966 resultados para Human herpesvirus 4
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The aim of this paper is to show that only in a society where human rights are honored and democracy is vigorous, the process of subjectivation be possible. It is a critical sociology research. The article is presented in two parts, the first, subject and subjectivity in contemporary times, analyze the obstacles that individuals have for subjective process, and the second, subject and human rights and subject and democracy we argue about the need for human rights and democracy for the process of subjectivation.
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The Ov/Br septin gene, which is also a fusion partner of MLL in acute myeloid leukaemia, is a member of a family of novel GTP binding proteins that have been implicated in cytokinesis and exocytosis. In this study, we describe the genomic and transcriptional organization of this gene, detailing seventeen exons distributed over 240 kb of sequence. Extensive database analyses identified orthologous rodent cDNAs that corresponded to new, unidentified 5' splice variants of the Ov/Br septin gene, increasing the total number of such variants to six. We report that splicing events, occurring at non-canonical sites within the body of the 3' terminal exon, remove either 1801 bp or 1849 bp of non-coding sequence and facilitate access to a secondary open reading frame of 44 amino acids maintained near the end of the 3' UTR. These events constitute a novel coding arrangement and represent the first report of such a design being implemented by a eukaryotic gene. The various Ov/Br proteins either differ minimally at their amino and carboxy termini or are equivalent to truncated versions of larger isoforms. Northern analysis with an Ov/Br septin 3' UTR probe reveals three transcripts of 4.4, 4 and 3 kb, the latter being restricted to a sub-set of the tissues tested. Investigation of the identified Ov/Br septin isoforms by RT-PCR confirms a complex transcriptional pattern, with several isoforms showing tissue-specific distribution. To date, none of the other human septins have demonstrated such transcriptional complexity.
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Objectives: Tetrahydrobiopterin (BH4) is an essential cofactor for endothelial nitric oxide synthase (eNOS) activity. BH4 levels are regulated by de novo biosynthesis; the rate-limiting enzyme is GTP cyclohydrolase I (GTPCH). BH4 activates and promotes homodimerisation of purified eNOS protein, but the intracellular mechanisms underlying BH4-mediated eNOS regulation in endothelial cells remain less clear. We aimed to investigate the role of BH4 levels in intracellular eNOS regulation, by targeting the BH4 synthetic pathway as a novel strategy to modulate intracellular BH4 levels. Methods: We constructed a recombinant adenovirus, AdGCH, encoding human GTPCH. We infected human endothelial cells with AdGCH, investigated the changes in intracellular biopterin levels, and determined the effects on eNOS enzymatic activity, protein levels and dimerisation. Results: GTPCH gene transfer in EAhy926 endothelial cells increased BH4 >10-fold compared with controls (cells alone or control adenovirus infection), and greatly enhanced NO production in a dose-dependent, eNOS-specific manner. We found that eNOS was principally monomeric in control cells, whereas GTPCH gene transfer resulted in a striking increase in eNOS homodimerisation. Furthermore, the total amounts of both native eNOS protein and a recombinant eNOS–GFP fusion protein were significantly increased following GTPCH gene transfer. Conclusions: These findings suggest that GTPCH gene transfer is a valid approach to increase BH4 levels in human endothelial cells, and provide new evidence for the relative importance of different mechanisms underlying BH4-mediated eNOS regulation in intact human endothelial cells. Additionally, these observations suggest that GTPCH may be a rational target to augment endothelial BH4 and normalise eNOS activity in endothelial dysfunction states.
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Atheroma formation involves the movement of vascular smooth muscle cells (VSMC) into the subendothelial space. The aim of this study was to determine the involvement of PI3K and MAPK pathways and the importance of cross-talk between these pathways, in glucose-potentiated VSMC chemotaxis to serum factors. VSMC chemotaxis occurred in a serum gradient in 25 mmol/L glucose (but not in 5 mmol/L glucose) in association with increased phosphorylation (activation) of Akt and ERK1/2 in PI3K and MAPK pathways, respectively. Inhibitors of these pathways blocked chemotaxis, as did an mTOR inhibitor. VSMC expressed all class IA PI3K isoforms, but microinjection experiments demonstrated that only the p110beta isoform was involved in chemotaxis. ERK1/2 phosphorylation was reduced not only by MAPK pathway inhibitors but also by PI3K and mTOR inhibitors; when PI3K was inhibited, ERK phosphorylation could be induced by microinjected activated Akt, indicating important cross-talk between the PI3K and ERK1/2 pathways. Glucose-potentiated phosphorylation of molecules in the p38 and JNK MAPK pathways inhibited these pathways but did not affect chemotaxis. The statin, mevinolin, blocked chemotaxis through its effects on the MAPK pathway. Mevinolin-inhibited chemotaxis was restored by farnesylpyrophosphate but not by geranylgeranylpyrophosphate; in the absence of mevinolin, inhibition of farnesyltransferase reduced ERK phosphorylation and blocked chemotaxis, indicating a role for the Ras family of GTPases (MAPK pathway) under these conditions. In conclusion, glucose sensitizes VSMC to serum, inducing chemotaxis via pathways involving p110beta-PI3K, Akt, mTOR, and ERK1/2 MAPK. Cross-talk between the PI3K and MAPK pathways is necessary for VSMC chemotaxis under these conditions.
