Wave Propagation in Stochastic Spacetimes: Localization, Amplification and Particle Creation

Here we study novel effects associated with electromagnetic wave propagation in a Robertson-Walker universe and the Schwarzschild spacetime with a small amount of metric stochasticity. We find that localization of electromagnetic waves occurs in a Robertson-Walker universe with time-independent metric stochasticity, while time-dependent metric stochasticity induces exponential instability in the particle production rate. For the Schwarzschild metric, time-independent randomness can decrease the total luminosity of Hawking radiation due to multiple scattering of waves outside the black hole and gives rise to event horizon fluctuations and thus fluctuations in the Hawking temperature.Comment: 26 pages, 1 Postscript figure, submitted to Phys. Rev. D on July 29, 199

FMRpolyG accumulates in FMR1 premutation granulosa cells

Abstract Background Fragile X premutation (Amplification of CGG number 55–200) is associated with increased risk for fragile X-Associated Premature Ovarian Insufficiency (FXPOI) in females and fragile X-associated tremor/ataxia syndrome (FXTAS) predominantly in males. Recently, it has been shown that CGG repeats trigger repeat associated non-AUG initiated translation (RAN) of a cryptic polyglycine-containing protein, FMRpolyG. This protein accumulates in ubiquitin-positive inclusions in neuronal brain cells of FXTAS patients and may lead to protein-mediated neurodegeneration. FMRpolyG inclusions were also found in ovary stromal cells of a FXPOI patient. The role of FMRpolyG expression has not been thoroughly examined in folliculogenesis related cells. The main goal of this study is to evaluate whether FMRpolyG accumulates in mural granulosa cells of FMR1 premutation carriers. Following FMRpolyG detection, we aim to examine premutation transfected COV434 as a suitable model used to identify RAN translation functions in FXPOI pathogenesis. Results FMRpolyG and ubiquitin immunostained mural granulosa cells from six FMR1 premutation carriers demonstrated FMRpolyG aggregates. However, co-localization of FMRpolyG and ubiquitin appeared to vary within the FMR1 premutation carriers’ group as three exhibited partial ubiquitin and FMRpolyG double staining and three premutation carriers demonstrated FMRpolyG single staining. None of the granulosa cells from the five control women expressed FMRpolyG. Additionally, human ovarian granulosa tumor, COV434, were transfected with two plasmids; both expressing 99CGG repeats but only one enables FMRpolyG expression. Like in granulosa cells from FMR1 premutation carriers, FMRpolyG aggregates were found only in COV434 transfected with expended CGG repeats and the ability to express FMRpolyG. Conclusions Corresponding with previous studies in FXTAS, we demonstrated accumulation of FMRpolyG in mural granulosa cells of FMR1 premutation carriers. We also suggest that following further investigation, the premutation transfected COV434 might be an appropriate model for RAN translation studies. Detecting FMRpolyG accumulation in folliculogenesis related cells supports previous observations and imply a possible common protein-mediated toxic mechanism for both FXPOI and FXTAS

Conjunctival melanoma and melanocytic intra-epithelial neoplasia

The rarity of conjunctival melanoma has impeded progress in the management of patients with this cancer; however, much progress has occurred in recent years. Primary acquired melanosis is now differentiated histologically into hypermelanosis and conjunctival melanocytic intra-epithelial neoplasia, for which an objective reproducible scoring system has been developed. Mapping and clinical staging of conjunctival disease has improved. Adjunctive radiotherapy and topical chemotherapy have made tumour control more successful, with reduced morbidity. Genetic analyses have identified BRAF and other mutations, which may predict responsiveness to new chemotherapeutic agents, for example Vemurafenib, should metastatic disease develop. Multicentre studies are under way to enhance survival prediction by integrating clinical stage of disease with histological grade of malignancy and genetic abnormalities. Such improved prognostication would not only be more relevant to individual patients, but would also provide greater opportunities for basic science research

Management of conjunctival malignant melanoma: a review and update

Conjunctival malignant melanoma is a pigmented lesion of the ocular surface. It is an uncommon but potentially devastating tumor that may invade the local tissues of the eye, spread systemically through lymphatic drainage and hematogenous spread, and recur in spite of treatment. Despite its severity, the rarity of available cases has limited the evidence for diagnosis and management. This review will provide an overview of the epidemiology, presentation, diagnosis, management, and surveillance of conjunctival melanoma, with an emphasis on recent advances in biological therapies to treat this disease