Patch dynamics in grazed subtropical native pastures in south-east Queensland

Patch formation is common in grazed grasslands but the mechanisms involved in the formation and maintenance of patches are not clear. To increase our knowledge on this subject we examined possible reasons for patch formation and the influence of management on changes between patch states in three experiments in native pasture communities in the Crows Nest district, south-east Queensland. In these communities, small-scale patches (tall grassland (dominated by large and medium tussock grasses), short swards (dominated by short tussock grasses and sedges), and lawns (dominated by stoloniferous and/or rhizomatous grasses)) are readily apparent. We hypothesized that the formation of short sward and lawn patches in areas of tall grassland was due to combinations of grazing and soil fertility effects. This was tested in Experiment 1 by applying a factorial combination of defoliation, nutrient application and transplants of short tussock and stoloniferous species to a uniform area of tall grassland. Total species density declined during the experiment, was lower with high nutrient applications, but was not affected by defoliation. There were significant changes in abundance of species that provided support for our hypotheses. With light defoliation and low nutrients, the tall grassland remained dominated by large tussock grasses and contained considerable amounts of forbs. With heavy defoliation, the pastures were dominated by medium tussock grasses and there were significant decreases in forbs and increases in sedges (mainly with low nutrients) and stoloniferous grasses (mainly with high nutrients). Total germinable seed densities and those of most species groups were significantly lower in the heavy defoliation than the light defoliation plots. Total soil seed numbers were not affected by nutrient application but there were fewer seeds of the erect forbs and more sedge seeds in plots with high nutrients. The use of resting from grazing and fire to manage transitions between patches was tested. In Experiment 2, changes in species density and abundance were measured for 5 years in the three patch types with and without grazing. Experiment 3 examined the effects of fire, grazing and resting on short sward patches over 4 years. In Experiment 2, total species density was lower in lawn than short sward or tall grassland patches, and there were more species of erect forbs than other plant groups in all patch types. The lawn patches were originally dominated by Cynodon spp. This dominance continued with grazing but in ungrazed patches the abundance of Cynodon spp. declined and that of forbs increased. In the short sward patches, dominance of short tussock grasses continued with grazing but in ungrazed plots their abundance declined while that of large tussock grasses increased. The tall grassland patches remained dominated by large and medium tussock species. In Experiment 3, fire had no effect on species abundance. On the grazed plots the short tussock grasses remained dominant but where the plots were rested from grazing the small tussock grasses declined and the large tussock grasses increased in abundance. The slow and relatively small changes in these experiments over 4 or 5 years showed how stable the composition of these pastures is, and that rapid changes between patch types are unlikely.

The use of recombinant activated factor VII for refractory bleeding post complex cardiothoracic surgery

We reviewed the outcome following use of recombinant activated factor VII (rVIIa) in patients with major bleeding post cardiothoracic surgery in our unit between January 2002 and July 2004. The unit consists of 16 cardiothoracic intensive care beds in a public metropolitan teaching hospital which serves as a referral centre for heart and lung transplant surgery Patients with refactory bleeding following cardiothoracic surgical procedures who were treated with rVIIa were identified. A total of 12 episodes of rVIIa use were recorded in ten patients, including three episodes with ventricular assist devices, and 5 heart and/or lung transplants. The median dose used was 85 mu g/kg. Chest tube drainage decreased in all patients following administration of rVIIa; median chest tube drainage decreased front 445 ml/h to 171 ml/h (P=0.03). Despite cessation of bleeding, mortality was high, when rVIIa was used after more than 24 hours. In six episodes, despite early rVIIa use (within six hours), continued bleeding necessitated return to theatre, where a surgical source of bleeding was found. In this small retrospective study, rVIIa significantly reduced bleeding that was refractory to standard blood product transfusion. In this series of patients., those that did not respond to rVIla early in the postoperative phase were found to have a surgical source of bleeding.

Presumed consent in organ donation: the devil is in the detail

This article follows the recent publication of the Organs for Donation Task Force report, "Organs for Transplants", and considers the debate surrounding a change in the law in favour of presumed consent in organ donation.

