МЕТАСОМАТИЧЕСКИЕ И МАГМАТИЧЕСКИЕ ПРОЦЕССЫ В МАНТИЙНОЙ ЛИТОСФЕРЕ БИРЕКТИНСКОГО ТЕРРЕЙНА СИБИРСКОГО КРАТОНА И ИХ ВЛИЯНИЕ НА ЭВОЛЮЦИЮ ЛИТОСФЕРЫ

The area of studies covers the north-eastern part of the Siberian craton (the Birekte terrain), Russia. The influence of metasomatic and magmatic processes on the mantle lithosphere is studied based on results of analyses of phlogopite- and phlogopite-amphibole-containing deep-seated xenoliths from kimberlites of the Kuoika field. In the kimberlitic pipes, deep-seated xenoliths with mantle phlogopite- and phlogopite-amphibole mineralization are developed in two genetically different rock series: magnesian (Mg) pyroxenite-peridotite series (with magnesian composition of rocks and minerals) and phlogopite-ilmenite (Phl-Ilm) hyperbasite series (with ferrous types of rocks and minerals). This paper is focused on issues of petrography and mineralogy of the xenoliths and describes the evidence of metasomatic / magmatic genesis of phlogopite and amphibole. We report here the first data set of 40Ar/39Ar age determinations for phlogopite from the rocks of the magnesian pyroxenite-peridotite series and the ferrous Phl-Ilm hyperbasite series.The Mg series is represented by a continuous transition of rocks from Sp, Sp-Grt, Grt clinopyroxenite and ortopyroxenite to websterite and lherzolite. Many researchers consider it as a layered intrusion in the mantle [Ukhanov et al., 1988; Solov’eva et al., 1994]. The mantle metasomatic phlogopite and amphibole are revealed in all petrographic types of the rocks in this series and compose transverse veins and irregular patchs at grain boundaries of primary minerals. At contacts of xenolith and its host kimberlite, grains of phlogopite and amphibole are often cut off, which gives an evidence of the development of metasomatic phlogopite-amphibole mineralization in the rocks before its’ entraiment into the kimberlite. In the xenoliths with exsolution pyroxene megacrystalls, comprising parallel plates of clino- and orthopyroxene ± garnet ± spinel (former high-temperature pigeonite [Solov’eva et al., 1994]), the metasomatic phlogopite-amphibole aggregate mainly replace laminar intergrowths of one of pyroxenes and garnet and also develops in the re-crystallized fine-grained rock matrix. This suggests a considerable period of time between the crystallization of rocks of the pyroxenite-peridotite series and the development of phlogopite-amphibole metasomatism.The Phl-Ilm hyperbasites comprise a complex association of parageneses represented by garnet- and garnetless pyroxenites, websterites, olivine websterites, orthopyroxenites, lherzolites and olivinites. A specific feature of this series is high contents of K, Ti and Fe in the rocks and minerals. The content of phlogopite is widely variable, from a few percent to 40–80 %. The content of ilmenite ranges from a few percent to 15 %, rarely to 30–40 %. Mica and ilmenite contents sharply decrease in garnetized xenolithes, where these two minerals, as soon as olivine and pyroxenes are replaced by garnet.Euhedral, subhedral, sideronitic and porphyraceous structures in garnetless xenoliths suggest the primary magmatic genesis of the rocks. In the series of Phl-Ilm hyperbasites, a special type of parageneses is represented by strongly deformed phlogopite-amphibole rocks with newly-formed chromite and relict resorbed ilmenite and clinopyroxene. Phl-Ilm rock series is also characterized by a variety of autometasomatic and metasomatic reaction structures. Garnet and phlogopite develop nearly simultaneously at the sub-solidus stage: garnet develops due to cooling of the primary magmatic rocks, and phlogopite develops under the influence of residual rich in potassium and volatiles fluids – melts. Phlogopite in the rocks of the Phl-Ilm series form porphyraceous plates, late intergranular xenomorphic grains, porphyroblasts of the solidus stage and strongly deformed irregular plates in the phlogopite-amphibole rocks. Amphibole occurs in garnetless parageneses