7 research outputs found

    The expression of wild-type pendrin (SLC26A4) in human embryonic kidney (HEK 293 Phoenix) cells leads to the activation of cationic currents

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    Objective: The SLC26A4 protein (pendrin) seems to be involved in the exchange of chloride with other anions, therefore being responsible for iodide organification in the thyroid gland and the conditioning of the endolymphatic fluid in the inner ear. Malfunction of SLC26A4 leads to Pendred syndrome, characterized by mild thyroid dysfunction often associated with goiter and/or prelingual deafness. The precise function of the SLC26A4 protein, however, is still elusive. An open question is still whether the SLC26A4-induced ion exchange mechanism is electrogenic or electroneutral. Recently, it has been shown that human pendrin expressed in monkey cells leads to chloride currents. Methods: We overexpressed the human SLC26A4 isoform in HEK293 Phoenix cells and measured cationic and anionic currents by the patch-clamp technique in whole cell configuration. Results: Here we show that human pendrin expressed in human cells does not lead to the activation of chloride currents, but, in contrast, leads to an increase of cationic currents. Conclusion: Our experiments suggest that the SLC26A4-induced chloride transport is electroneutral when expressed in human cellular systems

    Functional characterization of wild-type and a mutated form of SLC26A4 identified in a patient with pendred syndrome

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    BACKGROUND: Malfunction of the SLC26A4 protein leads to prelingual deafness often associated with mild thyroid dysfunction and goiter. It is assumed that SLC26A4 acts as a chloride/anion exchanger responsible for the iodide organification in the thyroid gland, and conditioning of the endolymphatic fluid in the inner ear. METHODS: Chloride uptake studies were made using HEK293-Phoenix cells expressing human wild type SLC26A4 (pendrin) and a mutant (SLC26A4(S28R)) we recently described in a patient with hypothyroidism, goiter and sensorineural hearing loss. RESULTS: Experiments are summarized showing the functional characterization of wild type SLC26A4 and a mutant (S28R), which we described recently. This mutant protein is transposed towards the cell membrane, however, its transport capability is markedly reduced if compared to wild-type SLC26A4. Furthermore, we show that the SLC26A4 induced chloride uptake in HEK293-Phoenix cells competes with iodide, and, in addition, that the chloride uptake can be blocked by NPPB and niflumic acid, whereas DIDS is ineffective. CONCLUSIONS: The functional characteristics of SLC26A4(S28R) we describe here, are consistent with the clinical phenotype observed in the patient from which the mutant was derived

    A Search for Coincident Neutrino Emission from Fast Radio Bursts with Seven Years of IceCube Cascade Events

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    This paper presents the results of a search for neutrinos that are spatially and temporally coincident with 22 unique, nonrepeating fast radio bursts (FRBs) and one repeating FRB (FRB 121102). FRBs are a rapidly growing class of Galactic and extragalactic astrophysical objects that are considered a potential source of high-energy neutrinos. The IceCube Neutrino Observatory\u27s previous FRB analyses have solely used track events. This search utilizes seven years of IceCube cascade events which are statistically independent of track events. This event selection allows probing of a longer range of extended timescales due to the low background rate. No statistically significant clustering of neutrinos was observed. Upper limits are set on the time-integrated neutrino flux emitted by FRBs for a range of extended time windows

    Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

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    Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49\ub74% (95% uncertainty interval [UI] 46\ub74–52\ub70). The TFR decreased from 4\ub77 livebirths (4\ub75–4\ub79) to 2\ub74 livebirths (2\ub72–2\ub75), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83\ub78 million people per year since 1985. The global population increased by 197\ub72% (193\ub73–200\ub78) since 1950, from 2\ub76 billion (2\ub75–2\ub76) to 7\ub76 billion (7\ub74–7\ub79) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2\ub70%; this rate then remained nearly constant until 1970 and then decreased to 1\ub71% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2\ub75% in 1963 to 0\ub77% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2\ub77%. The global average age increased from 26\ub76 years in 1950 to 32\ub71 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59\ub79% to 65\ub73%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1\ub70 livebirths (95% UI 0\ub79–1\ub72) in Cyprus to a high of 7\ub71 livebirths (6\ub78–7\ub74) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0\ub708 livebirths (0\ub707–0\ub709) in South Korea to 2\ub74 livebirths (2\ub72–2\ub76) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0\ub73 livebirths (0\ub73–0\ub74) in Puerto Rico to a high of 3\ub71 livebirths (3\ub70–3\ub72) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2\ub70% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation

