Triple taper stem design shows promising fixation and bone remodelling characteristics: radiostereometric analysis in a randomised controlled trial.

Cemented femoral stems with force closed fixation designs have shown good clinical results despite high early subsidence. A new triple-tapered stem in this category (C-stem AMT) was introduced in 2005. This study compares this new stem with an established stem of similar design (Exeter) in terms of migration (as measured using radiostereometric analysis), peri-prosthetic bone remodelling (measured using dual energy x-ray densitometry, DXA), Oxford Hip Score, and plain radiographs. A total of 70 patients (70 hips) with a mean age of 66 years (53 to 78) were followed for two years. Owing to missing data of miscellaneous reasons, the final analysis represents data from 51 (RSA) and 65 (DXA) patients. Both stems showed a typical pattern of migration: Subsidence and retroversion that primarily occurred during the first three months. C-stem AMT subsided less during the first three months (p = 0.01), before stabilising at a subsidence rate similar to the Exeter stem from years one to two. The rate of migration into retroversion was slightly higher for C-stem AMT during the second year (p = 0.03). Whilst there were slight differences in movement patterns between the stems, the C-stem AMT exhibits good early clinical outcomes and displays a pattern of migration and bone remodelling that predicts good clinical performance.

Somatostatin and octreotide interfere with calcium signalling in pancreatic beta-cells but not in normal and pathological parathyroid cells.

Somatostatin and its analogue octreotide exert antisecretory actions in several endocrine tissues. Somatostatin and octreotide (100 nM) promptly and reversibly counteracted glucose stimulated elevations of the concentration of cytoplasmic Ca2+ ([Ca2+]i) in mouse pancreatic beta-cells. In contrast both somatostatin and octreotide failed to affect basal or high Ca2+ stimulated [Ca2+]i of normal bovine, and adenomatous or hyperplastic human parathyroid cells. Furthermore, PTH release of these cells was unaltered by 1-1000 nM somatostatin and octreotide. The results indicate that somatostatin and octreotide lack direct actions on parathyroid cells, which contrasts to their effects on calcium signalling in cells from pancreatic islets.