Search

Cerebral ischemia can occur at any stage in life, but clinical consequences greatly differ depending on the developmental stage of the affected brain structures. Timing of the lesion occurrence seems to be critical, as it strongly interferes with neuronal circuit development and determines the way spontaneous plasticity takes place. Translational stroke research requires the use of animal models as they represent a reliable tool to understand the pathogenic mechanisms underlying the generation, progression, and pathological consequences of a stroke. Moreover, in vivo experiments are instrumental to investigate new therapeutic strategies and the best temporal window of intervention. Differently from adults, very few models of the human developmental stroke have been characterized, and most of them have been established in rodents. The models currently used provide a better understanding of the molecular factors involved in the effects of ischemia; however, they still hold many limitations due to matching developmental stages across different species and the complexity of the human disorder that hardly can be described by segregated variables. In this review, we summarize the key factors contributing to neonatal brain vulnerability to ischemic strokes and we provide an overview of the advantages and limitations of the currently available models to recapitulate different aspects of the human developmental stroke.

Many aspects associated with the application of nanotechnology to agricultural activities are still unknown. In particular, there is not enough information on nanotoxicology in crops and we do not know the fate of nanoparticles in crops. Multiple experiments were carried out to study the effects of titanium oxide nanoparticles (nTiO2) on barley (Hordeum vulgare). Germinating seeds were exposed to 0, 500, 1000, and 2000 mg l−1nTiO2. Seed germination percentage, mitotic index, root elongation, and Ti concentration in seedlings were observed. In a greenhouse experiment, plants of barley were grown to physiological maturity in control soil and soil enriched with 500 and 1000 mg nTiO2 mg kg−1, respectively. The duration of the growth cycle and the plant biomass was influenced by nTiO2 compared to control plants. Concentrations of Ti were not very high with the exception of roots. However, the nTiO2 soil amendment had an impact on composition and nutritional quality of barley grains. Concentrations of Ca, Mn, and Zn in kernels were increased by nTiO2 treatments. Concentration of amino acids was affected by the treatments as well. nTiO2 treatments have the potential to influence the food chain and processing and economics of barley.

Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a "maladaptive" strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke.

Calcium deficiency disorders in fruit, such as bitter pit (BP), have puzzled researchers for years, and little is known regarding the mechanisms involved in the development of these physiophaties. Previous studies have suggested abscisic acid (ABA) as an alternative treatment to influence calcium allocation to the fruit, by regulating stomatal conductance and transpiration in leaves. We explored the feasibility of this approach in ‘Super chief’, an apple cultivar susceptible to BP, with the specific purpose to elucidate the mechanisms underpinning calcium partitioning and its resulting availability in the fruit cells through field trials and molecular analysis. Our findings reveal that foliar spraying with ABA, carried out four times during the season (starting from 66 DAFB) can be effective in apple bitter pit prevention, via a preferential supply of Ca2+ to fruit. Higher amounts of Ca2+ have been detected in treated apples at harvest and, consistently, the transcriptional analysis evidenced, in the same samples, the down-regulation of three genes involved in Ca2+ partitioning (MdACA8, MdCAX and MdCDPK). These data are in agreement with the hypothesis that BP prevention could be associated to the increased Ca2+ concentration in the apoplast and a coordinated regulation of specific Ca2+-related genes.