Cationic polyelectrolyte hydrogel fosters fibroblast spreading, proliferation, and extracellular matrix production: Implications for tissue engineering

Fibrous encapsulation is known to occur to many prosthetic implants and is thought to be due to the cells not adhering adequately to the surface. For developing new materials able to enhance cellular adhesion by mimicking extracellular matrix components, polyelectrolyte polymers, characterized by tunable surface charges, have been proposed. Here we demonstrate that panoply of cell functions over a two-dimensional substratum is influenced by surface charge. We have at first generated structurally related polyelectrolyte substrata varying in their positive surface charge amount and subsequently evaluated a variety of behaviors of human primary fibroblasts seeded on these polymers. The proportion of adherent, spreading, and proliferating cells was increased significantly on cationic hydrophilic surfaces when compared with the neutral base surface. The extent of cell spreading correlated with cytoskeleton organization as assessed using immunofluorescence techniques. In the key experiment, the presence of cationic charges on cell adhesion-resistant neutral surface increased the synthesis of collagen I and III, the release of their metabolites, and the expression of their mRNA by fibroblasts. Interestingly, the scarce collagen deposits on neutral polymer consisted, for the most part, of collagen I while collagen III was present only in traces probably due to the secretion of metalloproteinase-2 by non-adherent fibroblasts. Taken together, these results show that polyelectrolyte films may promote the attachment of fibroblast cells as well as their normal secretory phenotype. Both effects could be potentially useful in integrating soft connective tissue to the implant, decreasing the chance of its fibrous encapsulation.     

Tauroursodeoxycholate inhibits human cholangiocarcinoma growth via Ca2+-, PKC-, and MAPK-dependent pathways

Tauroursodeoxychate (TUDCA) is used for the treatment of cholangiopathies including primary sclerosing cholangitis, which is considered the primary risk factor for cholangiocarcinoma. The effect of TUDCA on cholangiocarcinoma growth is unknown. We evaluated the role of TUDCA in the regulation of growth of the cholangiocarcinoma cell line Mz-ChA-1. TUDCA inhibited the growth of Mz-ChA-1 cells in concentration- and time-dependent manners. TUDCA inhibition of cholangiocarcinoma growth was blocked by BAPTA-AM, an intracellular Ca(2+) concentration ([Ca(2+)](i)) chelator, and H7, a PKC-alpha inhibitor. TUDCA increased [Ca(2+)](i) and membrane translocation of the Ca(2+)-dependent PKC-alpha in Mz-ChA-1 cells. TUDCA inhibited the activity of MAPK, and this inhibitory effect of TUDCA was abrogated by BAPTA-AM and H7. TUDCA did not alter the activity of Raf-1 and B-Raf and the phosphorylation of MAPK p38 and JNK/stress-activated protein kinase. TUDCA inhibits Mz-ChA-1 growth through a signal-transduction pathway involving MAPK p42/44 and PKC-alpha but independent from Raf proteins and MAPK p38 and JNK/stress-activated protein kinases. TUDCA may be important for the treatment of cholangiocarcinoma.     

Requirement for RecFOR-mediated recombination in priA mutant

Restart of arrested replication forks is an important process and PriA, the main Escherichia coli replication restart protein, is essential for viability under any condition that increases the frequency of fork arrest. In priA mutant, replication forks are arrested by spontaneously occurring roadblocks and blocked replication forks persist as a result of the defect in replication restart. In the present work, we analysed how recombination proteins contribute to the viability of the priA mutant. RecFOR-mediated homologous recombination occurs in a large fraction of priA mutant cells, indicating a frequent formation of DNA single strand gaps and their recombinational repair. This high level of homologous recombination renders the proteins that resolve Holliday junctions recombination intermediates essential for viability. When homologous recombination is blocked at early steps by recFOR or recA inactivation, exonuclease V-mediated DNA degradation is required for full viability of priA mutants, indicating that unrepaired gaps are broken and that DNA degradation of the broken DNA allows the formation of viable cells. Models for the formation of single strand DNA gaps consequently to a replication restart defect and for gap processing are proposed.     

