In vitro effects of 0 to 120 Grays of irradiation on bone viability and release of growth factors.

BACKGROUND: High dose radiation therapy is commonly used in maxillofacial surgeries to treat a number of head and neck tumors. Despite its widespread use, little information is available regarding the effects of irradiation on bone cell viability and release of growth factors following dose-dependent irradiation. METHODS: Bone samples were collected from porcine mandibular cortical bone and irradiated at doses of 0, 7.5, 15, 30, 60 and 120 Grays. Thereafter, cell viability was quantified, and the release of growth factors including TGFß1, BMP2, VEGF, IL1ß and RANKL were investigated over time. RESULTS: It was observed that at only 7.5Gy of irradiation, over 85 % of cells were non-vital and by 60 Gy, all cells underwent apoptosis. Furthermore, over a 7-fold decrease in VEGF and a 2-fold decrease in TGFß1 were observed following irradiation at all tested doses. Little change was observed for BMP2 and IL1ß whereas RANKL was significantly increased for all irradiated samples. CONCLUSIONS: These results demonstrate the pronounced effects of irradiation on bone-cell vitality and subsequent release of growth factors. Interestingly, the largest observed change in gene expression was the 7-fold decrease in VEGF protein following irradiation. Future research aimed at improving our understanding of bone following irradiation is necessary to further improve future clinical treatments.

Volumetric regression ratio of the primary tumor and metastatic lymph nodes after induction chemotherapy predicts overall survival in head and neck squamous cell carcinoma: a retrospective analysis.

PURPOSE: We looked for any predictive value of change in primary tumor and metastatic lymph node volumes after induction chemotherapy (IC) on oncologic outcome in head and neck squamous cell carcinoma (HNSCC). METHODS: Nineteen patients with stage IVA/B HNSCC treated between 2004 and 2010 with at least one cycle of IC (docetaxel, cisplatin and 5-fluorouracil/TPF) and concomitant chemoradiotherapy (CRT) with cisplatin were retrospectively analyzed. Volumes were calculated separately for primary tumor (Vtm), lymph node metastases (Vln) and their sum (Vsum) on computed tomography (CT) images before and after IC. The effect of volumetric changes on locoregional failure (LRF), distant metastasis (DM) and overall survival (OS) was assessed. P values <0.05 were considered as statistically significant. RESULTS: The median follow-up of surviving patients was 25 months (range: 10.7-83.3). The median number of cycles and duration of TPF was 3 (range: 1-4) and 44 days (range: 4-116), respectively. Empirical area under the curve (AUC) analyses for death, LRF and DM revealed optimal cut-off values of Vtm diminution (30.54%, AUC: 87%) and Vsum decrease (35.45%, AUC: 64.55%) only for OS (p <0.05). Among those, a reduction in Vsum more than 35.4% between pre- and post-IC was significantly correlated with better OS (100 vs 43% at 2 years, p <0.05). CONCLUSION: Volumetric shrinkage of the tumor load after IC assessed with CT seems to predict OS. The assessment of volumetric shrinkage upon IC might be used to decide whether to offer patients alternative strategies like palliative/de-intensified treatments or more aggressive combined modalities after IC.

High dose-rate versus low dose-rate brachytherapy for lip cancer.

PURPOSE: To analyze the outcome after low-dose-rate (LDR) or high-dose-rate (HDR) brachytherapy for lip cancer. METHODS AND MATERIALS: One hundred and three patients with newly diagnosed squamous cell carcinoma of the lip were treated between March 1985 and June 2009 either by HDR (n = 33) or LDR brachytherapy (n = 70). Sixty-eight patients received brachytherapy alone, and 35 received tumor excision followed by brachytherapy because of positive resection margins. Acute and late toxicity was assessed according to the Common Terminology Criteria for Adverse Events 3.0. RESULTS: Median follow-up was 3.1 years (range, 0.3-23 years). Clinical and pathological variables did not differ significantly between groups. At 5 years, local recurrence-free survival, regional recurrence-free survival, and overall survival rates were 93%, 90%, and 77%. There was no significant difference for these endpoints when HDR was compared with LDR brachytherapy. Forty-two of 103 patients (41%) experienced acute Grade 2 and 57 of 103 patients (55%) experienced acute Grade 3 toxicity. Late Grade 1 toxicity was experienced by 34 of 103 patients (33%), and 5 of 103 patients (5%) experienced late Grade 2 toxicity; no Grade 3 late toxicity was observed. Acute and late toxicity rates were not significantly different between HDR and LDR brachytherapy. CONCLUSIONS: As treatment for lip cancer, HDR and LDR brachytherapy have comparable locoregional control and acute and late toxicity rates. HDR brachytherapy for lip cancer seems to be an effective treatment with acceptable toxicity.

Glycogen synthase kinase 3beta (GSK3beta) regulates differentiation and proliferation in neural stem cells from the rat subventricular zone.

On the basis of its inhibition by SB216763, we identified the multifunctional enzyme Glycogen Synthase Kinase 3beta (GSK3beta) as a central regulator for differentiation and cell survival of adult neural stem cells. Detected by proteomic approaches, members of the Wnt/beta-catenin signaling pathway appear to participate in enhanced neuronal differentiation and activated transcription of beta-catenin target genes during GSK3beta inhibition, associated with decreased apoptosis.

Comparison of statistical approaches for the analysis of proteome expression data of differentiating neural stem cells.

Comparative proteomic studies often use statistical tests included in the software for the analysis of digitized images of two-dimensional electrophoresis gels. As these programs include only limited capabilities for statistical analysis, many studies do not further describe their statistical approach. To find potential differences produced by different data processing, we compared the results of (1) Student's t-test using a spreadsheet program, (2) the intrinsic algorithms implemented in the Phoretix 2D gel analysis software, and (3) the SAM algorithm originally developed for microarray analysis. We applied the algorithms to proteome data of undifferentiated neural stem cells versus in vitro differentiated neural stem cells. We found (1) 367 spots differentially expressed using Student's t-test, (2) 203 spots using the algorithms in Phoretix 2D, and (3) 119 spots using the algorithms in SAM, respectively, with an overlap of 42 spots detected by all three algorithms. Applying different statistical approaches on the same dataset resulted in divergent set of protein spots labeled as statistically "significant". Currently, there is no agreement on statistical data processing of 2DE datasets, but the statistical tests applied in 2DE studies should be documented. Tools for the statistical analysis of proteome data should be implemented and documented in the existing 2DE software.