The growth of six saxicolous lichens transplanted to lime-rich and lime-poor substrates in south Gwynedd, Wales

The objectives of this study were to investigate: (1) whether foliose lichen thalli could be transplanted from one substrate to another and (2) whether such transplants could be used to study the influence of the substrate on growth. Hence, six saxicolous lichens, with contrasting distributions on lime-rich and lime-poor substrates in South Gwynedd, Wales, were transplanted onto slate, granite, asbestos and cement. Fragments of the perimeters of thalli were glued to the different substrates using Bostic adhesive. Parmelia conspersa (Ehrh. Ex Ach.)Ach. and Parmelia saxatilis (L.)Ach., fragments increased in area over 15 months on slate and granite but decreased in area or did not survive on asbestos and cement. Fragments of Xanthoria parietina (L.)Th.Fr. and Physcia tenella (Scop.)DC. em Bitt. did not survive on slate and granite while some fragments survived but grew poorly on asbestos and cement. Parmelia glabratula ssp. fuliginosa (Fr. ex Duby)Laund. fragments decreased in area on all substrates and especially on cement and asbestos while Physcia orbicularis (Neck.)Poetsch fragments increased in area on granite and cement, decreased on asbestos and did not change significantly on slate. The results suggested that the distribution of P. conspersa and P. saxatilis was determined primarily by physico-chemical properties of the substrate. By contrast, P. glabratula ssp. fuliginosa may have responded to the transplant procedure while X. parietina, Ph. tenella and Ph. orbicularis may require nutrient enrichment to grow successfully on a substrate.

Characterizing the hierarchical structures of bioactive sol-gel silicate glass and hybrid scaffolds for bone regeneration

Bone is the second most widely transplanted tissue after blood. Synthetic alternatives are needed that can reduce the need for transplants and regenerate bone by acting as active temporary templates for bone growth. Bioactive glasses are one of the most promising bone replacement/regeneration materials because they bond to existing bone, are degradable and stimulate new bone growth by the action of their dissolution products on cells. Sol-gel-derived bioactive glasses can be foamed to produce interconnected macropores suitable for tissue ingrowth, particularly cell migration and vascularization and cell penetration. The scaffolds fulfil many of the criteria of an ideal synthetic bone graft, but are not suitable for all bone defect sites because they are brittle. One strategy for improving toughness of the scaffolds without losing their other beneficial properties is to synthesize inorganic/organic hybrids. These hybrids have polymers introduced into the sol-gel process so that the organic and inorganic components interact at the molecular level, providing control over mechanical properties and degradation rates. However, a full understanding of how each feature or property of the glass and hybrid scaffolds affects cellular response is needed to optimize the materials and ensure long-term success and clinical products. This review focuses on the techniques that have been developed for characterizing the hierarchical structures of sol-gel glasses and hybrids, from atomicscale amorphous networks, through the covalent bonding between components in hybrids and nanoporosity, to quantifying open macroporous networks of the scaffolds. Methods for non-destructive in situ monitoring of degradation and bioactivity mechanisms of the materials are also included. © 2012 The Royal Society.

Decellularization of bovine corneas for tissue engineering applications

Scaffolds derived from processed tissues offer viable alternatives to synthetic polymers as biological scaffolds for regenerative medicine. Tissue-derived scaffolds provide an extracellular matrix (ECM) as the starting material for wound healing and the functional reconstruction of tissues, offering a potentially valuable approach for the replacement of damaged or missing tissues. Additionally, acellular tissue may provide a natural microenvironment for host-cell migration and the induction of stem cell differentiation to contribute to tissue regeneration. There are a number of processing methods that aim to stabilize and provide an immunologically inert tissue scaffold. Furthermore, these tissue-processing methods can often be applied to xenogenic transplants because the essential components of the ECM are often maintained between species. In this study, we applied several tissue-processing protocols to the cornea in order to obtain a decellularized cornea matrix that maintained the clarity and mechanical properties of the native tissue. Histology, mechanical testing and electron microscopy techniques were used to assess the cell extraction process and the organization of the remaining ECM. In vitro cell seeding experiments confirmed the processed corneas’ biocompatibility.

