856 resultados para ANTICOAGULANT PATHWAYS
Resumo:
In cancer patients treated for venous thromboembolism (VTE), including deep-vein thrombosis (DVT) and pulmonary embolism (PE), analyzing mortality associated with recurrent VTE or major bleeding is needed to determine the optimal duration of anticoagulation.This was a cohort study using the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) Registry database to compare rates of fatal recurrent PE and fatal bleeding in cancer patients receiving anticoagulation for VTE.As of January 2013, 44,794 patients were enrolled in RIETE, of whom 7911 (18%) had active cancer. During the course of anticoagulant therapy (mean, 181 ± 210 days), 178 cancer patients (4.3%) developed recurrent PE (5.5 per 100 patient-years; 95% CI: 4.8-6.4), 194 (4.7%) had recurrent DVT (6.2 per 100 patient-years; 95% confidence interval [CI]: 5.3-7.1), and 367 (8.9%) bled (11.3 per 100 patient-years; 95% CI: 10.2-12.5). Of 4125 patients initially presenting with PE, 43 (1.0%) died of recurrent PE and 45 (1.1%) of bleeding; of 3786 patients with DVT, 19 (0.5%) died of PE, and 55 (1.3%) of bleeding. During the first 3 months of anticoagulation, there were 59 (1.4%) fatal PE recurrences and 77 (1.9%) fatal bleeds. Beyond the third month, there were 3 fatal PE recurrences and 23 fatal bleeds.In RIETE cancer patients, the rate of fatal recurrent PE or fatal bleeding was much higher within the first 3 months of anticoagulation therapy.
Resumo:
Autoantibodies against complement C1q (anti-C1q) strongly correlate with the occurrence of lupus nephritis and hypocomplementemia in systemic lupus erythematosus (SLE). Although a direct pathogenic role of anti-C1q has been suggested, the assumed complement-activating capacity remains to be elucidated. Using an ELISA-based assay, we found that anti-C1q activate the classical (CP) and lectin pathways (LP) depending on the anti-C1q immunoglobulin-class repertoire present in the patient's serum. IgG anti-C1q resulted in the activation of the CP as reflected by C4b deposition in the presence of purified C1 and C4 in a dose-dependent manner. The extent of C4b deposition correlated with anti-C1q levels in SLE patients but not in healthy controls. Our data indicate that SLE patient-derived anti-C1q can activate the CP and the LP but not the alternative pathway of complement. These findings are of importance for the understanding of the role of anti-C1q in SLE suggesting a direct link to hypocomplementemia.
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Background: We use an approach based on Factor Analysis to analyze datasets generated for transcriptional profiling. The method groups samples into biologically relevant categories, and enables the identification of genes and pathways most significantly associated to each phenotypic group, while allowing for the participation of a given gene in more than one cluster. Genes assigned to each cluster are used for the detection of pathways predominantly activated in that cluster by finding statistically significant associated GO terms. We tested the approach with a published dataset of microarray experiments in yeast. Upon validation with the yeast dataset, we applied the technique to a prostate cancer dataset. Results: Two major pathways are shown to be activated in organ-confined, non-metastatic prostate cancer: those regulated by the androgen receptor and by receptor tyrosine kinases. A number of gene markers (HER3, IQGAP2 and POR1) highlighted by the software and related to the later pathway have been validated experimentally a posteriori on independent samples. Conclusion: Using a new microarray analysis tool followed by a posteriori experimental validation of the results, we have confirmed several putative markers of malignancy associated with peptide growth factor signalling in prostate cancer and revealed others, most notably ERRB3 (HER3). Our study suggest that, in primary prostate cancer, HER3, together or not with HER4, rather than in receptor complexes involving HER2, could play an important role in the biology of these tumors. These results provide new evidence for the role of receptor tyrosine kinases in the establishment and progression of prostate cancer.
