Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aging and menopause are the two main determinants of osteoporosis, a rarifying osteopathy due to bone loss. Type I osteoporosis observed in post-menopausal women is characterized mainly by trabecular bone loss results from an unbalanced coupling between resorption and formation inducing a thinning of trabeculae and from an increased osteoclast activation resulting in irreversible trabecular perforation. Anti-osteoclastic drugs prevent trabecular and cortical bone loss. Drugs that stimulate osteoblastic proliferation thicken trabecular plates but do not restore the normal trabecular microarchitecture after complete destruction of a large number of trabeculae. In type II osteoporosis, cortical bone loss is favoured by secondary hyperparathyroidism and is responsible for hip fracture. Calcium and vitamin D supplementations decrease the risk of hip fractures by reducing the secondary hyperparathyroidism.
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PMID:[Mechanisms of bone loss in osteoporosis]. 779 29

Testosterone has importance both as a sex hormone and as an anabolic steroid promoting bone formation. Osteoporosis is associated with both hypogonadism and corticosteroid therapy. Testosterone levels are reduced by long term prednisolone treatment. Although high dose inhaled corticosteroid therapy may cause a variety of systemic effects including adrenal suppression, dermal thinning and a reduction in total bone calcium, its effect on testosterone levels is not known. Testosterone, luteinizing hormone, follicle stimulating hormone and sex hormone binding globulin were therefore measured in 35 male patients with respiratory disease attending an outpatient clinic (median age 58, range 21-75 years). They were grouped according to steroid therapy and compared with 19 age matched controls. Mean (SD) testosterone levels were 33% lower in 12 men on long term oral prednisolone [14.5 (6.0) nmol 1-1] than in controls [21.7 (6.3) nmol 1-1], but were not significantly reduced in 10 patients on low dose inhaled beclomethasone [200-800 micrograms day-1: 19.7 (3.7)] nor in 13 men taking high dose inhaled beclomethasone [1500-2,250 micrograms day-1: 17.9 (5.6)]. Levels of luteinizing hormone, follicle stimulating hormone and sex hormone binding globulin were similar in all four groups. These cross sectional data confirm that long term systemic corticosteroid therapy reduces testosterone levels. However, testosterone was reduced by only 18% (NS) by long term inhaled corticosteroids. Other mechanisms to explain the disordered bone metabolism should now be explored.
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PMID:Testosterone levels during systemic and inhaled corticosteroid therapy. 780 37

Osteoporosis, a bone-thinning disease that leads to fractures, affects 25 million Americans, mostly women. The good news is that this disease is preventable and treatable. Adequate nutrition, for example, is estimated to reduce the impact of osteoporosis by as much as one half. The bad news is that unless more attention is given to communicating preventive strategies, osteoporosis and its related costs will continue to escalate. To make osteoporosis a priority among health professionals and communicators, The American Dietetic Association, in cooperation with National Diary Council, held a conference on this subject in November 1993. Recognized national experts addressed the issue of osteoporosis from various perspectives. This article summarizes the information presented at this conference. Prevention of osteoporosis focuses on increasing peak bone mass, which is usually reached between the age of 30 to 35 years, and reducing bone loss in later years. Bone health is influenced by three major interacting factors: diet, exercise, and estrogen. To optimize bone health, accumulating scientific findings support intakes of calcium and vitamin D exceeding current Recommended Dietary Allowances (RDAs) for these nutrients. Unfortunately, most women in the United States, in particular female adolescents, do not consume the RDA for calcium. Although recommendations to prevent osteoporosis can be made, there are several obstacles to translating these recommendations into action. Examples include failure to inspire people to make lifestyle changes early in life and to provide understandable recommendations. To be facilitators of change and not just nutrition experts, dietitians and other health professionals need to overcome these obstacles and to effectively market the risks of and prevention strategies for osteoporosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Osteoporosis: visions for care and prevention--a conference report. 819 63

