Interleukin-1F7B (IL-1H4/IL-1F7) is processed by caspase-1 and mature IL-1F7B binds to the IL-18 receptor but does not induce IFN-gamma production

We have recently reported the identification of four novel members of the interleukin-1 (IL-1) family which we designated as IL-1 homologue 1-4 (IL-1H1-4). These proteins exhibit significant sequence homology to other members of the IL-1 family. Of these homologues, only IL-1H4 (renamed IL-1F7b) was predicted to contain a propeptide domain and a caspase cleavage site. We now report that caspase-1 cleaves IL-1F7b at the predicted site to generate mature IL-1F7b. Caspase-4 was also able to process IL-1F7b, albeit inefficiently. Other caspases and Granzyme-B did not cleave IL-1F7b. Furthermore, adenovirus-mediated expression of IL-1F7b in HEK 293 cells led to in situ processing and secretion of mature IL-1F7b. In a screen to identify a potential receptor, both pro and mature IL-1F7b bound to the soluble IL-18 receptor alpha-Fc (IL-18Ralpha-Fc) but not to the soluble IL-1R-Fc or ST2R-Fc fusion proteins. Mature IL-1F7b bound to the IL-18Ralpha-Fc protein with higher affinity than the pro form, although the affinities for both proteins were significantly lower than that observed for IL-18. Consistent with this observation, only IL-18 and not IL-1F7b induced IFN-gamma production by KG1a cells. We also report that pro and mature IL-1F7b form homodimers with association constants of 4 microM and 5 nM, respectively, suggesting biological relevance to IL-1F7b processing. Finally, we have localized the expression of IL-1F7b protein in discrete cell populations including plasma cells and tumor cells. These data suggest that IL-1F7b may be involved in immune response, inflammatory diseases and/or cancer.     

Photographic measurement of pleural surface motion during lung oscillation

The regional pleural surface expansion of an excised dog lung was measured during high-frequency ventilation (HFV) using synchronized stroboscopic photography to stop lung motion at 20 evenly spaced intervals over a respiratory cycle during ventilation at 1 Hz with a volume of 100 ml, 15 Hz with 100 ml, or 30 Hz with 50 ml. The lungs were also photographed during quasi-static deflation. The pleural surface was marked with ink dots to form 84 approximately square figures. The side lengths and areas of each of the 84 "squares" were measured for each frame of each photo sequence. At 1 Hz and during the quasi-static deflation the lung ventilated nearly synchronously, although minor nonuniformities were noted on both small and large length scales. At 15 and 30 Hz, the lung expanded asynchronously and nonuniformly, with a 78% increase in surface expansion per 100 ml of tracheal tidal volume, as frequency was increased from 1 to 30 Hz. These nonuniformities in expansion suggest marked interregional airflow and elastic wave propagation in the parenchyma during HFV.     

Analysis of Andes frogs (Phrynopus, Leptodactylidae, Anura) phylogeny based on 12S and 16S mitochondrial rDNA sequences

South American leptodactylid frogs of the genus Phrynopus occur in cloud-forest, páramo, subpáramo and puna habitats (1000–4400 m elevation) from Colombia to Bolivia. Currently, there are 34 described species; however, many additional species new to science have been reported from Colombia, Peru, and Bolivia. The phylogeny of the species-diverse Phrynopus is unknown and the position of the genus within Leptodactylidae is poorly understood. We present the results of a phylogenetic study based on 12S and 16S mitochondrial rDNA. Fifteen species of Phrynopus from Bolivia to Ecuador are included, along with several other genera of Leptodactylidae and representatives of other frog families. Our results indicate that Phrynopus is phylogenetically nested within Eleutherodactylus , whereas Phyllonastes is phylogenetically nested within Phrynopus . Based on the recovered phylogeny, we transfer Phrynopus simonsii to Eleutherodactylus , and show that Phrynopus carpish needs to be removed from Phrynopus . Eleven of the 13 Phrynopus species occurring in Central Peru share the absence of an external and internal ear.     