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Liver is unique in its capacity to regenerate in response to injury or tissue loss. Hepatocytes and other liver cells are able to proliferate and repopulate the liver. However, when this response is impaired, the contribution of hepatic progenitors becomes very relevant. Here, we present an update of recent studies on growth factors and cytokine-driven intracellular pathways that govern liver stem/progenitor cell expansion and differentiation, and the relevance of these signals in liver development, regeneration and carcinogenesis. Tyrosine kinase receptor signaling, in particular, c-Met, epidermal growth factor receptors or fibroblast growth factor receptors, contribute to proliferation, survival and differentiation of liver stem/progenitor cells. Different evidence suggests a dual role for the transforming growth factor (TGF)-β signaling pathway in liver stemness and differentiation. On the one hand, TGF-β mediates progression of differentiation from a progenitor stage, but on the other hand, it contributes to the expansion of liver stem cells. Hedgehog family ligands are necessary to promote hepatoblast proliferation but need to be shut off to permit subsequent hepatoblast differentiation. In the same line, the Wnt family and β-catenin/T-cell factor pathway is clearly involved in the maintenance of liver stemness phenotype, and its repression is necessary for liver differentiation during development. Collectively, data indicate that liver stem/progenitor cells follow their own rules and regulations. The same signals that are essential for their activation, expansion and differentiation are good candidates to contribute, under adequate conditions, to the paradigm of transformation from a pro-regenerative to a pro-tumorigenic role. From a clinical perspective, this is a fundamental issue for liver stem/progenitor cell-based therapies.
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Two enoxaparin dosage regimens are used as comparators to evaluate new anticoagulants for thromboprophylaxis in patients undergoing major orthopaedic surgery, but so far no satisfactory direct comparison between them has been published. Our objective was to compare the efficacy and safety of enoxaparin 3,000 anti-Xa IU twice daily and enoxaparin 4,000 anti-Xa IU once daily in this clinical setting by indirect comparison meta-analysis, using Bucher's method. We selected randomised controlled trials comparing another anticoagulant, placebo (or no treatment) with either enoxaparin regimen for venous thromboembolism prophylaxis after hip or knee replacement or hip fracture surgery, provided that the second regimen was assessed elsewhere versus the same comparator. Two authors independently evaluated study eligibility, extracted the data, and assessed the risk of bias. The primary efficacy outcome was the incidence of venous thomboembolism. The main safety outcome was the incidence of major bleeding. Overall, 44 randomised comparisons in 56,423 patients were selected, 35 being double-blind (54,117 patients). Compared with enoxaparin 4,000 anti-Xa IU once daily, enoxaparin 3,000 anti-Xa IU twice daily was associated with a reduced risk of venous thromboembolism (relative risk [RR]: 0.53, 95% confidence interval [CI]: 0.40 to 0.69), but an increased risk of major bleeding (RR: 2.01, 95% CI: 1.23 to 3.29). In conclusion, when interpreting the benefit-risk ratio of new anticoagulant drugs versus enoxaparin for thromboprophylaxis after major orthopaedic surgery, the apparently greater efficacy but higher bleeding risk of the twice-daily 3,000 anti-Xa IU enoxaparin regimen compared to the once-daily 4,000 anti-Xa IU regimen should be taken into account.
Resumo:
Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways.
Resumo:
Current guidelines of antithrombotic therapy suggest early initiation of vitamin K antagonists (VKA) in non-cancer patients with venous thromboembolism (VTE), and long-term therapy with low-molecular weight heparin (LMWH) for those with cancer. We used data from RIETE (international registry of patients with VTE) to report the use of long-term anticoagulant therapy over time and to identify predictors of anticoagulant choice (regarding international guidelines) in patients with- and without cancer. Among 35,280 patients without cancer, 82% received long-term VKA (but 17% started after the first week). Among 4,378 patients with cancer, 66% received long term LMWH as monotherapy. In patients without cancer, recent bleeding (odds ratio [OR] 2.70, 95% CI 2.26-3.23), age >70 years (OR 1.15, 95% CI 1.06-1.24), immobility (OR 2.06, 95% CI 1.93-2.19), renal insufficiency (OR 2.42, 95% CI 2.15-2.71) and anemia (OR 1.75, 95% CI 1.65-1.87) predicted poor adherence to guidelines. In those with cancer, anemia (OR 1.83, 95% CI 1.64-2.06), immobility (OR 1.51, 95% CI 1.30-1.76) and metastases (OR 3.22, 95% CI 2.87-3.61) predicted long-term LMWH therapy. In conclusion, we report practices of VTE therapy in real life and found that a significant proportion of patients did not receive the recommended treatment. The perceived increased risk for bleeding has an impact on anticoagulant treatment decision.
