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Biomedical subjects

A Dhem

Publications and source records attributed to A Dhem.

At least 19 recordsLinked to original sources
PubMed1992

Ossification of the human fetal ilium.

Ossification of the ilium is similar to that of a long bone. It possesses three cartilaginous epiphyses and one cartilaginous process. Moreover, it undergoes peculiar osteoclastic resorption, comparable with that of the cranium bones. Asymmetrical ossification of the ilium, haversian bone remodelling and apposition of chondroid tissue posterosuperiorly to the acetabulum most probably emphasize the importance of mechanical factors in the morphogenesis of the hip bone during fetal life.

Fetus↗
PubMed1992

The fate of the quiescent surfaces of lamellar bone.

Microradiographic and histologic analysis of undemineralized bone was performed in 62 subjects aged 18-97 years. Ten of these samples were also submitted to scanning electron microscopy. Besides the usual lamellar bone remodeling, all types of bone surfaces, namely both haversian and vascular canals and the endosteal and trabecular surfaces, were involved in weathering alterations of the superficial lamellae, resulting in eroded outlines, less deeply notched than the Howship lacunae and devoid of osteoclast. Present as soon as early adult life and randomly distributed, these aspects were recorded in all the bone pieces examined. These observations were consistent with the hypothesis of a particular destructive process in all the quiescent lamellar bone surfaces without osteoclast participation, termed delitescence, which could be partly responsible for age-related bone loss.

Adolescent↗
PubMed1991

Localised mastocytosis at the bone and porous coated interface of a knee prosthesis.

A porous coated tibial plateau component, which was not loose, was removed 6 weeks after operation. An absence of bony ingrowth was demonstrated by histological and microradiographic examination. The radiolucent space was filled by young connective tissue and inflammation was indicated by the presence of a few macrophages or foreign body giant cells; there was also an increased number of mast cells near the metallic beads. Such inflammatory cells have not previously been reported around a firmly fixed joint prosthesis, but they have been associated with metallic particles. Since accumulations of mast cells can interfere with the process of bony ingrowth, further studies of removed porous coated prostheses should be made with adequate histological techniques so that the clinical significance of these cells can be better understood.

Aged↗
PubMed1991

Long-term sequelae of pelvis irradiation: histological and microradiographical study of a femoral head.

Despite the lack of radiological signs, a femoral head showed histological and microradiographical features of osteonecrosis, 54 years after massive irradiation of the right hip. Intertrabecular spaces were invaded by connectivo-vascular tissue with focal accumulation of mast cells, and several resorption foci were filled with mononucleated cells. Moreover, all the microradiographs showed peculiar hypercalcified lines, sometimes containing empty osteocytic lacunae, the origin of which is difficult to precise. This study suggests that massive irradiation of weight-bearing epiphyses may be responsible for particularly long-term hypovascularity, osteonecrosis and disturbed bone remodeling.

Female↗
PubMed1991

[Histomorphometry and photodensitometry of osteons with hypercalcified ring of human compact bone].

Osteons with hypercalcified ring were measured by photodensitometry and histomorphometry in the tibial diaphysis of 20 male and female subjects died from 23 to 93 years, the age-related decrease of cortical bone volume corresponded to wide Haversian canals. However, the osteons with a hypercalcified ring had a narrow canal. Moreover, the radio pacity of the hypermineralized ring was 20 to 30% higher than the adjacent parts of the osteon and the central part was nearly never less mineralized than the peripheric one. So the hypercalcified ring did not appear to be an arrest line. It may be suggested that it constitutes a sign of cortical bone senescence.

Absorptiometry, Photon↗
PubMed1991

[A microradiographic and histological study of a case of dentinogenesis imperfecta type I].

Four temporary teeth, extracted for periodontal infection reasons, from a 53-months-old child with osteogenesis imperfecta, have been coated in methyl metacrylate and prepared for microradiographic analysis and light microscopic study. The enamel and dentin of three teeth (51, 65 and 85) don't show any particularity, some how the cementum is remarkably thin. Pulp chambers was large and contain a great number of calcifications. Some of them present a radial striation around a radio-transparent center, and when coloured with blue of methylen, they revealed inflammatory or fibroblastic cells. The fourth tooth (55) shows a dentinogenetic overproduction which closed the major part of the pulp chamber. The dentin presents two rows of different aspect, separated with a calcified bond. The mantle dentin contains sinuous tubules with a type I arrangement of SIAR classification (1986). But, in the deepest dentin, they are very little size and joined together while approaching the center of the tooth and coast along cellular inclusions, pathognomonic sign of dentinogenesis imperfecta. The pulpal space not obliterated contains a calcification with radial and microlacunary aspect.

