Magnesium whitlockite, a calcium phosphate crystal of special interest in pathology.

Whitlockite (in fact magnesium whitlockite) is a calcium orthophosphate crystal in which, in biological conditions, magnesium is partly substituted for calcium. Identified in X-ray or electron diffraction patterns, it occurs in physiological or pathological conditions at extra or intratissular sites, mainly in tissues of non-epithelial origin. In a range of pathological calcifications investigated by X-ray diffraction, we noted that whitlockite appeared to be frequently associated with apatite, particularly in "dystrophic calcifications" of tuberculous origin. These personal observations could be correlated with documented data in oral pathology (dental calculus, salivary stones, and dental caries). Whitlockite deposits have also been reported in non-infectious conditions, such as in aortic media, cartilage, and bone tissue. Whereas the formation of both apatite and magnesium whitlockite appears to be caused by the binding of their constituting ions with proteolipids, magnesium inhibits apatite originating from amorphous calcium phosphate to the benefit of whitlockite formation. Possibly, the development of magnesium whitlockite may provide an interesting marker for magnesium metabolism. Further studies linking histology to crystallography might relate the crystal to issues, such as tuberculous calcifications or diseases of bone tissue, and might be useful for potential diagnostic orientation.

Metastatic carcinoma of presumed prostatic origin in cremated bones from the first century A.D.

A cremated pelvis dating from the first century A.D. showed evidence of osteosclerotic metastasis, presumably secondary to prostate carcinoma. The case demonstrates the importance of microradiography in palaeopathology as well as some of the structural changes seen in cremated bone.

A historic skeleton with osteomyelosclerosis.

A case of osteomyelosclerosis (ie, an advanced stage of the myeloproliferative disorder named myelofibrosis) was reported in an adult male skeleton dating from the 17th or 18th century. The diagnosis was founded on the presence of a newly formed microspongiosa and a thickening of the preexisting trabeculae. A subperiosteal thickening of the cortical bone was also noted.

Skeletal fluorosis: histomorphometric findings.

Histomorphometric analysis of undecalcified sections was performed in transiliac biopsy cores taken from 29 patients (16 men, 13 women, aged 51 +/- 17 years) suffering from skeletal fluorosis due to chronic exposure to fluoride. The origin of the exposure, known in 20 patients, was either by water (endemic or sporadic), or industrial, or in a few cases iatrogenic. Measured on calcified bone using a specific ion electrode, bone fluoride content was significantly high in each specimen (mean +/- SD: 0.79 +/- 0.36% of bone ash) as compared to control values (less than 0.10%). The radiologically evident osteosclerosis observed in each patient was confirmed by the significant increase of cancellous bone volume (40.1 +/- 11.2 vs. 19.0 +/- 2.8% in controls, p less than 0.0001). There were significant increases in cortical width (1292 +/- 395 vs. 934 +/- 173 microns, p less than 0.0001) and porosity (14.4 +/- 6.4 vs. 6.5 +/- 1.7%, p less than 0.002), but without reduction of cortical bone mass. Osteoid parameters were significantly increased in fluorotic patients. The increase in cancellous osteoid perimeter was almost threefold greater than that noted in cancellous eroded perimeter. The fluorotic group had a greater number of osteoblasts than controls, with a very high proportion of flat osteoblasts. In 15 patients doubly labeled with tetracycline, the mineral apposition rate was significantly decreased, while mineralization lag time significantly increased. Bone formation rate and adjusted apposition rate were significantly decreased in skeletal fluorosis. Cancellous wall width was normal in fluorosis but the formation period and active formation period were significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Topographical distribution of fluoride in iliac bone of a fluoride-treated osteoporotic patient.

The electron microprobe was used to display the topographical distribution pattern of fluoride (F) at the microscopical level in the iliac bone of an osteoporotic patient treated with fluoride. Composite x-ray image of F K alpha emission revealed a high concentration of fluoride in the periosteal and endosteal bone layers, in the cancellous bone, and in certain osteons, which corresponded to the bone formed during the period of fluoride treatment. Fluoride was also concentrated around the Haversian canals in the vicinity of the capillary blood vessels by a diffusion process. Morphometric analysis showed that more cancellous bone than cortical bone is formed.

Skeletal fluorosis: histomorphometric analysis of bone changes and bone fluoride content in 29 patients.