and deformed phlogopite-amphibole rocks in amounts of a few percent and up to 40–50%, respectively. Petrographically, the differentiated series of phlogopite-ilmenite hyperbasites belongs to mantle magmatites, except for younger deformed phlogopite-amphibole rocks from zones of deep faults.Unlike corresponding minerals in the Mg pyroxenite-peridotite series, minerals from the Phl-Ilm hyperbasites are characterized by lower magnesium index (Mg#), considerably higher contents of TiO2 and FeO, and lower contents of Cr2O3 (Table). In diagrams Mg# – TiO2 and Mg# – Cr2O3, metasomatic phlogopite points from Mg series rocks are significantly distant from points of mica from the phlogopite-ilmenite parageneses (Fig. 24). In the parageneses of the Mg pyroxenite-peridotite series, phlogopite plates have homogenous compositions in contrast to zonal phlogopite in the Phl-Ilm hyperbasites. In Phl-Amph metasomatites of the Mg series, amphibole is represented by typical pargasite, and its chemical composition is sharply different from that of K-richterite from the deformed phlogopite-amphibole rocks of the series of the Phl-Ilm hyperbasites (Table).The 40Ar/39Ar age in the range from 1640 to 1800 Ma (Fig. 25) is determined for phlogopite from the metasomatic phlogopite-amphibole veinlets and intergranular reaction patches in the garnet olivine websterite of the Mg series. For mica from the garnetless Phl-Ilm websterites, ages are 869 and 851 Ma (Fig. 25). Mica from the garnet-containing Phl-Ilm lherzolites is much younger (608 and 495 Ma). The age of mica from the deformed phlogopite-amphibole rock is 167 Ma, which is close to the age of kimberlites of the Kuoika field.Metasomatic phlogopite (1640–1800 Ma) originated somewhat later than the Birekte terrain accretion to the Siberian craton (1.8–1.9 Ga) [Rosen, 2003], and its age determination may be explained by a partial loss of 40Ar in the analysed medium. This age is also close to the late episode when the crust was formed in the Birekte block 1.8–2.1 Ga ago [Nasdala et al., 2014], and corresponds to the time when radiogenic osmium was supplied into the mantle lithosphere from the subduction zone (1.7–2.2 Ga, according to [Pernet et al., 2015]). In analyses of minerals in the pyroxenite-peridotite series from the Obnazhennaya pipe, data on the oxygen isotope geochemistry give evidence of an ancient subduction component (Fig. 26). It can be thus assumed that in the mantle lithosphere of the Birekte terrain, phlogopite-amphibole metasomatism took place due to fluids-melts ascending from the subduction zone about 1.8 Ga ago and correlates to the accretion of this block to the Siberian craton. The complex magmatic series of Phl-Ilm rocks formed later than the Mg pyroxenite-peridotite series. The more ancient ages of phlogopite (869–851 Ma) from PhlIlm hyperbasites are somewhat higher than the most ancient dating of alkaline ultrabasic-carbonatite Tomtor massif (800 Ga, according to [Entin et al., 1990]) and the time when the breakup of Rodinia began (825 Ga, according to [Li et al., 2008]). The difference may be explained by an advance occurrence of high-potassium, titanian, ferrous magmatites in the mantle lithosphere of the Birekte block as compared to their appearance on the surface. Phlogopite from xenoliths with subsolidus garnetization is significantly younger in age (500–600 Ma), may be, due to a loss of radiogenic argon caused by mica replacement. H2O, K, Ba, F and Cl were abundantly released during the replacement and supplied into the upper layers of the crust and mantle. The mantle high-potassium and high titanian Phl-Ilm series seems comagmatic with the surficial potassium ultramafites and mafites of the Siberian Platform and associated with the earlier episode of the Rodinia breakup.