Hen egg white avidin is increasingly used in the clinic as part of multifactor treatments such as pretargeted radionuclide therapy of cancer or as an antidote of biotinylated drugs. Taking into account that naturally occurring human antiavidin antibodies (HAVA) are common in humans, the present work investigates avidin immunogenicity as part of risk/benefit evaluations. Sera from 139 oncology patients naive to avidin were confirmed to exhibit HAVA with lognormally distributed titers. HAVA were boosted after avidin treatment, with no correlation with the avidin dose or with the basal titer. No antibody-related clinical symptoms were observed in 21 HAVA-positive patients treated with avidin. In mouse models, high mouse antiavidin antibody titers, induced to simulate the worst human condition, neither reduced the biotin uptake of intratissue-injected avidin nor affected the capacity of intravenously injected avidin to clear a biotinylated drug from circulation. In both models the avidin treatment was well tolerated. Results indicate that avidin immunogenicity does not affect its safety and efficacy, thus encouraging its further use in clinical applications.

In this work we explored phenomenologically the visual complexity of the material attributes on the basis of the contours that define the boundaries of a visual object. The starting point is the rich and pioneering work done by Gestalt psychologists and, more in detail, by Rubin, who first demonstrated that contours contain most of the information related to object perception, like the shape, the color and the depth. In fact, by investigating simple conditions like those used by Gestalt psychologists, mostly consisting of contours only, we demonstrated that the phenomenal complexity of the material attributes emerges through appropriate manipulation of the contours. A phenomenological approach, analogous to the one used by Gestalt psychologists, was used to answer the following questions. What are contours? Which attributes can be phenomenally defined by contours? Are material properties determined only by contours? What is the visual syntactic organization of object attributes? The results of this work support the idea of a visual syntactic organization as a new kind of object formation process useful to understand the language of vision that creates well-formed attribute organizations. The syntax of visual attributes can be considered as a new way to investigate the modular coding and, more generally, the binding among attributes, i.e., the issue of how the brain represents the pairing of shape and material properties.

We investigated the effect of chromatic variations on the reading process with normal and dyslexic readers. We demonstrate that color can induce wholeness, parts-whole organization and phenomenal fragmentation during reading and comprehension tasks within written texts made up of words and non-words in the following conditions: monochromatic (the whole text colored with only one color), word (each word colored in different color), half word (half word colored with a color different from the one of the second half), syllable (every syllable colored with a different color) and letter (each letter with a different color). The dependent variables considered were reading time, reading errors and incorrect answers to a comprehension test. The main results demonstrated that these parameters of reading performance are all influenced by the five aforementioned chromatic conditions. These outcomes manifest similar trends in four groups of readers: children and adults combined with normal or dyslexic readers. Possible applied research and clinical applications are discussed together with some basic questions related to color vision suggesting that the main purposes of color for living beings is to generate wholeness, parts-whole organization and perceptual segmentation.

Color is one among many attributes that are involved in the similarity principle. Grouping by color is believed to be less effective when compared with other attributes such as shape and luminance. The main purpose of this work is to explore the role played by color in determining visual grouping and wholeness, not only in relation to further similarity attributes but also to other principles such as proximity, good continuation and past experience. Conditions, different from those used by Gestalt psychologists, were chosen, and aimed to understand how color can influence visual organization and through it, other perceptual and complex processes such as reading and visual word recognition. In fact, involving cognitive and metacognitive domains, permits exploration of broader issues concerning perception, memory, knowledge, representation and learning, where color can express its biological advantages for humans more clearly. These processes can be assimilated to the Gestalt past experience considered as a principle of its own kind not fully explored in relation to the other principles. As a consequence, these conditions allow color to be pitted against past experience and against a number of principles at the same time. The results demonstrated that color can strongly influence grouping, shape and the process of segmentation of words involved in the reading task. Therefore, color not only is one among the many principles of grouping but an essential component for the foundation of the more complex organization aimed at creating wholeness, part-whole formation and fragmentation.

In this work we demonstrate that next to figure–ground segregation and perceptual grouping, as proposed by Gestalt psychologists, there is a further and more complex kind of organization related to the way object attributes like shape and color are organized to create a visual object. More particularly, through new logical and phenomenal implications, we explore the complexity of the phenomenal coloration and the syntactic relation between shape and color. Moreover, we extract the main laws ruling their phenomenal logic and organization. Finally, we present new conditions and a new paradigm based on the drawings and paintings made spontaneously by children of different ages in a drawing/painting task. Using this paradigm, it is assumed that the way children organize shape and color in their drawings and paintings is related to the way the visual system perceives their syntactic relation. The results show that, under the conditions studied, shape and color are organized as juxtaposed and in sequential order with the shape becoming hierarchically the core reference for the color. These results suggest a visual syntactic organization as a new kind of object formation process useful for understanding the language of vision and the implications for art and biology.