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Science Bulletin Dec 2023After two continents collide, plate convergence and orogenesis are sustained because subducted continental lithosphere continues pulling the surface plate. It remains...
After two continents collide, plate convergence and orogenesis are sustained because subducted continental lithosphere continues pulling the surface plate. It remains controversial how, why, and when continental plate convergence and collision slow down and eventually cease. We use an unprecedented data coverage and present a regional-scale seismic tomographic image of the mantle structure beneath the Tibetan Plateau. In the mantle transition zone, we identify multiple high-velocity anomalies and interpret them as detached pieces of the Indian continental slab. Facilitated by internal heterogeneity of the continental lithosphere, piecewise slab detachments could reduce the slab pull force, resulting in the Miocene slowdown of the India-Eurasia convergence and coeval diachronous potassic volcanism in southern Tibet. We propose that slab detachment is a mechanism that eventually will lead to the end of the Indo-Eurasian continental collision and the Himalayan orogeny.
PubMed: 37919155
DOI: 10.1016/j.scib.2023.10.017 -
Radiology Case Reports Aug 2024Choroidal detachment (CD) is a rare and potentially vision-threatening complication of glaucoma surgery. Inflammation and prolonged ocular hypotony can promote fluid...
Choroidal detachment (CD) is a rare and potentially vision-threatening complication of glaucoma surgery. Inflammation and prolonged ocular hypotony can promote fluid accumulation between the choroid and sclera. Risk factors include trauma, advanced age, use of anticoagulant medications, systemic hypertension, atherosclerosis, and diabetes. CD ultrasound findings will show 2 layers, detaching as far anteriorly as the ciliary bodies, that protrude convexly into the vitreous without extending to the optic disc, often described as the appositional or In contrast, retinal detachments will show a distinct "V" shape due to the retina's fixation to the optic nerve head posteriorly. In the case of hemorrhagic CD, therapy should be targeted at reducing intraocular pressure. In this case, the patient was started on atropine and prednisolone drops and discontinued on all glaucoma medications in the left eye. While serous choroidal detachments are usually benign, persistent choroidal effusions may cause significant morbidity with hemorrhagic CD having a worse prognosis. Point of care ultrasound can help emergency physicians quickly distinguish between choroidal and retinal detachments and thus guide management in a safe and timely manner.
PubMed: 38737180
DOI: 10.1016/j.radcr.2024.04.017 -
European Journal of Ophthalmology Jul 2023Descemet´s membrane ruptures (with a discontinuation of Descemet´s membrane and double detached coiled edges) in the context of complicated anterior segment surgery...
PURPOSE
Descemet´s membrane ruptures (with a discontinuation of Descemet´s membrane and double detached coiled edges) in the context of complicated anterior segment surgery have rarely been described and its management can be challenging. We report a modified Descemet stripping only (DSO) technique associated with ripasudil drops to treat these cases when other techniques fail.
METHODS
We describe two cases of large Descemet´s membrane detachments associated with Descemet´s ruptures after cataract surgery that did not respond to two SF intracameral injections. As the detached Descemet's membrane and coiled edges might have prevented endothelial cell migration, we decided to perform a modified DSO with post-operative ripasudil drops to promote corneal clearance.
RESULTS
Both cases improved significantly in unaided and best corrected visual acuity (BCVA), corneal clearance and pachymetry, avoiding the need for an endothelial keratoplasty. Endothelial cells were observed on specular microscopy within the area of the descemetorhexis.
CONCLUSION
DSO with ripasudil drops might be a valuable tool to recover corneal clearance and avoid endothelial keratoplasty in complex Descemet´s membrane detachments with ruptures that do not respond to other treatments.
Topics: Humans; Fuchs' Endothelial Dystrophy; Descemet Membrane; Endothelium, Corneal; Visual Acuity; Endothelial Cells; Descemet Stripping Endothelial Keratoplasty
PubMed: 35435049
DOI: 10.1177/11206721221095598 -
Ophthalmology. Retina Oct 2022
Topics: Humans; Judgment; Retinal Detachment; Scleral Buckling; Surgeons; Vitrectomy
PubMed: 36192088
DOI: 10.1016/j.oret.2022.05.015 -
International Journal of Retina and... 2019Retinoschisis and retinal detachment are distinguished based on features in clinical examination. Even to skilled examiners, some cases may be diagnostic challenges.... (Review)
Review
BACKGROUND
Retinoschisis and retinal detachment are distinguished based on features in clinical examination. Even to skilled examiners, some cases may be diagnostic challenges. Infrared and wide-angle infrared reflectance imaging are relatively new modalities that can provide additional diagnostic information. Non-contact infrared reflectance imaging (also described as near-infrared imaging) highlights sub-retinal features which may otherwise be obscured by standard retinal photography. It is non-invasive and uses the retina's ability to absorb, reflect or scatter infrared light to produce high quality images.
