Petrogenesis, Sources, and Tectonic Settings of Triassic Volcanic Rocks in the Ela Mountain Area of the East Kunlun Orogen: Insights from Geochronology, Geochemistry and Hf Isotopic Compositions

The Ela Mountain area is located at the easternmost point of the East Kunlun Orogen, in which voluminous igneous rocks developed in the Triassic period, and it is a good place to investigate the tectonic evolution of the Paleo-Tethys Ocean. In this study, petrological, geochemical, zircon U-Pb geochronology and zircon Hf isotope studies were carried out on the volcanic rocks in the Ela Mountain area. Dacite (239.3 ± 1.4 Ma) exhibits calc-alkaline I-type characteristics, and rhyolite (237.8 ± 2.1 Ma) is similar to high-K calc-alkaline highly fractionated I-type volcanic rock. The petrogenesis shows that both rhyolite and dacite originated from the partial melting of the mafic lower crust of the Mesoproterozoic under relatively high temperature and low pressure. Dacite and rhyolite were derived from the same or similar parent magma, and they are volcanic rocks with different differentiation degrees formed in the same magmatic pulse activity. Differing from rhyolite and dacite, basaltic andesite shows a relatively young age (234 ± 1.2 Ma), mainly originating from the partial melting of the lithospheric mantle modified by subducted slab-derived fluids; the magma was contaminated with a small amount of crustal source components and experienced the fractional crystallization of mafic minerals before the eruption to the surface. This study on the tectonic environment of these volcanic rocks shows that they were formed in the environment of slab failure in the late stage of syn-collision, and that they are different types of volcanic rocks from different sources under similar tectonic environments. The volcanic rocks of the Ela Mountain area in this contribution provide important evidence for Middle Triassic to Late Triassic syn-collisional magmatism in the slab failure stages. The results of this study constrain the lower age limit of the closure of the Paleo-Tethys Ocean and the initial time of extension of the late stage of syn-collision, providing important information regarding regional tectonic evolution processes and volcanic activity history. They can be applied to regional tectonic evolution, petrology, volcanic stratigraphy and mineral deposits related to volcanic rocks

Petrogenesis, Sources, and Tectonic Settings of Triassic Volcanic Rocks in the Ela Mountain Area of the East Kunlun Orogen: Insights from Geochronology, Geochemistry and Hf Isotopic Compositions

The Ela Mountain area is located at the easternmost point of the East Kunlun Orogen, in which voluminous igneous rocks developed in the Triassic period, and it is a good place to investigate the tectonic evolution of the Paleo-Tethys Ocean. In this study, petrological, geochemical, zircon U-Pb geochronology and zircon Hf isotope studies were carried out on the volcanic rocks in the Ela Mountain area. Dacite (239.3 ± 1.4 Ma) exhibits calc-alkaline I-type characteristics, and rhyolite (237.8 ± 2.1 Ma) is similar to high-K calc-alkaline highly fractionated I-type volcanic rock. The petrogenesis shows that both rhyolite and dacite originated from the partial melting of the mafic lower crust of the Mesoproterozoic under relatively high temperature and low pressure. Dacite and rhyolite were derived from the same or similar parent magma, and they are volcanic rocks with different differentiation degrees formed in the same magmatic pulse activity. Differing from rhyolite and dacite, basaltic andesite shows a relatively young age (234 ± 1.2 Ma), mainly originating from the partial melting of the lithospheric mantle modified by subducted slab-derived fluids; the magma was contaminated with a small amount of crustal source components and experienced the fractional crystallization of mafic minerals before the eruption to the surface. This study on the tectonic environment of these volcanic rocks shows that they were formed in the environment of slab failure in the late stage of syn-collision, and that they are different types of volcanic rocks from different sources under similar tectonic environments. The volcanic rocks of the Ela Mountain area in this contribution provide important evidence for Middle Triassic to Late Triassic syn-collisional magmatism in the slab failure stages. The results of this study constrain the lower age limit of the closure of the Paleo-Tethys Ocean and the initial time of extension of the late stage of syn-collision, providing important information regarding regional tectonic evolution processes and volcanic activity history. They can be applied to regional tectonic evolution, petrology, volcanic stratigraphy and mineral deposits related to volcanic rocks