Введение. Влияние процессов мантийного метасоматизма и магматизма на эволюцию литосферной мантии в северо-восточном Биректинском террейне Сибирского кратона рассмотрено на примере флогопит- и флогопит-амфиболсодержащих глубинных ксенолитов из кимберлитов Куойкского поля (рис. 1). Глубинные ксенолиты с мантийной флогопитовой и флогопит-амфиболовой минерализацией в кимберлитовых трубках поля развиты в двух генетически разных сериях пород: магнезиальной (Mg) пироксенит-перидотитовой (с магнезиальным составом пород и минералов) и в серии флогопит-ильменитовых (Phl-Ilm) ги- пербазитов (с железистым типом пород и минералов). В настоящей работе уделяется большое внимание петрографии и минералогии ксенолитов с мантийной флогопитовой и флогопит-амфиболовой минерализацией, и приводятся новые данные по 40Ar/39Ar возрасту флогопита.Методы исследований. Флогопит- и флогопит-амфиболсодержащие парагенезисы ксенолитов были детально изучены в образцах и шлифах. Зерна минералов были проанализированы на содержания главных оксидов на рентгеновском электронно-зондовом микроанализаторе JXA-8200 в Институте геохимии им. А.П. Виноградова СО РАН (г. Иркутск). Анализ изотопного состава кислорода в гранате выполнен в аналитическом центре ДВГИ ДВО РАН (г. Владивосток) на масс-спектрометре Finnigan MAT 252, [Ignatiev, Velivetskaya, 2004]. Определение возраста флогопита 40Ar/39Ar методом произведено в Институте земной коры СО РАН (г. Иркутск) с использованием мультиколлекторного масс-спектрометра Argus VI.Петрография и минералогия. Магнезиальная (Mg) серия представлена непрерывным переходом пород от Sp, Sp-Grt, Grt клинопироксенитов, ортопироксенитов к вебстеритам, оливиновым вебстеритам и лерцолитам и рассматривается рядом исследователей как расслоенная интрузия в мантии [Ukhanov et al., 1988; Solov’eva et al., 1994]. Мантийная метасоматическая флогопит-амфиболовая минерализация проявлена во всех петрографических типах пород серии и развита в виде секущих прожилков и неправильных участков по границам зерен первичных минералов (рис. 4, 5). В ксенолитах с мегакристаллами пироксенов, состоящих из параллельных пластинок клино- и ортопироксена ± граната ± шпинели (структуры распада высокотемпературного пижонита [Solov’eva et al., 1994]), метасоматический флогопит-амфиболовый агрегат развивается преимущественно по пластинчатым вросткам одного из пироксенов и граната и в перекристаллизованной мелкозернистой матрице пород. Это указывает на значительный интервал времени между кристаллизацией пород пироксенит-перидотитовой серии и развитием флогопит-амфиболового метасоматизма. Phl-Ilm гипербазиты также образуют сложную ассоциацию парагенезисов, представленных Phl-Ilm гранатовыми и безгранатовыми пироксенитами, вебстеритами, оливиновыми вебстеритами, ортопироксенитами, лерцолитами и оливинитами. Характерной особенностью серии являются высокие содержания K, Ti, Fe в породах и минералах. Содержание флогопита в породах широко варьируется – от первых процентов до 40–80 %, ильменита – от первых до 15 %, реже до 30–40 %. Количество слюды и ильменита резко уменьшается в гранатизированных ксенолитах, в которых гранат интенсивно замещает эти минералы, а также первичные силикаты. Панидиоморфнозернистые, гипидиоморфнозернистые, сидеронитовые и порфировидные структуры в негранатизированных ксенолитах указывают на первичный магматический генезис пород. Для пород серии характерно также разнообразие автометасоматических и метасоматических структур. Гранат и флогопит развиваются на субсолидусном этапе близко одновременно: первый за счет охлаждения первичных магматических пород (рис. 11, 12, 14), а второй при воздействии на них остаточных флюидов-расплавов, обогащенных калием и летучими (рис. 8). Особый тип парагенезисов в серии Phl-Ilm гипербазитов представляют сильно деформированные флогопит-амфиболовые породы с новообразованным хромитом и с реликтовыми резорбированными ильменитом и клинопироксеном (рис. 21–23). Дифференцированная серия флогопит-ильменитовых гипербазитов по петрографическим признакам относится к мантийным магматитам, за исключением более поздних деформированных флогопит-амфиболовых пород из зон глубинных разломов. В отличие от соответствующих минералов Mg пироксенит-перидотитовой серии, минералы из Phl-Ilm гипербазитов имеют значительно меньшую магнезиальность (Mg#) и содержат существенно больше TiO2, FeO и меньше Cr2O3 (таблица). Точки метасоматических флогопитов из пород Mg серии на диаграммах Mg# – TiO2 и Mg# – Cr2O3 существенно отделены от поля точек слюд из флогопит-ильменитовых парагенезисов (рис. 24). Амфибол, представленный в Phl-Amph метасоматитах Mg серии типичным паргаситом по химическому составу резко отличается от K-рихтерита из деформированных флогопит-амфиболовых пород серии Phl-Ilm гипербазитов (таблица).40Ar/39Ar датирование слюды. 