101 resultados para callus induction
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BACKGROUND/AIMS: Genes encoding for some of the mitochondrial proteins are under the control of the transcriptional factor hypoxia inducible factor-1 alpha (HIF-1 alpha), which can accumulate under normoxic conditions in inflammatory states. The aim of this study was to evaluate the effects of cobalt chloride (CoCl(2), a hypoxia mimicking agent), tumour necrosis factor-alpha (TNF-alpha) and toll-like receptor (TLR) -2, -3 and -4 agonists on HIF-1 alpha accumulation, and further on HIF-1 alpha-mediated modulation of mitochondrial respiration in cultured human hepatocytes. METHODS: The human hepatoma cell line HepG2 was used in this study. Cells were treated with CoCl(2), TNF-alpha and TLR-2, -3 and -4 agonists. HIF-1 alpha was determined by Western blotting and mitochondrial respiration in stimulated cells by high-resolution respirometry. RESULTS: CoCl(2), TNF-alpha and TLR agonists induced the expression of HIF-1 alpha in a time-dependent fashion. TNF-alpha and CoCl(2), but not TLR agonists, induced a reduction in complex I-, II- and IV-dependent mitochondrial oxygen consumption. TNF-alpha-associated reduction of cellular oxygen consumption was abolished through inhibition of HIF-1 alpha activity by chetomin (CTM). Pretreatment with cyclosporine A prevented CoCl(2)-induced reduction of complex I- and II-dependent mitochondrial oxygen consumption and TNF-alpha-induced reduction of complex-I-dependent respiration, implicating the involvement of the mitochondrial permeability transition pore openings. TNF-alpha and TLR-2, -3 and -4 agonists induced the expression of vascular endothelial growth factor, which was partially abolished by the blockage of HIF-1 alpha with CTM. CONCLUSIONS: The data suggest that HIF-1 alpha modulates mitochondrial respiration during CoCl(2) and TNF-alpha stimulation, whereas it has no effect when induced with TLR-2, -3 and -4 agonists.
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Dendritic cells (DCs) represent the first line defence of the innate immune system following infection with pathogens. We exploratively addressed invasion and survival ability of Neospora caninum, a parasite causing abortion in cattle, in mouse bone marrow DCs (BMDCs), and respective cytokine expression patterns. Immature BMDCs were exposed to viable (untreated) and nonviable parasites that had been inactivated by different means. Invasion and/or internalization, as well as intracellular survival and proliferation of tachyzoites were determined by NcGRA2-RT-PCR and transmission electron microscopy (TEM). Cytokine expression was evaluated by reverse transcription (RT)-PCR and cytokine ELISA. Transmission electron microscopy of DCs stimulated with untreated viable parasites revealed that N. caninum was able to invade and proliferate within BMDCs. This was confirmed by NcGRA2-RT-PCR. On the other hand, no viable parasite organisms were revealed by TEM when exposing BMDCs to inactivated parasites (nonviability demonstrated by NcGRA2-RT-PCR). Cytokine expression analysis (as assessed by both RT-PCR and ELISA) demonstrated that both viable and nonviable parasites stimulated mBMDCs to express IL-12p40, IL-10 and TNF-alpha, whereas IL-4 RNA expression was not detected. Thus, exposure of mBMDCs to both viable and nonviable parasites results in the expression of cytokines that are relevant for a mixed Th1/Th2 immune response.
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BACKGROUND Induction chemotherapy followed by definitive chemoradiotherapy is an intensified treatment approach for locally advanced squamous cell carcinoma of the head and neck (HNSCC) that might be associated with high rates of toxicity. MATERIALS AND METHODS The data of 40 consecutive patients who underwent induction chemotherapy with docetaxel-containing regimens followed by intensity-modulated radiotherapy (IMRT) and concomitant systemic therapy for unresectable locally advanced HNSCC were retrospectively analyzed. Primary objectives were RT-related acute and late toxicity. Secondary objectives were response to induction chemotherapy, locoregional recurrence-free survival (LRRFS), overall survival (OS), and influencing factors for LRRFS and OS. RESULTS The median follow-up for surviving patients was 21 months (range, 2-53 months). Patients received a median of three cycles of induction chemotherapy followed by IMRT to 72 Gy. Three patients died during induction chemotherapy and one during chemoradiotherapy. Acute RT-related toxicity was of grade 3 and 4 in 72 and 3 % of patients, respectively, mainly dysphagia and dermatitis. Late RT-related toxicity was mainly xerostomia and bone/cartilage necrosis and was of grade 3 and 4 in 15 % of patients. One- and 2-year LRRFS and OS were 72 and 49 % and 77 and 71 %, respectively. CONCLUSION Induction chemotherapy followed by chemoradiotherapy using IMRT was associated with a high rate of severe acute and late RT-related toxicities in this selected patient cohort. Four patients were lost because of fatal complications. Induction chemotherapy did not compromise the delivery of full-dose RT; however, the use of three cycles of concomitant cisplatin was impaired.