Rapid Progression of Foveomacular Retinoschisis in Young Myopics

PURPOSE: To describe a foveomacular retinoschisis that has not been described. METHODS: Patients with foveomacular retinoschisis were included. Exclusion criteria included refractive error over -6.00 diopters, presence of posterior staphyloma, positive RS1-gene mutation, family history of retinoschisis, optic disk abnormalities, or glaucoma. Vitrectomy was performed on eyes with functional or structural deterioration. RESULTS: Seventeen eyes from 10 patients (15-30 years old, 8 females and 2 males) with foveoschisis were recruited, with bilateral involvement in 7 patients and unilateral in 3 patients. Vitrectomy was performed in 13 eyes (13/17, 76.5%). Seven eyes (6 patients) were operated soon after the first presentation because of poor vision and severe foveoschisis. Six eyes (6 patients) were operated 2 weeks to 13 months later because of deterioration of vision and foveoschisis. Preoperative vision was 20/134 ± 20/165, and postoperative vision was 20/25 ± 20/57, with visual improvement of 6.9 (4-14) lines. The mean postoperative follow-up period was 36.5 (15-69) months. Four eyes (4 patients) were asymptomatic, despite progression of foveoschisis. Three eyes (3 patients) maintained normal macula structures. CONCLUSION: We report a foveomacular retinoschisis characterized by young age of onset, female predominant, no highly myopia, mostly bilateral involvement, and rapid progression of foveoschisis and visual acuity. Vitrectomy is effective in restoring anatomical structure and stabilize vision

Correlation between Retinal Changes and Visual Function in Late-Stage Vogt-Koyanagi-Harada Disease: An Optical Coherence Tomography Study

Purpose. To characterize the optical coherence tomography (OCT) findings in late-stage Vogt-Koyanagi-Harada (VKH) disease and its correlation with visual function. Methods. The records of patients with late-stage VKH disease (defined as ≥12 months from disease onset) were retrospectively reviewed. The analysis focused on the OCT findings and microperimetry, in addition to the possible correlation between morphology and functional findings. Results. Twenty-nine patients (58 eyes) were included. Mean age at onset was 34.24 ± 10.67 years. The OCT revealed that the outer retina and retinal pigment epithelium (RPE) were mainly affected. These effects included RPE thickening and breakage or disappearance of the cone outer segment tip (COST) line and/or inner segment/outer segment (IS/OS) junction. The COST line and IS/OS results were related to macular function and the interval between symptom onset and initiation of high-dose corticosteroid treatment (all P<0.01). Eyes with intact COST lines demonstrated intact IS/OS and normal RPE layers as well as better visual function and normal retinal sensitivity. Conclusions. The OCT findings are strongly correlated with macular function, as well as other clinical findings in late-stage VKH. With respect to the COST line and retinal sensitivity especially, the OCT and microperimetry findings may be useful for evaluating later-stage VKH

Gene Expression Changes under Cyclic Mechanical Stretching in Rat Retinal Glial (Müller) Cells

<div><p>Objective</p><p>The retina is subjected to tractional forces in various conditions. As the predominant glial element in the retina, Müller cells are active players in all forms of retinal injury and disease. In this study, we aim to identify patterns of gene expression changes induced by cyclic mechanical stretching in Müller cells.</p><p>Methods</p><p>Rat Müller cells were seeded onto flexible bottom culture plates and subjected to a cyclic stretching regimen of 15% equibiaxial stretching for 1 and 24 h. RNA was extracted and amplified, labeled, and hybridized to rat genome microarrays. The expression profiles were analyzed using GeneSpring software, and gene ontology analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to select, annotate, and visualize genes by function and pathway. The selected genes of interest were further validated by Quantitative Real-time PCR (qPCR).</p><p>Results</p><p>Microarray data analysis showed that at 1 and 24 h, the expression of 532 and 991 genes in the Müller cells significantly (t-test, p<0.05) differed between the mechanically stretched and unstretched groups. Of these genes, 56 genes at 1 h and 62 genes at 24 h showed more than a twofold change in expression. Several genes related to response to stimulus (e.g., Egr2, IL6), cell proliferation (e.g., Areg, Atf3), tissue remodeling (e.g., PVR, Loxl2), and vasculogenesis (e.g., Epha2, Nrn1) were selected and validated by qPCR. KEGG pathway analysis showed significant changes in MAPK signaling at both time points.</p><p>Conclusions</p><p>Cyclic mechanical strain induces extensive changes in the gene expression in Müller cells through multiple molecular pathways. These results indicate the complex mechanoresponsive nature of Müller cells, and they provide novel insights into possible molecular mechanisms that would account for many retinal diseases in which the retina is often subjected to mechanical forces, such as pathological myopia and proliferative vitreoretinopathy.</p></div

