46 research outputs found

    An Explanation for Terson Syndrome at Last: the Glymphatic Reflux Theory

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    Terson Syndrome (TS) describes the presence of intraocular hemorrhage in patients with intracranial hemorrhage, typically subarachnoid hemorrhage. Despite TS being a well-defined and frequently occurring phenomenon, its pathophysiology remains controversial. This review will present the current understanding of TS, with view to describing a contemporary and more plausible pathomechanism of TS, given recent advances in ophthalmic science and neurobiology. Previously proposed theories include a sudden rise in intracranial pressure (ICP) transmitted to the optic nerve sheath leading to rupture of retinal vessels; or intracranial blood extending to the orbit via the optic nerve sheath. The origin of blood in TS is uncertain, but retinal vessels appear to be an unlikely source. In addition, an anatomical pathway for blood to enter the eye from the intracranial space remains poorly defined. An ocular glymphatic system has recently been described, drainage of which from the globe into intracranial glymphatics is reliant on the pressure gradient between intraocular pressure and intracranial pressure. The glymphatic pathway is the only extravascular anatomical conduit between the subarachnoid space and the retina. We propose that subarachnoid blood in skull base cisterns near the optic nerve is the substrate of blood in TS. Raised ICP causes it to be refluxed through glymphatic channels into the globe, resulting in intraocular hemorrhage. We herewith present glymphatic reflux as an alternative theory to explain the phenomenon of Terson Syndrome

    Correlation of Serotype-Specific Dengue Virus Infection with Clinical Manifestations

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    Dengue virus (DENV) causes disease in millions of people annually and disproportionately affects those in the developing world. DENVs may be divided into four serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) and a geographical region may be affected by one or more DENV serotypes simultaneously. Infection with DENV may cause life-threatening disease such as dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), but more often causes less severe manifestations affecting a wide range of organs. Although many previous reports have explored the role of the different DENV serotypes in the development of severe manifestations, little attention has focused on the relative role of each DENV serotype in the development of cutaneous, respiratory, gastrointestinal, musculoskeletal, and neurological manifestations. We recruited a large group of participants from four countries in South America to compare the prevalence of more than 30 manifestations among the four different DENV serotypes. We found that certain DENV serotypes were often associated with a higher prevalence of a certain manifestation (e.g., DENV-3 and diarrhea) or manifestation group (e.g., DENV-4 and cutaneous manifestations)

    High frequency plantlet regeneration from rhizomatous buds in Mantisia spathulata Schult. and Mantisia wengeri Fischer and analysis of genetic uniformity using RAPD markers

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    140-146A protocol has been devised for enhanced in vitro regeneration of critically endangered Mantisia spathulata Schult. and Mantisia wengeri Fischer. Highest Bud Forming Capacity (BFC) of 6.10±0.55 with an average of 19.93±3.19 roots was obtained for M. spathulata within 5-6 weeks in Murashige and Skoogs (MS) medium supplemented with a combination of 10.0 μM of N⁶-benzyladenine (BA) and 2.5μM of ⍺-naphtalene acetic acid (NAA). For M. wengeri, BFC of 7.82±0.73 and 20.86±1.65 roots was achieved in MS media supplemented with a combination of 5.0μM BA and 2.5μM of NAA RAPD markers were used to evaluate the genetic stability of in vitro raised hardened plantlets. Similarity coefficient among the regenerated plants ranged between 0.85-0.98 for M. spathulata and 0.83-0.98 for M. wengeri. Maximum of 88 and 90% genetic similarity were obtained between in vitro raised hardened plantlets and mother stock of M. spathulata and M. wengeri, respectively through RAPD analysis. The hardened plantlets after RAPD analysis on being transferred to soil of experimental garden showed no marked phenotypic variations in vegetative or floral characteristics
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