Life Sciences Commons^™

Cryofixation Of Heart Tissue For X-Ray Microanalysis, Alice Warley

Scanning Microscopy

Cryofixation of tissues is necessary to be able to study the concentrations of elements by X-ray microanalysis. Simple dissection of heart tissue fragments of the size needed for optimum cryofixation by the conventional methods of plunge or slam freezing leads to the development of ischaemia in the tissue fragments and a consequent redistribution of the diffusible elements. Heart tissue can be frozen in vivo using liquid nitrogen cooled Cu clad pliers, but the morphological detail is preserved better if the cooled pliers are exposed to liquefied propane immediately before freezing, Concentrations of Na are lower and concentrations of K are …

Strontium And Bromide As Tracers In X-Ray Microanalysis Of Biological Tissue, Joanna Wroblewski, Samuel Sagström, Helmy Mulders, Godfried M. Roomans

Scanning Microscopy

Since energy dispersive X-ray microanalysis cannot distinguish between isotopes of the same element, alternative methods have to be used to get information similar to that obtained in experiments with radioactive tracers. In the present study, strontium was used as a tracer for calcium, and bromide as a tracer for chloride. Rats were injected with strontium chloride in vivo, and the uptake of strontium in the acinar cells of the submandibular gland was studied. Eventually a Sr/Ca ratio of 0.3 was reached. In some animals, secretion of mucus had been elicited by stimulation with isoproterenol 4 h prior to injection …

Microscopy Analysis Of Dental Titanium Casting Investment Materials, H. J. Mueller

Scanning Microscopy

Scanning electron microscopy (SEM) analysis and qualitative energy dispersive x-ray microanalysis (EDS) of investment materials for dental titanium casting were performed. Two commercial investment materials, Ohara and Castmatic, and an experimental zirconia material were analyzed. The microstructural constituents and the unfired and fired structures were included. Larger refractory particles and matrix embedding smaller particles were observed with each material. Detection of aluminum, silicon, magnesium, zirconium and oxygen provided a basis to reason the presence of alumina (Al₂O₃), silica (SiO₂), magnesia (MgO), and zirconia (ZrO₂). Hence, Ohara contained quartz and an alumino-silicate, Castmatic …

Biuret Staining And X-Ray Microanalysis For Locating Grafted Poly(Methyl Acrylate) On Wool Fibers, R. R. Bresee, P. A. Annis

Scanning Microscopy

Biuret reagent was used to stain wool fibers with copper so the location of a small amount of poly(methyl acrylate) grafted onto the fibers could be determined by energy dispersive x-ray microanalysis of copper. The grafted polymer was determined to be located in regions of the fibers where cuticle had been previously damaged. The amount of grafted polymer present was too small for secondary electron imaging to be useful for locating the polymer grafts.

X-Ray Microanalysis Of Calcium Containing Organelles In Resin Embedded Tissue, G. Nicaise, I. Gillot, A. K. Julliard, E. Keicher, S. Blaineau, J. Amsellem, J. C. Meyran, M. L. Hernandez-Nicaise, B. Ciapa, C. Gleyzal

Scanning Microscopy

The localization of calcium in cell organelles at the electron microscope level is often achieved through cytochemical techniques, and verified by X-ray microanalysis. Various methods have been used to cytochemically detect calcium or calcium-binding sites : calcium loading, calcium substitution by strontium, barium, or even lead, and calcium precipitation by oxalate, phosphate, fluoride, or pyroantimonate. Their results may have heuristic value, particularly in preliminary studies of poorly known cell types. A complementary and more physiological approach is offered by quantitative measurement of the total calcium content of organelles after cryofixation.

Resin embedding is less demanding than cryomicrotomy and gives better …