Blockade of interleukin 6 signaling improves the survival rate of transplanted bone marrow stromal cells and increases locomotor function in mice with spinal cord injury

Bone marrow stromal cells (BMSCs) have the potential to improve functional recovery in patients with spinal cord injury (SCI); however, they are limited by low survival rates after transplantation in the injured tissue. Our objective was to clarify the effects of a temporal blockade of interleukin 6 (IL-6)/IL-6 receptor (IL-6R) engagement using an anti-mouse IL-6R monoclonal antibody (MR16-1) on the survival rate of BMSCs after their transplantation in a mouse model of contusion SCI. MR16-1 cotreatment improved the survival rate of transplanted BMSCs, allowing some BMSCs to differentiate into neurons and astrocytes, and improved locomotor function recovery compared with BMSC transplantation or MR16-1 treatment alone. The death of transplanted BMSCs could be mainly related to apoptosis rather than necrosis. Transplantation of BMSC with cotreatment of MR16-1 was associated with a decrease of some proinflammatory cytokines, an increase of neurotrophic factors, decreased apoptosis rates of transplanted BMSCs, and enhanced expression of survival factors Akt and extracellular signal-regulated protein kinases 1/2. We conclude that MR16-1 treatment combined with BMSC transplants helped rescue neuronal cells and axons after contusion SCI better than BMSCs alone by modulating the inflammatory/immune responses and decreasing apoptosis. © 2013 by the American Association of Neuropathologists, Inc.

Early transplantation of mesenchymal stem cells after spinal cord injury relieves pain hypersensitivity through suppression of pain-related signaling cascades and reduced inflammatory cell recruitment

Bone marrow-derived mesenchymal stem cells (BMSC) modulate inflammatory/immune responses and promote motor functional recovery after spinal cord injury (SCI). However, the effects of BMSC transplantation on central neuropathic pain and neuronal hyperexcitability after SCI remain elusive. This is of importance because BMSC-based therapies have been proposed for clinical treatment. We investigated the effects of BMSC transplantation on pain hypersensitivity in green fluorescent protein (GFP)-positive bone marrow-chimeric mice subjected to a contusion SCI, and the mechanisms of such effects. BMSC transplantation at day 3 post-SCI improved motor function and relieved SCI-induced hypersensitivities to mechanical and thermal stimulation. The pain improvements were mediated by suppression of protein kinase C-γ and phosphocyclic AMP response element binding protein expression in dorsal horn neurons. BMSC transplants significantly reduced levels of p-p38 mitogen-activated protein kinase and extracellular signal-regulated kinase (p-ERK1/2) in both hematogenous macrophages and resident microglia and significantly reduced the infiltration of CD11b and GFP double-positive hematogenous macrophages without decreasing the CD11b-positive and GFP-negative activated spinal-microglia population. BMSC transplants prevented hematogenous macrophages recruitment by restoration of the blood-spinal cord barrier (BSCB), which was associated with decreased levels of (a) inflammatory cytokines (tumor necrosis factor-α, interleukin-6); (b) mediators of early secondary vascular pathogenesis (matrix metallopeptidase 9); (c) macrophage recruiting factors (CCL2, CCL5, and CXCL10), but increased levels of a microglial stimulating factor (granulocyte-macrophage colony-stimulating factor). These findings support the use of BMSC transplants for SCI treatment. Furthermore, they suggest that BMSC reduce neuropathic pain through a variety of related mechanisms that include neuronal sparing and restoration of the disturbed BSCB, mediated through modulation of the activity of spinal-resident microglia and the activity and recruitment of hematogenous macrophages.