Child, Preschool↗
PubMed1990

Early development of the primitive cranial vault in the chick embryo.

The calcified tissues involved in the early morphogenesis of the cranial vault were studied by microradiographic analysis and histological techniques in 12 chick embryos on the 9th, 12th, and 14th days of incubation. On the 9th day, the frontal, parietal, and squamosal bones are comprised of a thin lamina of chondroid tissue deposited at a short distance from the fibers of the dura mater. Woven bone formation takes place in the calvarial mesenchyme only after the 12th day of incubation and occurs mainly on the external side of the chondroid primordium. The present data obviously indicate that the primitive desmocranium of the chick embryo, which is usually known to be formed by intramembranous ossification, consists first of chondroid tissue. This tissue represents thus the initial modality of skeletogenic differentiation within the cephalic mesenchyme of the cranial vault.

Animals↗
PubMed1990

Radiation osteitis of the clavicle following radiotherapy and radical neck dissection of head and neck cancer.

The bone alterations in the region of the clavicle (3 cases) are similar to those we have observed and described elsewhere in the skeleton i.e., the mandible, maxillary and ethmoid bones. Rarefaction is the result of three different types of bone destruction: osteoclasia, a kind of osteocytic osteolysis only observed after irradiation and obviously related with infection, and a pure demineralization of the osseous tissue by contact with pus. Reconstruction processes, although unable to prevent spontaneous fracture, are also present and correspond to islets of chondroid tissue surrounded by lamellar bone. However, these recently deposited calcified tissues are already necrotic since most of their lacunae are empty.

Clavicle↗
PubMed1989

Physical and histomorphological characteristics of iliac crest bone differ according to the grade of osteoarthritis at the hand.

The amount of cortical and trabecular bone was studied in 32 iliac crest necropsy specimens from women 60-75 years of age and examined according to the grade of osteoarthritis. Three different methods to evaluate bone mass were used: dual photon absorptiometry, physical assessment according to Archimedes' principle, and histomorphometry. Patients were divided into groups--with or without osteoarthritis--according to the presence of osteoarthritis on hand x rays. A significantly increased amount of cortical and trabecular bone mass was found in those who had osteoarthritis at the hands. Percent pure/crude bone volume and trabecular width were found to be increased with osteoarthritic grade, indicating that primary osteoarthritis is probably part of a generalized bone disease.

Absorptiometry, Photon↗
PubMed1989

Haversian bone remodelling in human fetus.

Haversian bone remodelling used to be considered an attribute of adult bone. In the present paper, typical haversian remodelling was observed in the humerus, ulna, radius, femur, tibia, fibula and 6th and 7th ribs as soon as the 24th week. Its aspect suggests an already ancient occurrence. Remodelling was found in the same bone pieces of the neonate as well as in the clavicle and the other ribs. Mechanical factors may be responsible for starting the remodelling but their effects could be modulated by metabolic needs. Other still unknown factors might play a role too.

Bone Development↗
PubMed1989

Microradiographic and histological study of the styloid process of the temporal bone.

In order to establish the mechanisms underlying the morphogenesis of the so-called 'elongated styloid process', a comparative microradiographic and histological study was performed on 19 long and short processes. Some morphological differences between short and long processes are noticed. Numerous partially calcified cartilaginous islets are observed within the trabecular bone of very long styloid processes or covering their tip. Calcified fibrous tissue or calcified fibrocartilage sometimes contributes to the thickening of enlarged styloid processes. But the growth of the process does not seem to be due either to calcification or to ossification of the stylohyoid ligament, as thought in the past. Mechanical stresses stretching the second branchial arch during the fetal development probably induce a variable involvement of the different parts of Reichert's cartilage in the morphogenesis of the styloid process. The so-called 'elongated styloid process' should thus be congenital. However, a further growth is still possible through the activity of the cartilaginous cap of the tip.

Aged↗
PubMed1989

Unusual variations of the vasculonervous elements of the human axilla. Report of three cases.

Three cases of multiple anomalies involving the vessels and nerves of the axilla are reported. The main common characteristic between them was the unilateral existence of a superficial brachial artery. The other arterial variations encountered were mostly represented by an assembling of some of the usual branches of the axillary artery in a common trunk which we called thoracdorso-subscapular trunk. In two cases, this trunk gave rise to the posterior circumflex humeral artery. Several nervous anomalies accompanied these atypical vascular patterns. The medial fasciculus of the brachial plexus was absent in one subject and an aberrant course of the brachial artery through the median loop was then observed. The two other cadavers showed variations in the distribution of the intermediate trunk and lateral fasciculus of the plexus. Embryologically, the persistence of various segmental arteries in the axilla seems to be responsible for the described anomalies. Otherwise, the present study indicates that the segmental origin of the axillary artery and its pattern of branching may determine the arrangement of the brachial plexus during the fetal development.

