Consumo de fibra alimentar por crianças e adolescentes com constipação crônica: influência da mãe ou cuidadora e relação com excesso de peso Dietary fiber intake for children and adolescents with chronic constipation: influence of mother or caretaker and relationship with overweight

OBJETIVO: Avaliar a influência da mãe ou da cuidadora sobre o consumo de fibra alimentar por crianças e adolescentes com constipação crônica bem como sua relação com a ocorrência de excesso de peso. MÉTODOS: Estudo transversal com 38 crianças e adolescentes com constipação funcional e suas respectivas cuidadoras. Para análise do consumo de fibra alimentar, foi utilizado o registro alimentar de três dias. Peso e estatura foram aferidos para verificar o estado nutricional. A história familiar de constipação foi investigada. RESULTADOS: A maioria dos pacientes com constipação (89,5%; 34/38) apresentava consumo insuficiente de fibra (inferior à idade +5g). Das 38 cuidadoras, apenas uma (2,6%) apresentou ingestão de fibra superior à recomendação mínima (20g/dia). Excesso de peso foi encontrado em 28,9% (11/38) dos pacientes e em 60,5% (23/38) das suas responsáveis. Associação entre excesso de peso e presença de constipação foi verificada entre as cuidadoras (p=0,046). As crianças e adolescentes do sexo feminino com excesso de peso apresentaram menor ingestão de fibra, comparadas às sem excesso de peso (p=0,011). Nos pacientes do sexo masculino, essa associação não foi observada. O consumo de fibra pelas cuidadoras com excesso de peso foi inferior ao das demais (p=0,027). Observou-se correlação entre consumo de fibra pelas crianças com constipação e suas cuidadoras, nos sexos masculino (r=+0,561; p=0,005) e feminino (r=+0,782; p<0,001). CONCLUSÕES: Observou-se relação entre o consumo de fibra alimentar por crianças e adolescentes com constipação crônica e suas respectivas cuidadoras. O consumo insuficiente de fibra associou-se ao excesso de peso e à presença de constipação no gênero feminino.<br>OBJECTIVE: To evaluate the influence of the mother or caretaker on the consumption of dietary fiber by children and adolescents with chronic constipation and its relationship with the occurrence of overweight. METHODS: This cross-sectional study enrolled 38 children and adolescents with functional constipation and their respective caretakers. A three-day food register was used for the analysis of the dietary fiber consumption. Weight and height were measured to verify the nutritional status. Familiar history of constipation was investigated. RESULTS: Most patients with constipation (89.5%; 34/38) presented insufficient fiber consumption (less than age+5g). Out of 38, only 1 (2.6%) caretaker presented fiber ingestion greater than the minimum recommendation (20g/day). Overweight was found in 11/38 (28.9%) patients and 23/38 (60.5%) caretakers. An association between overweight and the presence of constipation was verified among caretakers (p=0.046). For female children and adolescents there was an association between overweight and lower fiber ingestion (p=0.011). This association was not observed for male patients. The consumption of fiber by caretakers with overweight was lower than those without overweight (p=0.027). There was correlation between the consumption of fiber in constipated children and their caretakers for male (r=+0.561; p=0.005) and female patients (r=+0.782; p<0.001). CONCLUSIONS: There was a relationship between the consumption of dietary fiber by children and adolescents with chronic constipation and their caretakers. In females, the insufficient consumption of fiber was associated with overweight and with the presence of constipation

Dynamin regulates the dynamics and mechanical strength of the actin cytoskeleton as a multifilament actin-bundling protein

The dynamin GTPase is known to bundle actin filaments, but the underlying molecular mechanism and physiological relevance remain unclear. Our genetic analyses revealed a function of dynamin in propelling invasive membrane protrusions during myoblast fusion in vivo. Using biochemistry, total internal reflection fluorescence microscopy, electron microscopy and cryo-electron tomography, we show that dynamin bundles actin while forming a helical structure. At its full capacity, each dynamin helix captures 12-16 actin filaments on the outer rim of the helix. GTP hydrolysis by dynamin triggers disassembly of fully assembled dynamin helices, releasing free dynamin dimers/tetramers and facilitating Arp2/3-mediated branched actin polymerization. The assembly/disassembly cycles of dynamin promote continuous actin bundling to generate mechanically stiff actin super-bundles. Super-resolution and immunogold platinum replica electron microscopy revealed dynamin along actin bundles at the fusogenic synapse. These findings implicate dynamin as a unique multifilament actin-bundling protein that regulates the dynamics and mechanical strength of the actin cytoskeletal network

Contrasting roles for actin in the cellular uptake of cell penetrating peptide conjugates

The increased need for macromolecular therapeutics, such as peptides, proteins and nucleotides, to reach intracellular targets necessitates more effective delivery vectors and a higher level of understanding of their mechanism of action. Cell penetrating peptides (CPPs) can transport a range of macromolecules into cells, either through direct plasma membrane translocation or endocytosis. All known endocytic pathways involve cell-cortex remodelling, a process shown to be regulated by reorganisation of the actin cytoskeleton. Here using flow cytometry, confocal microscopy and a variety of actin inhibitors we identify how actin disorganisation in different cell types differentially influences the cellular entry of three probes: the CPP octaarginine – Alexa488 conjugate (R8-Alexa488), octaarginine conjugated Enhanced Green Fluorescent Protein (EGFP-R8), and the fluid phase probe dextran. Disrupting actin organisation in A431 skin epithelial cells dramatically increases the uptake of EGFP-R8 and dextran, and contrasts strongly to inhibitory effects observed with transferrin and R8 attached to the fluorophore Alexa488. This demonstrates that uptake of the same CPP can occur via different endocytic processes depending on the conjugated fluorescent entity. Overall this study highlights how cargo influences cell uptake of this peptide and that the actin cytoskeleton may act as a gateway or barrier to endocytosis of drug delivery vectors

Is immunosenescence influenced by our lifetime “dose” of exercise?

The age-associated decline in immune function, referred to as immunosenescence, is well characterised within the adaptive immune system, and in particular, among T cells. Hallmarks of immunosenescence measured in the T cell pool, include low numbers and proportions of naïve cells, high numbers and proportions of late-stage differentiated effector memory cells, poor proliferative responses to mitogens, and a CD4:CD8 ratio <1.0. These changes are largely driven by infection with Cytomegalovirus, which has been directly linked with increased inflammatory activity, poor responses to vaccination, frailty, accelerated cognitive decline, and early mortality. It has been suggested however, that exercise might exert an anti-immunosenescence effect, perhaps delaying the onset of immunological ageing or even rejuvenating aged immune profiles. This theory has been developed on the basis of evidence that exercise is a powerful stimulus of immune function. For example, in vivo antibody responses to novel antigens can be improved with just minutes of exercise undertaken at the time of vaccination. Further, lymphocyte immune-surveillance, whereby cells search tissues for antigens derived from viruses, bacteria, or malignant transformation, is thought to be facilitated by the transient lymphocytosis and subsequent lymphocytopenia induced by exercise bouts. Moreover, some forms of exercise are anti-inflammatory, and if repeated regularly over the lifespan, there is a lower morbidity and mortality from diseases with an immunological and inflammatory aetiology. The aim of this article is to discuss recent theories for how exercise might influence T cell immunosenescence, exploring themes in the context of hotly debated issues in immunology