Resumo:
Studies conducted on volcanic islands have greatly contributed to our current understanding of how organisms diversify. The Canary Islands archipelago, located northwest of the coast of northern Africa, harbours a large number of endemic taxa. Because of their low vagility, mygalomorph spiders are usually absent from oceanic islands. The spider Titanidiops canariensis, which inhabits the easternmost islands of the archipelago, constitutes an exception to this rule. Here, we use a multi-locus approach that combines three mitochondrial and four nuclear genes to investigate the origins and phylogeography of this remarkable trap-door spider. We provide a timeframe for the colonisation of the Canary Islands using two alternative approaches: concatenation and species tree inference in a Bayesian relaxed clock framework. Additionally, we investigate the existence of cryptic species on the islands by means of a Bayesian multi-locus species delimitation method. Our results indicate that T. canariensis colonised the Canary Islands once, most likely during the Miocene, although discrepancies between the timeframes from different approaches make the exact timing uncertain. A complex evolutionary history for the species in the archipelago is revealed, which involves two independent colonisations of Fuerteventura from the ancestral range of T. canariensis in northern Lanzarote and a possible back colonisation of southern Lanzarote. The data further corroborate a previously proposed volcanic refugium, highlighting the impact of the dynamic volcanic history of the island on the phylogeographic patterns of the endemic taxa. T. canariensis includes at least two different species, one inhabiting the Jandia peninsula and central Fuerteventura and one spanning from central Fuerteventura to Lanzarote. Our data suggest that the extant northern African Titanidiops lineages may have expanded to the region after the islands were colonised and, hence, are not the source of colonisation. In addition, T. maroccanus may harbour several cryptic species.
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Background. The “Cooking and Active Leisure” Tu y Alícia por la Salud (CAL-TAS) Program is a schoolbased pilot that addresses healthy lifestyle needs of Spanish secondary school students with initiatives that research has proven to improve dietary and physical activity behaviors. Objective. The objectives were to perform a Program Impact Pathways (PIP) analysis to describe key activities and processes of the CAL-TAS Program, identify Critical Quality Control Points (CCPs), and identify a suite of common indicators of healthy lifestyles to be applied across participant schools. Methods. The CAL-TAS Program designers and implementation team developed this PIP analysis through an iterative process and presented the results for feedback at the seven-country Healthy Lifestyles Program Evaluation Workshop held in Granada, Spain, 13–14 September 2013, under the auspices of the Mondelēz International Foundation. Results. The team identified three PIP CCPs: teachers’ motivation and training, changes in students’ knowledge of healthy lifestyles, and changes in students’ healthy lifestyle behavior. The selected indicators of the program’s impact on healthy lifestyles are adequacy of food intake, level of knowledge of healthy lifestyles gained, and adequacy of physical activity level according to World Health Organization recommendations. A clear definition of impact indicators, as well as collection of accurate data on healthy lifestyle behaviors and knowledge, is essential to understanding the effectiveness of this program before it can be scaled up. Conclusions. CAL-TAS is an effective secondary school-based program encouraging healthy lifestyles. The PIP analysis was instrumental in identifying CCPs to sustain and improve the quality of the program. The team hopes to sustain and improve the program through these program evaluation recommendations.
Resumo:
Cyanobacteria are a diverse group of oxygenic photosynthetic bacteria that inhabit in a wide range of environments. They are versatile and multifaceted organisms with great possibilities for different biotechnological applications. For example, cyanobacteria produce molecular hydrogen (H2), which is one of the most important alternatives for clean and sustainable energy. Apart from being beneficial, cyanobacteria also possess harmful characteristics and may become a source of threat to human health and other living organisms, as they are able to form surface blooms that are producing a variety of toxic or bioactive compounds. The University of Helsinki Culture Collection (UHCC) maintains around 1,000 cyanobacterial strains representing a large number of genera and species isolated from the Baltic Sea and Finnish lakes. The culture collection covers different life forms such as unicellular and filamentous, N2-fixing and non-N2-fixing strains, and planktonic and benthic cyanobacteria. In this thesis, the UHCC has been screened to identify potential strains for sustainable biohydrogen production and also for strains that produce compounds modifying the bioenergetic pathways of other cyanobacteria or terrestrial plants. Among the 400 cyanobacterial strains screened so far, ten were identified as high H2-producing strains. The enzyme systems involved in H2 metabolism of cyanobacteria were analyzed using the Southern hybridization approach. This revealed the presence of the enzyme nitrogenase in all strains tested, while none of them are likely to have contained alternative nitrogenases. All the strains tested, except for two Calothrix strains, XSPORK 36C and XSPORK 11A, were suggested to contain both uptake and bidirectional hydrogenases. Moreover, 55 methanol extracts of various cyanobacterial strains were screened to identify potent bioactive compounds affecting the photosynthetic apparatus of the model cyanobacterium, Synechocystis PCC 6803. The extract from Nostoc XPORK 14A was the only one that modified the photosynthetic machinery and dark respiration. The compound responsible for this effect was identified, purified, and named M22. M22 demonstrated a dual-action mechanism: production of reactive oxygen species (ROS) under illumination and an unknown mechanism that also prevailed in the dark. During summer, the Baltic Sea is occupied by toxic blooms of Nodularia spumigena (hereafter referred to as N. spumigena), which produces a hepatotoxin called nodularin. Long-term exposure of the terrestrial plant spinach to nodularin was studied. Such treatment resulted in inhibition of growth and chlorosis of the leaves. Moreover, the activity and amount of mitochondrial electron transfer complexes increased in the leaves exposed to nodularin-containing extract, indicating upregulation of respiratory reactions, whereas no marked changes were detected in the structure or function of the photosynthetic machinery. Nodularin-exposed plants suffered from oxidative stress, evidenced by oxidative modifications of various proteins. Plants initiated strategies to combat the stress by increasing the levels of alpha-tocopherol, mitochondrial alternative oxidase (AOX), and mitochondrial ascorbate peroxidase (mAPX).
