Bone
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Orchiectomized (ORX) rats were used to examine the extent to which their increased bone resorption and decreased bone density might relate to increases in RANKL, an essential cytokine for bone resorption. Serum testosterone declined by >95% in ORX rats 1 and 2 weeks after surgery (p<0.05 versus sham controls), with no observed changes in serum RANKL. In contrast, RANKL in bone marrow plasma and bone marrow cell extracts was significantly increased (by approximately 100%) 1 and 2 weeks after ORX. ⋯ Data from regression analyses were consistent with a potential role for testosterone in suppressing RANKL production in bone marrow, and also suggested that soluble RANKL in bone marrow might promote bone resorption. RANKL inhibition prevented ORX-related deficits in trabecular BMD, trabecular architecture, and periosteal bone formation while increasing cortical and trabecular bone volume and density. These results support the investigation of RANKL inhibition as a strategy for preventing bone loss associated with androgen ablation or deficiency.
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Review Case Reports
Stereotactic radiosurgery for spinal metastases: case report and review of treatment options.
The spine is the most common site for bone metastases. Spinal metastases can impact quality of life by causing severe pain, limitation of motion, and increased requirements for pain medication. ⋯ In this report, we examine the efficacy and possible advantages of single fraction SRS using a state-of-the-art tomotherapy machine in the treatment of a patient with spinal metastases from breast cancer. We also review the literature on treatment of spinal metastases using SRS, SBRT, and other modalities.
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We used dual X-ray absorptiometry (DXA) to measure calcaneal bone mineral density (BMD) and estimate the prevalence of osteoporosis in a population with distal forearm fracture and a normative cohort. ⋯ The age-adjusted prevalence of osteoporosis based on calcaneal BMD is higher in individuals with distal forearm fracture than in population-based controls. BMD impairment is associated with increased odds ratio for forearm fracture in both women and men but the differences between cases and controls are more pronounced in men than in women, which may have implications in fracture prevention.
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Recent large trials indicate that adherence associated with a daily regimen of vitamin D is low and limits anti-fracture efficacy with vitamin D supplementation. The aim of this report is to describe changes of 25-hydroxyvitamin D (25(OH)D) serum concentrations achieved with a single oral dose of 300000 IU vitamin D3. ⋯ Based on our observations, a single oral dose of 300000 IU vitamin D3 raises mean 25(OH)D serum concentrations to the target mean of above 75 nmol/l at 3 months and a mean level of 69 nmol/l at 6 months. As calcium absorption is enhanced with higher 25(OH)D serum concentrations, calcium supplementation may need downward adjustment with this regimen to avoid mild hypercalcemia.