We usually look forward to a well-written paper about central aspects of your research. But sometimes you are frustrated. Maybe someone has done (almost) the same experiments, but was quicker in getting the work published. Then you can at least publish your results, probably in a less prestigous journal, to confirm these findings.
But when the just published paper comes to the opposite conclusions, and has done all the right experiments, your work can become almost worthless. This just happened to me with a paper (https://web.archive.org/web/20120611091452/http://www.nature.com/nm/journal/v13/n12/abs/nm1672.html?) in the December issue of Nature Medicine about the role PPARgamma in osteoclastogenesis. The group of Ronald Evans used mice with a conditional knockout of PPARgamma in osteoclasts to study the role of this nuclear hormone receptor in bone diseases. Their elegant work clearly shows that PPARgamma promotes osteoclast differentiation and activation.
Unfortunately we have very different results in a tissue culture model of osteoclast differentiation, consistent with previous publications. But it is hard to argue with a mouse model. We will carefully look at the data to decide where we go from here. But for now it's just frustrating.