Involvement of different protein kinases and phospholipases A2 in phorbol ester (TPA)-induced arachidonic acid liberation in bovine platelets

The effect of various phospholipase A2 and protein kinase inhibitors on the arachidonic acid liberation in bovine platelets induced by the protein kinase activator 12-O-tetradecanoylphorbol-13-acetate (TPA) was studied. TPA stimulates arachidonic acid release mainly by activating group IV cytosolic PLA2 (cPLA2), since inhibitors of this enzyme markedly inhibited arachidonic acid formation. However, group VI Ca2+-independent PLA2 (iPLA2) seems to contribute to the arachidonic acid liberation too, since the relatively specific iPLA2 inhibitor bromoenol lactone (BEL) decreased arachidonic acid generation in part. The pronounced inhibition of the TPA-induced arachidonic acid release by the protein kinase C (PKC) inhibitors GF 109203X and Ro 31-82220, respectively, and by the p38 MAP kinase inhibitor SB 202190 suggests that the activation of the PLA2s by TPA is mediated via PKC and p38 MAP kinase.     

Paradoxical attenuation of leukocyte rolling in response to ischemia- reperfusion and extracorporeal blood circulation in inflamed tissue

In contrast to acute preparations such as the exteriorized mesentery or the cremaster muscle, chronically instrumented chamber models allow one to study the microcirculation under "physiological" conditions, i.e., in the absence of trauma-induced leukocyte rolling along the venular endothelium. To underscore the importance of studying the naive microcirculation, we implanted titanium dorsal skinfold chambers in hamsters and used intravital fluorescence microscopy to study venular leukocyte rolling in response to ischemia-reperfusion injury or extracorporeal blood circulation. The experiments were performed in chambers that fulfilled all well-established criteria for a physiological microcirculation as well as in chambers that showed various extents of leukocyte rolling due to trauma, hemorrhage, or inflammation. In ideal chambers with a physiological microcirculation (<30 rolling leukocytes/mm vessel circumference in 30 s), ischemia-reperfusion injury and extracorporeal blood circulation significantly stimulated leukocyte rolling along the venular endothelium and, subsequently, firm leukocyte adhesion. In contrast, both stimuli failed to elicit leukocyte rolling in borderline chambers (30-100 leukocytes/mm), and in blatantly inflamed chambers with yet higher numbers of rolling leukocytes at baseline (>100 leukocytes/mm), we observed a paradoxical reduction of leukocyte rolling after ischemia-reperfusion injury or extracorporeal blood circulation. A similar effect was observed when we superfused leukotriene B4 (LTB4) onto the chamber tissue. The initial increase in leukocyte rolling in response to an LTB4 challenge was reversed by a second superfusion 90 min later. These observations underscore 1) the benefit of studying leukocyte-endothelial cell interaction in chronically instrumented chamber models and 2) the necessity to strictly adhere to well-established criteria of a physiological microcirculation.     

In vitro cell response to a polymer surface micropatterned by laser interference lithography

This presentation will introduce laser interference lithography to prepare a periodic line and point micropatterns for study of cell-surface interactions. This process provides a straightforward micropatterning technique based on selective laser ablation of polymers utilizing the periodic energy distribution of two or more beam interference patterns. The micropatterns were characterized by atomic force microscopy, while the surface chemical modification was analyzed using X-ray photoelectron spectroscopy. Human pulmonary fibroblasts cultured on the surface of polycarbonate bearing line micropatterns were elongated, spindlelike, and oriented themselves along the line patterns with all different groove widths. In contrast, cells cultured on point patterns were also bipolar but showed no orientation. Further investigations demonstrated that human pulmonary fibroblast cells cultured on line and point micropatterns showed inflammatory response.     

Suppression of plant defence response by a mycorrhiza helper bacterium

The aim of the present study was to determine whether the mycorrhiza helper bacterium Streptomyces sp. AcH 505 could serve as a biocontrol agent against Heterobasidion root and butt rot. Bacterial influence on mycelial growth of Heterobasidion sp. isolates, on the colonization of wood discs and Norway spruce (Picea abies) roots was determined. The effect of AcH 505 on plant photosynthesis, peroxidase activity and gene expression, and needle infections were investigated. AcH 505 was antagonistic to 11 of 12 tested fungal Heterobasidion isolates. The antagonism resulted in a suppression of fungal colonization of Norway spruce roots and wood discs. Mycelial growth rate of the 12th strain, Heterobasidion abietinum 331 was not affected by AcH 505, and colonization of roots by this fungal strain was promoted by AcH 505. Bacterial inoculation led to decreased peroxidase activities and gene expression levels in roots. AcH 505 promotes plant root colonization by Heterobasidion strains that are tolerant to antifungal metabolites produced by the bacterium. This may result from unknown bacterial factors that suppress the plant defence response.     