Ubiquitin dependent proteolysis is activated in apoptotic fibroblasts in culture

The ubiquitin mediated pathway constitutes an early response in cultured cells where apoptosis, assessed by internucleosomal specific DNA fragmentation, was induced by serum withdrawal. Data demonstrate that nuclear ubiquitin proteolytic system, but not cytoplasmic, is activated. This activation is paralleled by a substantial chromatin de-condensation. We suggest that chromatin relaxation is causative of the fragmentation since it exposes the DNA to nucleolytic attack. Finally, maintenance of homeostasis and induction of apoptosis seem to undergo a parallel contemporary pathway with a possible mutual feedback.     

Influence of sympathetic vascular regulation on heart-rate scaling structure: spinal cord lesion as a model of progressively impaired autonomic control.

Estimation of self-similarity is a promising tool for quantifying alterations in cardiovascular dynamics. To evaluate the as yet unexplored influence of sympathetic vascular regulation on the scaling exponent, namely on the parameter characterizing self-similarity, we studied patients with a spinal cord injury as a model of progressively impaired vascular control. We considered 24 able-bodied subjects (AB) and 23 paraplegics with increasing lesion levels: between T(12) and L(4) (n=7); T(5) and T(11) (n=9); and C(6) and T(4) (n=7). We recorded the heart rate in three conditions characterized by increasing sympathetic activation: supine (SUP), sitting (SIT) and exercise (EXE). We calculated the scaling exponent by detrended fluctuation analysis (H(DFA)). Sympathetic activation had different effects on H(DFA), depending on the lesion level. H(DFA) tended to decrease in AB from SUP (0.85+0.02; mean+SEM) and SIT (0.84+0.02) to EXE (0.79+0.02). It remained constant in the T(12)-L(4) group (0.92+0.04, 0.94+0.05 and 0.94+0.04, respectively), while it increased significantly in the T(5)-T(11) group (0.88+0.07, 0.94+0.05, 1.00+0.08) and increased even more in the C(6)-T(4) group (0.83+0.07, 0.91+0.05, 1.06+0.06). Results suggest that heart-rate self-similarity depends on vascular sympathetic control, because it is altered by spinal-cord lesions, even when cardiac neural control is intact.     

Attractiveness of year-old polyethylene Isonet sex pheromone dispensers for Lobesia botrana

In this study, we have compared the release of sex pheromone from mating disruption dispensers exposed in the field for 12 months and from calling females. The main pheromone component of the grapevine moth, Lobesia botrana (D. and S.) (Lepidoptera: Tortricidae), is (E)‐7,(Z)‐9‐dodecadienyl acetate, and a minor component is (Z)‐9‐dodecenyl acetate. Aged dispensers from two different years emitted a much higher amount of both pheromone components than calling females. However, the summer temperature during field exposure influenced the release from mating disruption dispensers the following year. In the wind tunnel, male L. botrana were equally attracted to 12‐month, field‐exposed dispensers, a standard monitoring pheromone lure, and to synthetic (E)‐7,(Z)‐9‐dodecadienyl acetate sprayed at the rate of 0.6–60 ng h^?1. Field trapping tests confirmed that aged dispensers from both years were at least as attractive to L. botrana males as a standard monitoring pheromone lure. The possible contribution of previously applied dispensers to the mating disruption efficacy during following applications is discussed.     

One year of pollen monitoring in an urban network,perugia, central italy

Pollen monitoring at three locations in the area of Perugia is reported for the period November 1988-October 1989. A meteorological station which automatically provided data (temperature, precipitation, relative humidity, direction and velocity of wind), was located beside each trap. The study was correlated with a phenological investigation in urban and rural areas surrounding the traps in order to test the validity of using the results as indicators in a monitoring network. The aerobiological data of the three monitoring stations allows the following conclusions: 1) no notable differences were recorded during the principal period of pollination considering the flowering trends of the local anemophilous flora are taking into account, 2) from a quantitative point of view, values from Central Perugia and West Perugia were higher than those from East Perugia, 3) from a qualitative point of view, the station located in the old city area was characterized by a significant presence of Urticaceae pollen, while pollen of the Gramineae was prevalent in the two stations located in the recently built areas.     

