Publications by authors named "Rohan R"

Information Security Awareness (ISA) is a significant concept that got considerable attention recently and can assist in minimizing the risks associated with information security breaches. Several measurement scales have been developed in this regard, as measuring users' ISA is paramount. Although ISA specific scales are very important, yet what methodological rigor they use in terms of initial conceptualization of ISA, data collection and analysis during the development, and scale validation of such scales are some unknown aspects.

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Introduction/aim: Given the lack of information on safety of coronavirus disease 2019 (COVID-19) vaccination in myasthenia gravis (MG) patients, we aimed to review our experience after surveying patients, as part of routine clinical practice, to ensure that advice on safety is accurate.

Methods: We performed a retrospective chart review of MG patients from the Prosserman Family Neuromuscular Clinic at the Toronto General Hospital who received two injections of any COVID-19 vaccine from February to August 2021. Demographic data were abstracted from the patient medical records.

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Background: Giant intracranial aneurysms (GIAs) are treacherous lesions and in spite of the many advances, endovascular therapy (EVT) of GIAs is challenging.

Objective: A retrospective analysis of our results with microsurgery of GIAs is presented to examine the role of microsurgery in the current trend of EVT.

Materials And Methods: Between 1996 and 2019, 134 patients with 147 GIAs had microsurgery by the senior author in a single institute.

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A novel protocol to generate and control porosity in polymeric structures is presented for fabrication of single ion polymer electrolyte (SIPE) membranes for lithium ion batteries. A series of SIPEs with varying ratios of aliphatic and aromatic segments was successfully synthesized and subsequently blended with PVDF-HFP to fabricate membranes of various sizes of pores. The membranes were characterized using techniques including SEM, solvent uptake capacity measurement and ionic conductivity.

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Angiogenesis is the process by which new blood vessels are formed from existing vessels. Mammalian populations, including humans and mice, harbor genetic variations that alter angiogenesis. Angiogenesis-regulating gene variants can result in increased susceptibility to multiple angiogenesis-dependent diseases in humans.

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Tsunami on 26th December 2004 which affected the entire costal belt of Sri Lanka caused over 30,000 deaths and about 8000 disappearances. The Forensic Unit of the Karapitiya Teaching Hospital alone handled over 1100 deaths, of which about 450 unidentified bodies were dispatched for mass burial, after recording external appearances and all other important personal data, which helped us to establish identity of another 120 victims within next 6 weeks. The visiting forensic team from Colombo, arrived on 27th, assisted us in recording details of 1500 victims of "Peraliya" railway incident.

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Objective: To determine whether endometriosis can be treated with the angiogenesis inhibitor endostatin and the effect of this treatment on fertility and reproduction.

Design: Pharmacologic intervention in a surgically induced model of endometriosis and in female mice undergoing mating.

Setting: Animal research facility.

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Objective: To determine whether nonsteroidal antiinflammatory drugs (NSAIDs) affect the establishment and progression of endometriotic lesions in a murine model.

Design: Pharmacologic intervention in a surgically induced murine model of abdominal/peritoneal endometriosis.

Setting: Animal research facility.

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Angiogenesis is controlled by a balance between stimulatory growth factors and endogenous inhibitors. We propose that the balance of stimulators and inhibitors, as well as the general sensitivity of the endothelium to these factors, varies from individual to individual. Indeed, we have found that individual mouse strains have dramatically different responses to growth factor-induced neovascularization.

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Angiogenesis is regulated by the balance between angiogenic stimulators and inhibitors. Numerous reports have demonstrated that tumors induce aggressive angiogenesis by up-regulating the production of angiogenesis stimulating growth factors to overcome the baseline levels of endogenous inhibitors. However, the possibility of large differences in the host's responsiveness to angiogenic factors has been largely overlooked.

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Purpose: This study was designed to gain an insight into the inflammatory milieu into which a donor limbal graft is routinely introduced. The objective of this study was to modulate this environment by gene therapy with the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1 RA).

Methods: In a mouse model, the ocular surface cytokine environment associated with a conjunctivalized cornea was assessed 4 weeks after injury.

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Ovulation and conversion of the follicle into the corpus luteum involve remarkable changes in vascular permeability and neovascularization of the luteinizing granulosa layer. To evaluate the importance of these vascular events in follicle rupture and luteal development, sequential experiments were designed in which vehicle or angiogenic inhibitors (TNP-470 or angiostatin) were injected directly into the preovulatory follicle of rhesus monkeys during spontaneous menstrual cycles. After control injections, 13 of 14 animals exhibited serum levels of progesterone (P) during the subsequent luteal phase that were comparable to untreated animals in our colony.

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The murine VEGF gene is alternatively transcribed to yield the VEGF(120), VEGF(164), and VEGF(188) isoforms, which differ in their potential to bind to heparan sulfate and neuropilin-1 and to stimulate endothelial growth. Here, their role in retinal vascular development was studied in mice selectively expressing single isoforms. VEGF(164/164) mice were normal, healthy, and had normal retinal angiogenesis.