Exploratory pot experiments on sensitiveness of different crops to sodium: D. Barley

Summary The effect of sodium on barley has been investigated by means of three pot experiments, of which one was on a humic sandy soil and two on an artificial soil complex (dusarit/quartz-sand mixture).In two of these experiments the effect of sodium — as nitrate of soda — was studied by comparison with calcium nitrate. At low potassium levels sodium was found to excercise a positive effect, but with an ample supply of potassium no differences between the effects of the two nitrate fertilizers were observed.In the third experiment a wide variation in the potassium and sodium levels was introduced by the application of these elements adsorbed to dusarit, all treatments receiving nitrogen in the form of calcium nitrate. Little influence was exercised by the total level of monovalent ions (10, 20 and 40 per cent respectively, of the adsorbed bases). Three-quarters, or possibly seven-eights of the potassium was found to be replaceable by sodium without causing significant changes in the yields of grain and straw.From a survey of the available literature it cannot yet be concluded whether the importance of sodium for barley is limited to a beneficial effect resulting from its mere replacement of potassium, when too little of the latter is available, or whether this importance may be regarded as essential in the sense that sodium has a yield-increasing effect, even in the presence of a sufficiency of potassium.     

Autecology of an arsenite chemolithotroph: sulfide constraints on function and distribution in a geothermal spring

Previous studies in an acid-sulfate-chloride spring in Yellowstone National Park found that microbial arsenite [As(III)] oxidation is absent in regions of the spring outflow channel where H(2)S exceeds approximately 5 microM and served as a backdrop for continued efforts in the present study. Ex situ assays with microbial mat samples demonstrated immediate As(III) oxidation activity when H(2)S was absent or at low concentrations, suggesting the presence of As(III) oxidase enzymes that could be reactivated if H(2)S is removed. Cultivation experiments initiated with mat samples taken from along the H(2)S gradient in the outflow channel resulted in the isolation of an As(III)-oxidizing chemolithotroph from the low-H(2)S region of the gradient. The isolate was phylogenetically related to Acidicaldus and was characterized in vitro for spring-relevant properties, which were then compared to its distribution pattern in the spring as determined by denaturing gradient gel electrophoresis and quantitative PCR. While neither temperature nor oxygen requirements appeared to be related to the occurrence of this organism within the outflow channel, H(2)S concentration appeared to be an important constraint. This was verified by in vitro pure-culture modeling and kinetic experiments, which suggested that H(2)S inhibition of As(III) oxidation is uncompetitive in nature. In summary, the studies reported herein illustrate that H(2)S is a potent inhibitor of As(III) oxidation and will influence the niche opportunities and population distribution of As(III) chemolithotrophs.     

Robotic totally endoscopic multivessel coronary artery bypass grafting: procedure development, challenges, results

Closed-chest totally endoscopic coronary artery bypass grafting (TECAB) is feasible using robotic technology. During the early phases, TECAB was restricted to single bypass grafts to the left anterior descending artery system. Because most patients referred for coronary artery bypass surgery have multivessel disease, development of endoscopic multiple bypass grafting is mandatory. Experimental work on multivessel TECAB was carried out in the early 2000s, and first clinical cases were already performed. With further technological development of operating robots, double, triple, and quadruple TECAB has become feasible both on the arrested heart and on the beating heart. To date, 161 cases of multivessel TECAB using the da Vinci telemanipulation systems are published in the literature. The main advances enabling multivessel TECAB were the availability of a robotic endostabilizer for beating heart procedures and increased surgeon skills using remote access heart-lung machine perfusion and endo-cardioplegia. Both internal mammary arteries can be harvested and both radial artery and vein graft can be used in multivessel TECAB. Y-grafting and sequential grafting are feasible. Multivessel endoscopic surgical revascularization can be combined with percutaneous coronary interventions in advanced hybrid coronary revascularization. Time requirements for multivessel TECAB are significant, and conversion rates to larger thoracic incisions are higher than those observed for single-vessel TECAB. Clinical short- and long-term outcomes, however, seem to meet the standards of open coronary bypass surgery through sternotomy. The main advantages of multivessel TECAB are a completely preserved sternum, use of double internal mammary artery even in risk groups, and a remarkably short recovery time.