Distribution of hyaluronan in the epiphysial growth plate: turnover by CD44-expressing osteoprogenitor cells.
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In the present study, we have examined the distribution of both hyaluronan and its receptor, CD44, during the process of endochondral ossification in the mouse tibia. Histochemical staining revealed that a large amount of hyaluronan was present in the lacunae located in the zone of hypertrophy, but it was greatly reduced or absent from the zone of erosion. In addition, hyaluronan was present in the cytoplasm of osteoprogenitor cells located in the zone of erosion. These cells also expressed CD44 on their surfaces, as revealed by double-label immunohistochemistry. These results suggested that the osteoprogenitor cells may use CD44 to bind and internalize hyaluronan, and subsequently degrade it with lysosomal enzymes. To test this possibility, we examined the human cell line, MG-63, which closely resembles osteoprogenitor cells. These cells produced several different forms of CD44, as determined by western blotting (85, 116 and 150 kDa). In addition, the binding of isotopically labeled hyaluronan to detergent extracts of these cells was blocked by a monoclonal antibody to CD44. Similarly, the degradation of hyaluronan by these cultured cells was also inhibited by a monoclonal antibody to CD44. To determine if these cells could remove hyaluronan from the growth plate, the cells were cultured directly on top of thin sections of the epiphysial region of long bone. After 16 hours, the sections were stained for hyaluronan. The MG-63 cells removed significant amounts of hyaluronan present in the zone of hypertrophy, and this effect was blocked by an excess of soluble hyaluronan and by a monoclonal antibody to CD44.(ABSTRACT TRUNCATED AT 250 WORDS) (+info)
Sclerosteosis in a Spanish male: first report in a person of Mediterranean origin.
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We report the first observation of sclerosteosis in Spain. To the best of our knowledge, this is the first case of sclerosteosis in a person of Mediterranean origin with no known Dutch ancestors. He has the characteristic phenotype of the disease with right facial nerve palsy and syndactyly and the typical radiological features, including generalised bone sclerosis and cortical widening of the tubular bones. (+info)
Physeal distraction and cell proliferation in the growth plate.
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We studied the cellular response to physeal distraction in the growth plates of skeletally immature rabbits. We used a new method of labelling and detection of proliferating cells with bromodeoxyuridine (BUdR) and an anti-BUdR antibody. The application of an external fixator but no distraction force produced no changes in the growth plates. After five days of distraction at a maximum force of 20 N, the growth plate became thicker, mainly because of an increase in the number of hypertrophic chondrocytes, but there was no evidence of increased cell proliferation. Recent fractures were seen at the junction of growth plate and metaphysis but the increase in bone length was insignificant. After ten days of distraction at the same maximum force, the chondrocyte columns had become disorganised and cell proliferation was significantly decreased. There was an increase in bone length due to distraction of the fracture gap. In this model, physeal distraction did not stimulate cell proliferation, but actually inhibited it. The apparent increase in growth-plate thickness produced by distraction is not due to increased cell production, but results from inhibition of endochondral ossification and the consequent accumulation of hypertrophic chondrocytes. Any growth after distraction depends on the ability of growth-plate chondrocytes to divide. The decrease in proliferative activity which we found after ten days of distraction suggests the need for caution in the use of such procedures in young children. (+info)
Enthesopathy of the patellar tendon insertion associated with isotretinoin therapy.
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A 99mTc-MDP bone scan performed on a 34-yr-old female for suspected osteomyelitis of the proximal tibia revealed focally increased activity in both tibial tuberosities due to enthesopathies secondary to chronic isotretinoin therapy. Physicians should be aware that isotretinoin therapy can cause abnormal bone scans and not mistake these abnormalities for other diseases such as osteomyelitis. Second, bone scans may be helpful in diagnosing and following isotretinoin bone toxicity. (+info)
Continuous positive airway pressure is effective in treating upper airway oedema.
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The case of a patient with diffuse idiopathic skeletal hyperostosis (DISH) and upper airway oedema, is described. The patient presented with alveolar hypoventilation and obstructive apnoeas during sleep. Intravenous steroids (methylprednisolone, 160 mg.day-1) for 5 days did not reduce the oedema. However, it was rapidly reversed by the use of nasal continuous positive airway pressure (nCPAP). In addition, daytime pulmonary gas exchange was improved and sleep apnoea abolished. This beneficial effect made tracheostomy unnecessary. This case report suggests that CPAP can be a potentially useful therapeutic alternative to tracheostomy in the clinical management of upper airway oedema. (+info)
Proliferative bone lesions in rats fed a diet containing glucocorticoid for up to two years.