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To develop a model for the study of physiological angiogenesis, we transplanted ovarian follicles onto striated muscle tissue and analyzed the process of microvascularization in vivo using repeated fluorescence microscopy. Follicles were mechanically isolated from unstimulated as well as pregnant mare's serum gonadotropin (PMSG)- or PMSG/luteinizing hormone (LH)-stimulated Syrian golden hamster ovaries and were transplanted as free grafts into dorsal skinfold chambers of untreated or synchronized hamsters. Follicles lacking thecal cell layers did not vascularize regardless whether harvested from unstimulated or PMSG-stimulated animals, but underwent granulosa cell apoptosis, as indicated in vivo by nuclear condensation and fragmentation of bisbenzimide-stained follicular tissue.

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Aim: To examine the response of the insulinlike growth factor (IGF) system in the kidney during a state of extreme growth.

Methods: We studied the mRNA expression of IGF-I, IGF-I receptor, and IGF-binding proteins (BP) using sensitive RNase protection assays following subcutaneous implantation of growth hormone pituitary cells (GH(3)) in rats.

Results: Within 5 weeks, the serum GH levels increased from 18.

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Aim: We studied control of the epidermal growth factor (EGF) receptor and its ligands during kidney injury, since they may be importantly involved in repair.

Methods: The folic acid model of renal injury was used in these studies. Messenger RNA (mRNA) was evaluated by solution hybridization.

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Choroidal neovascularization in age-related macular degeneration is a frequent and poorly treatable cause of vision loss in elderly Caucasians. This choroidal neovascularization has been associated with the expression of vascular endothelial growth factor (VEGF). In current animal models choroidal neovascularization is induced by subretinal injection of growth factors or vectors encoding growth factors such as VEGF, or by disruption of the Bruch's membrane/retinal pigment epithelium complex with laser treatment.

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Vascular endothelial growth factor (VEGF), a factor that is critical for development of the vascular system in mouse embryos, exists as at least three isoforms, VEGF120, VEGF164, and VEGF188. The isoforms have different affinities for heparan sulfate as well as for the three known VEGF receptors, VEGFR-1 (Flt-1), VEGFR-2 (Flk-1), and neuropilin-1, suggesting that different VEGF isoforms may play distinct roles in vascular development. To determine whether there are differences in the organ-specific expression patterns that would support this concept, we used a quantitative RNase protection assay (RPA) to determine the distribution of different VEGF isoform mRNA in developing and adult mouse organs.

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We studied gene expression for transforming growth factor (TGF)-alpha, epidermal growth factor (EGF), heparin binding (HB) EGF, and the EGF receptor following acute renal failure induced by mercuric chloride administration to gain insight into potential mechanisms of renal repair. Twenty four hours after HgCl2, 2 mg/kg, creatinine increased from 0.3+/-0.

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In situ hybridization was used on frozen tissue sections with digoxigenin-labelled antisense riboprobes to inhibin/activin alpha and beta(A) subunits to determine whether inhibin/activin subunit mRNA expression was associated with development of growing, steroidogenically active follicles during follicle recruitment after ovulation. Cell proliferation-associated nuclear antigen Ki-67 protein and cytochrome P450 aromatase expression in granulosa cells were determined immunohistochemically and used as markers for granulosa cell proliferation and steroidogenesis, respectively, on days 3, 5 and 7 after the onset of oestrus. The amounts of inhibin/activin alpha and beta(A) subunit mRNA and P450 aromatase protein were greater (102, 93, and 238%, respectively; P < 0.

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Many diseases, including cancer, are dependent on the growth of new blood vessels, a process known as angiogenesis. Differences in an individual's ability to grow new blood vessels may influence the rate of progression of these diseases. Here we show that different strains of inbred mice have an approximately 10-fold range of response to growth factor-stimulated angiogenesis in the corneal micropocket assay.

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Background: Curcumin is a small-molecular-weight compound that is isolated from the commonly used spice turmeric. In animal models, curcumin and its derivatives have been shown to inhibit the progression of chemically induced colon and skin cancers. The genetic changes in carcinogenesis in these organs involve different genes, but curcumin is effective in preventing carcinogenesis in both organs.

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Tumor vascularization is accompanied by the migration of stromal cells, including endothelial cells, smooth muscle cells, and fibroblasts, into the tumor. The biological contributions of stromal cells to tumor vascularization have not been well-defined, partly due to the difficulty of culturing stromal cells in the presence of large numbers of fast-growing tumor cells. To address this problem, a strategy was devised to kill tumor cells but not stromal cells.

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Diabetic retinopathy is a leading cause of adult vision loss and blindness. Much of the retinal damage that characterizes the disease results from retinal vascular leakage and nonperfusion. This study shows that diabetic retinal vascular leakage and nonperfusion are temporally and spatially associated with retinal leukocyte stasis (leukostasis) in the rat model of streptozotocin-induced diabetes.

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Purpose: The expression of vascular endothelial growth factor (VEGF) and its high-affinity receptors VEGFR-1 and VEGFR-2 was investigated in normal eyes.

Methods: Monkey and rat eyes were surgically removed in animals under deep anesthesia and immediately prepared for study. Ocular VEGF, VEGFR-1, and VEGFR-2 expression was studied using a combination of in situ hybridization, northern blot analysis, immunohistochemistry, immunoassay, and reverse transcription-polymerase chain reaction.

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