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Spermatogenesis, i.e sperm production in the seminiferous tubules of the testis, is a complex process that takes over one month to complete. Life-long ability of sperm production ultimately lies in a small population of undifferentiated cells, called spermatogonial stem cells (SSCs). These cells give rise to differentiating spermatogonia, which are committed to mature into spermatozoa. SSCs represent a heterogeneous population of cells and many aspects of their basic biology are still unknown. Understanding the mechanisms behind the cell fate decision of these cells is important to gain more insights into the causes of infertility and testis cancer. In addition, an interesting new aspect is the use of testis-derived stem cells in regenerative medicine. Our data demonstrated that adult mouse testis houses a population of Nanog-expressing spermatogonia. Based on mRNA and protein analysis these cells are enriched in stage XII of the mouse seminiferous epithelial cycle. The cells derived from this stage have the highest capacity to give rise to ES cell-like cells which express Oct4 and Nanog. These cells are under tight non- GDNF regulation but their fate can be dictated by activating p21 signalling. Comparative studies suggested that these cells are regulated like ES cells. Taken together these data imply that pluripotent cells are present in the adult mammalian testis. CIP2A (cancerous inhibitor of PP2A) has been associated with tumour aggressiveness and poor prognosis. In the testis it is expressed by the descendants of stem cells, i.e. the spermatogonial progenitor cells. Our data suggest that CIP2A acts upstream of PLZF and is needed for quantitatively normal spermatogenesis. Classification of CIP2A as a cancer/testis gene makes it an attractive target for cancer therapy. Study on the CIP2A deficient mouse model demonstrates that systemic inhibition of CIP2A does not severely interfere with growth and development or tissue or organ function, except for the spermatogenic output. These data demonstrate that CIP2A is required for quantitatively normal spermatogenesis. Hedgehog (Hh) signalling is involved in the development and maintenance of many different tissues and organs. According to our data, Hh signalling is active at many different levels during rat spermatogenesis: in spermatogonia, spermatocytes and late elongating spermatids. Localization of Suppressor of Fused (SuFu), the negative regulator of the pathway, specifically in early elongating spermatids suggests that Hh signalling needs to be shut down in these cells. Introduction of Hh signalling inhibitor resulted in an increase in germ cell apoptosis. Follicle-stimulating hormone (FSH) and inhibition of receptor tyrosine kinases resulted in down-regulation of Hh signalling. These data show that Hh signalling is under endocrine and paracrine control and it promotes germ cell survival.
Resumo:
One of the most limiting factors affecting the larval rearing of Ucides cordatus in the laboratory is a period of high mortality, which usually occurs late in the course of the larviculture during the metamorphosis from the zoeal to the megalopal phase. The objective of the present research was to analyze the post-embryonic development of U. cordatus on an individual basis and, in particular, to search for patterns linking disturbances in the molting process to the high larval death rates observed in massive larvicultures. A total of 50 larvae were individually reared from hatching to metamorphosis into the megalopal phase under controlled conditions, fed a combination of microalgae and rotifers. The survivorship rate was 70% until zoea V. The 35 surviving zoea V larvae followed two different pathways. Eleven underwent metamorphosis directly to megalopa, eighteen molted to zoea VI and six died as zoea V. In the last molting event, only two zoea VI larvae reached the megalopal stage, while the remaining sixteen died. In further observation under microscope, 13 of the dead zoea VI showed characteristics of the pre-molt stage and pereiopods disproportionably large in relation to the carapace. The observed pattern resembles the Molt Death Syndrome (MDS) described for other decapod species, in which larvae die in the late pre-molt phase of the molting cycle. We suggest that U. cordatus larvae develop disturbances in the molting process similar to the MDS described for other species and that these disturbances are related to a more complex pathway involving the emergence of larval stage zoea VI.