MAIN BODY
The aim of this review is to describe the role of wide-field infrared imaging in screening, diagnosing, and monitoring structural peripheral retinal disorders including retinoschisis, retinal detachment or combined retinoschisis rhegmatogenous detachments. Infrared imaging can also be used to monitor anterior segment inflammation. Heidelberg Wide-Field Module lens and Heidelberg Spectralis HRA + OCT machine (Heidelberg Engineering, Heidelberg, Germany) were used to obtain noncontact, wide-field infrared images on each study eye. Pseudocolor photos were captured by Optos Optomap (Optos, Inc, Massachusetts, USA).
CONCLUSION
Wide angle infrared imaging offers a quick, noncontact, and noninvasive way to help specialists accurately diagnose, monitor for progression, and educate patients about retinal detachment, retinoschisis and even anterior segment inflammation.
PubMed: 31890288
DOI: 10.1186/s40942-019-0188-5 -
Frontiers in Immunology 2022The nature of the culture dish surface and the technique used to detach adherent cells could very likely influence the cell viability and cell membrane protein integrity...
The nature of the culture dish surface and the technique used to detach adherent cells could very likely influence the cell viability and cell membrane protein integrity of harvested macrophages. Several previous studies assessed the detachment efficacies of enzymatic and non-enzymatic methods for harvesting the single cell suspensions of macrophages, but a comprehensive study assessing different dissociation methods and culture conditions for detaching functionally different macrophage populations has not yet been reported. In this study, the well-established GM-CSF and M-CSF differentiated bone marrow derived macrophage models (GM-BMDMs and M-BMDMs), we compared four commonly used enzymatic (trypsin and accutase) and non-enzymatic (PBS and EDTA) dissociation methods along with necessary mechanical detaching steps (scraping and pipetting) to evaluate the viable cell recovery and cell surface marker integrality of GM-BMDMs and M-BMDMs cultured on standard cell culture dish (TC dish), or on culture dish (noTC dish) that was not conditioned to enhance adherence. The data showed that accutase yielded a better recovery of viable cells comparing with PBS and EDTA, especially for tightly adherent GM-BMDMs on TC dishes, with a relatively higher level of detected cell membrane marker F4/80 than trypsin. An additional gradient centrifugation-based dead cell removal approach could increase the proportion of viable cells for TC cultured GM-BMDMs after accutase dissociation. Furthermore, transcriptome analysis was performed to evaluate the putative influence of culture dishes. At steady state, BMDMs cultured on noTC dishes exhibited more proinflammatory gene expression signatures (e.g. IL6, CXCL2 and ILlβ) and functions (e.g. TNF and IL17 signaling pathways). Similar inflammatory responses were observed upon LPS challenge regardless of culture conditions and differentiation factors. However, in LPS treated samples, the difference of gene expression patterns, signaling pathways and molecular functions between TC and noTC cultured BMDMs were largely dependent on the types of growth factors (M-CSF and GM-CSF). This observation might provide valuable information for macrophage studies.
Topics: Animals; Cell Culture Techniques; Edetic Acid; Granulocyte-Macrophage Colony-Stimulating Factor; Lipopolysaccharides; Macrophage Colony-Stimulating Factor; Macrophages; Mice; Phenotype; Trypsin
PubMed: 35874686
DOI: 10.3389/fimmu.2022.920232 -
Journal of Ophthalmic & Vision Research 2018To determine 1) which components of retinal function are impaired after rhegmatogenous retinal detachment, 2) which outer retinal pathways (rod- or cone-driven) are more...
PURPOSE
To determine 1) which components of retinal function are impaired after rhegmatogenous retinal detachment, 2) which outer retinal pathways (rod- or cone-driven) are more severely affected, and 3) whether there is concomitant inner retinal dysfunction.
METHODS
We conducted a prospective observational study in a large academic institution. We performed preoperative electroretinography on eight patients to assess outer and inner retinal function. In all cases, a comparison between the eye with the detached retina and the control fellow eye was made.
RESULTS
Eyes with a detached retina had significantly lower a-wave and b-wave amplitudes with respect to both rod- and cone-dominated testing parameters ( < 0.05) and reduced 30 Hz flicker responses compared to fellow eyes ( < 0.05); the effect size was similar for all significantly reduced parameters (r~0.6). There were no significant differences between eyes with detached retinas and control fellow eyes with respect to b/a-wave ratios, a-wave latencies, or b-wave latencies.
CONCLUSION
Patients with rhegmatogenous retinal detachment have preoperative outer retinal dysfunction equally affecting both rod- and cone-driven pathways, and they have minimal inner retinal dysfunction.
PubMed: 30090179
DOI: 10.4103/jovr.jovr_161_17 -
Science (New York, N.Y.) Feb 2021Kinesin motors are essential for the transport of cellular cargo along microtubules. How the motors step, detach, and cooperate with each other is still unclear. To...
