Social networks in elderly across Facebook: an exam of the extension of the socioemotional selectivity theory

Diante das novas possibilidades de se relacionar socialmente propiciadas pelo advento das Tecnologias de Informação e Comunicação, em especial, via Facebook, levanta-se a necessidade de identificar, entre idosos, se os pressupostos das teorias gerontológicas se estendem às relações sociais online. Sendo assim, foram desenvolvidos três estudos empíricos que compuseram a presente Dissertação cujos dados foram interpretados à luz da Teoria da Seletividade Socioemocional (TSSE). Os objetivos dos estudos foram: 1) descrever características de utilização e motivações para uso do Facebook entre idosos; 2) verificar se um dos construtos associados à TSSE se mostra válido para idosos brasileiros; e 3) examinar o quanto a TSSE se estende às relações sociais de idosos estabelecidas por meio do Facebook. Os estudos foram baseados em dados coletados de 153 idosos usuários de serviços públicos de acesso à Internet na cidade de São Paulo (M= 68,1 anos; DP= 6,5; 77,8% feminino). Utilizou-se levantamentos a respeito de informações sociodemográficas, de utilização e motivações para o uso do Facebook e referentes às variáveis indicativas dos pressupostos da TSSE, a saber: idade, perspectiva de tempo futuro, tamanho das redes sociais, proximidade afetiva com os membros da rede e satisfação com a vida. A amostra, composta por alta escolaridade média e frequente utilização do Facebook, apontou motivos relativos à informação e socialização. Quatro perfis de usuários (Explorador, Solitário, Familiar e Sociável) puderam ser identificados com auxílio de Análise de Correspondência Multipla. O construto de Perspectiva de Tempo Futuro foi avaliado a partir da análise psicométrica de uma escala de medida do mesmo e revelou uma composição fatorial parcialmente semelhante à de estudos internacionais, com destaque para um terceiro fator explicativo e distinto. Por fim, um modelo de relações entre variáveis indicativas dos pressupostos da TSSE foi testado por meio de análise de equações estruturais (Path Analysis para variáveis manifestas) e parcialmente confirmado. Foram encontradas associações diretas e mediadas por PTF entre idade e satisfação com a vida, e relações diretas entre idade e tamanho das redes sociais, conforme predito pela Teoria. Indicadores de seletividade socioemocional, como redução no tamanho das redes e proximidade emocional não foram associadas a satisfação com a vida. Os dados sugerem que as relações sociais via Facebook pressupõem a atuação de um conjunto variado de motivações e de mecanismos adaptativos associados à satisfação com vida na velhiceFaced of new possibilities to relate socially, encouraged by the advent of Information and Communication Technologies, in particular by Facebook, there is a need to identify among the elderly if assumptions of gerontological theories are also valid for the virtual context. Thus, three empirical studies were developed what composed the present dissertation whose data were interpreted through Socioemotional Selectivity Theory (SST). The study objectives were 1) describe use characteristics and motivations for Facebook using among the elderly; 2) verifying if one of the constructs associated to the SST is valid for Brazilian elderlies; and 3) examining how much SST extends to the social relationships of olderly people established through Facebook. A survey was performed with elderlies, recruited from public Internet access services in the city of São Paulo (M= 68,1 years; SD= 6,5; 77,8% female). Surveys were used in relation to sociodemographic characteristics, Facebook usage and surveys were used regarding and referring to the variables indicative of the SST assumptions, namely: age, Future Time Perspective (FTP), network size, closeness affective with network and life satisfaction. The sample, composed of high average schooling and Facebook\'s frequent use, pointed motivations related to information and socialization. Four profiles of Facebook users (Explorer, Loner, Familiar and Sociable) could be identified by Multiple Correspondence Analysis. The concept of FTP was evaluated from the psychometric analysis of a measurement scale of the same and revealed a factorial composition partially similar to that of international studies, with emphasis on a third explanatory and distinct factor. Finally, a relationships model between variables indicative of the SST assumptions was tested by structural equation analysis means (Path Analysis for manifest variables) and partially confirmed. Were found direct and mediated FTP associations between age and life satisfaction, and the direct relationships between age and size of social networks, as predicted by Theory. Socioemotional selectivity indicators, such as networks size reduction and the emotional proximity were not related with life satisfaction. The data suggest social relations by Facebook presupposes the performance of a differentiated set of social goals and adaptive mechanisms associated with life satisfaction in old ag

