The value of subcutaneous xenografts for individualised radiotherapy in HNSCC: Robust gene signature correlates with radiotherapy outcome in patients and xenografts.

PURPOSE: To assess the robustness of prognostic biomarkers and molecular tumour subtypes developed for patients with head and neck squamous cell carcinoma (HNSCC) on cell-line derived HNSCC xenograft models, and to develop a novel biomarker signature by combining xenograft and patient datasets. MATERIALS AND METHODS: Mice bearing xenografts (n = 59) of ten HNSCC cell lines and a retrospective, multicentre patient cohort (n = 242) of the German Cancer Consortium-Radiation Oncology Group (DKTK-ROG) were included. All patients received postoperative radiochemotherapy (PORT-C). Gene expression analysis was conducted using GeneChip Human Transcriptome Arrays. Xenografts were stratified based on their molecular subtypes and previously established gene classifiers. The dose to control 50 % of tumours (TCD50) was compared between these groups. Using differential gene expression analyses combining xenograft and patient data, a gene signature was developed to define risk groups for the primary endpoint loco-regional control (LRC). RESULTS: Tumours of mesenchymal subtype were characterized by a higher TCD50 (xenografts, p < 0.001) and lower LRC (patients, p < 0.001) compared to the other subtypes. Similar to previously published patient data, hypoxia- and radioresistance-related gene signatures were associated with high TCD50 values. A 2-gene signature (FN1, SERPINE1) was developed that was prognostic for TCD50 (xenografts, p < 0.001) and for patient outcome in independent validation (LRC: p = 0.007). CONCLUSION: Genetic prognosticators of outcome for patients after PORT-C and subcutaneous xenografts after primary clinically relevant irradiation show similarity. The identified robust 2-gene signature may help to guide patient stratification, after prospective validation. Thus, xenografts remain a valuable resource for translational research towards the development of individualized radiotherapy.

Reduced overnight memory consolidation and associated alterations in sleep spindles and slow oscillations in early Alzheimer's disease.

Spatial navigation critically underlies hippocampal-entorhinal circuit function that is early affected in Alzheimer's disease (AD). There is growing evidence that AD pathophysiology dynamically interacts with the sleep/wake cycle impairing hippocampal memory. To elucidate sleep-dependent consolidation in a cohort of symptomatic AD patients (n = 12, 71.25 ± 2.16 years), we tested hippocampal place learning by means of a virtual reality task and verbal memory by a word-pair association task before and after a night of sleep. Our results show an impaired overnight memory retention in AD compared with controls in the verbal task, together with a significant reduction of sleep spindle activity (i.e., lower amplitude of fast sleep spindles, p = 0.016) and increased duration of the slow oscillation (SO; p = 0.019). Higher spindle density, faster down-to-upstate transitions within SOs, and the time delay between SOs and nested spindles predicted better memory performance in healthy controls but not in AD patients. Our results show that mnemonic processing and memory consolidation in AD is slightly impaired as reflected by dysfunctional oscillatory dynamics and spindle-SO coupling during NonREM sleep. In this translational study based on experimental paradigms in animals and extending previous work in healthy aging and preclinical disease stages, our results in symptomatic AD further deepen the understanding of the memory decline within a bidirectional relationship of sleep and AD pathology.

A Novel 2-Metagene Signature to Identify High-Risk HNSCC Patients amongst Those Who Are Clinically at Intermediate Risk and Are Treated with PORT.

(1) Background: Patients with locally advanced head and neck squamous cell carcinoma (HNSCC) who are biologically at high risk for the development of loco−regional recurrences after postoperative radiotherapy (PORT) but at intermediate risk according to clinical risk factors may benefit from additional concurrent chemotherapy. In this matched-pair study, we aimed to identify a corresponding predictive gene signature. (2) Methods: Gene expression analysis was performed on a multicenter retrospective cohort of 221 patients that were treated with postoperative radiochemotherapy (PORT-C) and 283 patients who were treated with PORT alone. Propensity score analysis was used to identify matched patient pairs from both cohorts. From differential gene expression analysis and Cox regression, a predictive gene signature was identified. (3) Results: 108 matched patient pairs were selected. We identified a 2-metagene signature that stratified patients into risk groups in both cohorts. The comparison of the high-risk patients between the two types of treatment showed higher loco−regional control (LRC) after treatment with PORT-C (p < 0.001), which was confirmed by a significant interaction term in Cox regression (p = 0.027), i.e., the 2-metagene signature was indicative for the type of treatment. (4) Conclusion: We have identified a novel gene signature that may be helpful to identify patients with high-risk HNSCC amongst those at intermediate clinical risk treated with PORT, who may benefit from additional concurrent chemotherapy.