The role of disturbance and resource availability in structuring plant communities

Disturbances alter competitive hierarchies by reducing populations and altering resource regimes. The interaction between disturbance and resource availability may strongly influence the structure of plant communities, as observed in the recolonization of seagrass beds in outer Florida Bay that were denuded by sea-urchin overgrazing. There is no consensus concerning the interaction between disturbance and resource availability on competition intensity (CI). On the other hand, species diversity is dependent on both factors. Peaks in species diversity have been observed to occur when both resource availability and disturbance intensity are high, thus implying that CI is low. Based on this supposition of previous models, I presented the resource-disturbance hypothesis as a graphical model to make predictions of CI as a function of both disturbance intensity and the availability of a limiting resource. The predictions of this model were tested in two experiments within a seagrass community in south Florida, in which transplants of Halodule wrightii were placed into near-monocultures of Syringodium filiforme in a full-factorial array. In the first experiment, two measures of relative CI were calculated based on the changes in the short-shoot number (SS) and of rhizome length (RHL) on the transplants. Both light and disturbance were identified as important factors, though the interaction between light * disturbance was not significant. Relative CISS ranged between 0.2 and 1.0 for the high light and high disturbance treatments and the relative CIRHL < 0 for the same treatments, though results were not significantly different due to high variability and low sample size. These results, including a contour schematic using six data points from the different treatment combinations, preliminarily suggests that the resource-disturbance hypothesis may be used may be used as a next step in developing our understanding of the mechanisms involved in structuring plant communities. Furthermore, the focus of the model is on the outcome of CI, which may be a useful predictor of changes in species diversity. Further study is needed to confirm the results of this study and validate the usefulness of this model in other systems. ^

Potential for Cell-Transplant Therapy with Human Neuronal Precursors to Treat Neuropathic Pain in Models of PNS and CNS Injury: Comparison of hNT2.17 and hNT2.19 Cell Lines

Effective treatment of sensory neuropathies in peripheral neuropathies and spinal cord injury (SCI) is one of the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord is a logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the potential of transplant of cells to treat chronic pain. Cell lines derived from the human neuronal NT2 cell line parentage, the hNT2.17 and hNT2.19 lines, which synthesize and release the neurotransmitters gamma-aminobutyric acid (GABA) and serotonin (5HT), respectively, have been used to evaluate the potential of cell-based release of antinociceptive agents near the lumbar dorsal (horn) spinal sensory cell centers to relieve neuropathic pain after PNS (partial nerve and diabetes-related injury) and CNS (spinal cord injury) damage in rat models. Both cell lines transplants potently and permanently reverse behavioral hypersensitivity without inducing tumors or other complications after grafting. Functioning as cellular minipumps for antinociception, human neuronal precursors, like these NT2-derived cell lines, would likely provide a useful adjuvant or replacement for current pharmacological treatments for neuropathic pain.

The role of teleost grazers in a relatively pristine seagrass ecosystem

Trophic downgrading of ecosystems necessitates a functional understanding of trophic cascades. Identifying the presence of cascades, and the mechanisms through which they occur, is particularly important for seagrass meadows, which are among the most threatened ecosystems on Earth. Shark Bay, Western Australia provides a model system to investigate the potential importance of top-down effects in a relatively pristine seagrass ecosystem. The role of megagrazers in the Shark Bay system has been previously investigated, but the role of macrograzers (i.e., teleosts), and their importance relative to megagrazers, remains unknown. The objective of my dissertation was to elucidate the importance of teleost macrograzers in transmitting top-down effects in seagrass ecosystems. Seagrasses and macroalgae were the main food of the abundant teleost Pelates octolineatus, but stable isotopic values suggested that algae may contribute a larger portion of assimilated food than suggested by gut contents. Pelates octolineatus is at risk from numerous predators, with pied cormorants (Phalacrocorax varius) taking the majority of tethered P. octolineatus. Using a combination of fish trapping and unbaited underwater video surveillance, I found that the relative abundance of P. octolineatus was greater in interior areas of seagrass banks during the cold season, and that the mean length of P. octolineatus was greater in these areas compared to along edges of banks. Finally, I used seagrass transplants and exclosure experiments to determine the relative effect of megagrazers and macrograzers on the establishment and persistence of three species of seagrasses in interior microhabitats. Teleost grazing had the largest impact on seagrass species with the highest nutrient content, and these impacts were primarily observed during the warm season. My findings are consistent with predictions of a behaviorally-mediated trophic cascade initiated by tiger sharks (Galeocerdo cuvier) and transmitted through herbivorous fishes and their predators.