Kinesin motors are essential for the transport of cellular cargo along microtubules. How the motors step, detach, and cooperate with each other is still unclear. To dissect the molecular motion of kinesin-1, we developed germanium nanospheres as ultraresolution optical trapping probes. We found that single motors took 4-nanometer center-of-mass steps. Furthermore, kinesin-1 never detached from microtubules under hindering load conditions. Instead, it slipped on microtubules in microsecond-long, 8-nanometer steps and remained in this slip state before detaching or reengaging in directed motion. Unexpectedly, reengagement and thus rescue of directed motion was more frequent. Our observations broaden our knowledge on the mechanochemical cycle and slip state of kinesin. This state and rescue need to be accounted for to understand long-range transport by teams of motors.
Topics: Adenosine Triphosphate; Biological Transport; Germanium; Kinesins; Kinetics; Lipid Bilayers; Microtubules; Models, Biological; Nanospheres; Optical Tweezers; Single Molecule Imaging
PubMed: 33574186
DOI: 10.1126/science.abd9944 -
Journal of Molecular Biology Jan 2019Meters of DNA wrap around histone proteins to form nucleosomes and fit inside the micron-diameter nucleus. For the genetic information encoded in the DNA to become...
Meters of DNA wrap around histone proteins to form nucleosomes and fit inside the micron-diameter nucleus. For the genetic information encoded in the DNA to become available for transcription, replication, and repair, the DNA-histone assembly must be disrupted. Experiment has indicated that the outer stretches of nucleosomal DNA "breathe" by spontaneously detaching from and reattaching to the histone core. Here, we report direct observation of spontaneous DNA breathing in atomistic molecular dynamics simulations, detailing a microscopic mechanism of the DNA breathing process. According to our simulations, the outer stretches of nucleosomal DNA detach in discrete steps involving 5 or 10 base pairs, with the detachment process being orchestrated by the motion of several conserved histone residues. The inner stretches of nucleosomal DNA are found to be more stably associated with the histone core by more abundant nonspecific DNA-protein contacts, providing a microscopic interpretation of nucleosome unraveling experiments. The CG content of nucleosomal DNA is found to anticorrelate with the extent of unwrapping, supporting the possibility that AT-rich segments may signal the start of transcription by forming less stable nucleosomes.
Topics: DNA; Histones; Humans; Molecular Dynamics Simulation; Nucleic Acid Conformation; Nucleosomes
PubMed: 30468737
DOI: 10.1016/j.jmb.2018.11.013 -
Ophthalmic Surgery, Lasers & Imaging... Nov 2022Determine clinical characteristics and long-term outcomes of fellow eyes for patients with prior repair of rhegmatogenous retinal detachments due to a giant retinal tear...
BACKGROUND AND OBJECTIVE
Determine clinical characteristics and long-term outcomes of fellow eyes for patients with prior repair of rhegmatogenous retinal detachments due to a giant retinal tear (GRT).
STUDY DESIGN
Retrospective case series of patients who underwent vitreoretinal surgery between January 2005 and August 2017 for GRT at the Bascom Palmer Eye Institute with a minimum of one year of follow-up information. Patients with a traumatic or post-vitrectomy GRT were excluded.
MAIN OUTCOME MEASURES
Visual acuity and rate of retinal events in fellow eyes.
RESULTS
The study group included 51 patients; 40 others were excluded due to having less than one year of follow-up ( = 27), a history of inciting trauma ( = 11), or a GRT occurring post-vitrectomy ( = 2). The mean age was 49.9 years (range 14 to 81) and mean follow-up duration was 6.9 years (range 1 to 16). During the follow-up interval, prophylactic laser retinopexy was performed in 5 fellow eyes for retinal breaks (9.8%) and in one fellow eye with a progressing retinoschisis cavity (2.0%). One patient had a previous history of a retinal break in the fellow eye. Vitreoretinal surgery was performed in 6 (11.8%) fellow eyes for rhegmatogenous retinal detachments, of which one was caused by a GRT. Three patients (5.9%) already had a retinal detachment repair in the fellow eye prior to presentation and one patient presented with bilateral giant retinal tear associated retinal detachments (GRT-RDs) at the initial visit. Overall, there was a retinal event in 33.3% of fellow eyes. Myopia was the most commonly documented associated factor (31%), followed by lattice degeneration (22%), and known or suspected inherited vitreoretinopathy (4%).
CONCLUSIONS
Retinal tears and/or detachments were encountered relatively frequently in the fellow eye of patients with a history of GRT-RD during follow-up, but the rate of GRTs in the fellow eye (4%) was below what has been generally reported in the literature. Regular dilated fundus exams are warranted for patients with a history of GRT. .
Topics: Humans; Adolescent; Young Adult; Adult; Middle Aged; Aged; Aged, 80 and over; Retinal Perforations; Retinal Detachment; Retrospective Studies; Vitrectomy; Visual Acuity
PubMed: 36378614
DOI: 10.3928/23258160-20221018-01