RESUMO
Iron (Fe) is an essential metal involved in a wide spectrum of physiological functions. Sub-cellular characterization of the size, composition, and distribution of ferritin(iron) can provide valuable information on iron storage and transport in health and disease. In this study we employ magnetic force microscopy (MFM), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS) to characterize differences in ferritin(iron) distribution and composition across injured and non-injured tissues by employing a rodent model of spinal cord injury (SCI). Our biophysical and ultrastructural analyses provide novel insights into iron distribution which are not obtained by routine biochemical stains. In particular, ferritin(iron) rich lysosomes revealed increased heterogeneity in MFM signal from tissues of SCI animals. Ultrastructural analysis using TEM elucidated that both cytosolic and lysosomal ferritin(iron) density was increased in the injured (spinal cord) and non-injured (spleen) tissues of SCI as compared to naïve animals. In-situ EELs analysis revealed that ferritin(iron) was primarily in Fe3+ oxidation state in both naïve and SCI animal tissues. The insights provided by this study and the approaches utilized here can be applied broadly to other systemic problems involving iron regulation or to understand the fate of exogenously delivered iron-oxide nanoparticles.
Assuntos
Ferritinas/metabolismo , Ferro/metabolismo , Nanopartículas Metálicas/química , Traumatismos da Medula Espinal/metabolismo , Animais , Citosol/química , Citosol/metabolismo , Citosol/ultraestrutura , Modelos Animais de Doenças , Ferritinas/química , Ferritinas/ultraestrutura , Humanos , Ferro/química , Lisossomos/efeitos dos fármacos , Lisossomos/ultraestrutura , Nanopartículas Metálicas/efeitos adversos , Nanopartículas Metálicas/uso terapêutico , Microscopia Eletrônica de Transmissão , Ratos , Roedores , Espectroscopia de Perda de Energia de Elétrons , Traumatismos da Medula Espinal/tratamento farmacológico , Baço/química , Baço/metabolismo , Baço/ultraestruturaRESUMO
Simultaneous 3D articulograph and ultrasonograph techniques were used to monitor the chewing, swallowing, oral soft tissue and tongue movements of six subjects whilst consuming varying numbers (1, 2 and 4) of a confectionery product. Modifying the number of confectionery units had a variable effect on chewing, swallowing and oral soft tissue movements during the start of the chewing sequence. The distance, range and velocity of chin movement were significantly lower when 1 confectionery unit was consumed compared with 2 and 4 during the middle stage of the chewing sequence. Significant differences in modioli movement were observed during the initial stages of chewing allowing the identification of a working and non-working side, whilst no differences in thyroid cartilage movement were noted over the whole chewing sequence. Increasing the number of confectionery units caused a significant increase in the index of tongue movement during the end of the eating sequence, although the mean index of tongue movement over the total chewing sequence remained constant. Jaw movement correlated with tongue movement, where for all samples, gape decreased linearly as the chewing sequence progressed, reflected in a similar decline in the index of tongue movement. The lack of differences in the index of tongue movement observed over the start and middle of the chewing sequence as a consequence of the number of confectionery units consumed suggested that the change in the physical properties of the bolus had a greater effect on the index of tongue movement than the change in bolus size.
