Sequestration of Ca in simian nasal mucosa: Determination of Ca molarity in ex vivo tissue by simultaneous off-axis Scanning Transmission Ion Microscopy, Particle Induced X-Ray Emission and Elastic Backscattering Spectrometry

A technique to determine the molar concentration of elements in ex vivo tissue sections by Particle Induced X-ray Emission (PIXE) has been developed. The method is based on simultaneous off-axis scanning transmission ion microscopy (OA-STIM) and Elastic Backscattering Spectrometry (EBS) measurement of the sample thickness and major element (H, C, N, O) composition. The method was applied to determine the molarity of localised Ca concentration hot-spots in the outer epithelium tissue of nasal mucosa of a rhesus macaque subject infected with simian immunodeficiency virus (SIV). The results show Ca sequestration in concentration hot-spots and outer epithelial tissue that significantly exceeded the Ca concentration in the surrounding tissues. This may originate from mineralisation and/or Ca enhancement in goblet cells. [Display omitted] Sequestration of Ca in concentration hot-spots in the outer epithelium of nasal mucosa of a subject infect with simian immunodeficiency virus (SIV). •A MeV ion microprobe technique to measure the molarity of life elements in ex-vivo tissue sections has been developed.•The method is based on using the EBS andoff-axis STIM data to determien hte major element composition that is used to refine the PIXE composition.•Ca molarities in nansal mucosal tissue was determined.•Ca sequestration in concentration “hot-spots” was obseerved in a SIV infected subject.