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Objective. The use of glucocorticoids (GCs) in the treatment of RA is a frequent cause of bone loss. In vitro, however, this same class of steroids has been shown to promote the recruitment and/or maturation of primitive osteogenic precursors present in the colony forming unit-fibroblastic (CFU-F) fraction of human bone and marrow. In an effort to reconcile these conflicting observations, we investigated the effects of the synthetic GC dexamethasone (Dx) on parameters of growth and osteogenic differentiation in cultures of bone marrow stromal cells derived from a large cohort of adult human donors (n=30). Methods. Marrow suspensions were cultured in the absence and presence of Dx at concentrations between 10 pm and 1 µm. After 28 days we determined the number and diameter of colonies formed, the total number of cells, the surface expression of receptors for selected growth factors and extracellular matrix proteins and, based on the expression of the developmental markers alkaline phosphatase (AP) and the antigen recognized by the STRO-1 monoclonal antibody, the proportion of cells undergoing osteogenic differentiation and their extent of maturation. Results. At a physiologically equivalent concentration, Dx had no effect on the adhesion of CFU-F or on their subsequent proliferation, but did promote their osteogenic differentiation and further maturation. These effects were independent of changes in the expression of the receptors for fibroblast growth factors, insulin-like growth factor 1, nerve growth factor, platelet-derived growth factors and parathyroid hormone/parathyroid hormone-related protein, but were associated with changes in the number of cells expressing the 2 and 4, but not ß1, integrin subunits. At supraphysiological concentrations, the effects of Dx on the osteogenic recruitment and maturation of CFU-F and their progeny were maintained but at the expense of a decrease in cell number. Conclusions. A decrease in the proliferation of osteogenic precursors, but not in their differentiation or maturation, is likely to be a key factor in the genesis of GC-induced bone loss.
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This article argues that productive work represents a mode of human flourishing unfortunately neglected in much current political theorizing. Focusing on Habermasian critical theory, I contend that Habermas’s dualist theory of society, on account of the communicative versus instrumental reason binary which underpins it, excludes work and the economy from ethical reflection. To avoid this uncritical turn, we need a concept of work that retains a core emancipatory referent. This, I claim, is provided by Alasdair MacIntyre’s notion of ‘practice’. The notion of ‘practice’ is significant in suggesting an alternative conception of human productivity that is neither purely instrumental nor purely communicative, but rather both simultaneously, a form of activity which issues in material products and yet presumes a community of workers engaged in intersubjective self-transformation. However, we can endorse MacIntyre’s notion of ‘practice’ only if we reject his totalizing anti-modernism and insist on the emancipatory potentialities of modern institutions.
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Aquaporin-4 (AQP4) has recently been implicated in the pathogenesis of neuromyelitis optica(NMO) where it has been identifed as the first defined autoantigen pertinent to an infammatory demyelinating disorder of the human CNS. Furthermore, a recent case report has shown a lack of AQP4 expression in the spinal cord lesions of NMO. However, the pattern of AQP4 expression in multiple sclerosis (MS) tissues has not been well-defned. In the present investigation we have confirmed a lack of expression of AQP4 in optic and spinal cord lesions in NMO which contrasted sharply with the increased levels of AQP4 expression seen in MS lesions. Furthermore a detailed immunohistochemical and semi-quantitative analysis is used to describe the expression pattern of AQP4 on well-characterized tissue microarray samples of MS and control white matter. Anatomically AQP4 was more highly expressed in all categories of MS tissue compared to normal control tissues with the most abundant expression in active lesions. Within active lesions AQP4 expression was significantly correlated with expression of the pro-infammatory cytokine osteopontin. At the cellular level dual-labelling immunofluoresence demonstrated that increased expression of AQP4 was most pronounced at the astrocytic endfeet but was also associated with the cell bodies of astrocytes in the tissue parenchyma. The finding of increased AQP4 expression in MS lesions in contrast to the lack of expression in NMO lesions may suggest different mechanisms of initiation and progression between the two disease states.