Bone fluoride content (BFC) was measured and histomorphometric analysis of undecalcified sections was performed in transiliac biopsy cores from 29 patients (16 men, 13 women, aged 51 +/- 17 years) suffering from skeletal fluorosis due to chronic exposure to fluoride. The origin of the exposure, known in 20 patients, was either hydric (endemic or sporadic) or industrial, or in a few cases iatrogenic. Measured on calcined bone using a specific ion electrode, BFC was significantly high in each specimen (mean +/- SD; 0.79 +/- 0.36% on bone ash). The radiologically evident osteosclerosis observed in each patient was confirmed by a significant increase in cancellous bone volume (40.1 +/- 11.2% vs. 19.0 +/- 2.8% in controls, p less than 0.0001). There were significant increases in cortical width (1292 +/- 395 mcm vs. 934 +/- 173 mcm, p less than 0.0001) and porosity (14.4 +/- 6.4% vs. 6.5 +/- 1.7%, p less than 0.002), but without reduction of cortical bone mass. Cancellous osteoid volume and perimeter, as well as width of osteoid seams, were significantly increased in fluorotic patients. The increase in cancellous osteoid perimeter was almost three-fold greater than that noted in cancellous eroded perimeter. In 15 patients doubly labeled with tetracycline, the mineral apposition rate was significantly decreased, mineralization lag time was significantly increased. The fluorotic group had a greater number of osteoblasts than controls with a very high proportion of flat osteoblasts. The ultrastructural characteristics reflecting the activity of the bone cells were clearly visible on electron microscopy. Bone formation rate and adjusted apposition rate were significantly decreased in skeletal fluorosis. On stained sections and microradiographs, bone tissue showed typical modifications for skeletal fluorosis (linear formation defects, mottled bone). The volume of cancellous interstitial mineralization defects and the proportion of mottled periosteocytic lacunae were markedly increased in skeletal fluorosis. These two parameters were significantly correlated together but neither of these was significantly correlated with BFC. Renal function did not significantly influence the changes in BFC and histomorphometry of fluorotic patients. Skeletal fluorosis is thus characterized by an unbalanced coupling in favor of bone formation, and a great number of osteoblasts with a high proportion of flat osteoblasts.(ABSTRACT TRUNCATED AT 400 WORDS)

Biophysical study of bone mineral in biopsies of osteoporotic patients before and after long-term treatment with fluoride.

Crystallographic characteristics of bone mineral were examined in a group of 60 osteoporotic patients before and after 3 to 6 years of fluoride therapy. The age of the mineral was evaluated by means of X-ray absorption, as degree of mineralization of bone tissue (MDBT). Crystallinity was evaluated by measuring both X-ray diffraction line broadening, beta (31.0) and beta (00.2), and the crystallinity index (CI) by infrared spectrometry. The a and c unit-cell parameters were determined by powder X-ray diffraction. Bone fluoride content was measured by specific electrode. Patients were divided in two groups according to MDBT before treatment: one group with MDBT values less than or equal to mean value; another group with MDBT values greater than mean value. In the first group, trabecular bone volume (TBV) did not change significantly during therapy. In the second group, an increase of TBV was observed. Osteoporoses can then be distinguished, on MDBT criterion, between osteoporosis with hypermaturated mineral and osteoporosis with hypomaturated mineral. The MDBT before treatment permits one to predict the effect of fluoride therapy on TBV. In the two groups there was a significant increase in bone fluoride content between the onset and the end of treatment. Bone fluoride content increased linearly during therapy without any plateau effect. Crystallographic modifications induced by fluoride explain the mechanical and chemical improvement of bone.

Ultrastructural study of the long-term development of two experimental cutaneous calcinoses (topical calciphylaxis and topical calcergy) in the rat.

Skin calcification induced by topical calciphylaxis was provoked by a subcutaneous injection of iron chloride in rats previously sensitized by dihydrotachysterol. A cutaneous topical calcergy was induced by an injection of potassium permanganate. An electron-microscopical study of the long-term evolution of both these models of calcification was made. After the initial stages, mineralization of the connective tissue continued by a secondary nucleation process without matrix vesicles. The mineral composed of needle-like structures, apatite in nature, was mainly deposited between and around collagen fibrils, and showed various arrangements in calcified plaques. Intrafibrillar calcification was rarely observed and appeared only in the later stages. The extension of calcified deposits then stopped. Finally, there was a fragmentation of the mineralized area which was progressively surrounded by uncalcified collagen fibrils. A demineralization process, caused by cells such as macrophages and multinucleated giant cells, rather than a resorption of the calcified deposits, was noted. It is important to emphasize that, in both models of ectopic calcification, an evolution toward ectopic ossification was never observed, which is perhaps due to the absence of extensive resorption mechanisms.

