Purpose. To examine the effects of two doses of low-frequency (12 Hz), low-magnitude (0.3 g), whole body vibration on markers of bone formation and resorption in postmenopausal women.
Methods. Women were recruited and randomized into a sham vibration control group, one time per week vibration group (1×/week), or three times per week vibration group (3×/week). Vibration exposure consisted of 20 minutes of intermittent vibration for the 1×/week and 3×/week groups, and sham vibration (<0.1 g) for the control group for eight weeks. Double-blinded primary outcome measures were urine markers of bone resorption: N-telopeptide X normalised to creatinine (NTx/Cr) and bone formation: bone-specific alkaline phosphatase (ALP).
Results. Forty-six women (59.8 ± 6.2 years, median 7.3 years since menopause) were enrolled. NTx/Cr was significantly reduced (34.6%) in the 3×/wk vibration group but not in the 1×/wk vibration group compared with sham control (P < .01) group. No effect of time or group allocation was observed on the bone formation marker ALP (P = .27).
Conclusion. We have shown for the first time that low-frequency, low-magnitude vibration 3×/week for eight weeks in postmenopausal women results in a significant reduction in NTx/Cr, a marker of bone resorption, when compared with sham vibration exposure.
Reaction of 4-t-butoxycyclopent-2-enone with (E)-1-(pheny1thio)oct-2-enyllithium in tetrahydrofuran containing 1.5 equivalents of hexamethylphosphoric triamide at - 78� followed by treatment of the resulting enolate with one equivalent of triphenyltin chloride and then with methyl 7-iodohept-5-ynoate at - 20� gives the vicinally dialkylated cyclopentanone, methyl (a-9-oxo-1l-t-butoxy-13-(phenylthio)prost-14-en-5-ynoate, as a 1 : 1 mixture of diastereomers epimeric at C13, in 70-72% overall yields from the octenyllithium reagent. Stereoselective reduction of the C9 carbonyl, conversion of the sulfide into the allylically transposed alcohol, and removal of the t-butyl group by means of iron(III) chloride in acetic anhydride at 0� provides a triacetate which is converted into racemic methyl 5,6-didehydroprostaglandin F2a methyl ester as a 1 : 1 mixture of diastereomers epimeric at C15.
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