Análise imunoistoquímica após terapia fotodinâmica com cloro-alumínio ftalocianina em tecidos gengivais de humanos

Although photodynamic therapy have been used as a useful tool over the past 30 years in oncology, few clinical trials have been conducted in dentistry. Photodynamic therapy (PDT) uses non - toxic photosensitizers and selective which are administered in target cells followed by local application of visible light, producing reactive oxygen species capable of causing cell death by apoptosis or necrosis, injured the local vasculature, and exert important effects on the im mune system. New generations of photosensitizing agents, such as nanoparticulate phthalocyanines, has shown excellent results in antitumor and antibacterial activity . In this context, the present work constitutes the first clinical protocol of local appli cation of nanoemulsion chloro - aluminum phthalocyanine (AlClFc) followed by irradiation in human gingiva, and analyzed descriptively and comparatively , by means of immunohistochemistry , the expression of RANK , RANKL , OPG and VEGF in a split - mouth model . Eight healthy volunteers with clinical indication for extraction were included in the study . Seven days before the extraction, was injected in the gingiva of participants, 5 μ M of nanoemulsion AlClFc followed by irra diation with diode laser (660nm , 7 J/cm2 ), the contralateral side was used as control. Tissue specimens were removed seven days after the TFD is performed. Tissues sample were divided into two groups (test and con trol groups) for histological and immunohistochemical analysis. Patients were monitored at days, 0, 7, 14 and 30 to assess adverse effects of the therapy. Vascular alterations were seen in gingival samples that received PDT. Areas of edema and vascular con gestion, and intense vascularization were viewed . Additionally, dystrophic calcification in subepithelial region were observed in the test group. The results showed a similar pattern of immunostaining scores of RANK, RANKL and VEGF between the test and co ntrol groups, with no statistically significant difference (p = 0.317, p = 0.777, p = 0 .814, respectively). RANK and RANKL exhibited weak or absent immunostaining in most specimens analyzed. There was n o immunostaining for OPG. VEGF showed moderate to stro ng immunostaining in specimens from the test group. In addition, the clinical study showed that therapy was well tolerated by all patients. Adverse effects were short - time and completely reversible. Taken together, the results presented in this study showe d that PDT mediated by nanoemulsion containing AlClPc is safe for clinical application in gingival tissue and suggests that a strong immunostaining for VEGF after therapy .

Análise da imuno expressão das proteínas IL-17, IL-23 E RORγt na patogenia da doença periodontal

Periodontal disease is a chronic inflammatory condition primarily caused by bacteria in dental biofilm, which interact with the host, thus determining the nature of the resulting disease. Despite the wide knowledge about the pathogenesis of these diseases, the exact composition of the T cell profile during the active phase of the disease (Th1, Th2 or Th17) remains unknown. This study aimed to evaluate by immunohistochemical expression, the presence of the markers (IL-17, IL-23 and RORγt), involved in Th17 response in clinically healthy gingiva cases (n = 32), biofilm-induced gingivitis (n = 30), chronic periodontitis (n = 32) and aggressive periodontitis (n = 25), in order to analyze if the expression and/or distribution of these molecules in lymphocytes and macrophages, present in the inflammatory infiltrate of periodontal tissue, influences the tissue destruction observed in these diseases. The morphological analysis of cases was performed which assessed the intensity of the inflammatory infiltrate in mild, moderate and intense. For each case, in the area with the most representative immunostaining, 5 fields were chosen and analyzed, both for the intensity of the inflammatory infiltrate as for the quantity of immunostained cells, based on predetermined scores: score 0 (absence of inflammatory infiltrate/immunostaining), score 1 (the infiltrate/immunostaining covered less than 25% of the field area), score 2 (the infiltrate/immunostaining occupied between 25 and 50%) and score 3 (infiltrate/immunostaining present in over 50% of the field area). From this, a median was generated representing each case. The intensity of the inflammatory infiltrate correlated with the disease progression, in other words, it was crescent from clinically healthy gingiva to aggressive periodontitis (P <0.001). It was detected the presence of IL-17, IL-23 and RORγt in most of the evaluated cases and the number of immunostained cells correlated with the intensity of the inflammatory infiltrate (P <0.001) and with the clinical parameters analyzed (P <0.001), showing a positive correlation, mainly moderate. Aggressive periodontitis showed a higher percentage of immunostaining for all markers in relation to other clinical conditions assessed, suggesting a possible association of these markers with the progression of this disease, in which the higher the loss of periodontal support, the greater the amount of inflammatory infiltrate and larger the number of immunostained cells.