Development and validation of a 6-gene signature for the prognosis of loco-regional control in patients with HPV-negative locally advanced HNSCC treated by postoperative radio(chemo)therapy.

PURPOSE: The aim of this study was to develop and validate a novel gene signature from full-transcriptome data using machine-learning approaches to predict loco-regional control (LRC) of patients with human papilloma virus (HPV)-negative locally advanced head and neck squamous cell carcinoma (HNSCC), who received postoperative radio(chemo)therapy (PORT-C). MATERIALS AND METHODS: Gene expression analysis was performed using Affymetrix GeneChip Human Transcriptome Array 2.0 on a multicentre retrospective training cohort of 128 patients and an independent validation cohort of 114 patients from the German Cancer Consortium - Radiation Oncology Group (DKTK-ROG). Genes were filtered based on differential gene expression analyses and Cox regression. The identified gene signature was combined with clinical parameters and with previously identified genes related to stem cells and hypoxia. Technical validation was performed using nanoString technology. RESULTS: We identified a 6-gene signature consisting of four individual genes CAV1, GPX8, IGLV3-25, TGFBI, and one metagene combining the highly correlated genes INHBA and SERPINE1. This signature was prognostic for LRC on the training data (ci = 0.84) and in validation (ci = 0.63) with a significant patient stratification into two risk groups (p = 0.005). Combining the 6-gene signature with the clinical parameters T stage and tumour localisation as well as the cancer stem cell marker CD44 and the 15-gene hypoxia-associated signature improved the validation performance (ci = 0.69, p = 0.001). CONCLUSION: We have developed and validated a novel prognostic 6-gene signature for LRC of HNSCC patients with HPV-negative tumours treated by PORT-C. After successful prospective validation the signature can be part of clinical trials on the individualization of radiotherapy.

Biomarker signatures for primary radiochemotherapy of locally advanced HNSCC - Hypothesis generation on a multicentre cohort of the DKTK-ROG.

PURPOSE: To develop prognostic biomarker signatures for patients with locally advanced head and neck squamous cell carcinoma (HNSCC) treated by primary radiochemotherapy (RCTx) based on previously published molecular analyses of the retrospective biomarker study of the German Cancer Consortium - Radiation Oncology Group (DKTK-ROG). MATERIAL AND METHODS: In previous studies on the retrospective DKTK-ROG HNSCC cohort treated with primary RCTx, the following clinical parameters and biomarkers were evaluated and found to be significantly associated with loco-regional tumour control (LRC) or overall survival (OS): tumour volume, p16 status, expression of cancer stem cell markers CD44 and SLC3A2, expressions of hypoxia-associated gene signatures, tumour mutational burden (TMB), single nucleotide polymorphisms (SNPs) in the ERCC2 gene (rs1799793, rs13181) and ERCC5 gene (rs17655) as well as the expression of CXCR4, SDF-1 and CD8. These biomarkers were combined in multivariable modelling using Cox-regression with backward variable selection. RESULTS: A baseline signature containing the widely accepted parameters tumour volume, p16 status, cancer stem cell marker expression (CD44), and hypoxia-associated gene expression has been defined, representing the main hypothesis of the study. Furthermore, the baseline signature was extended by additional prognostic biomarkers and a data-driven signature without any pre-hypothesis was generated for both endpoints. In these signatures, the SNPs rs1799793 and rs17655 as well as CXCR4, SDF-1 and SLC3A2 expression were additionally included. The signatures showed significant patient stratifications for LRC and OS. CONCLUSION: Three biomarker signatures were defined for patients with locally advanced HNSCC treated with primary RCTx for the endpoints LRC and OS. These signatures will be validated in the prospective HNprädBio study of the DKTK-ROG that recently completed recruitment, before potential application in an interventional trial.