40Ar/39Ar возраст флогопита из метасоматических флогопит-амфиболовых прожилков и межзерновых реакционных обособлений в гранатовом оливиновом вебстерите Mg серии варьируется в пределах 1640–1800 млн лет (рис. 25). Слюды из негранатизированных Phl-Ilm вебстеритов показали возраст 869 и 851 млн лет (рис. 25). В гранатизированных Phl-Ilm лерцолитах возраст слюд значительно меньше (608 и 495 млн лет). Слюда из деформированной флогопит-амфиболовой породы показала возраст 167 млн лет, близкий возрасту кимберлитов Куойкского поля.Дискуссия и результаты. Возраст метасоматического флогопита (1640–1800 млн лет) несколько ниже возраста присоединения Биректинского террейна к Сибирскому кратону (1.8–1.9 млн лет [Rosen, 2003]), что, возможно, объясняется частичной потерей 40Ar в анализируемой слюде. С другой стороны, это значение близко интервалу позднего эпизода формирования коры в Биректинском блоке 1.8–2.1 млрд лет [Nasdala et al., 2014] и соответствует времени привноса радиогенного осмия в мантийную литосферу из зоны субдукции (1.7–2.2 лет [Pernet-Fisher et al., 2015]). Геохимия изотопов кислорода в породах перидотит-пироксенитовой серии из трубки Обнаженная также свидетельствует о присутствии в них древней субдукционной компоненты (рис. 26). Это позволяет предположить, что мантийный флогопит-амфиболовый метасоматизм в литосферной мантии Биректинского террейна осуществлялся флюидами – расплавами, поступавшими из зоны субдукции примерно 1.8 млрд лет назад, и соответствует эпизоду присоединения этого блока к Сибирскому кратону. Сложная магматическая серия Phl-Ilm пород является более поздней по сравнению с Mg пироксенит-перидотитовой серией. Древний возраст флогопита (869–851 млн лет) из Phl-Ilm гипербазитов несколько превышает наиболее древние датировки щелочного ультраосновного – карбонатитового Томторского массива (800 млн лет [Entin et al., 1990]) и время начала распада суперконтинента Родиния (825 млн лет [Li et al., 2008]). Эта разница может быть объяснена опережающим проявлением высококалиевых, титанистых, железистых магматитов в мантийной литосфере Биректинского блока по сравнению с их проявлением на поверхности. Флогопит из ксенолитов с субсолидусной гранатизацией показывает существенно меньшие значения возраста (500–600 млн лет), вероятно, из-за потери радиогенного аргона при замещении слюды. Этот процесс высвобождал большое количество H2O, K, Ba, F и Cl, поступавших в верхние горизонты коры и мантии. Мантийная высококалиевая и высокотитанистая Phl-Ilm серия, по-видимому, комагматична поверхностным калиевым ультрамафитам и мафитам на Сибирской платформе и связана с ранним эпизодом раскола суперконтинента Родиния. Главные выводы. 1. Рассмотренные флогопитсодержащие серии ксенолитов из кимберлитовых трубок Куойкского поля принадлежат к разным генетическим образованиям и к разным этапам эволюции литосферной мантии Биректинского террейна. 2. Phl-Amph метасоматизм развивается по породам сложной магнезиальной пироксенит-перидотитовой серии ксенолитов, имеет геохимические черты зоны субдукции и маркирует этап, связанный с присоединением Биректинского континентального блока к Сибирскому кратону ~1.8–1.9 млрд лет. 3. Сложная железистая серия Phl-Ilm гипербазитов относится к типичным мантийным калиевым ультраосновным – основным магматитам. Начало формирования магматической серии Phl-Ilm гипербазитов в мантийной литосфере Биректинского террейна (~869–851 млн лет), возможно, соответствует самому раннему этапу распада суперконтинента Родиния

