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  • 1
    Online Resource
    Online Resource
    Effects of Burosumab Treatment on Mineral Metabolism in Children and Adolescents With X-linked Hypophosphatemia
    The Endocrine Society ; 2023
    In:  The Journal of Clinical Endocrinology & Metabolism Vol. 108, No. 10 ( 2023-09-18), p. e998-e1006
    Details
    In: The Journal of Clinical Endocrinology & Metabolism, The Endocrine Society, Vol. 108, No. 10 ( 2023-09-18), p. e998-e1006
    Abstract: Burosumab has been approved for the treatment of children and adults with X-linked hypophosphatemia (XLH). Real-world data and evidence for its efficacy in adolescents are lacking. Objective To assess the effects of 12 months of burosumab treatment on mineral metabolism in children (aged & lt;12 years) and adolescents (aged 12-18 years) with XLH. Design Prospective national registry. Setting Hospital clinics. Patients A total of 93 patients with XLH (65 children, 28 adolescents). Main Outcome Measures Z scores for serum phosphate, alkaline phosphatase (ALP), and renal tubular reabsorption of phosphate per glomerular filtration rate (TmP/GFR) at 12 months. Results At baseline, patients showed hypophosphatemia (−4.4 SD), reduced TmP/GFR (−6.5 SD), and elevated ALP (2.7 SD, each P & lt; .001 vs healthy children) irrespective of age, suggesting active rickets despite prior therapy with oral phosphate and active vitamin D in 88% of patients. Burosumab treatment resulted in comparable increases in serum phosphate and TmP/GFR in children and adolescents with XLH and a steady decline in serum ALP (each P & lt; .001 vs baseline). At 12 months, serum phosphate, TmP/GFR, and ALP levels were within the age-related normal range in approximately 42%, 27%, and 80% of patients in both groups, respectively, with a lower, weight-based final burosumab dose in adolescents compared with children (0.72 vs 1.06 mg/kg, P & lt; .01). Conclusions In this real-world setting, 12 months of burosumab treatment was equally effective in normalizing serum ALP in adolescents and children, despite persistent mild hypophosphatemia in one-half of patients, suggesting that complete normalization of serum phosphate is not mandatory for substantial improvement of rickets in these patients. Adolescents appear to require lower weight-based burosumab dosage than children.
    Type of Medium: Online Resource
    ISSN: 0021-972X , 1945-7197
    URL: Article
    DOI: 10.1210/clinem/dgad223
    RVK:
    XA 10000
    Language: English
    Publisher: The Endocrine Society
    Publication Date: 2023
    detail.hit.zdb_id: 2026217-6
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  • 2
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    DataSheet1.zip
    Frontiers Media SA ; 2022
    In:  Frontiers in Earth Science Vol. 10 ( 2022-4-1)
    Details
    In: Frontiers in Earth Science, Frontiers Media SA, Vol. 10 ( 2022-4-1)
    Abstract: The occurrence of mantle-derived peridotite xenoliths in phonolitic melts is a rare phenomenon, and is commonly ascribed to a mantle origin of the phonolite. The alternative possibility, that xenoliths are transported into evolving phonolite melts by mafic magmas, has received little attention. A unique tephriphonolite lava with phonolitic groundmass composition, from the active Cumbre Vieja volcano of La Palma (Canary Islands), allows to test these models. The lava contains abundant inclusions that represent the island’s major xenolith types: kaersutite-dominated cumulates, gabbros from the lower oceanic crust, and peridotites from the mantle. Our petrological investigations indicate that the tephriphonolite magma contained 3–4 wt% H 2 O and was stored in the lower crust at around 250–350 MPa and 900–950°C, at oxidized conditions (∆NNO of 2–3). The peridotite xenoliths are mantled by complex polyphase selvages, with adjacent up to 1.6 mm wide zonations where olivine compositions change from Fo 78-86 at the selvage contact to Fo 89-91 inside the xenoliths. We carried out diffusion modelling for Fe-Mg exchange and found that the peridotites had contact with intermediate to evolved alkaline melts over decades to centuries. This timescale is comparable to that inferred for basanite-hosted peridotite xenoliths from Cumbre Vieja. The following model is proposed: differentiation of evolved melts occurs in a magma accumulation zone in the lowermost oceanic crust beneath La Palma. The evolving melts receive periodic recharge by mantle-derived mafic magmas at intervals on the order of decades to a few centuries, comparable to historic eruption recurrences (80 years on average). Some of these recharge pulses carry mantle peridotite fragments that become deposited in the accumulation zone. Thus, these xenoliths do not reflect formation of the evolved melts in the mantle. Final ascent of the tephriphonolite was triggered by magma recharge some weeks before its eruption, resulting in entrainment and thorough mingling of a mixed xenolith population (cumulates, oceanic crust gabbros, peridotites). We infer that formation of phonolites in the lower crust beneath oceanic island volcanoes, and subsequent eruption, requires a balance between rates and volumes of magma recharge pulses and of eruptive events.
