227 research outputs found

    Importance of nanophytoplankton biomass during summer 2019 in a retreating marine-terminating glacier-fjord system, Marian Cove, West Antarctica (62°S)

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    The biogeochemical dynamics of fjords around Antarctica are strongly influenced by cryospheric, climatic, and oceanographic processes that occur on a seasonal scale. Furthermore, as global climate change continues, there is a growing awareness of the impact of ocean warming on glacier melting, which is expected to affect the composition of phytoplankton community structure in West Antarctica’s nearshore marine areas. In this study, we describe the role of hydrographic forcing on the short-term summer variability of the phytoplankton community in Marian Cove, an Antarctic glacial fjord (62°S). Phytoplankton and hydrographic variables were measured at five stations along the Marian Cove during summer 2019 (January–February). The highest concentrations of microphytoplankton biomass were found in the outer area of the fjord, whereas nanophytoplankton biomass displayed continued dominance during most of the summer period in Marian Cove. Hydrographic assessment showed that freshwater inputs from the glacier influenced the surface layer of the fjord, modulating phytoplankton biomass, which was dominated by nanodiatoms (Minidiscus sp., Thalassiosira spp.) and nanophytoflagellates (Cryptomonas spp., Phaeocystis sp.). Concurrent measurement of phytoplankton biomass and environmental conditions during December 2018–January 2019 indicated that a period of weak southeastern winds generated vertical stability, which led to the development of a major peak of microphytoplankton biomass in the outer cove, driven by warm, allochthonous, oceanic, nutrient-rich waters. High carbon biomass dominated by nanodiatoms and nanophytoflagellates was observed in cold, fresh, and low-light subsurface waters of the cove. Our results highlight the effects of a warming ocean, which may favor the summer resurgence of nanodiatom and nanophytoflagellate communities in Antarctic fjords due to increased glacial meltwater inputs

    Control of Ca2+ signals by astrocyte nanoscale morphology at tripartite synapses

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    International audienceMuch of the Ca2+ activity in astrocytes is spatially restricted to microdomains and occurs in fine processes that form a complex anatomical meshwork, the so-called spongiform domain. A growing body of literature indicates that those astrocytic Ca2+ signals can influence the activity of neuronal synapses and thus tune the flow of information through neuronal circuits. Because of technical difficulties in accessing the small spatial scale involved, the role of astrocyte morphology on Ca2+ microdomain activity remains poorly understood. Here, we use computational tools and idealized 3D geometries of fine processes based on recent super-resolution microscopy data to investigate the mechanistic link between astrocytic nanoscale morphology and local Ca2+ activity. Simulations demonstrate that the nano-morphology of astrocytic processes powerfully shapes the spatio-temporal properties of Ca2+ signals and promotes local Ca2+ activity. The model predicts that this effect is attenuated upon astrocytic swelling, hallmark of brain diseases, which we confirm experimentally in hypo-osmotic conditions. Upon repeated neurotransmitter release events, the model predicts that swelling hinders astrocytic signal propagation. Overall, this study highlights the influence of the complex morphology of astrocytes at the nanoscale and its remodeling in pathological conditions on neuron-astrocyte communication at so-called tripartite synapses, where astrocytic processes come into close contact with pre- and postsynaptic structures

    Control of CaÂČâș signals by astrocyte nanoscale morphology at tripartite synapses

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    Much of the CaÂČâș activity in astrocytes is spatially restricted to microdomains and occurs in fine processes that form a complex anatomical meshwork, the so-called spongiform domain. A growing body of literature indicates that those astrocytic CaÂČâș signals can influence the activity of neuronal synapses and thus tune the flow of information through neuronal circuits. Because of technical difficulties in accessing the small spatial scale involved, the role of astrocyte morphology on CaÂČâș microdomain activity remains poorly understood. Here, we use computational tools and idealized 3D geometries of fine processes based on recent super-resolution microscopy data to investigate the mechanistic link between astrocytic nanoscale morphology and local CaÂČâș activity. Simulations demonstrate that the nano-morphology of astrocytic processes powerfully shapes the spatio-temporal properties of CaÂČâș signals and promotes local CaÂČâș activity. The model predicts that this effect is attenuated upon astrocytic swelling, hallmark of brain diseases, which we confirm experimentally in hypo-osmotic conditions. Upon repeated neurotransmitter release events, the model predicts that swelling hinders astrocytic signal propagation. Overall, this study highlights the influence of the complex morphology of astrocytes at the nanoscale and its remodeling in pathological conditions on neuron-astrocyte communication at so-called tripartite synapses, where astrocytic processes come into close contact with pre- and postsynaptic structures