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In lucid dreams the dreamer is aware of dreaming and often able to influence the ongoing dream content. Lucid dreaming is a learnable skill and a variety of techniques is suggested for lucid dreaming induction. This systematic review evaluated the evidence for the effectiveness of induction techniques. A comprehensive literature search was carried out in biomedical databases and specific resources. Thirty-five studies were included in the analysis (11 sleep laboratory and 24 field studies), of which 26 employed cognitive techniques, 11 external stimulation and one drug application. The methodological quality of the included studies was relatively low. None of the induction techniques were verified to induce lucid dreams reliably and consistently, although some of them look promising. On the basis of the reviewed studies, a taxonomy of lucid dream induction methods is presented. Several methodological issues are discussed and further directions for future studies are proposed.
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To examine the behavior of the estrogenic biomarker vitellogenin (VTG) under the combined impact of estrogens and pathogens, parasite-infected or noninfected rainbow trout were exposed to two doses of 17beta-estradiol (E2). Infected and E2-exposed fish showed significantly lower hepatic VTG mRNA levels than healthy fish. Transcriptome data suggest that this was due to energetic constraints. Reduced responsiveness of the VTG biomarker in parasitized fish might obscure detection of low-level field exposure.
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Protection against malaria can be achieved by induction of a strong CD8(+) T-cell response against the Plasmodium circumsporozoite protein (CSP), but most subunit vaccines suffer from insufficient memory responses. In the present study, we analyzed the impact of postimmunization sporozoite challenge on the development of long-lasting immunity. BALB/c mice were immunized by a heterologous prime/boost regimen against Plasmodium berghei CSP that induces a strong CD8(+) T-cell response and sterile protection, which is short-lived. Here, we show that protective immunity is prolonged by a sporozoite challenge after immunization. Repeated challenges induced sporozoite-specific antibodies that showed protective capacity. The numbers of CSP-specific CD8(+) T cells were not substantially enhanced by sporozoite infections; however, CSP-specific memory CD8(+) T cells of challenged mice displayed a higher cytotoxic activity than memory T cells of immunized-only mice. CD4(+) T cells contributed to protection as well; but CD8(+) memory T cells were found to be the central mediator of sterile protection. Based on these data, we suggest that prolonged protective immunity observed after immunization and infection is composed of different antiparasitic mechanisms including CD8(+) effector-memory T cells with increased cytotoxic activity as well as CD4(+) memory T cells and neutralizing antibodies.
