115 resultados para phase variation
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Habitat suitability models, which relate species occurrences to environmental variables, are assumed to predict suitable conditions for a given species. If these models are reliable, they should relate to change in plant growth and function. In this paper, we ask the question whether habitat suitability models are able to predict variation in plant functional traits, often assumed to be a good surrogate for a species' overall health and vigour. Using a thorough sampling design, we show a tight link between variation in plant functional traits and habitat suitability for some species, but not for others. Our contrasting results pave the way towards a better understanding of how species cope with varying habitat conditions and demonstrate that habitat suitability models can provide meaningful descriptions of the functional niche in some cases, but not in others.
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Summary : Internal ribosome entry sites (IRES) are used by viruses as a strategy to bypass inhibition of cap-dependent translation that commonly results from viral infection. IRES are also used in eukaryotic cells to control mRNA translation under conditions of cellular stress (apoptosis, heat shock) or during the G2 phase of the cell cycle when general protein synthesis is inhibited. Variation in cellular expression levels has been shown to be inherited. Expression is controlled, among others, by transcriptional factors and by the efficiency of cap-mediated translation and ribosome activity. We aimed at identifying genomic determinants of variability in IRES-mediated translation of two representative IRES [Encephalomyocarditis virus (EMCV) and X-linked Inhibitor-of-Apoptosis (XIAP) IRES]. We used bicistronic lentiviral constructions expressing two fluorescent reporter transgenes. Lentiviruses were used to transduce seven different laboratory cell lines and B lymphoblastoid cell lines from the Centre d'Etude du Polymorphisme Humain (CEPH; 15 pedigrees; n=209); representing an in vitro approach to family structure allowing genome scan analyses. The relative expression of the two markers was assessed by FACS. IRES efficiency varies according to cellular background, but also varies, for a same cell type, among individuals. The control of IRES activity presents an inherited component (h2) of 0.47 and 0.36 for EMCV and XIAP IRES, respectively. A genome scan identified a suggestive Quantitative Trait Loci (LOD 2.35) involved in the control of XIAP IRES activity. Résumé : Les sites internes d'entrée des ribosomes (IRES = internal ribosome entry sites) sont utilisés par les virus comme une stratégie afin d'outrepasser l'inhibition de traduction qui résulte communément d'une infection virale. Les IRES sont également utilisés par les cellules eucaryotes pour contrôler la traduction de l'ARN messager dans des conditions de stress cellulaire (apoptose, choc thermique) ou durant la phase G2 du cycle cellulaire, situations durant lesquelles la synthèse générale des protéines est inhibée. La variation des niveaux d'expression cellulaire de transcription est un caractère héréditaire. L'expression des gènes est contrôlée entre autre par les facteurs de transcription et par l'efficacité de la traduction initiée par la coiffe ainsi que par l'activité des ribosomes. Durant cette étude nous avons eu pour but d'identifier les déterminants génomiques responsables de la variabilité de la traduction contrôlée par l'IRES. Ceci a été effectué en étudiant deux IRES représentatifs : l'IRES du virus de l'encéphalomyocardite (EMCV) et l'IRES de l'inhibiteur de l'apoptose XIAP (X-linked Inhibitor-of-Apoptosis). Nous avons utilisés des lentivirus délivrant un transgène bicistronique codant pour deux gènes rapporteurs fluorescents. Ces lentivirus ont été utilisés pour transduire sept différentes lignées cellulaires de laboratoire et des lignées cellulaires lymphoblastoïdes B du Centre d'Etude du Polymorphisme Humain (CEPH; 15 pedigrees; n=209) qui représentent une approche in vitro de la structure familiale et qui permettent des analyses par balayage du génome. L'expression relative des deux marqueurs fluorescents a été analysée par FACS. Nos résultats montrent que l'efficacité des IRES varie en fonction du type de cellules. Il varie aussi, pour le même type de cellules, selon les individus. Le contrôle de l'activité de l'IRES est un caractère héritable (héritabilité h2) de 0.47 et 0.36 pour les IRES de EMCV et XIAP respectivement. Le balayage du génome a permis l'identification d'un locus à effets quantitatifs [QTL Quantitative Trait Loci (LOD 2.35)] impliqué dans le contôle de l'activité de l'IRES de XIAP.
