Objective
To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients receiving glucocorticoids.
Methods
This is a 12‐month extension of a previously completed 1‐year trial of daily ALN, performed to evaluate the effects of ALN over a total of 2 years in 66 men and 142 women continuing to receive at least 7.5 mg of prednisone or equivalent daily. All patients received supplemental calcium and vitamin D. The primary end point was the mean percentage change in lumbar spine bone mineral density (BMD) from baseline to 24 months. Other outcomes included changes in hip and total body BMD, biochemical markers of bone turnover, radiographic joint damage of the hands, and vertebral fracture incidence.
Results
The mean (±SEM) lumbar spine BMD increased by 2.8 ± 0.6%, 3.9 ± 0.7%, and 3.7 ± 0.6%, respectively, in the groups that received 5 mg, 10 mg, and 2.5/10 mg of ALN daily (P ≤ 0.001) and decreased by −0.8 ± 0.6% in the placebo group (P not significant) over 24 months. In patients receiving any dose of ALN, BMD was increased at the trochanter (P ≤ 0.05) and maintained at the femoral neck. Total body BMD was increased in patients receiving 5 or 10 mg ALN (P ≤ 0.01). These 2 dose levels of ALN were more effective than placebo at all sites (P ≤ 0.05). Bone turnover markers (N‐telopeptides of type I collagen and bone‐specific alkaline phosphatase) decreased 60% and 25%, respectively, during treatment with ALN (P ≤ 0.05). There were fewer patients with new vertebral fractures in the ALN group versus the placebo group (0.7% versus 6.8%; P = 0.026). The safety profile was similar between treatment groups.
Conclusion
Alendronate is an effective, well‐tolerated therapy for the prevention and treatment of glucocorticoid‐induced osteoporosis, with sustained treatment advantages for up to 2 years.
Background and purpose:Tissue deposits of the anti-arrhythmic drug amiodarone are a major source of side effects (skin discoloration, etc.). We addressed the mechanism of the concentration of amiodarone in cells, and characterized the resulting vacuolar cytopathology and its evolution towards macroautophagy. Experimental approach: Sequestration of amiodarone in human cells (macrophages, smooth muscle cells, HEK 293a cells) was evaluated using its violet fluorescence and cytopathology using GFP-conjugated subcellular markers. Autophagic signalling was probed by immunoblotting for the effector protein LC3. A patient biopsy of amiodarone-induced blue-gray skin discoloration was investigated for the presence of macroautophagy (immunofluorescence for LC3). Key results: Most of the amiodarone (1-20 mM, 4-24 h) captured by cultured cells (macrophages were most avid) was present in enlarged vacuoles. The specific vacuolar ATPase (V-ATPase) inhibitors, bafilomycin A1 or FR167356, prevented vacuolization and drug uptake. Vacuoles in HEK 293a cells were positive for markers of late endosomes and lysosomes (GFP-Rab7, -CD63) and for an effector of macroautophagy, GFP-LC3. The vacuoles accumulated endogenous LC3 and filled with lipids (Nile red staining) following longer amiodarone treatments (Ն24 h). The electrophoretic mobility of both GFP-LC3 and endogenous LC3 changed, showing activation in response to amiodarone. Paraffin tissue sections of the pigmented skin exhibited granular LC3 accumulation in superficial dermis macrophages. Conclusion and implications: Vacuolar sequestration of amiodarone occurs at concentrations close to therapeutic levels, is mediated by V-ATPase and evolves towards persistent macroautophagy and phospholipidosis. This cytopathology is not cell type specific, but tissue macrophages appear to be particularly susceptible.
The functional responsiveness of human neutrophils is known to be initiated and modulated by protein tyrosine phosphorylation. The regulation of the levels of tyrosine phosphorylation is most likely the result of the coordinated actions of tyrosine kinases and phosphatases, which have so far been only very partially characterized. In the present study, we present evidence demonstrating that the stimulation of neutrophils by a variety of agonists (soluble as well as particulate) leads to the activation of the src-related tyrosine kinase lyn. The stimulation of tyrosine kinase activity of lyn was detected using an immune kinase assay as well as an in situ labeling technique. Phosphoaminoacid analysis of lyn indicated that the autophosphorylation of the kinase was exclusively on tyrosine residues. The time course of the activation of lyn is consistent with its playing a role in the early tyrosine phosphorylation responses of neutrophils. The ability of agonists with widely varying functional end responses to stimulate the activity of lyn indicates that this event plays a key and central role in the control of the activation of human neutrophils.
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