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BACKGROUND Insect bite hypersensitivity (IBH) is a recurrent allergic dermatitis of horses with similarities to human atopic eczema, caused by bites of insects of the genus Culicoides. Previous studies suggested a dysregulated T cell tolerance to Culicoides allergen in IBH-affected horses. OBJECTIVE We have investigated whether the suppressive function of CD4(+) CD25(high) cells is impaired in IBH-affected horses and possible ways to restore it. METHODS CD4(+) CD25(-) cells sorted from peripheral blood mononuclear cells (PBMC) were stimulated with irradiated autologous PBMC pulsed with Culicoides or tetanus toxoid as control antigen, in the presence of CD4(+) CD25(high) cells. Furthermore, Culicoides-specific CD4(+) CD25(high) regulatory cells were expanded or induced from CD4(+) CD25(-) cells in vitro in the presence of a combination of rIL-2 and rTGF-β1 (rIL-2/rTGF-β1) or of retinoic acid and rapamycin (RetA/Rapa). Proliferation was determined by [(3) H] thymidine incorporation and cytokine production measured by flow cytometry. RESULTS The ability of Culicoides- but not tetanus-stimulated CD4(+) CD25(high) cells to suppress proliferation of CD4(+) CD25(-) cells was significantly lower in IBH-affected horses (28%) than in healthy controls (86%). The decreased suppression in IBH-affected horses was associated with a significantly higher proportion of IL-4(+) cells and a lower percentage of FoxP3(+) IL-10(+) compared to controls. Addition of rIL-2/rTGF-β1 or of RetA/Rapa to Culicoides-stimulated CD4(+) CD25(high) cells from IBH-affected horses significantly increased the proportion of FoxP3(+) IL-10(+) cells. We also found that RetA/Rapa induced a more significant decrease in the frequency of IL-4(+) cells than rIL-2/rTGF-β1. Moreover, the suppressive activity of Culicoides-stimulated CD4(+) CD25(high) cells was significantly restored by both rIL-2/rTGF-β1and RetA/Rapa, albeit in an antigen-unspecific manner. In contrast, in vitro induced Culicoides-specific CD4(+) CD25(high) cells suppressed proliferation of CD4(+) CD25(-) cells in an antigen-specific manner. CONCLUSION AND CLINICAL RELEVANCE The in vitro induction of functional allergen-specific Treg cells in IBH-affected horses suggests a potential therapeutic use of these cells in allergy.
Induction of neurogenesis in the rat brain by Endothelial Progenitor Cells-derived paracrine factors
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Two healthy dogs were anaesthetized to undergo elective orthopaedic procedures. After premedication with methadone and acepromazine, general anaesthesia was induced with midazolam and S-ketamine. Immediately after anaesthetic induction, seizures occurred in both dogs. In the first dog the syndrome was characterized by tonic and clonic motor activity, muscular hypertone, hypersalivation, urination, defecation and hyperthermia. In the second dog muscular twitches of the temporal and masseter regions were observed, followed by increased skeletal muscles tone, hypersalivation, spontaneous urination and increase in body temperature. Recoveries from anaesthesia were uneventful and no seizures were observed. Considering the temporal association between anaesthetic induction and occurrence of seizures, and the fact that other causative factors could not be identified, it is hypothesized that S-ketamine played a role in determining the convulsive phenomena observed in these patients. S-ketamine might carry the potential for inducing seizures in otherwise healthy dogs, despite the concomitant use of GABA-ergic drugs.
Induction of angiogenesis in the rat brain by endothelial progenitor cells-derived paracrine factors
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Traditionally, ontologies describe knowledge representation in a denotational, formalized, and deductive way. In addition, in this paper, we propose a semiotic, inductive, and approximate approach to ontology creation. We define a conceptual framework, a semantics extraction algorithm, and a first proof of concept applying the algorithm to a small set of Wikipedia documents. Intended as an extension to the prevailing top-down ontologies, we introduce an inductive fuzzy grassroots ontology, which organizes itself organically from existing natural language Web content. Using inductive and approximate reasoning to reflect the natural way in which knowledge is processed, the ontology’s bottom-up build process creates emergent semantics learned from the Web. By this means, the ontology acts as a hub for computing with words described in natural language. For Web users, the structural semantics are visualized as inductive fuzzy cognitive maps, allowing an initial form of intelligence amplification. Eventually, we present an implementation of our inductive fuzzy grassroots ontology Thus,this paper contributes an algorithm for the extraction of fuzzy grassroots ontologies from Web data by inductive fuzzy classification.
