Home About us Contact
|
Home About us Contact | ||
|
|
||
Favourable Environment (favourable + environment)
Selected AbstractsMigration of cells into and out of peripheral nerve isografts in the peripheral and central nervous systems of the adult mouseEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2001Natalie A. Symons Abstract Peripheral nerve (PN) isografts provide a favourable environment for axon regeneration after peripheral and central nervous system (CNS) injury, but definitive information on the extent of cellular intermixing between donor and host tissues is lacking. We wished to compare migration patterns in fresh and predegenerate PN grafts, and also compare the extent of cell migration after transplantation to peripheral nervous system (PNS) versus CNS. To discern how host and donor cells interact after PN transplantation, sciatic nerve segments were transplanted from inbred adult mice into PN defects (PN,PN grafts) or into lesioned cerebral cortex of opposite gender siblings. Migrating male cells were identified using a Y-chromosome-specific probe and in situ hybridization methods, and characterized immunohistochemically. The extent of donor and host cellular intermixing was similar in fresh and predegenerate PN,PN isografts. There was substantial intermixing of donor and host cells by 8 days. Many host cells migrating into epineurial regions of grafts were immunopositive for F4/80 (macrophages). The endoneurium of grafted PN was also colonized by host cells; some were F4/80+ but many were immunostained with S-100 (Schwann cell marker). Donor S-100+ Schwann cells rapidly migrated out into proximal and distal host PN and by 12 weeks were found at least 2 mm from the grafts. Endoneurial microvessels in grafts were mostly donor-derived. By comparison, in male PN grafts to female CNS, even after 6 weeks few donor cells had migrated out into surrounding host cortex, despite the observation that almost all grafts contained regenerating axons and were thus attached to host CNS tissue. [source] Stromal cells promote bone invasion by suppressing bone formation in ameloblastomaHISTOPATHOLOGY, Issue 4 2008G S A Sathi Aims:, To study the stromal variation and role of stromal,tumour cell interaction in impaired bone formation as well as enhanced bone resorption in ameloblastoma. Methods and results:, Four types of stroma were observed histologically; fibrous, desmoplastic, myxoid and myxoid with hyalinization. Osteoblast and osteoclast were counted using haematoxylin and eosin sections and immunohistochemistry with CD68. After histomorphometric analysis, only fibrous and myxoid types of stroma were distinctly identified. Secreted frizzled-related peptide (sFRP)-2, transforming growth factor-beta 1 and receptor activator of nuclear factor-,B ligand (RANKL) revealed strong expression in myxoid type compared with the normal stroma. Bone morphogenetic protein (BMP)-2 was negative in myxoid type, but positive in normal stroma. Fibrous-type stroma showed weak expression of all antigens except RANKL compared with myxoid type. Conclusions:, The results suggest that stroma does not act only in bone resorption, but also in the suppression of new bone formation. sFRP-2 is the main factor for impaired bone formation. The expression of markers related to osteoclastogenesis and suppression of osteoblast formation is higher in myxoid-type than in fibrous-type stroma. Tumour cells create a favourable environment for impaired bone formation by secreting sFRP-2 as well as bone resorption by secreting RANKL and interleukin-6. [source] TGF-,1 alone and in combination with calcium hydroxide is synergistic to TGF-,1 production by osteoblasts in vitroINTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2000A. Jaunberzins Abstract Aim To examine the effects of calcium hydroxide (Ca(OH)2), transforming growth factor-beta (TGF-,1), and Ca(OH)2/TGF-,1 coadministration on TGF-,1 and interleukin-6 (IL-6) synthesis by early (subculture 1) and late (subculture 5) osteoblast cultures. Methodology Early and late cultures were established using bone cells harvested from 21-day-old fetal rat calvaria. Cell cultures of both early and late osteoblasts were divided into four groups: group 1, control; group 2, cells challenged with Ca(OH)2; group 3, cells challenged with TGF-,1; and group 4, cells challenged with Ca(OH)2 and TGF-,1 in combination. TGF-,1 and IL-6 levels for all groups were determined using ELISA methodology. Results anova and Tukey HS analyses revealed that osteoblasts of groups 3 and 4 significantly increased (P < 0.001) TGF-,1 synthesis in both early and late cultures of osteoblasts. IL-6 was not detected in any of the groups considered in this study. Conclusions Exogenous TGF-,1 has an autocrine effect on cell cultures of osteoblasts. Administration of TGF-,1 alone or in combination with Ca(OH)2 increases the synthesis of TGF-,1 in osteoblast cultures. Ca(OH)2 and TGF-,1 are compatible when placed in a culture of osteoblasts. Ca(OH)2 provides a favourable environment for the anabolic effects of TGF-,1. [source] Heterogeneous genetic structure in a Fagus crenata population in an old-growth beech forest revealed by microsatellite markersMOLECULAR ECOLOGY, Issue 5 2004Y. Asuka Abstract The within-population genetic structure of Fagus crenata in a 4-ha plot (200 × 200 m) of an old-growth beech forest was analysed using microsatellite markers. To assess the genetic structure, Moran's I spatial autocorrelation coefficient was calculated. Correlograms of Moran's I showed significant positive values less than 0.100 for short-distance classes, indicating weak genetic structure. The genetic structure within the population is created by limited seed dispersal, and is probably weakened by overlapping seed shadow, secondary seed dispersal, extensive pollen flow and the thinning process. Genetic structure was detected