metabolic activity in patients with septic shock.

Hepato-splanchnic metabolic activity is seen to be related to regional blood flow and oxygen/substrate availability in patients with sepsis. Catecholamines, which may modulate metabolic activity perse, are common to stabilize hemodynamics. We studied the effect of a dopexamine-induced increase in splanchnic blood flow (Qspl) on regional metabolic rate in 10 patients with septic shock requiring norepinephrine to maintain mean arterial pressure (>60 mmHg). Splanchnic blood flow was determined using the indocyanine-green method with hepatic venous sampling. We determined the hepato-splanchnic lactate, pyruvate, alanine, and glutamine turnover and the lactate/pyruvate and ketone body ratio as well as the endogenous glucose production (EGP) using the stable isotope approach. Qspl increased from 0.86 (0.79-1.15) to 0.96 (0.92-1.33) L/min/m2, not influencing any parameter of metabolic activity. We speculate that this finding is due to altered beta-adrenoreceptor-mediated thermogenic effects due to the interplay of different beta-sympathomimetics at the receptor site.

Gastrointestinal tract resuscitation in critically ill patients.

Particular research interest is currently focusing on the resuscitation of the gastrointestinal tract, because the gut is regarded to be both the "canary of the body", i.e. a sentinel organ during situations of compromised oxygen or substrate supply, as well as the "motor of multiple organ failure". Several therapeutic strategies have recently been proposed for the resuscitation of this organ system, aimed primarily at the augmentation of blood flow and oxygenation but also integrating nutritional or metabolic support and antioxidant administration.

NH2-terminal cleavage of xenopus fibroblast growth factor 3 is necessary for optimal biological activity and receptor binding.

Fibroblast growth factor 3 (FGF3) was originally identified as the mouse proto-oncogene Int-2, which is activated by proviral insertion in tumors induced by mouse mammary tumor virus. To facilitate the biological characterization of the ligand, we have analyzed its homologue in Xenopus laevis, XFGF3. Here we confirm that the X. laevis genome contains two distinct FGF3 alleles, neither of which is capable of encoding the NH2-terminally extended forms specified by the mouse and human FGF3 genes. Unlike the mammalian proteins, XFGF3 is efficiently secreted as a Mr 31,000 glycoprotein, gp31, which undergoes proteolytic cleavage to produce an NH2-terminally truncated product, gp27. Processing removes a segment of 18 amino acids immediately distal to the signal peptide that is not present in the mammalian homologues. By inserting an epitope-tag adjacent to the cleavage site, we show that a substantial amount of the gp27 is generated intracellularly, although processing can also occur in the extracellular matrix. Two residues are also removed from the COOH terminus. To compare the biological properties of the different forms, cDNAs were constructed that selectively give rise to the larger, gp31, or smaller, gp27, forms of XFGF3. As judged by their ability to cause morphological transformation of NIH3T3 cells, their mitogenicity on specific cell types, and their affinity for the IIIb and IIIc isoforms of Xenopus FGF receptors, gp27 has a much higher biological activity than gp31. Sequence comparison revealed an intriguing similar cleavage motif immediately downstream of the signal peptide cleavage site in the NH2-terminus of mouse and human FGF3. Analysis of secreted mutant mouse FGF3 confirmed an additional NH2-terminal processing at the corresponding sequence motif. NH2-terminal trimming of Xenopus and mammalian FGF3s may therefore be a prerequisite of optimal biological activity.

Domains of human respiratory syncytial virus P protein essential for homodimerization and for binding to N and NS1 protein.

In this report we used the two-hybrid technique to test for binding among human respiratory syncytial virus (HRSV) proteins involved in the control of viral replication. Besides the expected positive interactions for the nucleoprotein (N) with itself and the phosphoprotein (P), our results also demonstrated P-P interaction and P-NS1 binding. However, no interactions have been detected for the matrix protein M, the M2-1 and the M2-2 protein neither with each other nor in combination with the phosphoprotein P, the nucleoprotein N or the non-structural protein NS1. While the N-P interaction was abolished by N- and C-terminal deletions of both partners, C-terminal deletion mutants of P were still able to form homodimers. In contrast, the C-terminal region of P turned out to be essential for binding of NS1. N-N interaction was disrupted by any of the N- and C-terminal deletions.