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The variation in nitrogen use strategies and photosynthetic pathways among vascular epiphyte families was addressed in a white-sand vegetation in the Brazilian Central Amazon. Foliar nitrogen and carbon concentrations and their isotopic composition (δ15N and δ13C, respectively) were measured in epiphytes (Araceae, Bromeliaceae and Orchidaceae) and their host trees. The host tree Aldina heterophylla had higher foliar N concentration and lower C:N ratio (2.1 ± 0.06% and 23.6 ± 0.8) than its dwellers. Tree foliar δ15N differed only from that of the orchids. Comparing the epiphyte families, the aroids had the highest foliar N concentration and lowest C:N ratios (1.4 ± 0.1% and 34.9 ± 4.2, respectively). The orchids had more negative foliar δ15N values (-3.5 ± 0.2) than the aroids (-1.9 ± 0.7) and the bromeliads (-1.1 ± 0.6). Within each family, aroid and orchid taxa differed in relation to foliar N concentrations and C:N ratios, whereas no internal variation was detected within bromeliads. The differences in foliar δ15N observed herein seem to be related to the differential reliance on the available N sources for epiphytes, as well as to the microhabitat quality within the canopy. In relation to epiphyte foliar δ13C, the majority of epiphytes use the water-conserving CAM-pathway (δ13C values around -17), commonly associated with plants that live under limited and intermittent water supply. Only the aroids and one orchid taxon indicated the use of C3-pathway (δ13C values around -30).
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The immune and central nervous systems are functionally connected and interacting. The concept that the immune signaling to the brain which induces fever during infection and inflammation is mediated by circulating cytokines has been traditionally accepted. Administration of bacterial lipopolysaccharide (LPS) induces the appearance of a so-termed "cytokine cascade" in the circulation more or less concomitantly to the developing febrile response. Also, LPS-like fever can be induced by systemic administration of key cytokines (IL-1ß, TNF-alpha, and others). However, anti-cytokine strategies against IL-1ß or TNF-alpha along with systemic injections of LPS frequently lead to attenuation of the later stages of the febrile response but not of the initial phase of fever, indicating that cytokines are rather involved in the maintenance than in the early induction of fever. Within the last years experimental evidence has accumulated indicating the existence of neural transport pathways of immune signals to the brain. Because subdiaphragmatic vagotomy prevents or attenuates fever in response to intraperitoneal or intravenous injections of LPS, a role for vagal afferent nerve fibers in fever induction has been proposed. Also other sensory nerves may participate in the manifestation of febrile responses under certain experimental conditions. Thus, injection of a small dose of LPS into an artificial subcutaneous chamber results in fever and formation of cytokines within the inflamed tissue around the site of injection. This febrile response can be blocked in part by injection of a local anesthetic into the subcutaneous chamber, indicating a participation of cutaneous afferent nerve signals in the manifestation of fever in this model. In conclusion, humoral signals and an inflammatory stimulation of afferent sensory nerves can participate in the generation and maintenance of a febrile response.
Resumo:
Saccharomyces cerevisiae neutral trehalase (encoded by NTH1) is regulated by cAMP-dependent protein kinase (PKA) and by an endogenous modulator protein. A yeast strain with knockouts of CMK1 and CMK2 genes (cmk1cmk2) and its isogenic control (CMK1CMK2) were used to investigate the role of CaM kinase II in the in vitro activation of neutral trehalase during growth on glucose. In the exponential growth phase, cmk1cmk2 cells exhibited basal trehalase activity and an activation ratio by PKA very similar to that found in CMK1CMK2 cells. At diauxie, even though both cells presented comparable basal trehalase activities, cmk1cmk2 cells showed reduced activation by PKA and lower total trehalase activity when compared to CMK1CMK2 cells. To determine if CaM kinase II regulates NTH1 expression or is involved in post-translational modulation of neutral trehalase activity, NTH1 promoter activity was evaluated using an NTH1-lacZ reporter gene. Similar ß-galactosidase activities were found for CMK1CMK2 and cmk1cmk2 cells, ruling out the role of CaM kinase II in NTH1 expression. Thus, CaM kinase II should act in concert with PKA on the activation of the cryptic form of neutral trehalase. A model for trehalase regulation by CaM kinase II is proposed whereby the target protein for Ca2+/CaM-dependent kinase II phosphorylation is not the neutral trehalase itself. The possible identity of this target protein with the recently identified trehalase-associated protein YLR270Wp is discussed.