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Therapeutic drug monitoring (TDM) may contribute to optimizing the efficacy and safety of antifungal therapy because of the large variability in drug pharmacokinetics. Rapid, sensitive, and selective laboratory methods are needed for efficient TDM. Quantification of several antifungals in a single analytical run may best fulfill these requirements. We therefore developed a multiplex ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method requiring 100 μl of plasma for simultaneous quantification within 7 min of fluconazole, itraconazole, hydroxyitraconazole, posaconazole, voriconazole, voriconazole-N-oxide, caspofungin, and anidulafungin. Protein precipitation with acetonitrile was used in a single extraction procedure for eight analytes. After reverse-phase chromatographic separation, antifungals were quantified by electrospray ionization-triple-quadrupole mass spectrometry by selected reaction monitoring detection using the positive mode. Deuterated isotopic compounds of azole antifungals were used as internal standards. The method was validated based on FDA recommendations, including assessment of extraction yields, matrix effect variability (<9.2%), and analytical recovery (80.1 to 107%). The method is sensitive (lower limits of azole quantification, 0.01 to 0.1 μg/ml; those of echinocandin quantification, 0.06 to 0.1 μg/ml), accurate (intra- and interassay biases of -9.9 to +5% and -4.0 to +8.8%, respectively), and precise (intra- and interassay coefficients of variation of 1.2 to 11.1% and 1.2 to 8.9%, respectively) over clinical concentration ranges (upper limits of quantification, 5 to 50 μg/ml). Thus, we developed a simple, rapid, and robust multiplex UPLC-MS/MS assay for simultaneous quantification of plasma concentrations of six antifungals and two metabolites. This offers, by optimized and cost-effective lab resource utilization, an efficient tool for daily routine TDM aimed at maximizing the real-time efficacy and safety of different recommended single-drug antifungal regimens and combination salvage therapies, as well as a tool for clinical research.
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PURPOSE: This study aims to describe emotional distress and quality of life (QoL) of patients at different phases of their lung cancer and the association with their family physician (FP) involvement. METHODS: A prospective study on patients with lung cancer was conducted in three regions of Quebec, Canada. Patients completed, at baseline, several validated questionnaires regarding their psychosocial characteristics and their perceived level of FP involvement. Emotional distress [profile of mood states (POMS)] and QoL [European Organization for Research and Treatment of Cancer Quality of Life Core 30 (EORTC QLQ-C30)] were reassessed every 3-6 months, whether patients had metastasis or not, up to 18 months. Results were regrouped according to cancer phase. Mixed models with repeated measurements were performed to identify variation in distress and QoL. RESULTS: In this cohort of 395 patients, distress was low at diagnosis (0.79 ± 0.7 on a 0-4 scale), raising to 1.36 ± 0.8 at the advance phase (p < 0.0001). Patient's global QoL scores significantly decreased from the diagnosis to the advance phase (from 66 to 45 on a 0-100 scale; p < 0.0001). At all phases of cancer, FP involvement was significantly associated with patients' distress (p = 0.0004) and their global perception of QoL (p = 0.0080). These associations remained statistically significant even after controlling for age, gender, and presence of metastases. CONCLUSIONS: This study provides new knowledge on patients' emotional distress and QoL with cancer evolution and, particularly, their association with FP involvement. Other studies should be conducted to further explore FP role in cancer supportive care.
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Background: Previous studies reported an increase of mean platelet volume (MPV) in patients with acute ischemic stroke. However, its correlation with stroke severity has not been investigated. Moreover, studies on the association of MPV with functional outcome yielded inconsistent results. Methods: We included all consecutive ischemic stroke patients admitted to CHUV (Centre Hospitalier Universitaire Vaudois) Neurology Service within 24 h after stroke onset who had MPV measured on admission. The association of MPV with stroke severity (NIHSS score at admission and at 24 h) and outcome (Rankin Scale score at 3 and 12 months) was analyzed in univariate analysis. The chi(2) test was performed to compare the frequency of minor strokes (NIHSS score </=4) and good functional outcome (Rankin Scale score </=2) across MPV quartiles. The ANOVA test was used to compare MPV between stroke subtypes according to the TOAST classification. Student's two-tailed unpaired t test was performed to compare MPV between lacunar and nonlacunar strokes. MPV was generated at admission by the Sysmex XE-2100 automated cell counter (Sysmex Corporation, Kobe, Japan) from EDTA blood samples. Results: There was no significant difference in the frequency of minor strokes (p = 0.46) and good functional outcome (p = 0.06) across MPV quartiles. MPV was not associated with stroke severity or outcome in univariate analysis. There was no significant difference in MPV between stroke subtypes according to the TOAST classification (p = 0.173) or between lacunar and nonlacunar strokes (10.50 +/- 0.91 vs. 10.40 +/- 0.81 fl, p = 0.322). Conclusions: MPV, assessed within 24 h after ischemic stroke onset, is not associated with stroke severity or functional outcome.
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Inbreeding depression is one of the hypotheses explaining the maintenance of females within gynodioecious plant populations. However, the measurement of fitness components in selfed and outcrossed progeny depends on life-cycle stage and the history of inbreeding. Comparative data indicate that strong inbreeding depression is more likely to occur at later life-cycle stages. We used hermaphrodite individuals of Silene vulgaris originating from three populations located in different valleys in the Swiss Alps to investigate the effect of two generations of self- and cross-fertilization on fitness components among successive stages of the life cycle in a glasshouse experiment. We detected significant inbreeding depression for most life-cycle stages including: the number of viable and aborted seeds per fruit, probability of germination, above ground biomass, probability of flowering, number of flowers per plant, flower size and pollen viability. Overall, the intensity of inbreeding depression increased among successive stages of the life cycle and cumulative inbreeding depression was significantly stronger in the first generation (delta approximately 0.5) compared with the second generation (delta approximately 0.35). We found no evidence for synergistic epistasis in our experiment. Our finding of more intense inbreeding depression during later stages of the life cycle may help to explain the maintenance of females in gynodioecious populations of S. vulgaris because purging of genetic load is less likely to occur.
