The nuclease-hypersensitivity element III1 in the c-myc promoter is a good anticancer target since it largely controls transcriptional activation of the important c-myc oncogene. Recently, the guanine-rich strand of this element has been shown to form an equilibrium between G-quadruplex structures built from two different sets of G-stretches; two models of intramolecular fold-back antiparallel-stranded G-quadruplexes, called "basket" and "chair" forms, were proposed. Here, we show by NMR that two sequences containing these two sets of G-stretches form intramolecular propeller-type parallel-stranded G-quadruplexes in K(+)-containing solution. The two structures involve a core of three stacked G-tetrads formed by four parallel G-stretches with all anti guanines and three double-chain-reversal loops bridging three G-tetrad layers. The central loop contains two or six residues, while the two other loops contain only one residue.

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Purpose: To report a detachment that apparently separated photoreceptor inner segment myoids from inner segment ellipsoids as a manifestation of toxoplasmosis chorioretinitis in a patient with pachychoroid spectrum disease.Methods: Multimodal imaging including fundus photography, spectral domain and enhanced-depth imaging optical coherence tomography (OCT), indocyanine green angiography, and OCT angiography.Results: A 33-year-old man with a history of toxoplasmosis chorioretinitis reported 1 week of decreased vision to 20/200 in his right eye. Examination of the right eye demonstrated mild vitritis with recurrent chorioretinitis inferior to the fovea and adjacent to a chorioretinal scar. A dome-shaped, foveal photoreceptor layersplitting detachment was noted on OCT. Because degenerating cone photoreceptors are capable of shedding their inner segments, we inferred the location of the detachment at the level of the inner segment myoid and provided a histological example of such from an unrelated donor case. In addition, multimodal imaging revealed dilated choroidal veins (pachyvessels) with attenuation of the inner choroid in both eyes and asymptomatic findings of central serous chorioretinopathy in the left eye. After 1 month of antibiotic and steroid therapy, the chorioretinitis resolved, as did the detachment. Hyperreflective foci on the vitreoretinal interface were appreciated with en face OCT that appeared to aggregate throughout the course of therapy, induce inner retinal striae, and resolve without inducing epiretinal membrane formation.Conclusion: Patients with preexisting pachychoroid spectrum disease may manifest a more significant retinal fluid accumulation in the setting of superimposed chorioretinal inflammation. In this case of macular toxoplasmosis chorioretinitis, inflammation manifested as a retinal detachment at the level of photoreceptor inner segment myoids that we named as a bacillary layer detachment. In this case, inflammatory sequelae of toxoplasmosis reactivation responded well to oral and intravitreal therapy.

Recently, the two-repeat human telomeric d(TAGGGTTAGGGT) sequence has been shown to form interconverting parallel and antiparallel G-quadruplex structures in solution. Here, we examine the structures formed by the two-repeat Tetrahymena telomeric d(TGGGGTTGGGGT) sequence, which differs from the human sequence only by one G-for-A replacement in each repeat. We show by NMR that this sequence forms two novel G-quadruplex structures in Na + -containing solution. Both structures are asymmetric, dimeric G-quadruplexes involving a core of four stacked G-tetrads and two edgewise loops. The adjacent strands of the G-tetrad core are alternately parallel and antiparallel. All G-tetrads adopt syn·syn·anti·anti alignments, which occur with 5′-syn-anti-syn-anti-3′ alternations along G-tracks. In the first structure (head-to-head), two loops are at one end of the G-tetrad core; in the second structure (head-to-tail), two loops are located on opposite ends of the G-tetrad core. In contrast to the human telomere counterpart, the proportions of the two forms here are similar for a wide range of temperatures; their unfolding rates are also similar, with an activation enthalpy of 153 kJ/mol.

The DISCOVER iOCT study demonstrated both generalized feasibility and usefulness based on the surgeon-reported impact on surgical decision making. This large-scale study confirmed similar findings from other studies on the potential value and impact of iOCT on ophthalmic surgery.