Accuracy analysis of computer-assisted surgery for femoral trochanteric fracture using a fluoroscopic navigation system: Stryker ADAPT® system.

PURPOSE: ADAPT is a fluoroscopic computer-assisted surgery system which intraoperatively shows the distance from the tip of the screw to the surface of the femoral head, tip-to-head-surface distance (TSD), and the tip-apex distance (TAD) advocated by Baumgaertner et al. The study evaluated the accuracy of ADAPT. PATIENTS AND METHODS: A total of 55 patients operated with ADAPT between August 2016 and March 2017 were included as subjects. TSD and TAD were measured postoperatively using computed tomography (CT) and X-rays. The intraclass correlation coefficient (ICC) was checked in advance. The error was defined as the difference between postoperative and intraoperative measurement values of ADAPT. Summary statistics, root mean square errors (RMSEs), and correlations were evaluated. RESULTS: ICC was 0.94 [95% CI: 0.90-0.96] in TSD and 0.99 [95% CI: 0.98-0.99] in TAD. The error was -0.35 mm (-1.83 mm to 1.12 mm) in TSD and +0.63 mm (-5.65 mm to 4.59 mm) in TAD. RMSE was 0.63 mm in TSD and 1.53 mm in TAD. Pearson's correlation coefficient was 0.79 [95% CI: 0.66-0.87] in TSD and 0.83 [95% CI: 0.72-0.89] in TAD. There were no adverse events with ADAPT use. CONCLUSION: ADAPT is highly accurate and useful in guiding surgeons in properly positioning the screws.

Protein tyrosine phosphatase-PEST (PTP-PEST) regulates mast cell-activating signals in PTP activity-dependent and -independent manners.

Aggregation of the high-affinity IgE receptor (FcεRI) in mast cells leads to degranulation and production of numerous cytokines and lipid mediators that promote allergic inflammation. Tyrosine phosphorylation of proteins in response to FcεRI aggregation has been implicated in mast cell activation. Here, we determined the role of PTP-PEST (encoded by PTPN12) in the regulation of mast cell activation using the RBL-2H3 rat basophilic leukemia cell line as a model. PTP-PEST expression was significantly induced upon FcεRI-crosslinking, and aggregation of FcεRI induced the phosphorylation of PTP-PEST at Ser39, thus resulting in the suppression of PTP activity. By overexpressing a phosphatase-dead mutant (PTP-PEST CS) and a constitutively active mutant (PTP-PEST SA) in RBL-2H3 cells, we showed that PTP-PEST decreased degranulation and enhanced IL-4 and IL-13 transcription in FcεRI-crosslinked RBL-2H3 cells, but PTP activity of PTP-PEST was not necessary for this regulation. However, FcεRI-induced TNF-α transcription was increased by the overexpression of PTP-PEST SA and suppressed by the overexpression of PTP-PEST CS. Taken together, these results suggest that PTP-PEST is involved in the regulation of FcεRI-mediated mast cell activation through at least two different processes represented by PTP activity-dependent and -independent pathways.

PICOT, protein kinase C theta-interacting protein, is a novel regulator of FcepsilonRI-mediated mast cell activation.

PICOT (PKC-interacting cousin of thioredoxin) consists of one thioredoxin homology domain in the N-terminal and two tandem PICOT homology domains in the C-terminal. PICOT specifically interacts with protein kinase C theta (PKC-theta) via its thioredoxin homology domain and acts as an important modulator of T cell receptor (TCR)-signaling. Using PICOT overexpressing rat basophilic leukemia cells (RBL-2H3), we evaluated the effect of PICOT overexpression on the FcepsilonRI-mediated signaling. In comparison to the control cells, introduction of PICOT to RBL-2H3 cells induced increased degranulation and the activation of NFAT and in the expression of IL-4 and TNF-alpha transcripts by FcepsilonRI-crosslinking, whereas no significant change was observed with the elevation of ERK1/2 and p38 MAP kinase phosphorylation and NF-kappaB activation by FcepsilonRI aggregation. More interesting was the exogenous PICOT overexpression in RBL-2H3 cells causing a large decrease in the elevation of JNK phosphorylation. PICOT-regulated FcepsilonRI-mediated signals in RBL-2H3 cells and acted as a positive regulator on IL-4 and TNF-alpha expression, NFAT and degranulation signal pathways and a negative regulator on a JNK signal pathway. Considering that PICOT has no enzymatic activity, the regulation of PICOT on FcepsilonRI-signaling may depend on PICOT-associated molecule(s).