Analyses of molecular subtypes and their association to mechanisms of radioresistance in patients with HPV-negative HNSCC treated by postoperative radiochemotherapy.

PURPOSE: To assess the relation of the previously reported classification of molecular subtypes to the outcome of patients with HNSCC treated with postoperative radio(chemo)therapy (PORT-C), and to assess the association of these subtypes with gene expressions reflecting known mechanisms of radioresistance. MATERIAL AND METHODS: Gene expression analyses were performed using the GeneChip Human Transcriptome Array 2.0 on a multicentre retrospective patient cohort (N = 128) of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG) with locally advanced HNSCC treated with PORT-C. Tumours were assigned to four molecular subtypes, and correlation analyses between subtypes and clinical risk factors were performed. In addition, the classifications of eight genes or gene signatures related to mechanisms of radioresistance, which have previously shown an association with outcome of patients with HNSCC, were compared between the molecular subtypes. The endpoints loco-regional control (LRC) and overall survival (OS) were evaluated by log-rank tests and Cox regression. RESULTS: Tumours were classified into the four subtypes basal (19.5%), mesenchymal (18.8%), atypical (15.6%) and classical (14.1%). The remaining tumours could not be classified (32.0%). Tumours of the mesenchymal subtype showed a lower LRC compared to the other subtypes (p = 0.012). These tumours were associated with increased epithelial-mesenchymal transition (EMT) and overexpression of a gene signature enriched in DNA repair genes. The majority of the eight considered gene classifiers were significantly associated to LRC or OS in the whole cohort. CONCLUSION: Molecular subtypes, previously identified on HNSCC patients treated with primary radio(chemo)therapy or surgery, were related to LRC for patients treated with PORT-C, where mesenchymal tumours presented with worse prognosis. After prospective validation, subtype-based patient stratification, potentially in combination with other molecular classifiers, may be considered in future interventional studies in the context of personalised radiotherapy and may guide the development of combined treatment approaches.

Comparison of GeneChip, nCounter, and Real-Time PCR-Based Gene Expressions Predicting Locoregional Tumor Control after Primary and Postoperative Radiochemotherapy in Head and Neck Squamous Cell Carcinoma.

This article compares the expression and applicability of biomarkers, from single genes and gene signatures, identified in patients with locally advanced head and neck squamous cell carcinoma using the GeneChip Human Transcriptome Array 2.0, nCounter, and real-time PCR analyses. Two multicenter, retrospective cohorts of patients with head and neck squamous cell carcinoma from the German Cancer Consortium Radiation Oncology Group who received postoperative radiochemotherapy or primary radiochemotherapy were considered. Real-time PCR was performed for a limited number of 38 genes of the cohort who received postoperative radiochemotherapy only. Correlations between the methods were evaluated by the Spearman rank correlation coefficient. Patients were stratified based on the expression of putative cancer stem cell markers, hypoxia-associated gene signatures, and a previously developed seven-gene signature. Locoregional tumor control was compared between these patient subgroups using log-rank tests. Gene expressions obtained from nCounter analyses were moderately correlated to GeneChip analyses (median ρ = approximately 0.68). A higher correlation was obtained between nCounter analyses and real-time PCR (median ρ = 0.84). Significant associations with locoregional tumor control were observed for most of the considered biomarkers evaluated by GeneChip and nCounter analyses. In general, all applied biomarkers (single genes and gene signatures) classified approximately 70% to 85% of the patients similarly. Overall, gene signatures seem to be more robust and had a better transferability among different measurement methods.

Independent validation of tumour volume, cancer stem cell markers and hypoxia-associated gene expressions for HNSCC after primary radiochemotherapy.