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Breast cancer remains a major public health problem. Even if there is an increase in this cancer curability, metastatic breast cancer remains a lethal disease in the vast majority of cases. Therapeutic advances in the chemotherapeutic and targeted therapies fields induced an increase in survival, however the proportion of long survivors remains low. Phenotypic instability, an early process initiated during tumour progression, and continued on the metastatic stage of the disease, can be one of the putative hypotheses explaining these results. An increasing amount of scientific data are pledging for a reanalysis of the phenotypic profile regarding hormone receptors and HER-2 status of metastatic lesions in order to identify drugable targets and allow individualisation of the treatment of these metastatic breast cancer patients. Phenotypic changes between the primary tumour and the paired metastatic lymph nodes are a challenging pitfall, raising the question of which site has to be assessed in the adjuvant treatment decision process. This article presents a comprehensive analysis of the frequency of theses phenotypic changes altogether with new modalities to evaluate this phenotypic status.
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The benefit of bevacizumab (Bv) has been shown in different tumors including colorectal cancer, renal cancer, pulmonary non-small cell cancer and also breast cancer. However to date, there is no established test evaluating the angiogenic status of a patient and monitoring the effects of anti-angiogenic treatments. Tumor angiogenesis is the result of a balance between multiple pro- and anti¬angiogenic molecules. There is very little published clinical data exploring the impact of the anti-angiogenic therapy on the different angiogenesis-related molecules and the potential role of these molecules as prognostic or predictive factors.
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BACKGROUND: Cilengitide is a selective integrin inhibitor that is well tolerated and has demonstrated biologic activity in patients with recurrent malignant glioma. The primary objectives of this randomized phase 2 trial were to determine the safety and efficacy of cilengitide when combined with radiation and temozolomide for patients with newly diagnosed glioblastoma multiforme and to select a dose for comparative clinical testing. METHODS: In total, 112 patients were accrued. Eighteen patients received standard radiation and temozolomide with cilengitide in a safety run-in phase followed by a randomized phase 2 trial with 94 patients assigned to either a 500 mg dose group or 2000 mg dose group. The trial was designed to estimate overall survival benefit compared with a New Approaches to Brain Tumor Therapy (NABTT) Consortium internal historic control and data from the published European Organization for Research and Treatment of Cancer (EORTC) trial EORTC 26981. RESULTS: Cilengitide at all doses studied was well tolerated with radiation and temozolomide. The median survival was 19.7 months for all patients, 17.4 months for the patients in the 500 mg dose group, 20.8 months for patients in the 2000 mg dose group, 30 months for patients who had methylated O6-methylguanine-DNA methyltransferase (MGMT) status, and 17.4 months for patients who had unmethylated MGMT status. For patients aged ≤70 years, the median survival and survival at 24 months was superior to what was observed in the EORTC trial (20.7 months vs 14.6 months and 41% vs 27%, respectively; P = .008). CONCLUSIONS: Cilengitide was well tolerated when combined with standard chemoradiation and may improve survival for patients newly diagnosed with glioblastoma multiforme regardless of MGMT methylation status. The authors concluded that, from an efficacy and safety standpoint, future trials of this agent in this population should use the 2000 mg dose. Cancer 2012. © 2012 American Cancer Society.
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BACKGROUND: Sunitinib (SU) is a multitargeted tyrosine kinase inhibitor with antitumor and antiangiogenic activity. The objective of this trial was to demonstrate antitumor activity of continuous SU treatment in patients with hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Key eligibility criteria included unresectable or metastatic HCC, no prior systemic anticancer treatment, measurable disease, and Child-Pugh class A or mild Child-Pugh class B liver dysfunction. Patients received 37.5 mg SU daily until progression or unacceptable toxicity. The primary endpoint was progression-free survival at 12 weeks (PFS12). RESULTS: Forty-five patients were enrolled. The median age was 63 years; 89% had Child-Pugh class A disease and 47% had distant metastases. PFS12 was rated successful in 15 patients (33%; 95% confidence interval, 20%-47%). Over the whole trial period, one complete response and a 40% rate of stable disease as the best response were achieved. The median PFS duration, disease stabilization duration, time to progression, and overall survival time were 1.5, 2.9, 1.5, and 9.3 months, respectively. Grade 3 and 4 adverse events were infrequent. None of the 33 deaths were considered drug related. CONCLUSION: Continuous SU treatment with 37.5 mg daily is feasible and has moderate activity in patients with advanced HCC and mild to moderately impaired liver dysfunction. Under this trial design (>13 PFS12 successes), the therapy is considered promising. This is the first trial describing the clinical effects of continuous dosing of SU in HCC patients on a schedule that is used in an ongoing, randomized, phase III trial in comparison with the current treatment standard, sorafenib (ClinicalTrials.gov identifier, NCT00699374).
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We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.