    Type of Medium: Online Resource
    ISSN: 2296-6463
    URL: Article
    URL: Article
    DOI: 10.3389/feart.2022.761902
    DOI: 10.3389/feart.2022.761902.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2741235-0
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  • 3
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    Timing of carbon uptake by oceanic crust determined by rock reactivity
    Geological Society of America ; 2023
    In:  Geology Vol. 51, No. 9 ( 2023-09-01), p. 875-879
    Details
    In: Geology, Geological Society of America, Vol. 51, No. 9 ( 2023-09-01), p. 875-879
    Abstract: Carbonate formation during the alteration of oceanic crust is a global CO2 sink. Its timing and controls are not well understood, particularly in volcanic seamounts, which react with seawater over tens of millions of years. We report in situ U-Pb age dates of carbonate vein and void fill in 50–74 Ma basaltic basement of the Louisville Seamount Chain. More than 90% of the carbonate formed & lt;20 m.y. after seamount emplacement. Vesicle carbonate precipitated within 8 m.y. (median = 2.9 m.y.) whereas vein carbonate grew over longer time spans (median = 8.1 m.y.). The duration of carbonation was hence limited despite the basement’s long-term exposure to seawater. The age dates imply a rapid infill of vesicles by alteration of confined domains around vesicles. Carbonate formation in veins extended for longer periods of time, likely due to the late opening of fractures, which exposed fresh reactive rock surface to circulating seawater long after the formation of the basement. We suggest that carbonate growth ceased after the volcanic rocks were too altered to liberate sufficient Ca2+ and generate the alkalinity required for carbonate precipitation. A critical extent of rock reactivity is required to sustain carbonate formation. Carbonate precipitation likely ends after much of the exposed basaltic substrate has been altered and the rock reactivity drops below this critical threshold. These findings help to explain the generally short duration of carbonation in the flanks of mid-ocean ridges.
    Type of Medium: Online Resource
    ISSN: 0091-7613 , 1943-2682
    URL: Article
    DOI: 10.1130/G51238.1
    Language: English
    Publisher: Geological Society of America
    Publication Date: 2023
    detail.hit.zdb_id: 184929-3
    detail.hit.zdb_id: 2041152-2
    SSG: 13
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  • 4
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    Volcanically hosted venting with indications of ultramafic influence at Aurora hydrothermal field on Gakkel Ridge
    Springer Science and Business Media LLC ; 2022
    In:  Nature Communications Vol. 13, No. 1 ( 2022-10-31)
    Details
    In: Nature Communications, Springer Science and Business Media LLC, Vol. 13, No. 1 ( 2022-10-31)
    Abstract: The Aurora hydrothermal system, Arctic Ocean, hosts active submarine venting within an extensive field of relict mineral deposits. Here we show the site is associated with a neovolcanic mound located within the Gakkel Ridge rift-valley floor, but deep-tow camera and sidescan surveys reveal the site to be ≥100 m across—unusually large for a volcanically hosted vent on a slow-spreading ridge and more comparable to tectonically hosted systems that require large time-integrated heat-fluxes to form. The hydrothermal plume emanating from Aurora exhibits much higher dissolved CH 4 /Mn values than typical basalt-hosted hydrothermal systems and, instead, closely resembles those of high-temperature ultramafic-influenced vents at slow-spreading ridges. We hypothesize that deep-penetrating fluid circulation may have sustained the prolonged venting evident at the Aurora hydrothermal field with a hydrothermal convection cell that can access ultramafic lithologies underlying anomalously thin ocean crust at this ultraslow spreading ridge setting. Our findings have implications for ultra-slow ridge cooling, global marine mineral distributions, and the diversity of geologic settings that can host abiotic organic synthesis - pertinent to the search for life beyond Earth.