OBJECTIVE: To independently validate the impact of tumour volume, p16 status, cancer stem cell (CSC) marker expression and hypoxia-associated gene signatures as potential prognostic biomarkers for patients with locally advanced head and neck squamous cell carcinoma (HNSCC), who underwent primary radiotherapy or radiochemotherapy (RCTx). These markers have previously been reported in a study of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG) (Linge et al., 2016). MATERIALS AND METHODS: In this retrospective monocentric study, 92 patients with locally advanced HNSCC were included. Univariable and multivariable logistic regressions and Cox models presented in the study of the DKTK-ROG were validated using the area under the curve (AUC) and the concordance index (ci), respectively. The primary endpoint of this study was loco-regional tumour control (LRC) after primary RCTx. RESULTS: Although both cohorts significantly differed in the proportion of the tumour subsites, the parameters tumour volume, p16 status and N stage could be validated regarding LRC and overall survival (OS) using multivariable Cox regression (LRC ci: 0.59, OS ci: 0.63). These models were slightly improved by combination with the putative CSC marker CD44 (LRC ci: 0.61, OS ci: 0.69). The logistic regression model for 2-year LRC based on tumour volume, p16 status and CD44 protein was validated with an AUC of 0.64. The patient stratification based on hypoxia-associated gene signatures status was similar to the original study but without significant differences in LRC and OS. CONCLUSIONS: In this validation study, the inclusion of the putative CSC marker CD44 slightly improved the prognostic performance of the baseline parameters tumour volume, p16 status and N stage. No improvement was observed when including expressions of the hypoxia-associated gene signatures. Prospective validation on a larger cohort is warranted to assess the clinical relevance of these markers.

Repeat FMISO-PET imaging weakly correlates with hypoxia-associated gene expressions for locally advanced HNSCC treated by primary radiochemotherapy.

BACKGROUND: Hypoxia is an important factor of tumour resistance to radiotherapy, chemotherapy and potentially immunotherapy. It can be measured e.g. by positron emission tomography (PET) imaging or hypoxia-associated gene expressions from tumour biopsies. Here we correlate [18F]fluoromisonidazole (FMISO)-PET/CT imaging with hypoxia-associated gene expressions on a cohort of 50 head and neck squamous cell carcinoma (HNSCC) patients and compare their prognostic value for response to radiochemotherapy (RCTx). METHODS: FMISO-PET/CT images of 50 HNSCC patients were acquired at four time-points before and during RCTx. For 42 of these patients, hypoxia-associated gene expressions were evaluated by nanoString technology based on a biopsy obtained before any treatment. The FMISO-PET parameters tumour-to-background ratio and hypoxic volume were correlated to the expressions of 58 hypoxia-associated genes using the Spearman correlation coefficient ρ. Three hypoxia-associated gene signatures were compared regarding their correlation with the FMISO-PET parameters using their median expression. In addition, the correlation with tumour volume was analysed. The impact of both hypoxia measurement methods on loco-regional tumour control (LRC) and overall survival (OS) was assessed by Cox regression. RESULTS: The median expression of hypoxia-associated genes was weakly correlated to hypoxia measured by FMISO-PET imaging (ρ ≤ 0.43), with higher correlations to imaging after weeks 1 and 2 of treatment (p < 0.001). Moderate correlations were obtained between FMISO-PET imaging and tumour volume (ρ ≤ 0.69). Prognostic models for LRC and OS based on the FMISO-PET parameters could not be improved by including hypoxia classifiers. CONCLUSION: We observed low correlations between hypoxia FMISO-PET parameters and expressions of hypoxia-associated genes. Since FMISO-PET showed a superior patient stratification, it may be the preferred biomarker over hypoxia-associated genes for stratifying patients with locally advanced HNSCC treated by primary RCTx.

Wavelet-based analysis of time-variant adaptive structures.