    Association of APOA5 and APOC3 genetic polymorphisms with severity of hypertriglyceridemia in patients with cutaneous T-Cell lymphoma treated with bexarotene

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    Importance: hypertriglyceridemia is the most frequent and limiting adverse effect of bexarotene therapy in cutaneous T-cell lymphoma (CTCL). Despite standard prophylactic measures, there is a wide variability in the severity of this complication, which could be associated with both genetic and environmental factors. Objectives: to analyze the association between genetic polymorphisms of apolipoprotein genes APOA5, APOC3, and APOE and the severity of hypertriglyceridemia during bexarotene therapy and to optimize patient selection for bexarotene therapy based on adverse effect profile. Design, Setting, and Participants: this case series study was conducted in 12 university referral hospitals in Spain from September 17, 2014, to February 6, 2015. One hundred twenty-five patients with a confirmed diagnosis of CTCL who had received bexarotene therapy for at least 3 months were enrolled. Nine patients were excluded owing to missing analytic triglyceride level data, leaving a study group of 116 patients. Data on demographic and cardiovascular risk factor were collected, and a complete blood analysis, including lipid profile and genetic analysis from a saliva sample, was performed. Main Outcomes and Measures: primary outcomes were the maximal triglyceride levels reported in association with the minor alleles of the polymorphisms studied. Results: among 116 patients, the mean (SD) age was 61.2 (14.7) years, 69 (59.5%) were men, and 85 (73.2%) had mycosis fungoides, the most prevalent form of CTCL. During bexarotene therapy, 96 patients (82.7%) experienced hypertriglyceridemia, which was severe or extreme in 8 of these patients (8.3%). Patients who carried minor alleles of the polymorphisms did not show significant differences in baseline triglyceride concentrations. After bexarotene treatment, carriers of at least 1 of the 2 minor alleles of APOA5 c.-1131T>C and APOC3 c.*40C>G showed lower levels of triglycerides than noncarriers (mean [SD], 241.59 [169.91] vs 330.97 [169.03] mg/dL, respectively; P = .02). Conclusions and Relevance: these results indicate that the screening of APOA5 and APOC3 genotypes may be useful to estimate changes in triglyceride concentrations during bexarotene treatment in patients with CTCL and also to identify the best candidates for bexarotene therapy based on the expected adverse effect profile

    Sonidegib as a Locally Advanced Basal Cell Carcinoma Therapy in Real-life Clinical Setting: A National Multicentre Study

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    Background: Basal cell carcinoma (BCC) is the most prevalent cancer. A minority of BCCs have an aggressive behaviour (laBCC) and may require hedgehog pathway inhibitors such as sonidegib as its treatment. Objective: To describe the use of sonidegib in a large number of patients and provide more data on its real-life efficacy and safety profile.Methods: We conducted a retrospective and multicentric study that included patients treated with sonidegib. Epidemiological, effectiveness and safety data were collected.Results: A total of 82 patients with a mean age of 73.9 years were included. Ten patients had Gorlin syndrome. Median treatment duration was 6 months. Median follow-up duration was 34.2 months. Globally, 81.7% of the patients showed clinical improvement (52.4% partial response and 29.3% complete response), 12.2% clinical stability and 6.1% disease progression. There was no statistically significant difference in clinical improvement between the 24 h and 48 h sonidegib posology. After 6 months of treatment, 48.8% of the patients discontinued sonidegib. Prior vismodegib treatment and recurrent primary BCC were associated with a poorer response to sonidegib. At 6 months of treatment, 68.3% of the patients experienced at least one adverse effect. Conclusion: Sonidegib shows good effectiveness and acceptable safety profile in usual clinical practice.& COPY; 2023 AEDV. Published by Elsevier Espan & SIM;a, S.L.U.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    First-line treatment in lymphomatoid papulosis: a retrospective multicentre study