    Type of Medium: Online Resource
    ISSN: 2041-1723
    URL: Article
    DOI: 10.1038/s41467-022-34014-0
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2553671-0
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  • 5
    Online Resource
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    DataSheet1.zip
    Frontiers Media SA ; 2022
    In:  Frontiers in Earth Science Vol. 10 ( 2022-4-1)
    Details
    In: Frontiers in Earth Science, Frontiers Media SA, Vol. 10 ( 2022-4-1)
    Abstract: Mass transfer at shallow subduction levels and its ramifications for deeper processes remain incompletely constrained. New insights are provided by ocean island basalt (OIB) clasts from the Mariana forearc that experienced subduction to up to ∼25–30 km depth and up to blueschist-facies metamorphism; thereafter, the clasts were recycled to the forearc seafloor via serpentinite mud volcanism. We demonstrate that the rocks were, in addition, strongly metasomatized: they exhibit K 2 O contents (median = 4.6 wt%) and loss on ignition (median = 5.3 wt%, as a proxy for H 2 O) much higher than OIB situated on the Pacific Plate, implying that these were added during subduction. This interpretation is consistent with abundant phengite in the samples. Mass balance calculations further reveal variable gains in SiO 2 for all samples, and increased MgO and Na 2 O at one but losses of MgO and Fe 2 O 3 * at the other study site. Elevated Cs and Rb concentrations suggest an uptake whereas low Ba and Sr contents indicate the removal of trace elements throughout all clasts. The metasomatism was likely induced by the OIBs’ interaction with K-rich fluids in the subduction channel. Our thermodynamic models imply that such fluids are released from subducted sediments and altered igneous crust at 5 kbar and even below 200°C. Equilibrium assemblage diagrams show that the stability field of phengite significantly increases with the metasomatism and that, relative to not-metasomatized OIB, up to four times as much phengite may form in the metasomatized rocks. Phengite in turn is considered as an important carrier for K 2 O, H 2 O, and fluid-mobile elements to sub-arc depths. These findings demonstrate that mass transfer from the subducting lithosphere starts at low P / T conditions. The liberation of solute-rich fluids can evoke far-reaching compositional and mineralogical changes in rocks that interact with these fluids. Processes at shallow depths ( & lt;30 km) thereby contribute to controlling which components as well as in which state (i.e., bound in which minerals) these components ultimately reach greater depths where they may or may not contribute to arc magmatism. For a holistic understanding of deep geochemical cycling, metasomatism and rock transformation need to be acknowledged from shallow depths on.
    Type of Medium: Online Resource
    ISSN: 2296-6463
    URL: Article
    URL: Article
    DOI: 10.3389/feart.2022.826312
    DOI: 10.3389/feart.2022.826312.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2741235-0
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  • 6
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    Variant across-forearc compositions of slab-fluids recorded by serpentinites: Implications on the mobilization of FMEs from an active subduction zone (Mariana forearc)
    Elsevier BV ; 2020
    In:  Lithos Vol. 364-365 ( 2020-07), p. 105525-
    Details
    In: Lithos, Elsevier BV, Vol. 364-365 ( 2020-07), p. 105525-
    Type of Medium: Online Resource
    ISSN: 0024-4937
    URL: Article
    DOI: 10.1016/j.lithos.2020.105525
    RVK:
    TE 1000
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
    detail.hit.zdb_id: 1494884-9
    detail.hit.zdb_id: 221624-3
    SSG: 13
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  • 7
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    DataSheet1.zip
    Frontiers Media SA ; 2021
    In:  Frontiers in Earth Science Vol. 9 ( 2021-6-22)
    Details
    In: Frontiers in Earth Science, Frontiers Media SA, Vol. 9 ( 2021-6-22)