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A glucocorticoid was fed in the diet to 50 Sprague-Dawley rats/sex at 0, 0.03, 0.06, 0.12, 0.25, 0.50, and 1.0 mg/kg/day for up to 2 yr. A total of 1,400 rats were examined. Bone neoplasms (5 osteosarcomas and 2 osteomas), involving the head, occurred in 7 males that were fed the test compound at the highest dose (0.25 mg/kg) with long-term survivors. One osteoma and 1 hyperostotic lesion were seen in 2 males receiving lower doses (0.06 mg/kg and 0.12 mg/kg, respectively); 1 female rat that received the highest dose (1 mg/kg) had an osteosarcoma. The results suggest, but do not confirm, a relationship between glucocorticoid exposure and bone proliferations in male Sprague-Dawley rats. Other proliferative bone lesions included hyperostosis in a 0.12-mg/kg male, osteoma in a 0.06-mg/kg male, and osteosarcoma in 1 female at 1.0 mg/kg. The purpose of this report is to characterize the incidence and morphology of primary bone proliferative lesions found in rats of 1-yr glucocorticoid toxicity and 2-yr carcinogenicity studies conducted in our laboratory. (+info)
Spondylodiscitis in SAPHO syndrome. A series of eight cases.
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OBJECTIVE: To determine the frequency, clinical features, and radiological and bone scintigraphic changes of spondylodiscitis in patients with SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis). METHODS: The study was retrospective. Data from patients with the diagnostic criteria of SAPHO syndrome were analysed for clinical features, biological data (HLA B antigen), and pelvic and spine x rays. Spine computed tomography (CT) or magnetic resonance imaging (MRI) were also examined in some cases. RESULTS: 25 patients with a diagnosis of SAPHO were seen since 1985. Eight had spondylodiscitis. These included five with palmoplantar pustulosis, one with pustular psoriasis, one with psoriasis vulgaris, and one with chronic recurrent multifocal osteomyelitis without skin disease. The skin lesion occurred before the spondylodiscitis in four cases. Chest wall involvement was observed in four cases and sacroiliac joint lesions only in the case with osteomyelitis. HLA B27 was always negative and HLA B8 was found in four cases. Radiological findings consisted of erosive or sclerosing remodelling of endplates with a narrowed disc space; a reduced height of the vertebral body was also observed in some cases. These spinal lesions occurred in the three vertebral segments. Multiple sites of spondylodiscitis in the same patient were common. Bone scan showed mildly increased uptake and CT and MRI were useful for detecting signs of infection such as abscess. Enhanced signals on T2 weighted sequence or after injection of gadolinium were often observed. Follow up study of most of these patients suggests that the prognosis of spondylodiscitis in the SAPHO syndrome is favourable. CONCLUSIONS: Despite few description in the literature, spondylodiscitis in the SAPHO syndrome is common (32% in this series). These radiological findings are similar to the discovertebral changes of spondylodiscitis in ankylosing spondylitis, thus giving support to the relations between SAPHO syndrome and spondylarthropathies. However, this does not mean that the pathogenic mechanisms are the same in these two conditions. (+info)
Thallium-201 single photon emission computed tomography imaging of meningioma cells in hyperostosis.
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Hyperostosis is a well-known bony reaction associated with meningioma. However, it is difficult to determine preoperatively whether meningioma cells have invaded the bone, and if so, the extent of tumor invasion. Preoperative thallium-201 chloride single photon emission computed tomography (201Tl SPECT) was performed in four patients with meningioma and hyperostosis. The presence of meningioma cells in bone biopsy specimens was also investigated using standard histological techniques. 201Tl SPECT revealed increased uptake in three of the four patients. Biopsy specimens from these three patients revealed invasion of the bony lesions by meningioma cells in accordance with the 201Tl SPECT findings. 201Tl SPECT found no abnormal uptake in the other patient, in which there was also no histological evidence of tumor invasion of bone. Preoperative 201Tl SPECT can provide information on bone invasion by meningioma, which will facilitate preoperative planning of the extent of bony resection required at meningioma surgery. (+info)