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Biomedical subjects

E Bonucci

Publications and source records attributed to E Bonucci.

At least 127 records · Page 7Linked to original sources
PubMed1981

Fibrogenesis imperfecta ossium (clinical, biochemical and ultrastructural investigations).

The authors report a case of fibrogenesis imperfecta ossium (FIO). Only four cases diagnosed during life have previously been described in the literature. This is an extremely rare disease of entirely unknown aetiology. Clinical, biochemical and ultrastructural investigations were carried out. The most significant finding was the abnormal structure of the bone tissue, which was studied both by optical and electron microscopy on three successive biopsies of the iliac crest. In addition to deficient synthesis of the collagen fibrils, important anomalies related to the proteoglycans and the cellular elements were demonstrated. These have not been reported in previous cases. Some significant analogies with experimental lathyrism are also discussed.

Adult↗
PubMed1980

Fine structure of nuclei and cytoplasm of osteoclasts in Paget's disease of bone.

To investigate the fine structural features of nuclei and cytoplasm in osteoclasts from patients with Paget's disease of bone, eight bone biopsies were examined. Unusual paracrystalline filamentous formations were found with the nuclei of both actively resorbing and degenerating osteoclasts. These formations were made up of parallel arranged filaments which, in most cases, clustered together regularly. The filaments were slightly argyrophilic and this helped to differentiate them from the surrounding nuclear matrix, even when they were not aggregated in clusters. Argyrophilic filaments were also found loosely aggregated inside the cytoplasm of osteoclasts. In three biopsies two additional and unusual cytoplasmic inclusions were found. The first consisted of irregularly branching, highly argyrophilic membranous strands which were located inside membrane-bound vacuoles. The second consisted of spindle-shaped structures enclosed by two membranes and containing three or more tubules. It is suggested that these results stand as further morphological evidence in favour of the view that a virus, possibly of the paramyxovirus class, has a pathogenetic role in Paget's disease of bone.

Aged↗
PubMed1980

Bone oxalosis and renal osteodystrophy.

Bone biopsy specimens from four patients with hyperoxaluria who underwent hemodialysis were studied. Calcium oxalate crystals are laid down in marrow spaces and sometimes inside the bone matrix and uncalcified osteoid tissue. They are clearly visible by polarizing microscope and are stained grayish-brown by Pizzolato's method. Most are surrounded by basophilic, amorphous material. By electron microscope they appear as elongated, empty spaces and after hydrogen peroxide treatment appear as fragmented, slightly electron-dense, needle-like structures. In marrow spaces, oxalate crystals aggregate in round clusters surrounded by a granulomatous reaction. This, however, cannot remove the oxalate crystals. Bone histology shows advanced renal osteodystrophy, ie, severe osteomalacia and hyperparathyroidism. The granulomatous reaction induced by the oxalate crystals probably contributes to and worsens the changes from hyperparathyroidism.

Adolescent↗
PubMed1979

Resorption of uncalcified cartilage in the diaphysis of the chick embryo tibia.

The resorption of the uncalcified cartilage matrix of the middle third of the diaphysis in the chick embryo tibia has been studied using histological, histochemical and electron microscopic techniques. The first stage in the resorption process affects the periosteal bone, which is breached by osteoclasts at one or several points. Capillary vessels and clear, apparently undifferentiated cells penetrate through the holes so formed and reach the cartilage. The loss of acid proteoglycans to a depth of 10--20 micrometer into the matrix is the first sign of cartilage resorption; it is followed by the digestion of collagen fibrils, the opening of cell lacunae, chondrocyte degeneration and fragmentation and, lastly, the complete dissolution of the cartilage. This process is mediated by cells which probably derive from perivascular elements. Most of these cells have an undifferentiated appearance, but they have macrophagic properties, as is shown by phagocytotic activity along their plasma membrane, by the presence of lysosome-like bodies in their cytoplasm, and by their intense acid phosphatase activity. Resorption by giant cells of chondroclastic type only occurs at a late stage.

Animals↗
PubMed1979

25-hydroxycholecalciferol in the treatment of renal osteodystrophy in haemodialysed patients.

The effects of 25-OHD3 on renal osteodystrophy have been studied in 6 patients on maintenance haemodialysis. Administration of 25-OHD3, 50 microgram/day, did not improve biochemical data and intestinal absorption of calcium. With a dose of 100 microgram/day in all patients an increase in blood calcium levels eventually reaching hypercalcemic values was observed. In two cases a fall in alkaline phosphatase toward normal values was noted. In the same cases the treatment-induced hyperphosphatemia, uncontrolled by AI(OH)3 supplementation and similarly high iPTH levels were observed. In two cases repeated bone biopsy following 8 months treatment and not show substantial improvement of bone lesions. In one case addition of 1,25-(OH)2D3 to the treatment with 25-OHD3 led to a more rapid improvement in biochemical parameters and iPTH serum levels. Doses of 25-OHD3 capable to correct blood calcium levels and intestinal absorption of calcium, may have minimal benefit on the osteitis fibrosa component of the bone lesion.

Adolescent↗
PubMed1979

A histological investigation of skin lesions in onchocerciasis patients from Southern Togo.

