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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Radiologic assessment of the stage and treatment response of rheumatoid arthritis (RA) is based on the presence of bone erosions, joint-space narrowing, and osteoporosis. Most radiologic methods for staging RA lack interobserver correlation and are time consuming. Magnetic resonance (MR) imaging provides excellent depiction of soft-tissue abnormalities of the joints affected by RA, which allows detection of early changes. Nineteen joints of 17 patients with RA were studied with surface-coil MR imaging. Measurable abnormalities demonstrated by MR imaging but not clearly seen on plain radiographs included bone erosions, joint effusion, synovial sheath effusion, and cartilage irregularity and thinning. Seven patients of this group underwent MR imaging before and after 6 months of gold therapy. Four patients had significant interval changes on MR images that were not seen on plain radiographs. MR imaging may become a sensitive and objective method for quantitative assessment of the joint changes of RA.
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PMID:Rheumatoid arthritis: MR imaging manifestations. 362 62

To investigate the pathogenesis of osteoporosis in male hypogonadism we have investigated a heterogeneous group of 13 men with hypogonadism: 7 men (median age 60, range 31-79) with two or more vertebral crush fractures and 6 men (median age 61.5, range 28-76) without vertebral fractures. The group with crush fractures had trabecular and cortical osteoporosis as assessed by Singh grade, iliac crest trabecular bone volume, and metacarpal cortical area/total area. This was accompanied by an altered trabecular architecture with a reduction in number of trabeculae but no change in trabecular width, which contrasts with age-related bone loss in men where there is no reduction in trabecular number but thinning of trabeculae. The fracture group had significantly lower plasma 1,25-dihydroxyvitamin D [1,25(OH)2D] concentrations than the nonfracture group, and this was associated with malabsorption of calcium. Irrespective of the presence or absence of osteoporosis, treatment with testosterone led to a significant increase in total and free plasma 1,25(OH)2D and an improvement in calcium absorption measured with radiocalcium and by balance techniques. In addition, urine biochemistry, metabolic balance studies, and bone biopsy suggest that skeletal retention of calcium and bone formation are increased by testosterone treatment. We conclude that male hypogonadism causes both cortical and trabecular osteoporosis and altered trabecular architecture. A major risk factor for the development of osteoporosis is reduction in plasma 1,25(OH)2D, leading to malabsorption of calcium and reduced bone formation.
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PMID:Osteoporosis in hypogonadal men: role of decreased plasma 1,25-dihydroxyvitamin D, calcium malabsorption, and low bone formation. 376 4

Thinning of the upper cortex of the clavicle, measured on a standard chest radiograph, may help in the diagnosis of osteoporosis. No precise level at which osteoporosis occurs can be given, but a reading of 1.5 mm. or under is indicative of osteoporosis, while a smaller incidence is associated with readings of 2 mm. and above. There is significant correlation between thinning of the clavicular cortex and other radiological indications of osteoporosis. Thinning may occasionally point to unsuspected bone disease, in osteomalacia as well as in osteoporosis. As chest radiographs are taken in a high proportion of both outpatients and inpatients, the method has a wide applicability.
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PMID:Width of clavicular cortex in osteoporosis. 576 59

The radiological picture of the amputation stump for osteosarcoma was revised on 57 cases, in which a follow-up after surgery was possible for at least 4 months, with a maximum of over 12 years. In 51/57 cases (89%) no recurrency was observed; in 6/57 cases (11%) a local neoplastic recurrency was confirmed on clinical and histopathological grounds. The usual aspects of late modifications induced by surgery is osteoporosis of the residual bone, which may assume a geographical pattern, with thinning of the stump apex and formation of a periosteal spur directed towards to soft tissues. The typical pattern of the locally recurrent osteosarcoma is that of an infiltrating soft tissue mass with bone erosion and irregular flake-like calcifications. All these signs are evaluated and discussed in order to give a practical guideline to the differential diagnosis between surgery-induced modifications and local neoplastic recurrencies.
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PMID:[Radiographic evaluation of the amputation stump in osteosarcoma]. 659 80

