630 research outputs found

    Diagnosis and Treatment of the Modern Backache

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    There are two reasonably clear-cut forms of backache that lend themselves to a reasonably straight-forward form of treatment. These are (1) the ruptured intervertebral disc and (2) the degenerated intervertebral disc. In both instances, once a diagnosis can be reasonably made, treatment is at first conservative, and this form of treatment frequently issuccessful. In the absence of success, an operative procedure is available which offers reasonable hope of correction of the difficulty

    Complement increases release of proinflammatory and proangiogenic mediators by retinal pigment epithelial cells

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    Objectives. A mutation in complement factor H (CFH) gene, leading to augmented complement activation, is correlated with development of age-related macular degeneration (AMD). Therefore, the influence of complement on retinal pigment epithelial (RPE) cells was examined concerning their production of proinflammatory and proangiogenic mediators relevant in AMD. Methods. ARPE-19 cells were cultured with human or fetal calf serum (FCS). Therefore, complement containing native serum as well as the heat-inactivated form with inoperable complement was used. Further, RPE cells were treated with zymosan, a complement activating yeast particle. Serum and zymosan in combination was also tested. Levels of interleukin (IL)-6, -8 and vascular endothelial growth factor (VEGF) in supernatants were examined by ELISA. Results. Untreated RPE cells produced IL-6, -8 and VEGF constitutively. FCS or human serum led to a concentration dependent release of all mediators. Thereby, FCS increased the cytokine production stronger than human serum, native serum stronger than heat-inactivated. Zymosan only intensified IL-6 and -8 secretion. Combined treatment with serum and zymosan resulted in an additive release of IL-8 and VEGF. In contrast, secretion of IL-6 was synergistic. Conclusion. The enhanced expression of IL-6, -8 and VEGF by RPE after exposure to complement might explain the correlation between augmented complement production and inflammatory processes accompanying AMD. IL-6 production was strongly increased due to activation of complement within the serum by zymosan. Thus, complement activation could stimulate inflammatory processes by activated RPE cells leading to AMD

    Assessing cellular response to functionalized α-helical peptide hydrogels

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    α-Helical peptide hydrogels are decorated with a cell-binding peptide motif (RGDS), which is shown to promote adhesion, proliferation, and differentiation of PC12 cells. Gel structure and integrity are maintained after functionalization. This opens possibilities for the bottom-up design and engineering of complex functional scaffolds for 2D and 3D cell cultures.</p

    Retinal pigment epithelial cells respond to complement by an augmented production of vitronectin

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    Objectives: Genetic studies have demonstrated the role of activated complement on the alternative pathway during the development of age-related macular degeneration (AMD). The extracellular matrix component vitronectin can protect against activated complement. Drusen appear in the retina between the retinal pigment epithelial (RPE) cell layer and Bruch’s membrane. Drusen are hallmarks of early and late AMD and contain high amounts of vitronectin. Therefore this study addressed the influence of complement on the vitronectin production by RPE cells. Methods: ARPE-19 cells as model for RPE cells were cultivated with increasing amounts of human serum as complement source in its naïve and heat (and thereby complement) inactivated form. In another series of experiments zymosan as an activator of the alternative pathway of complement was tested alone and in combination with naïve human serum. Vitronectin was assayed in situ by immunohistochemistry, on protein level by western blot and by PCR after reverse transcription of total RNA. Results: A constitutive production of vitronectin by RPE cells was detected by all three tests. With naïve human serum increased vitronectin protein was found by immunohistochemistry and western blot while the number of mRNA transcripts was not significantly altered. The vitronectin production was further enhanced with the combination of zymosan and naïve human serum while heat inactivated serum showed lesser effect. Conclusion: Activated complement lead to an augmented vitronectin production by RPE cells on post-transcriptional level. Enhanced complement activation during AMD might also contribute in vivo to an enhanced production of vitronectin by RPE cells. On the one hand this can cause protection against activated complement but on the other hand the increased retinal vitronectin might contribute to thickening of Bruch’s membrane and may facilitate the development of drusen

    The ratio of pro- and anti-angiogenic cytokines produced by retinal pigment epithelial cells is shifted to support angiogenesis by complement

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    Purpose The complement system of age-related macular degeneration (AMD) patients is marginally but chronically over-activated. Retinal pigment epithelial (RPE) cells and photoreceptor cells undergo cell death during the development of this potentially blinding eye disease. In this study the balance between the pro-angiogenic vascular endothelial growth factor (VEGF) and the anti-angiogenic pigment epithelium-derived factor (PEDF) by RPE cells in response to complement serum was analysed. Methods Increasing concentrations of complement competent human serum were incubated with human RPE cells. Controls with the addition of zymosan to activate the complement cascade, zymosan alone, and heat-treated serum with inoperative complement were included. The secretion of VEGF and PEDF was measured by sandwich ELISA. Immunocytochemistry was performed for the in situ detection of VEGF and PEDF. The experiments were supplemented by RT-PCR expression analysis and Western Blot detection of both antagonists. Results Human complement competent serum stimulated the RPE cells to produce enhanced amounts of VEGF while unspecific stimuli showed no influence on the secretion of VEGF. The combination of complement competent serum and zymosan was revealed as the most effective treatment for an increased VEGF production. The PEDF-specific staining of RPE cells decreased with augmented concentrations of complement competent serum. PCR data showed an enhanced amount of VEGF-encoding transcripts and an unaltered or lower amount of PEDF-specific transcripts. Western Blots confirmed the shift in favour of VEGF when compared to PEDF after complement treatment of RPE cells. Conclusions Activated complement may shift the balance between VEGF and PEDF produced by RPE cells towards the blood vessel chemoattractant VEGF. This finding may reveal a mechanism how enhanced complement activation might contribute to a pro-angiogenic retinal environment supporting neovascularisation during the late stage of exsudative AMD