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In this study, we established cell culture conditions for primary equine hepatocytes allowing cytochrome P450 enzyme (CYP) induction experiments. Hepatocytes were isolated after a modified method of Bakala et al. (2003) and cultivated on collagen I coated plates. Three different media were compared for their influence on morphology, viability and CYP activity of the hepatocytes. CYP activity was evaluated with the fluorescent substrate 7-benzyloxy-4-trifluoromethylcoumarin. Induction experiments were carried out with rifampicin, dexamethasone or phenobarbital. Concentration-response curves for induction with rifampicin were created. Williams' medium E showed the best results on morphology and viability of the hepatocytes and was therefore used for the following induction experiments. Cells cultured in Dulbecco's Modified Eagle Medium were not inducible. Incubation with rifampicin increased the CYP activity in two different hepatocyte preparations in a dose dependent manner (EC50=1.20 μM and 6.06 μM; Emax=4.1- and 3.4-fold induction). No increase in CYP activity was detected after incubation with dexamethasone or phenobarbital. The hepatocyte culture conditions established in this study proved to be valuable for investigation of the induction of equine CYPs. In further studies, other equine drugs can be evaluated for CYP induction with this in vitro system.
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Resting endothelial cells express the small proteoglycan biglycan, whereas sprouting endothelial cells also synthesize decorin, a related proteoglycan. Here we show that decorin is expressed in endothelial cells in human granulomatous tissue. For in vitro investigations, the human endothelium-derived cell line, EA.hy 926, was cultured for 6 or more days in the presence of 1% fetal calf serum on top of or within floating collagen lattices which were also populated by a small number of rat fibroblasts. Endothelial cells aligned in cord-like structures and developed cavities that were surrounded by human decorin. About 14% and 20% of endothelial cells became apoptotic after 6 and 12 days of co-culture, respectively. In the absence of fibroblasts, however, the extent of apoptosis was about 60% after 12 days, and cord-like structures were not formed nor could decorin production be induced. This was also the case when lattices populated by EA.hy 926 cells were maintained under one of the following conditions: 1) 10% fetal calf serum; 2) fibroblast-conditioned media; 3) exogenous decorin; or 4) treatment with individual growth factors known to be involved in angiogenesis. The mechanism(s) by which fibroblasts induce an angiogenic phenotype in EA.hy 926 cells is (are) not known, but a causal relationship between decorin expression and endothelial cell phenotype was suggested by transducing human decorin cDNA into EA.hy 926 cells using a replication-deficient adenovirus. When the transduced cells were cultured in collagen lattices, there was no requirement of fibroblasts for the formation of capillary-like structures and apoptosis was reduced. Thus, decorin expression seems to be of special importance for the survival of EA.hy 926 cells as well as for cord and tube formation in this angiogenesis model.
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Background: Emotion research in neuroscience targets brain structures and processes involved in discrete emotion categories (e.g. anger, fear, sadness) or dimensions (e.g. valence, arousal, approach-avoidance), and usually relies on carefully controlled experimental paradigms with standardized and often simple emotion-eliciting stimuli like e.g. unpleasant pictures. Emotion research in clinical psychology and psychotherapy is often interested in very subtle differences between emotional states, e.g. differences within emotion categories (e.g. assertive, self-protecting vs. rejecting, protesting anger or specific grief vs. global sadness), and/or the biographical, social, situational, or motivational contexts of the emotional experience, which are desired to be minimized in experimental neuroscientific research. Objective: In order to facilitate the experimental and neurophysiological investigation of psychotherapeutically relevant emotional experiences, the present study aims at developing a priming procedure to induce specific, therapeutically and biographically relevant emotional states under controlled experimental conditions. Methodology: N = 50 participants who reported negative feelings towards another close person were randomly assigned to 2 different conditions. They fulfilled 2 different sentence completion tasks that were supposed to prime either ‘therapeutically productive’ or ‘therapeutically unproductive’ emotional states and completed an expressive writing task and several self-report measures of specific emotion-related constructs. The sentence completion task consisted in max. 22 sentence stems drawn from psychotherapy patients’ statements that have been shown to be typical for productive or unproductive therapy sessions. The subjects of the present study completed these sentence stems with regard to their own negative feelings towards the close person. Results: There were a substantial inter-individual variability concerning the number of completed sentences, and significant correlations between number of completed sentences and problem activation in both conditions. No differences were observed in general mood or problem activation between both groups after priming. Descriptively, there were differences between groups concerning emotion regulation aspects. Significant differences between groups in resolution of negative feelings towards the other person were found. Discussion: The results point in the expected direction, however the small sample sizes (after exclusion of several subjects) and low power hinder the detection of convincing significant effects. More data is needed in order to evaluate the efficacy of this emotional priming procedure.