Osteoporotic compression fractures of the spine differ from most other age-related fractures in that they usually are associated with minimal trauma and with loads no greater than those encountered during normal activities of daily living. With aging and osteoporosis, there is progressive resorption of bone, resulting in reductions in bone density, thinning of trabeculae, and loss of trabecular contiguity. These changes in trabecular bone structure are associated with losses in bone strength which are disproportionate to the reductions in bone mass alone. To explain this disproportionate loss of bone strength, the prevailing opinion is that density reductions in the vertebral centrum are accompanied by a reduction in the number of trabeculae, by preferential resorption of horizontal trabeculae, and by hypertrophy of the remaining vertical trabeculae. To evaluate this view of vertebral morphology, we performed three-dimensional stereological analysis of trabecular bone extracted from midsagittal sections of first lumbar vertebral bodies from 12 donors spanning an age of 27-81 years. We found that both the number (R2 = 0.63, P < 0.01) and thickness (R2 = 0.91, P < 0.01) of trabeculae decreased linearly with density (as expressed by bone volume fraction) whereas the spacing between the trabeculae (R2 = 0.61, P < 0.01) increased reciprocally. There were more vertical trabeculae with transverse trabeculae at all densities, and the number of vertical trabeculae changed with density at twice the rate of the number of transverse trabeculae (P < 0.001). These data do not support the prevailing view that there is preferential resorption of horizontal trabeculae or hypertrophy of the remaining vertical trabeculae.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of trabecular morphology in the etiology of age-related vertebral fractures. 827 69

Streptozotocin diabetic rats showed an increase of bone fragility (11.9 +/- 2.1 kg/cm2 vs. 16.8 +/- 2.0, P < 0.005) which was normalized by insulin treatment (18.3 +/- 4.2), indicating that osteoporosis was induced in diabetic rats. The rats were fed a zinc-deficient diet (0.16 mg/100 g) or a control diet (5.2 mg/100 g). This mild zinc-deficient diet did not lower the serum zinc level. The cortical bone of diabetic rats was shown to be markedly thinner by microscopic examination of ground cross-sections of the tibia. Zinc deficiency induced a reduction in the calcium content of diabetic bone when compared with the rats on a control diet. Urinary excretion of calcium and phosphorus was significantly increased in diabetic rats, and increased further when the rats were fed a zinc-deficient diet. Moreover. the bone calcium and phosphorus concentrations were significantly lower in these animals. These changes in the zinc-deficiency rats were not reversed by insulin treatment. Our findings suggest that osteoporosis in the diabetic rats was due to thinning of the bone cortex secondary to mineral loss and can be reversed by insulin treatment, and that these skeletal changes are greatly enhanced by mild zinc deficiency. In addition the effects of zinc deficiency cannot be completely reversed by insulin treatment.
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PMID:Zinc deficiency exaggerates diabetic osteoporosis. 840 52

A patient suffering from thalassaemia, with extreme osteoporosis, coarse trabeculation and cortical thinning of the bones, developed a pathological fracture of the left hip. This was treated by a single dose of radiotherapy. It is suggested that the radiotherapy facilitated the healing process by eliminating the causative factor of the fracture, which was the expanding and over-proliferating bone marrow.
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PMID:Pathological fracture in haemoglobinopathy: treatment by irradiation. 842 18

Inhaled corticosteroids are being given to more patients, at increasing doses and for longer periods of time. This has led to renewed concern about side-effects, particularly when higher doses (> 1 mg day-1) are used. The side-effects of particular concern are adrenocortical suppression, bone resorption, decreased growth in children, skin thinning and cataract formation. Changes in adrenocortical function are seen in a small proportion of patients given doses of 1-2 mg day-1. Long-term studies of the effect of inhaled corticosteroids on bone density are not available. Cross-sectional studies of bone density have been performed, but confounding variables, such as previous courses of oral corticosteroids and poor matching of control groups, make the studies difficult to interpret. Short-term effects on markers of bone turnover have been demonstrated, but their relevance to the long-term risk of osteoporosis is unclear. Studies reporting an increased incidence of skin changes and cataract formation are difficult to interpret because of confounding variables and inadequate control groups. Further studies of the long-term side-effects of inhaled corticosteroids are now required to enable prescribers to judge better the relative benefits and risks of this important asthma therapy.
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PMID:Safety of high-dose inhaled corticosteroids. 849 12

