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Biomedical subjects

E Bonucci

Publications and source records attributed to E Bonucci.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Evaluation of osteoblastic activity by morphometric comparison of alkaline phosphatase cytochemistry vs. tetracycline fluorescence.

Alkaline phosphatase (ALP) activity was used as a novel histomorphometric index of osteoblastic surfaces involved in mineralization. The enzyme cytochemical reaction was done on sections of low temperature processed, glycol methacrylate (GMA) embedded bone biopsies from 39 patients with various types of renal osteodystrophy (age 48 +/- 12 yrs; 19 males, 20 females) who had received tetracycline labelling. Sets of three serial sections were obtained from each tissue block: the 1st section (2 microns thick) was stained with Methylene blue Azure 11 for morphology; the 2nd section (2 microns thick) was used for ALP cytochemistry; the 3rd section was left unstained for UV microscopy. ALP positive osteogenic cells on bone surfaces displayed either of two distinct morphologies: a) typical plump, 'active' osteoblasts, and b) flat, elongated cells otherwise indistinguishable from 'bonelining cells'. These ALP+ flat cells were in contact with sites of active osteoid and mineral deposition and also codistributed with tetracycline labels outside of, and in continuity with, osteoid seams. Flat lining cells which were ALP negative were never associated with labels. Therefore, ALP activity also provided an objective criterion for differentiating two different 'phenotypes' among flat bone lining cells (ALP+ and ALP-), associated or not associated with matrix mineralization, respectively. The following histomorphometric variables were measured: Ob.S/BS, OS/BS, MS/BS and ALP.S/BS. Ob.S/BS, OS/BS and MS/BS were different in different types of ROD. However, OS/BS always exceeded MS/BS which, in turn, always exceeded Ob.S/BS. ALP.S/BS exceeded OS/BS in controls, mixed ROD and hyperparathyroidism, whereas the reverse occurred in osteomalacia and aplastic bone, due to the abundance of ALP lining cells over nonmineralizing surfaces.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Morphological investigation of epiphyseal cartilage after glutaraldehyde-malachite green fixation.

The glutaraldehyde-malachite green (GlMG) fixation has been reported to allow preservation of tissue lipids, mainly acidic phospholipids, that in the absence of malachite green are lost in the glutaraldehyde solution. This method has been used for the morphological study of calcifying epiphyseal cartilage, with particular reference to the presence of lipids in chondrocytes, cartilage matrix and calcification nodules. Both light and electron microscopy show that after GlMG-osmium fixation the chondrocytes contain cytoplasmic dense bodies. These have the same morphology as those found with the same method in other cells and tissues and considered to be lipid globules. However, they are not modified by treatment of GlMG-fixed specimens with chloroform-methanol. Formic acid decalcification induces partial solubilization of these bodies, whereas EDTA decalcification leaves them unchanged. They are found also in the pericellular space and in calcifying matrix. GlMG fixation improves the preservation of the crystal-associated organic structures (crystal ghosts) when the cartilage is decalcified before embedding. When these structures are demonstrated by the post-embedding decalcification and staining method, their morphology is similar to that found in controls. Moreover, GlMG fixation demonstrates the presence of typical rod-like, beaded structures, probably corresponding to proteoglycans, on the outer surface of the chondrocyte membrane. Although composition and role in calcification of the dense bodies remain uncertain, the important physiological implications that can be drawn from their presence in chondrocytes and cartilage matrix require further investigation.

Animals↗
PubMedDate not supplied

Calcified tissue histochemistry: from microstructures to nanoparticles.

It has long been recognized that histochemistry and cytochemistry offer the only ways of gathering information about the biochemical composition of tissues and cells without disrupting their microscopic architecture. A variety of methods have been put forward for studying nuclei acids, proteins, carbohydrates, lipids, enzymes and other components of intact tissues and cells. By now, many of these have only a historical interest. Some do, however, survive in microscopic and ultramicroscopic applications, and have become incorporated in the most refined and precise techniques that are currently available. Histochemical reactions range from the classic procedures carried out on histological sections to yield final stained products recognizable under the light microscope, to those which are applied on ultrathin sections, using heavy metals or other electron-dense compounds to reveal specific components under the electron microscope; others range from procedures based on the antigen-antibody reaction that are capable of revealing the presence of specific biological molecules, to the biophysical techniques which permit the qualitative and quantitative analysis of elements; lastly, there are the recently proposed ultra-high resolution methods that allow nanoparticles to be recognized. This brief review, which is based on personal experience and on the data in the literature, will discuss the most important methods now being used.

Animals↗