We devised a new method for examining the structural changes that occur in trabecular bone in aging and in osteoporosis. With simultaneous measurement of total perimeter and bone area in thin sections, indirect indices of mean trabecular plate thickness (MTPT) and mean trabecular plate density (MTPD) can be derived, such that trabecular bone volume = MTPD X MTPT. MTPD is an index of the probability that a scanning or test line will intersect a structural element of bone, and is the reciprocal of the mean distance between the midpoints of structural elements, multiplied by pi/2. We applied this method to iliac bone samples from 78 normal subjects, 100 patients with vertebral fracture, and 50 patients with hip fracture. The reduction in trabecular bone volume observed in normal subjects with increasing age was mainly due to a reduction in plate density, with no significant decrease in plate thickness. The further reduction in trabecular bone volume observed in patients with osteoporotic vertebral fracture was mainly due to a further reduction in plate density. There was a relatively smaller reduction in plate thickness that was statistically significant in males but not in females. Only in patients with hip fracture did trabecular thinning contribute substantially to the additional loss of trabecular bone in osteoporosis relative to age. These data indicate that age-related bone loss occurs principally by a process that removes entire structural elements of bone; those that remain are more widely separated and some may undergo compensatory thickening, but most slowly become reduced in thickness. We propose that the process of removal is initiated by increased depth of osteoclastic resorption cavities which leads to focal perforation of trabecular plates; this is followed by progressive enlargement of the perforations with conversion of plates to rods. The resulting structural changes are more severe in osteoporotic patients than in normal subjects, but have been completed in most patients before they develop symptoms.
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PMID:Relationships between surface, volume, and thickness of iliac trabecular bone in aging and in osteoporosis. Implications for the microanatomic and cellular mechanisms of bone loss. 663 May 13

Bone histology, bone mineral content, and calcium absorption were evaluated in 10 patients with primary biliary cirrhosis and osteopenia, before and after 1 yr of treatment with oral 25-hydroxycholecalciferol. Before treatment, quantitative histomorphometric analysis of full-thickness iliac crest bone biopsy specimens with double-tetracycline labeling demonstrated that 9 of 10 patients had osteoporosis. None had osteomalacia. Fasting intestinal calcium absorption correlated well with trabecular bone volume (r = 0.85). Bone mineral content measured by 125I-photon absorption was low in 6 of 10 patients, and it correlated poorly with iliac crest trabecular bone volume. After 1 yr of treatment with oral 25-hydroxyvitamin D3, bone mineral content fell in all 8 patients who were restudied. Iliac crest trabecular bone volume increased in 3 patients, 2 of whom had the greatest pretreatment impairment in calcium absorption, but fell in 5. Bone fractures continued to occur in 3 of 5 patients who were alive after 1 yr and developed for the first time in a sixth patient. We conclude that 25-hydroxyvitamin D3 is ineffective in reversing the bone thinning in the majority of primary biliary cirrhosis patients, but it may be helpful in a few selected patients.
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PMID:Osteoporosis in primary biliary cirrhosis: effects of 25-hydroxyvitamin D3 treatment. 707 48

In search for x-ray signs of skeletal involvement specific for each type of hereditary tubulopathies, the authors analyze the results of clinical and x-ray examinations of 144 children aged 2 to 16. Vitamin D-resistant rickets which was diagnosed in 83 children was found to be characterized by varus deformations of the lower limb bones, by systemic osteoporosis of various degrees with hypertrophy of the osseous beams in the epimetaphyseal compartments and accelerated bone age. In renal tubular acidosis diagnosed in 28 children the most typical findings were valgus deformation of the lower limb bones, an appreciable deceleration of bone age, systemic osteoporosis with thinning of osseous beams, the degree of bone deformation being the minimal or moderate. In 20 children with the de Toni-Debre--Fanconi disease the most frequent finding were valgus deformations of the lower limb bones, osteoporosis with drastic thinning of osseous beams unrelated to the degree of deformations and deceleration of bone age. Vitamin D-dependent rickets diagnosed in 13 children was characterized by varus deformations of the lower limb bones, hypertrophic osteoporosis, and normal parameters of bone age. Hence, our study demonstrated the possibility and high reliability of x-ray differential diagnosis of various forms of hereditary tubulopathies in children.
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PMID:[Radiographic criteria of differential diagnosis of hereditary tubulopathies in children]. 765 47

