Associations of Polymorphisms Localized in the 3'UTR Regions of the KRAS, NRAS, MAPK1 Genes with Laryngeal Squamous Cell Carcinoma.

BACKGROUND: Genetic variations, localized in the 3' untranslated region (UTR) in mitogen-activated protein kinase (MAPK) pathway-related genes, may alter the transcription and impact the pathogenesis of laryngeal squamous cell carcinoma (LSCC). The present study investigated the associations of single-nucleotide polymorphisms (SNP), localized in the 3'UTR) of the KRAS, NRAS, and MAPK1 genes with LSCC risk and clinicopathological features. METHODS: Genomic DNA and clinical data were collected from 327 adult men with LSCC. The control group was formed from 333 healthy men. Genotyping of the SNPs was performed using TaqMan SNP genotyping assays. Five KRAS, NRAS, and MAPK1 polymorphisms were analyzed. All studied genotypes were in Hardy-Weinberg equilibrium and had the same allele distribution as the 1000 Genomes project Phase 3 dataset for the European population. RESULTS: Significant associations of the studied SNPs with reduced LSCC risk were observed between NRAS rs14804 major genotype CC. Significant associations of the studied SNPs with clinicopathologic variables were also observed between NRAS rs14804 minor T allele and advanced tumor stage and positive lymph node status. SNP of MAPK1 rs9340 was associated with distant metastasis. Moreover, haplotype analysis of two KRAS SNPs rs712 and rs7973450 revealed that TG haplotype was associated with positive lymph node status in LSCC patients. CONCLUSIONS: According to the present study, 3'UTR SNP in the NRAS and MAPK1 genes may contribute to the identifications of patients at higher risk of LSCC lymph node and distant metastasis development.

Oppel-Kundt illusion balance.

Perceptual estimates of spatial dimensions of visual objects depend on their shape and surface attributes. The present psychophysical study emphasizes two main contributors to the Oppel­Kundt illusion: the outline of the filled space and the mode of filling. In past experiments, both factors have been considered significant. Our experiments were performed by using combined stimuli of the Oppel­Kundt figures and supplementary objects situated within the empty intervals of the figures. Line segments, empty and filled rectangles, blurred contours, and grey and color images were used for the supplementary stimuli role. The experimental data demonstrated an innate property of the objects to balance the illusion of distance if they were placed within the Oppel­Kundt figure and to create an illusion of extent when compared with an empty space interval. Both the balance magnitude and the induced illusion strength varied depending on the objects' spatial structure. The supplementary objects showed a tendency to differ from each other by their functional capacity and were ranked from lowest to highest: a line segment, a solid bar with a blurred outline, a contour of a rectangle, a solid fill rectangle, greyscale patterns, and color pictures. The experimental findings provided support for an explanation of the Oppel­Kundt illusion in terms of the spatial­temporal summation of excitations representing the object outline and surface attributes at the lower cortical levels of the visual system. Along with the facts already established in current literature, the experimental data gave rise to the assumption that any visual object could appear larger than its occupied area, and that the Oppel­Kundt illusion could become a separate case in the common sensory phenomenon of object size illusion.

Summation of two illusions of extent.

In the present visual psychophysical study, the Oppel­Kundt and and Müller­Lyer illusion magnitudes were measured separately (by single figures) and in combination (by two patterns superposed spatially). Data for 30 subjects revealed extensive variability both for the separate and combined illusion strength. Nevertheless, the effect of addition of the perceived length distortions was established. The combined illusions were significantly stronger than the separate ones. Dynamics of the misperceptions summation was studied by varying length of the Müller­Lyer wings in the superposed stimuli. According to the experimental data obtained, the two misperceptions in length occurred and combined into sensory response varying in dependence on the spatial parameters of the superposed stimuli and on the individual experimental accomplishment. The data supported an explanation for the origin of the filled/unfilled illusion: overestimate of a filled interval length developed due to the spatiotemporal integration along a continuous excitation path elicited by the real or imaginary contours of the filling.

Temporal dynamics of the Oppel-Kundt Illusion compared to the Müller-Lyer Illusion.

In psychophysical experiments, subjects reported whether the filled part of the Oppel-Kundt stimulus was longer than the empty one at different durations of the stimuli presentations. The experimental data yielded a smooth function indicating a gradual augmentation of the illusion strength within a relatively wide 100-1000 ms interval of the exposure durations. On the contrary, the experiments with the Müller-Lyer stimuli showed a gradual decrease of the illusion magnitude within the same interval of expositions. In the supplementary experiments, the stimuli with uniformly filled or outlined rectangles of fixed duration were used; various combinations of the rectangles with the regular sequences of filling stripes were also taken. It was demonstrated that the superposition of the stimuli did not change the illusion strength noticeably. The results obtained in the study support the suggestion that the filled interval overestimation in the Oppel-Kundt stimulus may be related to spatiotemporal integration along a continuous path of neural excitation evoked by the real and illusory contours of the filling.

Perceptual mislocalization of a single set of the Müller-Lyer wings.

In the present communication, a possible role of perceptual displacements of stimulus elements in the occurrence of visual illusions of extent has been considered. In psychophysical experiments with a single set of Müller-Lyer wings, subjects were asked to place an imaginary reference rectangle into a position that made the apex of the wings appear to be at the rectangle center. Three different stimulus parameters (the length, internal angle, or tilt angle of the wings) were used as independent variables in different series of experiments. It was demonstrated that the magnitude of perceptual displacements of stimulus terminator is commensurate with that of illusions of extent obtained in our previous studies of full versions of illusory figures. Good correspondence between the experimental data and the predictions of our computational model of automatic centroid extraction strongly supported the suggestion that the effects of centroid extraction are powerful enough to be considered as one of the main causes of illusions of extent of the Müller-Lyer type.

Contextual flanks' tilting and magnitude of illusion of extent.

The "centroid" explanation of the Müller-Lyer and similar illusions of extent supposes the perceptual positional shifts of the stimulus terminators in direction of the centers-of-masses of adjacent contextual flanks. In the present study, the validity of the assumption was tested in psychophysical examination of illusory figures comprising the Müller-Lyer wings or arcs of a circle as the contextual objects. In experiments, the illusion magnitude changes evoked by the tilting of stimulus flanks have been measured. A good resemblance between the experimental data and theoretical predictions was obtained that strongly supports the idea of local positional shifts and serves in favor of "centroid" explanation of illusions investigated.