Wavelet analysis is applied to identify the time-variant dynamics of adaptive structures. The wavelet-based power spectrum of the structural response, wavelet-based frequency response function (FRF) and wavelet-based coherence are used to identify continuously and abruptly varying natural frequencies. A cantilever plate with surface-bonded macro fibre composite-which alters the structural stiffness-is used to demonstrate the application of the methods. The results show that the wavelet-based input-output characteristics-i.e. the FRF and coherence-can identify correctly the dynamics of the analysed time-variant system and reveal the varying natural frequency. The wavelet-based coherence can be used not only for the assessment of the quality of the wavelet-based FRF but also for the identification.This article is part of the theme issue 'Redundancy rules: the continuous wavelet transform comes of age'.

Development and Validation of a Gene Signature for Patients with Head and Neck Carcinomas Treated by Postoperative Radio(chemo)therapy.

Purpose: The aim of this study was to identify and independently validate a novel gene signature predicting locoregional tumor control (LRC) for treatment individualization of patients with locally advanced HPV-negative head and neck squamous cell carcinomas (HNSCC) who are treated with postoperative radio(chemo)therapy (PORT-C).Experimental Design: Gene expression analyses were performed using NanoString technology on a multicenter training cohort of 130 patients and an independent validation cohort of 121 patients. The analyzed gene set was composed of genes with a previously reported association with radio(chemo)sensitivity or resistance to radio(chemo)therapy. Gene selection and model building were performed comparing several machine-learning algorithms.Results: We identified a 7-gene signature consisting of the three individual genes HILPDA, CD24, TCF3, and one metagene combining the highly correlated genes SERPINE1, INHBA, P4HA2, and ACTN1 The 7-gene signature was used, in combination with clinical parameters, to fit a multivariable Cox model to the training data (concordance index, ci = 0.82), which was successfully validated (ci = 0.71). The signature showed improved performance compared with clinical parameters alone (ci = 0.66) and with a previously published model including hypoxia-associated genes and cancer stem cell markers (ci = 0.65). It was used to stratify patients into groups with low and high risk of recurrence, leading to significant differences in LRC in training and validation (P < 0.001).Conclusions: We have identified and validated the first hypothesis-based gene signature for HPV-negative HNSCC treated by PORT-C including genes related to several radiobiological aspects. A prospective validation is planned in an ongoing prospective clinical trial before potential application in clinical trials for patient stratification. Clin Cancer Res; 24(6); 1364-74. ©2018 AACR.

Comparison of detection methods for HPV status as a prognostic marker for loco-regional control after radiochemotherapy in patients with HNSCC.

OBJECTIVE: To compare six HPV detection methods in pre-treatment FFPE tumour samples from patients with locally advanced head and neck squamous cell carcinoma (HNSCC) who received postoperative (N = 175) or primary (N = 90) radiochemotherapy. MATERIALS AND METHODS: HPV analyses included detection of (i) HPV16 E6/E7 RNA, (ii) HPV16 DNA (PCR-based arrays, A-PCR), (iii) HPV DNA (GP5+/GP6+ qPCR, (GP-PCR)), (iv) p16 (immunohistochemistry, p16 IHC), (v) combining p16 IHC and the A-PCR result and (vi) combining p16 IHC and the GP-PCR result. Differences between HPV positive and negative subgroups were evaluated for the primary endpoint loco-regional control (LRC) using Cox regression. RESULTS: Correlation between the HPV detection methods was high (chi-squared test, p < 0.001). While p16 IHC analysis resulted in several false positive classifications, A-PCR, GP-PCR and the combination of p16 IHC and A-PCR or GP-PCR led to results comparable to RNA analysis. In both cohorts, Cox regression analyses revealed significantly prolonged LRC for patients with HPV positive tumours irrespective of the detection method. CONCLUSIONS: The most stringent classification was obtained by detection of HPV16 RNA, or combining p16 IHC with A-PCR or GP-PCR. This approach revealed the lowest rate of recurrence in patients with tumours classified as HPV positive and therefore appears most suited for patient stratification in HPV-based clinical studies.

HPV status, cancer stem cell marker expression, hypoxia gene signatures and tumour volume identify good prognosis subgroups in patients with HNSCC after primary radiochemotherapy: A multicentre retrospective study of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG).