    Abstract: Molecular hydrogen (H 2 ) released during serpentinization of mantle rocks is one of the main fuels for chemosynthetic life. Processes of H 2 production at slow-spreading mid-ocean ridges (MORs) have received much attention in the past. Less well understood is serpentinization at passive continental margins where different rock types are involved (lherzolite instead of harzburgite/dunite at MORs) and the alteration temperatures tend to be lower ( & lt;200°C vs. & gt;200°C). To help closing this knowledge gap we investigated drill core samples from the West Iberia margin. Lherzolitic compositions and spinel geochemistry indicate that the exhumed peridotites resemble sub-continental lithospheric mantle. The rocks are strongly serpentinized, mainly consist of serpentine with little magnetite, and are generally brucite-free. Serpentine can be uncommonly Fe-rich, with X Mg = Mg/(Mg + Fe) & lt; 0.8, and shows distinct compositional trends toward a cronstedtite endmember. Bulk rock and silicate fraction Fe(III)/∑Fe ratios are 0.6–0.92 and 0.58–0.8, respectively; our data show that 2/3 of the ferric Fe is accounted for by Fe(III)-serpentine. Mass balance and thermodynamic calculations suggest that the sample’s initial serpentinization produced ∼120 to & gt;300 mmol H 2 per kg rock. The cold, late-stage weathering of the serpentinites at the seafloor caused additional H 2 formation. These results suggest that the H 2 generation potential evolves during the transition from continental break-up to ultraslow and, eventually, slow MOR spreading. Metamorphic phase assemblages systematically vary between these settings, which has consequences for H 2 yields during serpentinization. At magma-poor rifted margins and ultraslow-spreading MORs, serpentine hosts most Fe(III). Hydrogen yields of 120 to & gt;300 mmol and 50–150 mmol H 2 per kg rock, respectively, may be expected at temperatures of & lt;200°C. At slow-spreading MORs, in contrast, serpentinization may produce 200–350 mmol H 2 , most of which is related to magnetite formation at & gt;200°C. Since, in comparison to slow-spreading MORs, geothermal gradients at magma-poor margins and ultraslow-spreading MORs are lower, larger volumes of low-temperature serpentinite should form in these settings. Serpentinization of lherzolitic rocks at magma-poor margins should produce particularly high amounts of H 2 under conditions within the habitable zone. Magma-poor margins may hence be more relevant environments for hydrogenotrophic microbial life than previously thought.
    Type of Medium: Online Resource
    ISSN: 2296-6463
    URL: Article
    URL: Article
    DOI: 10.3389/feart.2021.673063
    DOI: 10.3389/feart.2021.673063.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2741235-0
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  • 8
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    Systematic changes in serpentine Si isotope signatures across the Mariana forearc – a new proxy for slab dehydration processes
    Elsevier BV ; 2021
    In:  Earth and Planetary Science Letters Vol. 575 ( 2021-12), p. 117193-
    Details
    In: Earth and Planetary Science Letters, Elsevier BV, Vol. 575 ( 2021-12), p. 117193-
    Type of Medium: Online Resource
    ISSN: 0012-821X
    URL: Article
    DOI: 10.1016/j.epsl.2021.117193
    RVK:
    TE 1000
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 300203-2
    detail.hit.zdb_id: 1466659-5
    SSG: 16,13
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  • 9
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    Mariana serpentinite mud volcanism exhumes subducted seamount materials: implications for the origin of life
    The Royal Society ; 2020
    In:  Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Vol. 378, No. 2165 ( 2020-02-21), p. 20180425-
    Details
    In: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, The Royal Society, Vol. 378, No. 2165 ( 2020-02-21), p. 20180425-
    Abstract: The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes.  Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean Drilling Program and International Ocean Discovery Program cores of serpentinite mudflows that confirm exhumation of various Pacific Plate lithologies, including subducted reef limestone; (4) petrologic, geochemical and paleontological data from the cores that show that Pacific Plate seamount exhumation covers greater spatial and temporal extents; (5) the inference that microbial communities associated with serpentinite mud volcanism may also be exhumed from the subducted plate seafloor and/or seamounts; and (6) the implications for effects of these processes with regard to evolution of life. This article is part of a discussion meeting issue ‘Serpentine in the Earth system’.
    Type of Medium: Online Resource
    ISSN: 1364-503X , 1471-2962
    URL: Article
    DOI: 10.1098/rsta.2018.0425
    RVK:
    AX 30011
    Language: English
    Publisher: The Royal Society
    Publication Date: 2020
    detail.hit.zdb_id: 208381-4
    detail.hit.zdb_id: 1462626-3
    SSG: 11
    SSG: 5,1
    SSG: 5,21
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