Femoral unicameral bone cyst in a medieval child. Radiological and pathological study.

Radiological, macroscopic and microscopic study of a unicameral cyst in the femur of a child of the early Middle Ages. The changes are similar to those known for unicameral cyst today.

[Histomorphometric profile of bone fluorosis induced by prolonged ingestion of Vichy Saint-Yorre water. Comparison with bone fluorine levels]. / Profil histomorphométrique de la fluorose osseuse induite par l'ingestion prolongée d'eau de Vichy Saint-Yorre. Comparaison avec le taux de fluor osseux.

Nine transiliac bone biopsies from 7 patients with skeletal fluorosis due to prolonged ingestion of often high quantities of Vichy Saint-Yorre water were analyzed. Four of these patients also suffered from a chronic renal failure. A histomorphometric study was possible in 8 out of the 9 biopsies. The measurement of bone fluoride content, and a microradiographic examination, were performed on all bone samples. The radiologically evident osteosclerosis observed in each patient was confirmed by the significant increase of trabecular bone volume. Furthermore, the osteoid surfaces were very extended but the thickness of osteoid seams was normal in 6 out of 8 cases. Two biopsies demonstrated a morphological evidence of osteomalacia with abnormally thick osteoid seams. Calcification rate, measured in one of these 2 cases after tetracycline double labeling, was extremely low (less than 0.20 micron/d). The bone fluoride content was significantly high in each specimen (greater than 0.40 bone ash%) and correlated with relative osteoid volume (r' = 0.91) and thickness index of osteoid seams (r' = 0.83). Histologically, bone tissue showed modifications classically reported in the various types of skeletal fluorosis (formation defects, mottled bone with mottled periosteocytic lacunae). In conclusion, the prolonged administration of Vichy Saint-Yorre water containing 8.5 mg of fluoride ion per liter, provokes a skeletal fluorosis. This intoxication appeared very quickly if the patient suffered from an even mild renal failure. Once again, it is shown that a disturbed renal function predisposes to an excessive retention of fluoride.

[Multidisciplinary study of the prolonged treatment of involution osteoporosis using sodium fluoride with calcium, phosphate and vitamin D]. / Etude multidisciplinaire du traitement prolongé de l'ostéoporose d'involution par le fluorure de sodium, avec calcium, phosphate et vitamine D.

A multidisciplinary study on the prolonged treatment of involution osteoporosis with fluoride was performed on a homogeneous population of 31 women aged 51 to 75 years (mean 64 years). The selection criteria were the following: significant backache, vertebral compression fractures on X-rays, bone biopsy evidence of osteoporosis, and absence of other risk factors after a complete workup. The patients were treated for a period of 3 to 6 years (mean 4 years) with daily doses of 30 mg (10 mg 3 times) fluorides ion associated during the last 3 years with 500 mg calcium twice daily, 750 mg phosphate and 1000 units vitamin D daily. The study demonstrated a favourable effect of the treatment on the backache and that it was well tolerated in the majority of cases, the side effects being intermittent osteo-articular pains of the lower extremities due to the fluoride in 9 patients, and gastric intolerance to the phosphate in 7. X-ray follow-up showed slowing of the vertebral compressions after the first year of treatment, but no effect on fractures of the extremities. There was no evidence of alterations in parameters of mineral and bone metabolism, and in endocrine, hepatic, renal or hematological assays. Histomorphometric and biophysical examination of biopsies indicated that, although there was no significant increase in the quantity of mineralized bone under the treatment, there was a very significant improvement in the crystallinity of the mineral substance, thus enhancing the quality of the bone tissue and its resistance to pressure. This study is the first in which a catamnesis of the patients was undertaken, 28 of them having received a clinical and radiological examination 2 years after the end of therapy: a favourable evolution was observed in most of the cases, both in those patients treated for a period of 3 years and in those whose treatment had lasted for a longer period.

Bilateral fractures of femoral neck in patients with moderate renal failure receiving fluoride for spinal osteoporosis.

