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Results for “Decalcification Technique”

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At least 55 records · Page 3Linked to original sources
PubMed1980

Evaluating the rat inner ear. A technique using scanning electron microscopy.

The laboratory rat is the most commonly used species in safety evaluation of pharmaceutical compounds. However, surface preparations of the organ of Corti (OC) are difficult to perform in this species largely due to problems in removing the thick, bony otic capsule. A modified technique was developed using rapid decalcification to solve this problem. In addition, scanning electron microscopy was used to quantitate hair cell damage and/or loss after exposure of the OC by microdissection. It was found that hair cell loss and amage could be easily detected and quantified in rats given gentamicin sulfate.

Animals↗
PubMed1972

Quantitative observations on mineralized and non-mineralized bone in the iliac crest.

The amounts of mineralized bone and osteoid in thin undecalcified sections of iliac crest have been measured in 68 control subjects at necropsy using a point-counting method. The effect of varying the site selected for quantitative study on the value obtained for total bone mass has been investigated in decalcified sections of iliac crest. The total bone mass shows individual variation within a fairly constant range with a mean of 22.7 +/- 0.5% up to the age of 50 years and then progressively falls to a mean of 15.5 +/- 1.1% for individuals aged > 50 years. Some of the lowest values in the range 5.5 to 16.4 (mean 8.9 +/- 1.9%) were observed in elderly women in the seventh to ninth decades. It is concluded that so-called senile osteoporosis is usually a manifestation of a normal aging process. In controls osteoid accounts for only about 0.1% of the area measured and for a maximum of 1.8% of bone with a mean mineralization of 99.5%. Osteoid is patchily distributed and the maximum number of birefringent lamellae in any seam is four. The results of quantitative histology carried out in different parts of the iliac crest indicate that there are variations with the distance of the site from the anterior superior spine and its depth below the crest surface. The importance of this in relation to the site and size of iliac crest biopsies used for quantitative histology is discussed. There is a significant correlation between the values for total bone mass when estimated by the point-counting technique in undecalcified sections and by a volumetric method using blocks of bone.

Adolescent↗
PubMed1978

Fluoride-induced mineralization within vacuoles in maturative ameloblasts of the rat.

Dense crystalline deposits appeared within vacuoles in rat maturative ameloblasts as a result of repeated injections of sodium fluoride. The crystals assumed varied arrangements but were always observed within intracellular vacuoles. The crystals resemble those of normal enamel and resist microincineration. They are readily dissolved by decalcification and leave behind an organic framework which matches the outline of the crystals. An experimental model is presented which may be useful in further studies of calcium transport, enamel matrix absorption or digestion of cellular debris.

Ameloblasts↗
PubMed1975

The use of transparent teeth in the teaching of preclinical endodontics.

Demineralized teeth, which were cleared and hardened in xylene, were used in the teaching of preclinical endodontics. The teeth appeared well suited for the purpose. Of 39 students attending the course, 30 students thought that the use of transparent teeth had facilitated the learning of endodontic techniques.

Decalcification Technique↗
PubMedDate not supplied

[Morphometric analysis of periosteocytic osteolysis: its application to the diagnosis of hyperparathyroidism].

The authors indicate the required methodologic conditions for the morphometric analysis of periosteocytic osteolysis, a reliable and specific feature of overactivity of the parathyroid gland. Indeed, significant periosteocytic enlargement has been found in 101 113 cases of primary hyperparathyroidism compared to 92 reference cases. The measurement of the size of the periosteocytic lacunae may be carried out either on hand of a micrometric eyepiece or of a picture analyser. It has to be carried out on decalcified bone sections of 5 microns thickness and it is necessary to measure at least 50 lacunae. The decalcification process unmasks an already partially decalcified crown of periosteocytic bone tissue the thickness of which is more important in the hyperparathyroidal bone than in normal bone. This zone has a peculiar collagen texture. The measurement of the peri-osteocytic enlargement is easy on stained sections of decalcified bone or on microradiographs of non-decalcified bone and, contrariwise, very dubious on stained sections of non-decalcified bone.

Automation↗
PubMed1991

The cumulative effect of disinfection, storage, histological fixation and demineralization on number and staining ability of gram-positive bacteria.

It has previously been shown experimentally using S. faecalis that the relative number of blue-staining Gram-positive bacteria was reduced by demineralizing agents as well as by disinfection (Wijnbergen & van Mullem 1987, van Mullem & Wijnbergen 1989). In this study the cumulative effect of disinfection, experimental period, fixation and demineralization was investigated. The use of additives to the fixative and the demineralizing agents to limit the loss of blue-staining bacteria was also studied. The numbers of bacteria were determined using a haemocytometer, and the percentage of blue-staining organisms were ascertained from smears. When compared with the start of the experiment, the sequence of disinfection with chlorhexidine, storage in PBS, fixation with neutral formaldehyde and demineralization with formic acid or EDTA appeared to reduce the relative numbers of Gram-positive staining bacteria. For storage periods of 0 and 4 days the reduction factors were 100 and 600, respectively, using formic acid. These factors were 50 and 95, respectively, using EDTA. Addition of cetyl pyridinium chloride to the fixative and the demineralizing agents, and addition of neutral formaldehyde to the demineralizing agents lowered these reduction factors to 80 and 200, respectively, for formic acid, and 40 and 85, respectively, for EDTA. If the results are extrapolated to animal experiments where disinfection, experimental period, fixation and demineralization form part of the experimental framework, even the lowest reduction in the number of blue-staining bacteria could lead to false interpretation of tissue sections.

Bacteriological Techniques↗
PubMed2002

Enhancement of osteoblast proliferation in vitro by selective enrichment of demineralized freeze-dried bone allograft with specific growth factors.

Decalcified freeze-dried bone allograft (DFDBA), believed to serve as a matrix for new bone growth and to contain various bone-inducing growth factors, is currently used to regenerate periodontal defects and to restore and maintain dental alveolar ridges. Growth factors within DFDBA are extracted during the demineralization process, thus rendering the allograft incapable of spontaneous osteogenesis; however, exogenous growth factor addition to DFDBA may enhance the osteogenic capacity of native osteoblasts. This study's purpose is to evaluate murine osteoblast proliferation in the presence of various exogenous soluble growth factors as measured by fluorescence units. Osteoblasts harvested from mouse pup calvaria were cultured with 2% residual calcium-DFDBA and supplemented by one of the following growth factors or combinations of these factors: transforming growth factor-beta (TGF-beta), insulin-like growth factor-I (IGF-I), platelet-derived growth factor (PDGF), fibroblast growth factors basic (bFGF), or vascular endothelial growth factors (VEGF). Osteoblast proliferation rates indicate that the in vitro supplementation of 2% residual calcium-DFDBA with the combination of IGF and TGF-beta, IGF and PDGF, and PDGF and TGF-beta significantly (P < or = .05) enhance murine osteoblast activity and proliferation at 7 days compared with the control containing no exogenous growth factors.

Adult↗