Delayed Development of Aneurysmal Dilatations in Patients with Extracranial Carotid Artery Dissections

Peer reviewe

Common variation in PHACTR1 is associated with susceptibility to cervical artery dissection

Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year). Minor cervical traumas, infection, migraine and hypertension are putative risk factors, and inverse associations with obesity and hypercholesterolemia are described. No confirmed genetic susceptibility factors have been identified using candidate gene approaches. We performed genome-wide association studies (GWAS) in 1,393 CeAD cases and 14,416 controls. The rs9349379[G] allele (PHACTR1) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69-0.82; P = 4.46 × 10(-10)), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 × 10(-3); combined P = 1.00 × 10(-11)). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction. Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions

Proceedings of the 24th Paediatric Rheumatology European Society Congress: Part three

From Springer Nature via Jisc Publications Router.Publication status: PublishedHistory: collection 2017-09, epub 2017-09-0

METASOMATIC AND MAGMATIC PROCESSES IN THE MANTLE LITHOSPHERE OF THE BIREKTE TERRAIN OF THE SIBERIAN CRATON AND THEIR EFFECT ON THE LITHOSPHERE EVOLUTION

The area of studies covers the north-eastern part of the Siberian craton (the Birekte terrain), Russia. The influence of metasomatic and magmatic processes on the mantle lithosphere is studied based on results of analyses of phlogopite- and phlogopite-amphibole-containing deep-seated xenoliths from kimberlites of the Kuoika field. In the kimberlitic pipes, deep-seated xenoliths with mantle phlogopite- and phlogopite-amphibole mineralization are developed in two genetically different rock series: magnesian (Mg) pyroxenite-peridotite series (with magnesian composition of rocks and minerals) and phlogopite-ilmenite (Phl-Ilm) hyperbasite series (with ferrous types of rocks and minerals). This paper is focused on issues of petrography and mineralogy of the xenoliths and describes the evidence of metasomatic / magmatic genesis of phlogopite and amphibole. We report here the first data set of 40Ar/39Ar age determinations for phlogopite from the rocks of the magnesian pyroxenite-peridotite series and the ferrous Phl-Ilm hyperbasite series.The Mg series is represented by a continuous transition of rocks from Sp, Sp-Grt, Grt clinopyroxenite and ortopyroxenite to websterite and lherzolite. Many researchers consider it as a layered intrusion in the mantle [Ukhanov et al., 1988; Solov’eva et al., 1994]. The mantle metasomatic phlogopite and amphibole are revealed in all petrographic types of the rocks in this series and compose transverse veins and irregular patchs at grain boundaries of primary minerals. At contacts of xenolith and its host kimberlite, grains of phlogopite and amphibole are often cut off, which gives an evidence of the development of metasomatic phlogopite-amphibole mineralization in the rocks before its’ entraiment into the kimberlite. In the xenoliths with exsolution pyroxene megacrystalls, comprising parallel plates of clino- and orthopyroxene ± garnet ± spinel (former high-temperature pigeonite [Solov’eva et al., 1994]), the metasomatic phlogopite-amphibole aggregate mainly replace laminar intergrowths of one of pyroxenes and garnet and also develops in the re-crystallized fine-grained rock matrix. This suggests a considerable period of time between the crystallization of rocks of the pyroxenite-peridotite series and the development of phlogopite-amphibole metasomatism.The Phl-Ilm hyperbasites comprise a complex association of parageneses represented by garnet- and garnetless pyroxenites, websterites, olivine websterites, orthopyroxenites, lherzolites and olivinites. A specific feature of this series is high contents of K, Ti and Fe in the rocks and minerals. The content of phlogopite is widely variable, from a few percent to 40–80 %. The content of ilmenite ranges from a few percent to 15 %, rarely to 30–40 %. Mica and ilmenite contents sharply decrease in garnetized xenolithes, where these two minerals, as soon as olivine and pyroxenes are replaced by garnet.Euhedral, subhedral, sideronitic and porphyraceous structures in garnetless xenoliths suggest the primary magmatic genesis of the rocks. In the series of Phl-Ilm hyperbasites, a special type of parageneses is represented by strongly deformed phlogopite-amphibole