in a western subplot of 50 × 200 m with immature soils and almost no dwarf bamboos (Sasa spp.), where small and intermediate-sized individuals were distributed in aggregations with high density because of successful regeneration. By contrast, genetic structure was not found in an eastern subplot of the same size with mature soils and Sasa cover, where successful regeneration was prevented, and the density of the small and intermediate-sized individuals was low. Moreover, genetic structure of individuals in a small-size class (diameter at breast height < 12 cm) was more obvious than in a large-size class (diameter at breast height , 12 cm). The apparent genetic structure detected in the 4-ha plot was therefore probably the result of the structure in the western portion of the plot and in small and intermediate-sized individuals that successfully regenerated under the favourable environment. The heterogeneity in genetic structure presumably reflects variation in the density that should be affected by differences in regeneration dynamics associated with heterogeneity in environmental conditions. [source] A novel model of wound healing in the SCID mouse using a cultured human skin substituteAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 1 2009Martin L Windsor SUMMARY Studies of skin graft behaviour in rodent excisional wound models are limited by the dominance of wound contracture and graft sloughing as primary healing responses. To slow skin contraction, polytetrafluoroethylene (Teflon) rings were inserted into dorso-lateral full-thickness wounds in SCID mice. Cultured skin substitutes (OrCel), composed of cultured human keratinocytes and fibroblasts in a bovine collagen sponge, were implanted within the rings. Examination and histology of grafts 14 days later showed graft take in four of six recipients, with 90% epithelialization and wound contraction of 31,47%. Immunohistochemical studies, using human-specific antisera to distinguish graft from host tissues, showed that regenerated tissue was predominantly human. Staining with anticytokeratin, revealed a multilayered, stratified neoepidermis. HBG were identified in keratinocytes in all epidermal layers. Langerhans cells were absent. Antihuman vimentin, used as a fibroblast marker, confirmed that cells of the neodermis were primarily of human origin. Neoepidermal keratinocytes, primarily in the basal and suprabasal layers, were also stained. Results suggest that the poly(tetrafluoroethylene) ring inhibited graft sloughing and provided a more favourable environment for the skin substitute to regenerate a substantially normal human skin. [source] Strategies for the endodontic management of concurrent endodontic and periodontal diseasesAUSTRALIAN DENTAL JOURNAL, Issue 2009PV Abbott Abstract Endodontic and periodontal diseases can provide many diagnostic and management challenges to clinicians, particularly when they occur concurrently. As with all diseases, a thorough history combined with comprehensive clinical and radiographic examinations are all required so an accurate diagnosis can be made. This is essential since the diagnosis will determine the type and sequence of treatment required. This paper reviews the relevant literature and proposes a new classification for concurrent endodontic and periodontal diseases. This classification is a simple one that will help clinicians to formulate management plans for when these diseases occur concurrently. The key aspects are to determine whether both types of diseases are present, rather than just having manifestations of one disease in the alternate tissue. Once it is established that both diseases are present and that they are as a result of infections of each tissue, then the clinician must determine whether the two diseases communicate via the periodontal pocket so that appropriate management can be provided using the guidelines outlined. In general, if the root canal system is infected, endodontic treatment should be commenced prior to any periodontal therapy in order to remove the intracanal infection before any cementum is removed. This avoids several complications and provides a more favourable environment for periodontal repair. The endodontic treatment can be completed before periodontal treatment is provided when there is no communication between the disease processes. However, when there is communication between the two disease processes, then the root canals should be medicated until the periodontal treatment has been completed and the overall prognosis of the tooth has been reassessed as being favourable. The use of non-toxic intracanal therapeutic medicaments is essential to destroy bacteria and to help encourage tissue repair. [source] Listeria monocytogenes infection in the face of innate immunityCELLULAR MICROBIOLOGY, Issue 5 2009Sinead C. Corr Summary Pathogen recognition and induction of immune responses are important for efficient elimination of infection. However, pathogens such as Listeria monocytogenes employ strategies to evade or modulate these defences, thus creating a more favourable environment that ensures their survival and pathogenesis. New insights into these strategies, particularly those targeting innate immunity, have recently emerged. L. monocytogenes is initially detected at the cell surface or in phagosomes by toll-like receptor 2 and in the cytosol by nuclear oligodimerization domain (NOD)-like receptors (NOD1, NOD2) and NALP3 and Ipaf. It carries out N-deacetylation of peptidoglycan to avoid this detection by toll-like receptor 2 and NOD-like receptors. L. monocytogenes modulates transcription of host immunity genes through modification of histones and chromatin remodelling. Furthermore, L. monocytogenes has recently been shown to avoid autophagy and induce apoptosis in immune effector cells. In this review we discuss some of these strategies, which have provided new insights into the interaction between L. monocytogenes and the immune response at a crucial stage of infection. [source] Nail infestation by Liposcelis bostrychophila BadonnelCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 6 2004Y.