Life Sciences Commons^™

Strontium, A Tracer To Study The Transport Of Calcium In Mineralizing Tissues By Electron Probe Microanalysis, Ernst-Rudolf Krefting, Kai Frentzel, Jörg Teßarek, Hans-Jürgen Höhling

Scanning Microscopy

In growth plate cartilage the mineralization starts extracellularly in the lower hypertrophic zone. The mineral formed is the calcium phosphate apatite. Enough calcium and phosphate must be available at the mineralization front as well as in regions with proceeding mineralization. There must be a transport of Ca (and phosphate) to these sites.

Electron probe X-ray microanalysis is a well established method to analyze element concentrations in small volumes, but it cannot discriminate isotopes. Strontium is similar to Ca in its chemical and biological behaviour and is therefore a suitable tracer to investigate the transport of Ca.

Small amounts of Sr …

Electron Probe Microanalysis Of The Otolithic Membrane. A Methodological And Quantitative Study, J. A. López-Escámez, F. J. Cañizares, P. V. Crespo, A. Campos

Scanning Microscopy

The effect of tissue preparation on calcium and potassium weight percents in the otoconial layer in the utricle and saccule was studied in four groups of OF1 mice with electron probe X-ray microanalysis. Glutaraldehyde and freeze-drying, glutaraldehyde and air-drying, air-drying, and cryo-fixation and freeze-drying were compared. Ca and K changed significantly in the utricle depending on the method used (P < 0.001), and K changed significantly in the saccule (P < 0.001 ). We chose cryo-fixation with freeze-drying for the quantitative analysis of the otolithic membrane because this method provided the highest values of Ca and K with minimum loss of Ca and K . Microcrystalline salt standards mounted on scanning electron microscopy holders were used for the quantification of Ca and K by the peak-to-local-background (P/B) ratio method. The P/B ratio in standards with reproducible results, when plotted against weight percent, gave a straight line for Ca (r = 0.99, P < 0.001) and K (r = 0.98, P < 0.001). The Ca and K weight percents in otoconia showed similar frequency distributions in the utricle and saccule.

Histochemical Demonstration And Microanalysis Of Possible Calcium Binding Sites In The Enamel Organ Of Rat Incisors, Y. Takano

Scanning Microscopy

The rat incisors obtained from rats perfused with high-calcium solution containing 30 to 50 mM CaCl₂ were processed for rapid freeze/freeze-substitution and embedded in epoxy resin. GBHA staining, a histochemical staining for calcium, of unhydrously prepared sections revealed a large number of granular Ca-GBHA reactions in the enamel organ, most of which being located along the lateral plasma membranes of the ameloblasts. In the ameloblast layer, the reaction was negative in the presecretory stage, became intense in concert with the onset of enamel matrix formation, and remained so by the end of the transitional stage where the reaction gradually …

The Influence Of Dietary Factors On The Risk Of Urinary Stone Formation, A. Hesse, R. Siener, H. Heynck, A. Jahnen

Scanning Microscopy

The action of various beverages and foods on the composition of the urine in the circadian rhythm and in the 24-hour urine has been investigated under standardized conditions. Orange juice leads to a significant increase of urinary pH and citric acid excretion. Black tea leads to a raised excretion of oxalic acid by only 7.9%. In the short term, beer increases diuresis, but afterwards leads to a compensatory antidiuresis with increased risk of stone formation. Depending on their composition, mineral waters have very different effects on the urinary constituents. Milk as well as cocoa beverage significantly increase calcium excretion; moreover, …

Particle Induced X-Ray Emission Microanalysis Of Root Samples From Beech (Fagus Sylvatica), M. Hult, B. Bengtsson, N. P. -O. Larsson, C. Yang

Scanning Microscopy

Beech seedlings (Fagus Sylvatica) were grown in a nutrient solution to which AlCl₃ had been added. The experiments were designed to evaluate the effect of aluminum on the localization of elements in plant root tissue. Cross-sections of roots were analyzed with micro-PIXE (particle induced X-ray emission) and Rutherford backscattering (RBS) simultaneously. A proton beam of either 30x30 μm² or 5x5 μm² was scanned over the samples, and quantitative elemental maps were created. Aluminum was found to accumulate in high concentrations (percent levels) in the epidermis and the outer layer of the cortex, when the nutrient …

Factors Affecting Fasting Urinary Calcium Excretion In Stone Former Patients On Different Dietary Calcium Intake, Piergiorgio Messa, Giuseppe Mioni, Rossana Franzon, Michele Messa, Aldo Cruciatti, Sandro Giannini, Angela D'Angelo

Scanning Microscopy

The effects of variable calcium content on daily and fasting urinary calcium and other lithogenic solutes excretion, on the bone turnover index (fasting hydroxyproline urinary excretion) and on the calciotropic hormones were studied in 312 stone former patients with an outpatient protocol and 15 stone former patients in an inpatient study. Furthermore in 60 of these patients, 30 while on a low calcium diet (LCD) and 30 on a free calcium home diet (FCD), the effects of an oral calcium load (OCL) on bone turnover index, calciotropic hormones and calcium excretion were evaluated. The results demonstrate that an LCD is …