Transplantes de córneas no estado do Rio Grande do Norte: aspectos epidemiológicos e clínicos

This study aimed to characterize in a clinical and epidemiological way the patients who are on a waiting list for transplantation and the patients transplanted with corneal tissue in a corneal transplants reference service in the state of Rio Grande do Norte. It is an epidemiological study of a quantitative approach, with cross-sectional, descriptive and analytical cut including all patients on the waiting list for transplantation (population A) and the patients already transplanted with a corneal tissue (population B) in a reference service. In population A, there was a census conducted of patients on the waiting list for corneal transplantation (n=62 patients). In population B, the sample was non-probabilistic and corresponded to all corneal transplants performed in the service in the period from 2010 to 2014 (n=258). This study is approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, in Opinion 876 177 and CAAE 37533014.8.0000.5537. Data were collected in full in the period from January to April 2015, by two instruments built to systematize the necessary data collection. After being coded and tabulated, data were analyzed using the Statistical Package for Social Sciences software, version 20.0. The definition of variables and their distribution patterns were presented as frequencies and measures of central tendency while, for multivariate analysis, the effect of magnitude measures were applied (prevalence ratio) and measures of association (chi-square test or Fisher's exact test) for a 0.05 significance level. The results are shown in two scientific articles coming from the field survey data. It was found that the epidemiological profile of patients on the waiting list (n=62) showed a prevalence of individuals aged over 50 years old, female (54.84%) and residents of the middle region of East Rio Grande do Norte (66.13%). The clinical profile of patients with corneal transplantation (n=258) was characterized by being male (51.16%) with an average age of 49.33 years old and 57.75% were coming from East Rio Grande do Norte. The average time on the waiting list was 172.63 days in elective transplants and 9.03 days in urgent transplants. Keratoconus was the main indicator condition to perform the transplant. For patients on the waiting list, the variable “type of disorder of the cornea” showed statistically significant association with gender and age. For patients with corneal transplants, the variable "type of disorder of the cornea" was associated with the variables gender, age, previous surgery, failure of previous graft, classification of the eye and glaucoma. By characterizing the clinical and epidemiological profile of corneal transplants, it is possible to question the reality, pointing about the care that should be offered and develop targeted interventions to collective and individual needs intrinsic to patients who need this surgery as a treatment option.

Epítese gengival removível: alternativa estética e de rápida resolução para repor tecidos periodontais anteriores

The gingiva, part of the masticatory mucosa tissue that covers the alveolar process and surrounds the cervical portion of teeth, has a definitive shape and texture associated with the eruption of teeth. Therefore, it must be included in rehabilitative planning, as the absence of papillae induces problems with esthetics, phonetics and food-impaction. The purpose of the present study was to approach the indications, limitations and techniques for making a removable artificial gingiva made of acrylic resin, by reporting on a clinical case. The patient, a 29-year-old woman, with the sequelae of periodontal disease, presented loss of interdental papilla causing “black holes”. She was dissatisfied with the esthetic appearance of her teeth, and also complained of long teeth and air escaping when she spoke. As treatment, prosthetic reconstruction was proposed, by means of a removable artificial gingiva (gingival epithesis) to simulate the presence of interdental papillae, providing better esthetics and phonetics. Gingival epithesis is an easily made, inserted and hygienically cleaned appliance that provides a simple and safe alternative solution for cases in which surgical techniques are limited.