    Human Complement Sera stimulates Basolateral Secretion of VEGF by Retinal Pigment Epithelial Cells

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    Purpose. A mutation in the complement factor H (CFH) gene, leading to increased complement activation, is correlated with the development of age-related macular degeneration (AMD). Therefore, the influence of complement on human retinal pigment epithelial (RPE) cells was examined in respect to their polarized secretion of vascular endothelial growth factor (VEGF). Methods. RPE cells were cultured on transwell filters with DMEM and 1 % foetal calf serum. At six weeks post confluence, when the RPE have pigmented, the density of the cell monolayer was measured by a permeability assay using sodium fluorescein. The cells were treated with human complement sera for 24 hours. The amount of VEGF secreted into the media was quantified by enzyme-linked immunosorbent assay. Furthermore, the cellular distribution of VEGF in complement treated cells grown in chamber slides was detected by immunocytochemistry, and PCR analysis was used to determine the expression of the growth factor in RPE cells. Results. Untreated RPE cells produced VEGF constitutively. Basal stimulation of polarized cells with human complement sera led to a concentration dependent increased release of the growth factor towards the basal compartment. Immunocytochemical staining and PCR analysis for VEGF also demonstrated a concentration dependent enhancement in response to complement. Conclusions. VEGF production towards the basal side was strongly increased when RPE cells were exposed to human complement sera applied to the basal side. Therefore, complement might play a significant role in AMD, as VEGF is known to stimulate vessel growth in the choroid and support pro-angiogenic processes

    Complement stimulates Retinal Pigment Epithelial Cells to undergo Pro-inflammatory Changes as in Early Age-Related Macular Degeneration

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    Purpose. A polymorphism in the complement factor H gene, leading to increased complement activation, is associated with the development of age-related macular degeneration (AMD). We therefore examined the effect of human complement sera (HCS) on retinal pigment epithelial (RPE) cells with respect to pro-inflammatory mediators relevant in early AMD. Methods. RPE cells were treated with HCS or heat-inactivated (HI)-HCS as a complement-deficient control. Cells were stained for C5b-9 using immunocytochemistry and immunofluorescence, and cell viability was determined. Interleukin (IL) -6, -8 and monocyte chemoattractant protein-1 (MCP-1) were quantified by ELISA and their expression was determined by RT-PCR. Intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and tumour necrosis factor-α (TNF-α) were analysed by western blotting. The intracellular distribution of nuclear factor (NF)-ƙB was investigated by immunofluorescence. Results. Concentration-dependent increased staining for C5b-9 was observed after HCS treatment, whereas cell viability decreased. ELISA and RT-PCR analysis revealed increased secretion and expression of IL-6, -8 and MCP-1. Western blot analysis showed a concentration-dependent enhancement in ICAM-1, VCAM-1 and TNF-α in response to HCS, and immunofluorescence staining revealed cytosolic to nuclear translocation of NF-ƙB. Conclusions. This study suggests that complement may stimulate RPE cells to create a pro-inflammatory environment via NF-ƙB activation which may support early AMD development

    A Grounded Theory of Veterans’ Experiences of Addiction-as-Occupation

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    This study examined how addiction emerges as an occupation in the lives of veterans. Its purpose was to facilitate better knowledge of how addiction is experienced as an occupation by this population, with the goal of destigmatizing addiction and paving the way for innovative ways to help people with addictions to build new occupational lives. Fifty-eight veterans diagnosed with a substance use disorder were recruited from a VA residential treatment center, of which 35 transcripts of the Indiana Psychiatric Illness Interview—a broad interview inquiring about participants’ life experiences—were randomly selected for grounded theory analysis following a 4-step coding procedure as outlined by Charmaz. Data revealed a five step occupational process: Being Initiated; Increasing Engagement; Establishing an Identity; Experiencing Discord and Defeat; and Finding Other Occupations. Addiction is discussed as a behavioral pattern, and the authors discuss how the use of new occupations may provide individuals with new patterns of organization, social interconnection, and identity development needed to sustain a move away from occupations of addiction

    On the extent and origins of genic novelty in the phylum nematoda

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    The phylum Nematoda is biologically diverse, including parasites of plants and animals as well as free-living taxa. Underpinning this diversity will be commensurate diversity in expressed genes, including gene sets associated specifically with evolution of parasitism.Here we have analyzed the extensive expressed sequence tag data (available for 37 nematode species, most of which are parasites) and define over 120,000 distinct putative genes from which we have derived robust protein translations. Combined with the complete proteomes of Caenorhabditis elegans and Caenorhabditis briggsae, these proteins have been grouped into 65,000 protein families that in turn contain 40,000 distinct protein domains. We have mapped the occurrence of domains and families across the Nematoda and compared the nematode data to that available for other phyla. Gene loss is common, and in particular we identify nearly 5,000 genes that may have been lost from the lineage leading to the model nematode C. elegans. We find a preponderance of novelty, including 56,000 nematode-restricted protein families and 26,000 nematode-restricted domains. Mapping of the latest time-of-origin of these new families and domains across the nematode phylogeny revealed ongoing evolution of novelty. A number of genes from parasitic species had signatures of horizontal transfer from their host organisms, and parasitic species had a greater proportion of novel, secreted proteins than did free-living ones.These classes of genes may underpin parasitic phenotypes, and thus may be targets for development of effective control measures
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