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    Background: Data regarding response to treatment in lymphomatoid papulosis (LyP) are scarce. Aim: To assess the daily clinical practice approach to LyP and the response to first-line treatments. Methods: This was a retrospective study enrolling 252 patients with LyP. Results: Topical steroids, methotrexate and phototherapy were the most common first-line treatments, prescribed for 35%, 20% and 14% of the patients, respectively. Complete response (CR) was achieved in 48% of treated patients. Eczematous lesions significantly increased relative risk (RR) of not achieving CR (RR = 1.76; 95% CI 1.16-2.11). Overall median time to CR was 10 months (95% CI 6-13 months), and 78% of complete responders showed cutaneous relapse; both results were similar for all treatment groups (P > 0.05). Overall estimated median disease-free survival (DFS) was 11 months (95% CI 9-13 months) but DFS for patients treated with phototherapy was 23 months (95% CI 10-36 months; P < 0.03). Having the Type A LyP variant (RR = 2.04; 95% CI 0.96-4.30) and receiving a first-line treatment other than phototherapy (RR = 5.33; 95% CI 0.84-33.89) were significantly associated with cutaneous early relapse. Of the 252 patients, 31 (13%) had associated mycosis fungoides unrelated to therapeutic approach, type of LyP or T-cell receptor clonality. Conclusions: Current epidemiological, clinical and pathological data support previous results. Topical steroids, phototherapy and methotrexate are the most frequently prescribed first-line treatments. Although CR and cutaneous relapse rates do not differ between them, phototherapy achieves a longer DFS. Presence of Type A LyP and use of topical steroid or methotrexate were associated with an increased risk of early relapse

    The Lovelace–De Morgan mathematical correspondence: A critical re-appraisal

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    Ada Lovelace is widely regarded as an early pioneer of computer science, due to an 1843 paper about Charles Babbage's Analytical Engine, which, had it been built, would have been a general-purpose computer. However, there has been considerable disagreement among scholars as to her mathematical proficiency. This paper presents the first account by historians of mathematics of the correspondence between Lovelace and the mathematician Augustus De Morgan from 1840--41. Detailed contextual analysis allows us to present a corrected ordering of the archive material, countering previous claims of Lovelace's mathematical inadequacies, and presenting a more nuanced assessment of her abilities

    Melanocortin-1 Receptor, Skin Cancer and Phenotypic Characteristics (M-SKIP) Project: Study Design and Methods for Pooling Results of Genetic Epidemiological Studies

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    Background: For complex diseases like cancer, pooled-analysis of individual data represents a powerful tool to investigate the joint contribution of genetic, phenotypic and environmental factors to the development of a disease. Pooled-analysis of epidemiological studies has many advantages over meta-analysis, and preliminary results may be obtained faster and with lower costs than with prospective consortia. Design and methods: Based on our experience with the study design of the Melanocortin-1 receptor (MC1R) gene, SKin cancer and Phenotypic characteristics (M-SKIP) project, we describe the most important steps in planning and conducting a pooled-analysis of genetic epidemiological studies. We then present the statistical analysis plan that we are going to apply, giving particular attention to methods of analysis recently proposed to account for between-study heterogeneity and to explore the joint contribution of genetic, phenotypic and environmental factors in the development of a disease. Within the M-SKIP project, data on 10,959 skin cancer cases and 14,785 controls from 31 international investigators were checked for quality and recoded for standardization. We first proposed to fit the aggregated data with random-effects logistic regression models. However, for the M-SKIP project, a two-stage analysis will be preferred to overcome the problem regarding the availability of different study covariates. The joint contribution of MC1R variants and phenotypic characteristics to skin cancer development will be studied via logic regression modeling. Discussion: Methodological guidelines to correctly design and conduct pooled-analyses are needed to facilitate application of such methods, thus providing a better summary of the actual findings on specific fields

    Melanocortin-1 receptor, skin cancer and phenotypic characteristics (M-SKIP) project

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    Background: For complex diseases like cancer, pooled-analysis of individual data represents a powerful tool to investigate the joint contribution of genetic, phenotypic and environmental factors to the development of a disease. Pooled-analysis of epidemiological studies has many advantages over meta-analysis, and preliminary results may be obtained faster and with lower costs than with prospective consortia. Design and methods. Based on our experience with the study design of the Melanocortin-1 receptor (MC1R) gene, SKin cancer and Phenotypic characteristics (M-SKIP) project, we describe the most important steps in planning and conducting a pooled-analysis of genetic epidemiological studies. We then present the statistical analysis plan that we are going to apply, giving particular attention to methods of analysis recently proposed to account for between-study heterogeneity and to explore the joint contribution of genetic, phenotypic and environmental factors in the development of a disease. Within the M-SKIP project, data on 10,959 skin cancer cases and 14,785 controls from 31 international investigators were checked for quality and recoded for standardization. We first proposed to fit the aggregated data with random-effects logistic regression models. However, for the M-SKIP project, a two-stage analysis will be preferred to overcome the problem regarding the availability of different study covariates. The joint contribution of MC1R variants and phenotypic characteristics to skin cancer dev
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