OBJECTIVE: To investigate the impact of the tumour volume, HPV status, cancer stem cell (CSC) marker expression and hypoxia gene signatures, as potential markers of radiobiological mechanisms of radioresistance, in a contemporary cohort of patients with locally advanced head and neck squamous cell carcinoma (HNSCC), who received primary radiochemotherapy (RCTx). MATERIALS AND METHODS: For 158 patients with locally advanced HNSCC of the oral cavity, oropharynx or hypopharynx who were treated at six DKTK partner sites, the impact of tumour volume, HPV DNA, p16 overexpression, p53 expression, CSC marker expression and hypoxia-associated gene signatures on outcome of primary RCTx was retrospectively analyzed. The primary endpoint of this study was loco-regional control (LRC). RESULTS: Univariate Cox regression revealed a significant impact of tumour volume, p16 overexpression, and SLC3A2 and CD44 protein expression on LRC. The tumour hypoxia classification showed a significant impact only for small tumours. In multivariate analyses an independent correlation of tumour volume, SLC3A2 expression, and the 15-gene hypoxia signature with LRC was identified (CD44 protein n/a because of no event in the CD44-negative group). Logistic modelling showed that inclusion of CD44 protein expression and p16 overexpression significantly improved the performance to predict LRC at 2years compared to the model with tumour volume alone. CONCLUSIONS: Tumour volume, HPV status, CSC marker expression and hypoxia gene signatures are potential prognostic biomarkers for patients with locally advanced HNSCC, who were treated by primary RCTx. The study also supports that the individual tumour volumes should generally be included in biomarker studies and that panels of biomarkers are superior to individual parameters.

Low Cancer Stem Cell Marker Expression and Low Hypoxia Identify Good Prognosis Subgroups in HPV(-) HNSCC after Postoperative Radiochemotherapy: A Multicenter Study of the DKTK-ROG.

PURPOSE: To investigate the impact of hypoxia-induced gene expression and cancer stem cell (CSC) marker expression on outcome of postoperative cisplatin-based radiochemotherapy (PORT-C) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: Expression of the CSC markers CD44, MET, and SLC3A2, and hypoxia gene signatures were analyzed in the resected primary tumors using RT-PCR and nanoString technology in a multicenter retrospective cohort of 195 patients. CD44 protein expression was further analyzed in tissue microarrays. Primary endpoint was locoregional tumor control. RESULTS: Univariate analysis showed that hypoxia-induced gene expression was significantly associated with a high risk of locoregional recurrence using the 15-gene signature (P = 0.010) or the 26-gene signature (P = 0.002). In multivariate analyses, in patients with HPV16 DNA-negative but not with HPV16 DNA-positive tumors the effect of hypoxia-induced genes on locoregional control was apparent (15-gene signature: HR 4.54, P = 0.006; 26-gene signature: HR 10.27, P = 0.024). Furthermore, MET, SLC3A2, CD44, and CD44 protein showed an association with locoregional tumor control in multivariate analyses (MET: HR 3.71, P = 0.016; SLC3A2: HR 8.54, P = 0.037; CD44: HR 3.36, P = 0.054; CD44 protein n/a because of no event in the CD44-negative group) in the HPV16 DNA-negative subgroup. CONCLUSIONS: We have shown for the first time that high hypoxia-induced gene expression and high CSC marker expression levels correlate with tumor recurrence after PORT-C in patients with HPV16 DNA-negative HNSCC. After validation in a currently ongoing prospective trial, these parameters may help to further stratify patients for individualized treatment de-escalation or intensification strategies. Clin Cancer Res; 22(11); 2639-49. ©2016 AACR.

Independent validation of the prognostic value of cancer stem cell marker expression and hypoxia-induced gene expression for patients with locally advanced HNSCC after postoperative radiotherapy.