Petrogenesis and Tectonic Implications of the Triassic Granitoids in the Ela Mountain Area of the East Kunlun Orogenic Belt

The East Kunlun Orogenic Belt is located in the western part of the Central Orogenic Belt of China, with a large number of Triassic igneous rocks parallel to the Paleo-Tethys ophiolite belt, which provides a large amount of geological information for the tectonic evolution of the Paleo-Tethys Ocean. The granitoids studied in this paper are located in the Ela Mountain area in the eastern part of the East Kunlun Orogenic Belt. Zircon U-Pb dating results show that these different types of granitoids were crystallized in the Triassic. The 247.5 Ma porphyritic granites from Zairiri (ZRR) displayed calc-alkaline I-type granite affinities, with the zircon &epsilon;Hf(t) values being mainly positive (&minus;0.5 to + 3.8, TDM2 of 1309&ndash;1031 Ma), indicating that they are derived from the partial melting of the juvenile crust and mixed with ancient crustal components. The 236.8 Ma Henqionggou (HQG) granodiorites and 237.5 Ma Daheba (DHB) granodiorites are high-K calc-alkaline I-type granite, and both have mafic microgranular enclaves (MMEs), showing higher and more varied Mg# (39.73&ndash;62.73), combined with their negative Hf isotopes (&epsilon;Hf(t) = &minus;2.6 to &minus;1.6, TDM2 = 1430&ndash;1369 Ma), suggesting that their primary magmas were the products of partial melting of the Mesoproterozoic lower crust that mixed with mantle-derived rocks. The 236.4 Ma DHB porphyritic diorites showed characteristics of high-K calc-alkaline I-type granitoids, with moderate SiO2 contents, medium Mg# values (40.41&ndash;40.65), with the Hf isotopes (&epsilon;Hf(t) = &minus;2.9 to &minus;0.5; TDM2 = 1451&ndash;1298 Ma) indistinguishably relative to contemporaneous host granodiorites and MMEs. The petrographic and geochemical characteristics indicate that the porphyritic diorites are the product of well-mixed magma derived from the Mesoproterozoic lower crust and lithospheric mantle. Based on the results of this paper and previous data, the chronology framework of Late Permian&ndash;Triassic magmatic rocks in the eastern part of the East Kunlun Orogenic Belt was constructed, and the magmatic activities in this area were divided into three peak periods, with each peak representing an extensional event in a particular tectonic setting, for example, P1 (slab roll-back in subduction period; 254&ndash;246 Ma), P2 (slab break-off in transition period of subduction and collision; 244&ndash;232 Ma), P3 (delamination after collision; 230&ndash;218 Ma)

Ocular Manifestations in a Chinese Pedigree of Familial Amyloidotic Polyneuropathy Carrying the Transthyretin Mutation c.401A&gt;G (p.Tyr134Cys)

Familial amyloid polyneuropathy (FAP) caused by a genetic mutation in transthyretin (TTR) is an autosomal dominant hereditary disease. The retrospective, observational case series study presents the ocular clinicopathological findings of five cases carrying the TTR mutation c.401A&gt;G (p.Tyr134Cys). Multimodal retinal imaging and electrophysiological examination, Congo red staining and immunohistochemical analysis of specimens, and genetic analyses were performed. Cases 1 and 2 were symptomatic with vitreous and retinal amyloid deposition and poor visual recovery. Case 3 had a symptomatic vitreous haze in the left eye with good postoperative visual recovery. The right eye of case 3 and the eyes of cases 4 and 5 were asymptomatic. Thicker retinal nerve fiber layer, retinal venous tortuosity with prolonged arteriovenous passage time on fluorescein angiography and retinal dysfunction detected by multifocal electroretinogram occurred even in asymptomatic eyes. Moreover, the internal limiting membrane from patients with FAP was stained positive for Congo red and transforming growth factor-&beta;1. The results highlight the amyloid deposition of mutant TTR in the optic disc and retina, even in the asymptomatic stage. The deposited amyloid leads to increased resistance to venous return and retinal functional abnormalities. Therefore, careful follow-up of structural and functional changes in the retina is needed, even in asymptomatic patients with FAP