Spatial fluctuations at vertices of epithelial layers: quantification of regulation by Rho pathway

In living matter, shape fluctuations induced by acto-myosin are usually studied in vitro via reconstituted gels, whose properties are controlled by changing the concentrations of actin, myosin and cross-linkers. Such an approach deliberately avoids to consider the complexity of biochemical signaling inherent to living systems. Acto-myosin activity inside living cells is mainly regulated by the Rho signaling pathway which is composed of multiple layers of coupled activators and inhibitors. We investigate how such a pathway controls the dynamics of confluent epithelial tissues by tracking the displacements of the junction points between cells. Using a phenomenological model to analyze the vertex fluctuations, we rationalize the effects of different Rho signaling targets on the emergent tissue activity by quantifying the effective diffusion coefficient, the persistence time and persistence length of the fluctuations. Our results reveal an unanticipated correlation between layers of activation/inhibition and spatial fluctuations within tissues. Overall, this work connects the regulation via biochemical signaling with mesoscopic spatial fluctuations, with potential application to the study of structural rearrangements in epithelial tissues.Comment: 8 pages, 3 figure

Medicina complementar no SUS: práticas integrativas sob a luz da Antropologia médica

O artigo examina a contribuição da Medicina complementar para o Sistema Único de Saúde - SUS em um novo contexto de institucionalização. A reflexão analisa políticas oficiais de instituições sanitárias, como a OMS e o Ministério da Saúde, além da literatura especializada no tema. As práticas integrativas e complementares no SUS, em meio a um itinerário de crescente legitimação, valorizam recursos e métodos não biomédicos relativos ao processo saúde/doença/cura, enriquecem estratégias diagnóstico/terapêuticas e podem favorecer o pluralismo médico no Brasil. Desse modo, o atual sistema público de saúde transporta para seu interior outros saberes e racionalidades de base tradicional, que passam a conviver com a lógica e os serviços convencionais da biomedicina. O artigo acentua a discussão antropológica sobre integralidade em políticas públicas de saúde, com ênfase nos aspectos sociais, simbólicos e culturais que as realidades sanitárias necessariamente abrigam. Em conclusão, chama-se a atenção para a necessidade de aprofundamento do conceito de integralidade, bem como para o enfrentamento dos desafios práticos que sua implantação requer.The article examines the contribution of Complementary Medicine to Sistema Único de Saúde (SUS - Brazil's National Health System) in a new institutionalization context. The reflection analyzes official policies of health institutions such as the WHO and the Ministry of Health, in addition to the specialized literature on the subject. The integrative and complementary practices within the SUS, in the midst of a path of increasing legitimacy, value non-biomedical resources and methods related to the health/disease/cure process, enrich diagnostic/therapeutic strategies, and may encourage medical pluralism in Brazil. Thus, the current public health system transports into its interior other traditional knowledge and rationalities, which start to coexist with the logic and conventional services of biomedicine. The article stresses the anthropological discussion about integrality in public health policies, with emphasis on the social, symbolic, and cultural aspects that the sanitary realities necessarily shelter. In conclusion, attention is drawn to the need to investigate the integrality concept, as well as to face the practical challenges its implantation requires