In normal individuals, peak bone mass is reached at 25-35 years of age and thereafter a decrease with age occurs in both sexes. An acceleration in the bone loss is observed in normal women at menopause. Because of either a low peak bone mass or a more pronounced bone loss with age or during menopause, some individuals reach the fracture threshold for bone mass and suffer spontaneous fractures. To understand the mechanism behind age related bone loss, one must recognize that bone in adults is continually renewed through internal reorganization by which bone is turned over by localized osteoclastic resorption followed by osteoblastic formation (remodelling). A total reconstruction of the resorptive and formative phase can be performed by histomorphometric methods applied on iliac crest bone biopsies and thereby give a detailed description of resorptive and formative events. By the remodelling process bone may be gained or lost by 3 mechanisms: 1. Reversible bone loss depending on the magnitude of the remodelling space, which is the amount of bone resorbed and not yet reformed during the remodelling sequence. 2. Irreversible thinning of the trabeculae due to a negative balance at the remodelling site. 3. Irreversible loss of whole trabecular elements caused by deep resorption lacunae perforating the trabecular plates. Although the bone mass is significantly reduced by 20-30% in postmenopausal osteoporotic patients with vertebral fractures compared with normal controls a substantial overlap exists. Our study and several other studies have shown that beside the slight reduction in trabecular bone volume significant differences in microstructure exist between osteoporotic patients and normal controls. These changes in structure are probably a consequence of trabecular plate perforations. Although osteoporotic patients in term of remodelling (bone turnover) are a very heterogeneous group, with patients having a low, normal and even increased bone turnover, no signs in the ongoing remodelling process was found in our study that could explain why these patients had developed osteopenia and changes in the trabecular structure. The bone balance was in the patients slightly negative but no different from the balance found in normal controls. The cause of osteoporosis may therefore be factors occurring earlier in life, maybe long before the manifestation of the disease. Bone mass at any age is the result of two variables--the amount of bone achieved during growth and the subsequent rate of bone loss. Peak bone mass at maturity may be of great importance in determining the risk of developing symptomatic osteoporosis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Bone histomorphometry in the pathophysiological evaluation of primary and secondary osteoporosis and various treatment modalities. 766 70

To understand the structural changes accompanying estrogen deficiency-induced bone loss, we examined the temporal changes in cancellous bone structure in an animal model of postmenopausal osteoporosis. Matured rats were subjected to bilateral ovariectomy, and groups of eight animals were sacrificed at 5-day intervals. Histomorphometric and trabecular strut analyses of the excised proximal tibia, and bone mineral density measurement of the distal femur, were used to investigate cancellous bone loss as a result of estrogen deficiency. There was an immediate increase in bone turnover after ovariectomy, as evidenced by rapid increases in osteoclast surface (400%) and bone formation rate (270%). The resultant time-dependent decrease in cancellous bone volume was highly related to a decrease in trabecular plate number and connectivity parameters, but was not related to the thickness of the remaining cancellous plates. Our results suggest that cancellous bone loss due to estrogen deficiency is the result of decreased connectivity, likely due to osteoclast perforation of trabecular plates, followed by complete removal of the plate without prior generalized thinning.
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PMID:Temporal changes in cancellous bone structure of rats immediately after ovariectomy. 774 75

Osteoporosis, which is correlated with low bone mass and increased bone fragility, is responsible for about 1.2 million fractures per year in the United States. We have used the three-dimensional (3-D), X-ray tomographic microscope to image the trabecular bone architecture of the proximal tibias of six Sprague-Dawley rats in vivo. Three of these rats were then ovariectomized to induce estrogen depletion, and three remained as controls. Five weeks later, the tibias were reimaged. The ovariectomized rats lost approximately 65% of their trabecular bone volume as compared with an insignificant change in the control rats. The connectivity density of the trabecular bone, as measured by the Euler characteristic, was linearly correlated with trabecular bone volume, even in the ovariectomized rats. Hypoestrogenemic bone loss manifested itself in greatly reduced connectivity and fewer trabecular elements, but not in thinning of trabeculae. The ability to microscopically image sequential changes in the 3-D architecture of trabecular bone in vivo will allow exploration of the earliest stages of hypoestrogenemic bone loss and to more rapidly test the effectiveness of new clinical treatments for this major public health problem.
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PMID:In vivo, three-dimensional microscopy of trabecular bone. 775 6


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