Improving the bothropic antivenom through affinity chromatography and proteomics

Every year, more than 100,000 deaths occur worldwide as a consequence of snakebite envenoming, and around 400,000 people suffer lasting injuries or disfigurements. The World Health Organization added snakebite envenoming to the list of Neglected Tropical Diseases in 2017 due to the severity of the disease and a lack of antivenoms in certain regions of the world, such as Sub-Saharan Africa and Asian populations. Antivenoms have been the only effective therapy for snakebite envenoming since the end of the XIX century. Despite their relevance, antivenoms have limitations, such as a high rate of adverse responses when injected into the human body. Although there has been significant progress in the study of snake venom composition and antivenom effectiveness, little is known about antivenoms at the molecular level. By affinity chromatography purification of specific antibodies against the venom toxins of Bothrops jararaca, we started with the bothropic antivenom (BAv) and produced an improved bothropic antivenom (iBAv). Then, BAv and iBAv were characterized by quantitative proteomic analysis, and the affinities of both antivenoms were evaluated by surface plasmon resonance (SPR) on chips covered with venom toxins. In addition, in vivo neutralization assays were performed in mice model. A total of 105 proteins were identified by proteomics and 55 were quantified. The results showed that serum proteins were significantly depleted in the iBAv, resulting in an antivenom enriched in heavy and light chains of immunoglobulins. iBAV was 2.8 times more effective to neutralize B. jararaca venom lethal activity. In vitro SPR assays revealed that iBAv generated 2.9 higher binding responses to B. jararaca venom toxins in comparison to BAv. The results of this study may aid in the characterization of existing antivenoms and contribute to the development of a new generation of enhanced antivenoms.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)88887.336072/2019-002017/20106-988887.336072/2019­002017/20106­

BoaγPLI: Structural and functional characterization of the gamma phospholipase A2 plasma inhibitor from the non-venomous Brazilian snake Boa constrictor.

Plasma in several organisms has components that promote resistance to envenomation by inhibiting specific proteins from snake venoms, such as phospholipases A2 (PLA2s). The major hypothesis for inhibitor's presence would be the protection against self-envenomation in venomous snakes, but the occurrence of inhibitors in non-venomous snakes and other animals has opened new perspectives for this molecule. Thus, this study showed for the first time the structural and functional characterization of the PLA2 inhibitor from the Boa constrictor serum (BoaγPLI), a non-venomous snake that dwells extensively the Brazilian territory. Therefore, the inhibitor was isolated from B. constrictor serum, with 0.63% of recovery. SDS-PAGE showed a band at ~25 kDa under reducing conditions and ~20 kDa under non-reducing conditions. Chromatographic analyses showed the presence of oligomers formed by BoaγPLI. Primary structure of BoaγPLI suggested an estimated molecular mass of 22 kDa. When BoaγPLI was incubated with Asp-49 and Lys-49 PLA2 there was no severe change in its dichroism spectrum, suggesting a non-covalent interaction. The enzymatic assay showed a dose-dependent inhibition, up to 48.2%, when BoaγPLI was incubated with Asp-49 PLA2, since Lys-49 PLA2 has a lack of enzymatic activity. The edematogenic and myotoxic effects of PLA2s were also inhibited by BoaγPLI. In summary, the present work provides new insights into inhibitors from non-venomous snakes, which possess PLIs in their plasma, although the contact with venom is unlikely