Specimens from unselected populations in an area of hyperendemic onchocerciasis were used to describe and quantify histological changes in the upper layers of the dermis and the findings were compared with the macroscopical lesions observed. 553 persons, the inhabitants of two villages in Southern Togo, were examined. 502 biopsies were processed histologically. Onchocerciasis prevalence was over 75% and macroscopical skin lesions were evident in 30--40% of the population examined. Histological changes typical for the infection existed in the dermis in 68.5%. A cellular infiltration was seen in 49%, changes in the elastic or collagenous fibrils in 28.9% of the specimen. The observations are described in detail. Signs of inflammatory as well as primary degenerative changes were seen in biopsies from all age-groups. When microscopic and macroscopic findings are compared, it can be noticed that atrophy may start at an early age without preceeding dermatitis and that inflammatory reactions may occur at all ages. After submersion in saline for 24 hours not all microfilariae had emerged from the skin snips as evidenced by the histological examination. In 12.1% of those that otherwise would have been diagnosed as negative, microfilariae were identified in the sections.

Adolescent↗
PubMed1979

Histochemical and electron microscopical investigations on the calcified keratin in the horn pearls of a glans carcinoma (calcified keratin).

The calcified keratin in the horn pearls of a glans carcinoma has been studied by histochemical and ultrastructural methods. The former have shown that the calcified areas contain glycoproteins and acid proteoglycans and have a concentration of sulphydryl groups greater than that of the surrounding, uncalcified keratin. Electron microscopy has shown the presence of intracellular needle- and filament-like crystals closely related to the keratinocyte filaments and similar to those found in other calcified tissues. Besides the close relationship discovered between crystals and keratinocyte filaments, the other main conclusions are that keratin calcification is an intracellular process and that keratin molecules are responsible for the induction and regulation of the process.

Aged↗
PubMed1978

X-ray diffraction and electron microscope study of osteons during calcification.

To obtain information on the changes in the inorganic bone fraction during calcification, low- and wide-angle X-ray diffraction techniques and electron microscopy have been applied to single osteon samples. The samples were cylindrically shaped and their axes corresponded to the axes of the Haversian canals. The selection was made according to the degree of calcification and the orientation of collagen bundles and inorganic particles. Osteons at both the initial and final stages of calcification were chosen. Arrangements of fiber bundles and inorganic particles in successive lamellae characteristic of three types of osteon were selected, that is, longitudinally structured osteons, transversely structured osteons, and alternately structured osteons. The results indicate that in osteonic lamellar bone there are two types of inorganic particles: (1) granules arranged in linear or needle-shapred entities with maximum width 40-45 A, which are regularly distributed at the level of the main band of the collagen fibrils where their maximum length reaches the length of the main band itself; that is , about 400 A; and (2) very long crystallites, with a diameter of 40-45 A, which grow with their crystallographic c-axis parallel to the collagen fibrils and cover much more than a major collagen period.

Adolescent↗
PubMed1977

Initial studies on the crystallinity of the mineral fraction and ash content of isolated human and bovine osteons differing in their degree of calcification.

Several groups containing 10--15 isolated osteons differing in their degree of maturity were analysed. Samples were isolated from undecalcified human and bovine bone sections. The crystallinity coefficient, defined as the ratio of the number of radiation-induced paramagnetic defects in the crystalline lattice of hydroxyapatite to the total ash content, was calculated. The results were compared with measurements performed on fragments of total cortical bone, primary periosteal bone, and inner circumferential lamellar bone. The results show a higher crystallinity of fully calcified osteons as compared with that found at the initial stage of calcification. No differences in the ash content were observed between human osteons, from different stages of calcification evaluated morphologically and by X-ray absorption. These differences were evident when bovine osteons differing in their stage of calcification were compared. Human fully calcified osteons contain 60% ash and their crystallinity coefficient is 52.1. Human osteons at the initial stage of calcification contain 57% ash and their crystallinity coefficient is 40.6. The same parameters for fully calcified bovine osteons and for bovine osteons at the initial stage of calcification are 59% ash, 62.6 crystallinity coefficient and 46% ash, 43.0 crystallinity coefficient, respectively.

Adult↗
PubMed1977

Osteocyte ultrastructure in renal osteodystrophy.

The ultrastructure of the osteocyte has been studied in 80 needle biopsies from the iliac crest of uremic subjects with renal osteodystrophy. Different types of osteocytes were present in the osseous trabeculae. Those recognizable in completely uncalcified osteoid tissue looked like normal osteocytes, even though the matrix was not mineralized. Those present in hypomineralized areas showed enlarged and irregular lacunae when examined under the light microscope; under the electron microscope these osteolytic-like changes were not evident and were found to have been produced by defective calcification of the perilacunar matrix. Osteocytes placed in matrix whose mineralization was normal were often surrounded by a border of crystals protruding side-to-side from the bone matrix into the lacunar space. Other osteocytes were placed in unusually wide lacunae. They showed evidence of osteolytic activity, chiefly consisting of irregularity of the lacunar wall, presence of flocculent, granular and filamentous material in the pericellular space, and calcification of mitochondria. Degenerating and degenerate osteocytes were also recognizable.

Adolescent↗
PubMed1977

Histologic, microradiographic and electron microscopic investigations of bone tissue in a case of craniodiaphyseal dysplasia.

The results of histologic, microradiographic and electron microscopic investigations carried out on two bone biopsies pertaining to a case of craniodiaphyseal dysplasia are reported. They show that the affected skeletal segments are chiefly characterized by enhancement of bone volume, and defective calcification of the bone matrix. Moreover, interstitial calcification of skeletal muscle has been found.

Bone Diseases, Developmental↗