[Cement augmentation in spinal surgery]. / Zementaugmentation in der Wirbelsäulenchirurgie.

Bone cement has been used in spinal surgery for as long as 50 years. In contemporary spinal surgery, cement augmentation of fractured osteoporotic vertebrae in the form of vertebroplasty/kyphoplasty as well as cement augmentation of pedicle screws in instrumented procedures of any etiology are established as standard procedures. Both procedures are very effective, although the benefits of vertebroplasty/kyphoplasty procedures have been controversially discussed in the past. Overall, complications rarely occur. The most relevant complication is cement leakage, which is asymptomatic in the majority of cases but in the worst case might lead to neurological deficits, embolic events and even circulatory collapse. Prevention of cement leakage is therefore crucial. Risk factors for cement leakage and preventive measures are presented in a comprehensive review based on the available literature.

Transcriptional analysis of rat photoreceptor cells reveals daily regulation of genes important for visual signaling and light damage susceptibility.

Photoreceptor cells face the challenge of adjusting their function and, possibly, their susceptibility to light damage to the marked daily changes in ambient light intensity. To achieve a better understanding of photoreceptor adaptation at the transcriptional level, this study aimed to identify genes which are under daily regulation in photoreceptor cells using microarray analysis and quantitative PCR. Included in the gene set obtained were a number of genes which up until now have not been shown to be expressed in photoreceptor cells, such as Atf3 (activating transcription factor 3) and Pde8a (phosphodiesterase 8A), and others with a known impact on phototransduction and/or photoreceptor survival, such as Grk1 (G protein-coupled receptor kinase 1) and Pgc-1α (peroxisome proliferator-activated receptor γ, coactivator 1alpha). According to their daily dynamics, the genes identified could be clustered in two groups: those with peak expression during the second part of the day which are uniformly promoted to cycle by light/dark transitions and those with peak expression during the second part of the night which are predominantly driven by a clock. Since Grk1 and Pgc-1α belong in the first group, the present results support a concept in which transcriptional regulation of genes by ambient light contributes to the functional adjustment of photoreceptor cells over the 24-h period.