    LSm4 Associates with the Plasma Membrane and Acts as a Co-factor in Cell Volume Regulation

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    ICln is a ubiquitous, multifunctional protein with functions in cell volume regulation and RNA processing, and is thus part of an intricate protein network critically involved in the homoeostasis of cells. To better understand this vital protein network in health and disease it is fundamental to characterize the interactions between the physiological pathways in which ICln is involved, as well as the spatio-temporal regulation of these interactions. In this study, we focused on the interaction between the two best studied pathways in which ICln is involved - regulatory volume decrease and RNA processing - and asked, whether or not the RNA processing factor and ICln interaction partner LSm4 may also have a function in cell volume regulation in NIH3T3 fibroblasts or HEK293 Phoenix cells. To address this question, we studied in isotonic and hypotonic conditions by FRET, biochemistry and electrophysiology, the intracellular distribution of the RNA processing factor LSm4, its interaction with ICln, as well as the involvement of LSm4 in the activation of the swelling dependent anion and osmolyte channel IClswell. In isotonic conditions, LSm4 associates with ICln, and the plasma membrane. Hypotonic cell swelling leads to the dissociation of LSm4 from the plasma membrane, and from ICln. Over-expression of LSm4 affects the translocation of ICln to the cell membrane and markedly inhibits the activation kinetics and current density of IClswell. These findings indicate that LSm4 not only acts in RNA processing, but also as a co-factor in cell volume regulation

    The ICln interactome

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    The many different functional phenotypes described in mammalian cells can only be explained by an intense interaction of the underlying proteins, substantiated by the fact that the number of independently expressed proteins in living cells seems not to exceed 25 K, a number way too small to explain the >250 K different phenotypes on a one-protein-one-function base. Therefore, the study of the interactome of the different proteins is of utmost importance. Here, we describe the present knowledge of the ICln interactome. ICln is a protein, we cloned and whose function was reported to be as divers as (i) ion permeation, (ii) cytoskeletal organization, and (iii) RNA processing. The role of ICln in these different functional modules can be described best as being a 'connector hub' with 'date hub' functio

    Scientific Opinion on the effect on public or animal health or on the environment on the presence of seeds of Ambrosia spp. in animal feed

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    The European Commission requested EFSA to provide a scientific opinion on the effect on public or animal health or on the environment on the further distribution of Ambrosia spp. in the European Union and on the importance of feed materials, in particular bird feed, in the dispersion of Ambrosia spp. The genus Ambrosia (Asteraceae family) is distributed worldwide. Ambrosia artemisiifolia (common ragweed) has heavily colonised several areas of South-East Europe. Ambrosia spp., both in their native range and in invaded areas, are of public health concern due to the allergenic properties of their pollen. The NDA Panel concluded that inhalation of the plant pollen causes rhino-conjunctivitis and asthma, with skin allergies and food allergy playing minor roles. Ambrosia may cross-sensitize patients to other allergens, including food allergens. There is some evidence for allergenicity of Ambrosia pollen in animals. With regard to the effects on the environment of the further distribution of Ambrosia spp. in the European Union, the PLH Panel concluded that there is no direct evidence that Ambrosia spp. cause extinction of plant species. However, there are some indications that A. artemisiifolia could become highly invasive in certain environmentally-valuable habitats and might be linked to an impoverishment of species richness, therefore further ecological studies are needed. The CONTAM Panel focused on the relative importance of animal feed, bird feed in particular, on the dispersion of Ambrosia. Ambrosia seeds may contaminate feed. However, animal feed materials compounded for use in livestock are extensively processed. This processing destroys Ambrosia seeds and hence the contribution of compounded feed to the dispersion of Ambrosia is considered to be negligible. Bird feed often contains significant quantities of Ambrosia seeds and remains unprocessed. Therefore, bird feed seems to play an important role in introducing Ambrosia to new, previously not infested area
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