Two patients with moderate renal failure sustained spontaneous bilateral hip fractures during treatment with fluoride, calcium, and vitamin D for osteoporosis. They had been taking sodium fluoride (40-60 mg/day) for 11 and 21 months, respectively. Histological examination of a specimen of the bone showed severe fluorosis in the first case, and quantitative analysis of bone showed osteomalacia and skeletal fluorosis in the other case. These abnormalities were considered to be the consequence of excessive retention of fluoride due to renal insufficiency. As bilateral femoral neck fractures are very rare these data suggest a causal link between fractures and fluoride in patients with renal failure. Thus fluoride should be given at a lower dosage, if at all, to patients with even mild renal failure.

Presumed calcified leiomyoma of the uterus. Morphologic and chemical studies of a calcified mass dating from the Neolithic period.

An isolated, calcified mass was found among human skeletal remains that were approximately 5,000 years old. A systematic study was undertaken that included histologic examination (stained sections, polarized light microscopy, microradiographs, and electron microscopy), x-ray diffraction, and concentrations of hydroxyproline and fluorine. The results allowed us to eliminate the diagnoses of bone tissue and intracavitary deposits such as bezoar and calculi. The mass consisted of calcified tissue, with a collagenous organic matrix and deposits of apatite, and it most probably was a calcified uterine leiomyoma.

Physical and chemical analyses of the mineral substance during the development of two experimental cutaneous calcifications in rats: topical calciphylaxis and topical calcergy.

In subcutaneous calcinoses induced in rats by topical calciphylaxis and topical calcergy, the ultrastructural aspects related to the evolution of calcified deposits were previously described. In the present study by means of X-ray diffraction, infrared spectrometry and electron spin resonance, different biophysical analyses are performed on the mineral substance deposited during development of calciphylaxis and calcergy. A rapid evolution of the calcium phosphate deposits into hydroxyapatite was noticed along the first 20 days of the calcinoses; from then, there is no important modification even at the later stages, and the characteristics of the mineral substance are mostly similar to that of bone tissue. The concentration of trace elements such as Mg2+ and Fe2+, is found higher in cutaneous calcinoses than in bone tissue.

Ultrastructural and cytochemical aspects of the initial phases of an experimental cutaneous calcinosis (calcergy) in the rat.

In rats a subcutaneous injection of KMnO4 leads to the calcification of the connective tissue. During mineral deposition, both intra- and extracellular changes are observed in the connective tissue. The intracellular phase is characterized by the formation of intramitochondrial granules and cytoplasmic vesicles, both in fibroblastic and extrinsic cells. In the extracellular phase, numerous heterogeneous matrix vesicles appear in the extracellular matrix. At the same time, globular particles which are resistant to microincineration, are observed between the collagen fibrils. The mineralization of the extracellular matrix takes place in two stages. The first stage comprises the appearance of needle-like structures and round aggregates. The needle-like structures are observed occasionally in the matrix vesicles and often in the extracellular matrix where they appear isolated or diverging from a central point. The round aggregates, composed of dense particles, are seen in the ground substance between the collagen fibrils. The second stage is characterized by a progressive mineralization of the collagen fibrils and the elastic fibers, without formation of extended calcified plaques.

Mineral substance of bone tissue and of experimental cutaneous calcinosis in rats: chemical analysis and ESR study.

The evolution of the mineral constituents of subcutaneous calcinosis induced in rats by topical calciphylaxis was studied by the method of quantitative chemical analysis, and after treatment with excited gases by electron spin resonance (ESR) analysis. Chemical data show that the genesis of the subcutaneous calcinosis does not significantly alter the concentration of Ca, P, F, CO3, Mg, and Fe in the mineral phase of the femoral bone of calciphylactic rats. In the calcinosis an important increase of the fluoride concentration is noticed in function of the time after challenging. There is also a high concentration of Mg2+ ions in the early stages of the experimental calcification. Iron injected for the challenging is continuously present in the calciphylactic tissue after this treatment. This suggests that subcutaneous calcinosis might be a means of fixing certain heavy metal ions. After treatment with excited gases, the proportions of the trapped CO33- and O3- radicals are of the same order of magnitude in calciphylactic tissue after 12 days and observations in bone mineral. These suggest that after 12 days the mineral of the calciphylactic tissue has a crystalline state close to that of bone.