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Objective: to investigate the effects of tetrahydrocannabinol; THC on human sperm function in vitro. Design: laboratory analysis of sperm motility with and without exposure to THC using computer assisted semen analysis (CASA) and acrosome reaction by fluoroscein isothiocyanate labelled peanut agglutinin (FITC-PNA) staining. Setting: An ART unit in a tertiary medical centre. Patients: semen was obtained from 78 men attending the Regional Fertility Centre, Belfast. Interventions: Sperm were divided into 90% (the best fertilizing potential used in assisted conception) and 45% (the poorer subpopulation) fractions by density centrifugation and incubated with, or without (controls), tetrahydrocannabinol (THC) at concentrations equivalent to therapeutic (0.032Ã??Ã?¯?Ã??Ã?ÂM) and recreational (4.8 and 0.32Ã??Ã?¯?Ã??Ã?ÂM) plasma levels, at 37Ã??Ã?¯?Ã??Ã?°C for 3 hours. Main outcome measures: Sperm motility, spontaneous and induced acrosome reactions Results: There was a dose-dependent decrease in percentage progressive motility (-21% at 4.8Ã???Ã??Ã?µM, p0.05) in the 90% fraction. The 45% fraction showed a greater decrease in percentage progressive motility (-56% at 4.8Ã???Ã??Ã?µM, p=0.011; -23% at 0.32Ã???Ã??Ã?µM, p= 0.039; and -28% at 0.032Ã???Ã??Ã?µM, p=0.004). A decrease in the straight line velocity; VSL (-10%) and the average path velocity; VAP (-10%) were also observed in the 90% fraction. A significant inhibition (-15% at 4.8Ã???Ã??Ã?µM, p=0.04) in spontaneous acrosome reaction was observed in the 90% fraction. The 45% fraction showed a more marked inhibition [-35% (p
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A 1.2 m sediment core from Lake Forsyth, Canterbury, New Zealand, records the development of the catchment/lake system over the last 7000 years, and its response to anthropogenic disturbance following European settlement c. 1840 AD. Pollen was used to reconstruct catchment vegetation history, while foraminifera, chironomids, Trichoptera, and the abundance of Pediastrum simplex colonies were used to infer past environmental conditions within the lake. The basal 30 cm of core records the transition of the Lake Forsyth Basin from a tidal embayment to a brackish coastal lake. Timing of closure of the lake mouth could not be accurately determined, but it appears that Lake Forsyth had stabilised as a slightly brackish, oligo mesotrophic shallow lake by about 500 years BP. Major deforestation occurred on Banks Peninsula between 1860 AD and 1890 AD. This deforestation is marked by the rapid decline in the main canopy trees (Prumnopitys taxifolia (matai) and Podocarpus totara/hallii (totara/mountain totara), an increase in charcoal, and the appearance of grasses. At around 1895 AD, pine appears in the record while a willow (Salix spp.) appears somewhat later. Redundancy analysis (RDA) of the pollen and aquatic species data revealed a significant relationship between regional vegetation and the abundance of aquatic taxa, with the percentage if disturbance pollen explaining most (14.8%) of the constrained variation in the aquatic species data. Principle components analysis (PCA) of aquatic species data revealed that the most significant period of rapid biological change in the lakes history corresponded to the main period of human disturbance in the catchment. Deforestation led to increased sediment and nutrient input into the lake which was accompanied by a major reduction in salinity. These changes are inferred from the appearance and proliferation of freshwater algae (Pediastrum simplex), an increase in abundance and diversity of chironomids, and the abundance of cases and remains from the larvae of the caddisfly, Oecetis unicolor. Eutrophication accompanied by increasing salinity of the lake is inferred from a significant peak and then decline of P. simplex, and a reduction in the abundance and diversity of aquatic invertebrates. The artificial opening of the lake to the Pacific Ocean, which began in the late 1800s, is the likely cause of the recent increase in salinity. An increase in salinity may have also encouraged blooms of the halotolerant and hepatotoxic cyanobacteria Nodularia spumigena.
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The analysis of chironomid taxa and environmental datasets from 46 New Zealand lakes identified temperature (February mean air temperature) and lake production (chlorophyll a (Chl a)) as the main drivers of chironomid distribution. Temperature was the strongest driver of chironomid distribution and consequently produced the most robust inference models. We present two possible temperature transfer functions from this dataset. The most robust model (weighted averaging-partial least squares (WA-PLS), n = 36) was based on a dataset with the most productive (Chl a > 10 lg l)1) lakes removed. This model produced a coefficient of determination (r2 jack) of 0.77, and a root mean squared error of prediction (RMSEPjack) of 1.31C. The Chl a transfer function (partial least squares (PLS), n = 37) was far less reliable, with an r2 jack of 0.49 and an RMSEPjack of 0.46 Log10lg l)1. Both of these transfer functions could be improved by a revision of the taxonomy for the New Zealand chironomid taxa, particularly the genus Chironomus. The Chironomus morphotype was common in high altitude, cool, oligotrophic lakes and lowland, warm, eutrophic lakes. This could reflect the widespread distribution of one eurythermic species, or the collective distribution of a number of different Chironomus species with more limited tolerances. The Chl a transfer function could also be improved by inputting mean Chl a values into the inference model rather than the spot measurements that were available for this study.