Late Triassic, Early and Middle Jurassic Radiolaria from ferromanganese-chert ‘nodules’ (Angelokastron, Argolis, Greece): evidence for prolonged radiolarite sedimentation in the Maliac-Vardar Ocean

In the Argolis, the Basal Sequence, constituting the eastern Pelagonian margin which bordered the Maliac-Vardar oceanic domain, includes shallow-water carbonates of Late Triassic-Early Jurassic, condensed pelagic limestones of Early-Middle Jurassic, radiolarian cherts of late Middle-Late Jurassic age and siliceous mudstones and sandstones rich in ophiolite fragments. Up-section, coarse breccias, including clasts of boninites derived from the ophiolite obducted onto the Pelagonian margin in Late Jurassic times crop out. Near Angelokastron a small quarry exposes pervasively sheared dark reddish-brown, radiolarian-bearing cherty shales with disrupted fragments of chert and chert nodules impregnated by ferro-manganese oxides. These shales occur in the footwall of a thrust bringing them into contact with the Pantokrator Limestone of the Basal Sequence. We collected more than 30 samples of the chert fragments and the shaly matrix. Thirteen nodules and one matrix sample yielded determinable radiolarians. Low to non-detectable concentrations of trace metals such as Co, Cr, Cu, Ni, Zn, and Pb indicate a hydrothermal origin of the ferro-manganese mineralization. The radiolarian taxa found indicate four age groups for the nodules that are embedded in the siliceous shale matrix that yielded a Middle Jurassic age (middle Bathonian). The first group includes a nodule of Late Triassic age (late Norian to Rhaetian); the second group nodules of Early Jurassic age (late early to late Pliensbachian and probably middle-late Toarcian); the third group nodules of early Middle Jurassic age (Aalenian–Bajocian); the last group finally includes nodules of late Middle Jurassic age (Bajocian–Bathonian). The presence of Upper Triassic to Middle Jurassic Mn-impregnated chert nodules in a Middle Jurassic matrix indicates a deep oceanic environment of deposition outside the Pelagonian realm (easternmost Adria Plate), which at that time was a shallow-water carbonate platform with a thin pelagic limestone cover. The chert nodules are with all certainty derived from the oceanic Maliac-Vardar domain and were, together with their host formation, tectonically emplaced onto the Pelagonian margin. We speculate that these nodules, more lithified than their matrix, were exhumed on the slope of an intra-oceanic accretionary wedge and were redeposited in the Middle Jurassic siliceous mudstones on the floor of the subducting Maliac-Vardar Ocean.     

Seed image analysis provides evidence of taxonomic differentiation within the Medicago L. sect. Dendrotelis (Fabaceae)

Morpho-colorimetric quantitative variables describing seed size, shape, colour and texture were analysed using image analysis techniques, in order to evaluate the variability among Medicago taxa sect. Dendrotelis and verify the current taxonomic treatment which divides this section into three species: M. arborea L., M. citrina (Font Quer) Greuter and M. strasseri Greuter, Matthäs & H. Risse. Further comparisons were conducted to discriminate among populations and regions of provenance. Data obtained were statistically analysed applying stepwise Linear Discriminant Analysis method (LDA), recording an overall cross-validated classification performance of 100% at species level. With regard to inter-population comparisons, percentages of correct discrimination above 98% were achieved and high performance was recorded in the discrimination among M. arborea taxa distinguished by region of provenance. For each of these statistical comparisons, the best discriminant variables chosen by the stepwise LDA were related to colour and textural information. Finally, the obtained results confirmed the validity of the proposed method to be highly diagnostic in the statistical assessment of the morpho-colorimetric traits variability of Medicago taxa seeds, both for the taxonomic differentiation at species level and regional and population groups.