Although granulocyte colony-stimulating factor (G-CSF) was originally isolated as an activity for the growth and differentiation of cells in granulocytic lineage, it has been gradually accepted that G-CSF may have a function on a wide variety of cells besides granulocytes. To elucidate the function of G-CSF on bone cells in vivo, we examined the bone tissue of transgenic mice that overexpress G-CSF. Transgenic mice express human G-CSF at an elevated level (1041 +/- 242 pg/ml in sera) under the direction of SRalpha promoter. We performed radiographic, routine histologic, and histomorphometric analyses of the bone tissue and serum biochemical assay. Nontransgenic littermates were examined as age-matched, wild-type controls in all experiments. Radiographic analysis revealed cortical thinning accompanied by enlarged bone marrow cavities in both vertebral bodies and long bones. Histologically, a decreased number and thickness of trabecular bones and cortical thinning were observed in lumber vertebrae as well as in femur specimens. The enlarged bone marrow cavities exhibited an increased number of mature neutrophilic granulocytes without apparent changes in other types of cells. The static and dynamic parameters reflecting bone resorption were found to be significantly increased in the transgenic mice. By contrast, no significant differences were detected in the parameters reflecting bone formation. Transgenic mice and littermate controls had similar serum calcium, phosphorous, and alkaline phosphatase levels. However, the serum osteocalcin level was significantly higher in transgenic mice. These findings indicate that G-CSF-expressing transgenic mice developed osteoporosis because of increased osteoclastic activity. Collectively, G-CSF could have a negative influence on bone homeostasis in vivo.
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PMID:Overexpression of the granulocyte colony-stimulating factor gene leads to osteoporosis in mice. 860 92

Osteoporosis is defined as "...a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture." Compared to normal bone, osteoporotic bone shows a reduction in the number of trabeculae, thinning of the trabeculae, and loss of connectivity of the trabeculae. The overall result is deterioration of bone strength and an increase in the susceptibility to fracture. Osteoporosis is essentially a "silent" disease until a fracture occurs. When multiple fractures occur, they can cause significant deformity of the spine, leading to kyphosis, loss of vertebral height, and subsequent loss of overall height. The patient with osteoporosis experiences chronic pain and back fatigue. In addition, gastrointestinal and respiratory symptoms may occur as a consequence of the changes in the skeletal shape.
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PMID:The epidemiology of osteoporosis. 885 43

The routine diagnosis of osteoporosis is based on radiological measurements of bone mineral content. An osteoporotic failure is influenced both by a loss of mineralized bone and internal bone structure. The structure cannot be estimated by bone reconstruction based on standard radiological equipment. To investigate the influence of structure on cancellous bone stiffness, a new finite element model of cancellous bone is developed. The model describes a cancellous bone unit as an open-celled structure. Trabecular length, trabecular thickness, diameter of trabecular connections, relative lattice disorder and relative bone loss determine the real architecture. Using this model, the loss of stiffness as a result of trabecular thinning and loss of trabecular connections is estimated. The volume fraction as a scalar value for a volume can not be a marker for orthotropic stiffness changes. A formula in the form Y = e(a *1 n(X) + b) can describe the correlation between cancellous bone stiffness and volume fraction. These formulas are appropriate for those cases, when the loss of bone mineral (decrease in trabecular thickness) is closely connected to a loss of structure (increasingly perforated trabecular network).
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PMID:The loss of stiffness as osteoporosis progresses. 889 46


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