rocks with newly-formed chromite and relict resorbed ilmenite and clinopyroxene. Phl-Ilm rock series is also characterized by a variety of autometasomatic and metasomatic reaction structures. Garnet and phlogopite develop nearly simultaneously at the sub-solidus stage: garnet develops due to cooling of the primary magmatic rocks, and phlogopite develops under the influence of residual rich in potassium and volatiles fluids – melts. Phlogopite in the rocks of the Phl-Ilm series form porphyraceous plates, late intergranular xenomorphic grains, porphyroblasts of the solidus stage and strongly deformed irregular plates in the phlogopite-amphibole rocks. Amphibole occurs in garnetless parageneses and deformed phlogopite-amphibole rocks in amounts of a few percent and up to 40–50%, respectively. Petrographically, the differentiated series of phlogopite-ilmenite hyperbasites belongs to mantle magmatites, except for younger deformed phlogopite-amphibole rocks from zones of deep faults.Unlike corresponding minerals in the Mg pyroxenite-peridotite series, minerals from the Phl-Ilm hyperbasites are characterized by lower magnesium index (Mg#), considerably higher contents of TiO2 and FeO, and lower contents of Cr2O3 (Table). In diagrams Mg# – TiO2 and Mg# – Cr2O3, metasomatic phlogopite points from Mg series rocks are significantly distant from points of mica from the phlogopite-ilmenite parageneses (Fig. 24). In the parageneses of the Mg pyroxenite-peridotite series, phlogopite plates have homogenous compositions in contrast to zonal phlogopite in the Phl-Ilm hyperbasites. In Phl-Amph metasomatites of the Mg series, amphibole is represented by typical pargasite, and its chemical composition is sharply different from that of K-richterite from the deformed phlogopite-amphibole rocks of the series of the Phl-Ilm hyperbasites (Table).The 40Ar/39Ar age in the range from 1640 to 1800 Ma (Fig. 25) is determined for phlogopite from the metasomatic phlogopite-amphibole veinlets and intergranular reaction patches in the garnet olivine websterite of the Mg series. For mica from the garnetless Phl-Ilm websterites, ages are 869 and 851 Ma (Fig. 25). Mica from the garnet-containing Phl-Ilm lherzolites is much younger (608 and 495 Ma). The age of mica from the deformed phlogopite-amphibole rock is 167 Ma, which is close to the age of kimberlites of the Kuoika field.Metasomatic phlogopite (1640–1800 Ma) originated somewhat later than the Birekte terrain accretion to the Siberian craton (1.8–1.9 Ga) [Rosen, 2003], and its age determination may be explained by a partial loss of 40Ar in the analysed medium. This age is also close to the late episode when the crust was formed in the Birekte block 1.8–2.1 Ga ago [Nasdala et al., 2014], and corresponds to the time when radiogenic osmium was supplied into the mantle lithosphere from the subduction zone (1.7–2.2 Ga, according to [Pernet et al., 2015]). In analyses of minerals in the pyroxenite-peridotite series from the Obnazhennaya pipe, data on the oxygen isotope geochemistry give evidence of an ancient subduction component (Fig. 26). It can be thus assumed that in the mantle lithosphere of the Birekte terrain, phlogopite-amphibole metasomatism took place due to fluids-melts ascending from the subduction zone about 1.8 Ga ago and correlates to the accretion of this block to the Siberian craton. The complex magmatic series of Phl-Ilm rocks formed later than the Mg pyroxenite-peridotite series. The more ancient ages of phlogopite (869–851 Ma) from PhlIlm hyperbasites are somewhat higher than the most ancient dating of alkaline ultrabasic-carbonatite Tomtor massif (800 Ga, according to [Entin et al., 1990]) and the time when the breakup of Rodinia began (825 Ga, according to [Li et al., 2008]). The difference may be explained by an advance occurrence of high-potassium, titanian, ferrous magmatites in the mantle lithosphere of the Birekte block as compared to their appearance on the surface. Phlogopite from xenoliths with subsolidus garnetization is significantly younger in age (500–600 Ma), may be, due to a loss of radiogenic argon caused by mica replacement. H2O, K, Ba, F and Cl were abundantly released during the replacement and supplied into the upper layers of the crust and mantle. The mantle high-potassium and high titanian Phl-Ilm series seems comagmatic with the surficial potassium ultramafites and mafites of the Siberian Platform and associated with the earlier episode of the Rodinia breakup