-C. Lin Summary We report an unusual case of nail infestation by Liposcelis bostrychophila Badonnel in a 70-year-old woman with onychomycosis. Liposcelis spp., also known as booklouse, are tiny insects that feed on fungi, lichen and decaying materials. In this case, the loosened hyperkeratotic nail provided a favourable environment for these insects. This is the second report of human infestation by Liposcelis spp. [source] Bacterial population dynamics and community structure in a pharmaceutical manufacturing water supply system determined by real-time PCR and PCR-denaturing gradient gel electrophoresisJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004M. Kawai Abstract Aims:, To control bacteria in the pharmaceutical water supply system. Methods and Results:, Bacteria were enumerated by conventional culture method and fluorescent vital staining. Activated carbon treatment and storage in a tank provided favourable environments for bacterial growth. The bacterial population of the water in both the post-activated carbon treatment and the tank was analysed by denaturing gradient gel electrophoresis (DGGE) with PCR-amplified 16S rDNA fragments including V6, -7, and -8 regions. The bacterial community structure in activated carbon treated water was stable throughout the year. Several kinds of bacteria such as genus Aquaspirillum and Methylobacterium were found in the water after activated carbon treatment. The bacterial community structure was changed and other bacteria such as mycobacteria were detected after storage. Mycobacteria were quantified in water samples using real-time PCR targeting the 16S rDNA gene. Mycobacteria were also detected in tap water and their number was increased 103,104 -fold higher after storage. Conclusion:, These data suggest the importance of culture-independent methods for quality control of water used in pharmaceutical manufacturing. Significance and Impact of the Study:, Critical steps and specified bacteria that should be controlled in the water supply system were recognized by culture-independent methods. These data will enable effective control of water used in the pharmaceutical industry. [source] Nitrogen fertilisation in coriander (Coriandrum sativum L.): a review and meta-analysisJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2009Alessandra Carrubba Abstract Nitrogen (N) fertilisation is one of the most important external inputs in assessing coriander seed yield and plant growth. Recent concerns related to the misuse of N fertilisers in agricultural environments, however, stress the opportunity for a fine-tuning of N management in order to optimise the use of this element, avoiding losses and reducing environmental hazards. In this study, some results from the literature concerning N fertilisation in coriander are reviewed and, by means of statistical analysis, an attempt is made to derive from them some general suggestions about practices of N fertilisation. In most cases examined, N fertilisation allowed a 10,70% increase in seed yields in comparison with each respective untreated control. The efficiency of use of this element, however, has proven to be greatly dependent on the overall fertility conditions of the growing site. The greatest yield advantages were actually found in more favourable environments, whereas in low-yielding environments plants reached their maximum yield with a comparatively reduced N supply. In low-yielding environments a careful risk/benefit assessment of this practice is therefore advisable. No definite conclusion could be drawn at this stage about essential oil yield and composition in relation to N fertilisation. Copyright © 2009 Society of Chemical Industry [source] Photosynthesis and water-use efficiency: A comparison between invasive (exotic) and non-invasive (native) speciesAUSTRAL ECOLOGY, Issue 1 2008KATE G. MCALPINE Abstract Invasive species have been hypothesized to out-compete natives though either a Jack-of-all-trades strategy, where they are able to utilize resources effectively in unfavourable environments, a master-of-some, where resource utilization is greater than its competitors in favourable environments, or a combination of the two (Jack-and-master). We examined the invasive strategy of Berberis darwinii in New Zealand compared with four co-occurring native species by examining germination, seedling survival, photosynthetic characteristics and water-use efficiency of adult plants, in sun and shade environments. Berberis darwinii seeds germinated more in shady sites than the other natives, but survival was low. In contrast, while germination of B. darwinii was the same as the native species in sunny sites, seedling survival after 18 months was nearly twice that of the all native species. The maximum photosynthetic rate of B. darwinii was nearly double that of all native species in the sun, but was similar among all species in the shade. Other photosynthetic traits (quantum yield and stomatal conductance) did not generally differ between B. darwinii and the native species, regardless of light environment. Berberis darwinii had more positive values of ,13C than the four native species, suggesting that it gains more carbon per unit water transpired than the competing native species. These results suggest that the invasion success of B. darwinii may be partially explained by combination of a Jack-of-all-trades scenario of widespread germination with a master-of-some scenario through its ability to photosynthesize at higher rates in the sun and, hence, gain a rapid height and biomass advantage over native species in favourable environments. [source] | |||||||||||||