Aged↗
PubMed1989

[Preservation of the external branch of the superior laryngeal nerve in thyroid surgery. An anatomic study of 30 dissections].

The authors stress the importance of the external branch of the superior laryngeal nerve in laryngeal physiology, by noting the consequences of its section during thyroid surgery. A rigorous anatomical study carried out on 15 fresh cadavers, i.e. 30 superior laryngeal nerves, reproducing the conditions of thyroid surgery, allowed precision of the time during surgery when the external branch is at risk of being damaged, especially during sectioning of the vascular pedicle of the upper pole and at the time of separation of the thyroid pole from the laryngeal axis. The study considers the anatomical variations of the territory of the superior thyroid artery and the various technical problems that are posed in preserving the external branch of the nerve. In the light of their findings, the authors advise that this nerve axis should be identified before ligature of the upper thyroid pedicle; if the advice is not followed then the external branch of the superior laryngeal nerve may be damaged or sectioned in approximately 15% of cases.

Female↗
PubMed1989

Biomechanical characteristics of iliac crest bone in elderly women according to osteoarthritis grade at the hand joints.

Postmortem iliac crest trabecular bone specimens were tested in compression to determine their mechanical characteristics. Trabecular bone volume and width were evaluated by histomorphometry and radiographic grading of osteoarthritis (OA) of hand joints was also done. Patients were divided into 2 groups: no or low grade OA (Group 1) and manifest OA Grades II-IV (Group 2). From the 27 specimens tested (women 56-80 years old), 17 were in Group 1 and 10 in Group 2. Significant differences in stiffness (E), compressive strength, trabecular bone volume and trabecular width between the 2 groups were found. In the group with manifest OA, bone was significantly stiffer, had a significantly increased compressive strength value, a significantly higher trabecular bone volume and trabecular width, compared to the group with no or low OA grade. Significant correlations were found between elastic modulus and trabecular bone volume and width, and also between compressive strength and trabecular bone volume and width. Our findings support the hypothesis that the primary defect in OA is not in the articular cartilage but in the subchondral bone and that primary OA is part of a more general bone disease.

Aged↗
PubMed1989

Microradiographic study of bone and tooth alterations in bovine fluorosis.

Exostoses were found in the 5th rib, the cannon bone and the mandible of a 6-year-old fluorotic cow. Microradiographic alterations of lamellar bone in these skeletal items included both matrix modifications and mineralization troubles. In the incisors, the enamel was covered by a layer of cementum, and the dentine presented numerous giant tubules and accentuation of incremental lines. In the cementum, hypomineralized areas were located along the periodontal fibres.

Animals↗
PubMed1979

[Role of the condylar cartilage in mandibular growth (author's transl)].

Our purpose is to bring a contribution to a better understanding of the role played by the condylar cartilage in children's mandibular growth. In the newborn, microradiographical analysis of frontal (fig. 1, 2 and 3 A) or sagittal sections (fig. 4 A) has been used to locate trabecular bone of endochondrial origin. This trabecular bone contains islets of calcified cartilage easy to identify in the microradiograph (fig. 3 B) or in the section itself after methylen blue staining (fig. 4 B) and resulting from the activity of the condylar cartilage (fig. 4 C). At four month of age, the condylar cartilage is still in activity (fig. 5 A and 5 B). From both morphological and physiological points of vue, this work leads to suggest that the condylar cartilage must be compared to a growing epiphyseal nucleus or to a so-called infertile extremity of a small long bone rather than with a true growing cartilage.

Cartilage↗
PubMed1978

[Significance of the haversian number].

The aim of this work is to show that the measurement of the haversian number, i.e. the number of haversian canals per unit surface in transverse sections of compact bone, is not suffisantly accurate to determine the degree of compact bone remodelling. At the beginning of adult life, the aspect of the interstitial bone indicates that one haversian canal can correspond to one to four osteons (fig. 1). With increasing age, the diameter of the osteons decreases (fig. 2) and, consequently, for a same remodelled surface of bone the number of haversian canals varies greatly. In the elderly, the dissociation between osteon production and that of haversian canals increases (fig. 3). Moreover, the presence of large, irregular cavities which are difficult to assimilate to one or more haversian canals tends also to diminish, in terms of remodeling, the significance of the haversian number.

Adolescent↗