The Use of Tocilizumab in 40 Patients With Polyarticular Juvenile Idiopathic Arthritis: the Results of a Retrospective Study

The issue of a therapy of children with juvenile idiopathic arthritis (JIA) with intolerance or insufficient effectiveness of methotrexate remains actual.Objective: Our aim was to study the efficacy and safety of tocilizumab in patients with polyarticular JIA.Methods. In a retrospective study, we studied the results of the use of tocilizumab in patients with active polyarticular JIA ( 5 active joints) resistant to prior therapy with methotrexate or a combination of methotrexate with other nonbiologic disease-modifying antiinflammatory drugs.Results. The data of 40 children (83% girls) with the onset median of polyarticular JIA of 4.8 (2.9, 8.1) years and the interval between the disease onset and the initiation of tocilizumab therapy of 5.7 (1.8, 8.5) years was analyzed. Tocilizumab was used as an intravenous infusion of 8 mg/kg (with a weight 30 kg) or 10 mg/kg (with a weight < 30 kg) every 4 weeks. The duration of tocilizumab monotherapy in 5 (13%) children was 1,109 days (452; 1,542). The stages of inactive disease (according to the criteria of C. Wallace, 2004) in 6 months of tocilizumab therapy reached 6 (15%) patients, in 42 months — 32 (80%) patients. In 3 patients, tocilizumab was canceled due to persistent remission. After 6 months of treatment, there was a marked decrease in erythrocyte sedimentation rate, C-reactive protein concentration, number of leukocytes and platelets (in all cases, p < 0.001) to normal values, which persisted throughout the whole period of drug administration. Predictors for achieving inactive disease were the initial (at the onset of tocilizumab therapy) number of peripheral blood leukocytes < 9.0X109/l [relative risk (RR) 1.92; 95% confidence interval (CI) 0.9–4.6)] and the absence of prior biological therapy (RR 1.92, 95% CI 0.9–4.6). The most frequent side effects of tocilizumab therapy were transient hypercholesterolemia (in 13), hypertriglyceridemia (in 4), transient grade II neutropenia (in 1).Conclusion. The long-term efficacy and relative safety of tocilizumab in children with polyarticular JIA have been showed

MRI Types of Cerebral Small Vessel Disease and Circulating Markers of Vascular Wall Damage

The evaluation of the clustering of magnetic resonance imaging (MRI) signs into MRI types and their relationship with circulating markers of vascular wall damage were performed in 96 patients with cerebral small vessel disease (cSVD) (31 men and 65 women; mean age, 60.91 ± 6.57 years). The serum concentrations of the tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor-A (VEGF-A), and hypoxia-inducible factor 1-α (HIF-1α) were investigated in 70 patients with Fazekas stages 2 and 3 of white matter hyperintensities (WMH) and 21 age- and sex-matched volunteers with normal brain MRI using ELISA. The cluster analysis excluded two patients from the further analysis due to restrictions in their scanning protocol. MRI signs of 94 patients were distributed into two clusters. In the first group there were 18 patients with Fazekas 3 stage WMH. The second group consisted of 76 patients with WMH of different stages. The uneven distribution of patients between clusters limited the subsequent steps of statistical analysis; therefore, a cluster comparison was performed in patients with Fazekas stage 3 WMH, designated as MRI type 1 and type 2 of Fazekas 3 stage. There were no differences in age, sex, degree of hypertension, or other risk factors. MRI type 1 had significantly more widespread WMH, lacunes in many areas, microbleeds, atrophy, severe cognitive and gait impairments, and was associated with downregulation of VEGF-A compared with MRI type 2. MRI type 2 had more severe deep WMH, lacunes in the white matter, no microbleeds or atrophy, and less severe clinical manifestations and was associated with upregulation of TNF-α compared with MRI type 1. The established differences reflect the pathogenetic heterogeneity of cSVD and explain the variations in the clinical manifestations observed in Fazekas stage 3 of this disease