OBJECTIVE: To validate the impact of HPV status, cancer stem cell (CSC) marker expression and tumour hypoxia status in patients with locally advanced head and neck squamous cell carcinoma (HNSCC), who received postoperative radiotherapy. The results of the exploration cohort have previously been reported by the German Cancer Consortium Radiation Oncology Group (DKTK-ROG; Lohaus et al., 2014; Linge et al., 2016). MATERIALS AND METHODS: For 152 patients with locally advanced HNSCC the impact of HPV16 DNA status, CSC marker expression and hypoxia-associated gene signatures on outcome of postoperative radiotherapy were retrospectively analysed. Out of them, 40 patients received postoperative radiochemotherapy. Cox models presented in a previous study were validated using the concordance index as a performance measure. The primary endpoint of this study was loco-regional control. Results were compared to those previously reported by DKTK-ROG. RESULTS: Loco-regional control, freedom from distant metastases and overall survival were inferior to the previously reported cohort. Despite of this, the prognostic value of the combination of HPV infection status, CSC marker expression (SLC3A2) and tumour hypoxia status could be validated in univariate analyses using an independent validation cohort. For multivariate models, the concordance index was between 0.58 and 0.69 in validation, indicating a good prognostic performance of the models. The inclusion of CD44 and the 15-gene hypoxia signature moderately improved the performance compared to a baseline model without CSC markers or hypoxia classifiers. CONCLUSIONS: The HPV status, CSC marker expression of CD44 and SLC3A2 as well as hypoxia status are potential prognostic biomarkers for patients with locally advanced HNSCC treated by postoperative radiotherapy.

The effect of intranasal orexin-A (hypocretin-1) on sleep, wakefulness and attention in narcolepsy with cataplexy.

Narcolepsy with cataplexy is a sleep dysregulation disorder with alterations of REM sleep, i.e., sleep onset REM periods and REM sleep instability. Deficient orexin-A (hypocretin-1) signaling is assumed to be a major cause of narcolepsy with cataplexy. In this study we investigated fourteen subjects with narcolepsy with cataplexy in a within-subject, random-order crossover, placebo-controlled design. Patients received double-blinded intranasal orexin-A (435 nmol) or sterile water (placebo) in the morning. Administration was preceded by an adaptation night and followed by a modified maintenance of wakefulness test, attention testing and a second full night of polysomnographic recording. We found comparable sleep behavior during the adaptation nights between both conditions. After orexin-A administration patients had less wake-REM sleep transitions and a decreased REM sleep duration. In the subsequent night, patients showed an increased N2 duration. In the test of divided attention, patients had fewer false reactions after orexin-A administration. Our results support orexin-A to be a REM sleep stabilizing factor and provide functional signs for effects of orexin-A on sleep alterations and attention in narcolepsy with cataplexy.

Biomechanical study of the Delta plate and the TriLock Delta condyle trauma plate.

PURPOSE: The aim of this study was to evaluate in mandibular condylar process fractures the biomechanical stability of osteosynthesis using the Delta plate and the TriLock Delta condyle trauma plate and to compare these with 2 4-hole miniplates. MATERIALS AND METHODS: The condyles of 120 porcine mandibles were fractured at a defined location. After anatomic reduction, the fractures were fixed with a Delta plate, a TriLock Delta condyle trauma plate, or 2 4-hole miniplates (40 per group). Each group was subjected to linear loadings in 4 different directions with a universal mechanical testing machine (TIRA Test 2720). Yield load and yield displacement were measured for the 2 Delta plates and the 2 miniplates. Means were derived and compared for statistical significance using the Kruskal-Wallis test with a confidence level of 95% (P < .05). RESULTS: None of the plates broke. In 4 cases using the double miniplate and in 2 cases using the Delta plate, osteosynthesis screw loosening was registered. In lateral-to-medial and anterior-to-posterior directions, the 2 miniplates tolerated the highest loads. From medial to lateral and from posterior to anterior, the TriLock Delta condyle trauma plate resisted the highest loads. However, there was a statistically significant difference among all osteosynthesis systems only for medial-to-lateral loads. Statistical analysis for displacement showed significant differences among all plates in the 4 directions. CONCLUSIONS: This biomechanical study indicates that for rigid internal fixation of condylar fractures of the mandible, similar to 2 miniplates, the 2 Delta plates (Delta plate with gliding holes and TriLock Delta plate) fulfill the principles of a functional and stable osteosynthesis. Both are able to resist physiologic strains. The locking plate (TriLock Delta condyle trauma plate) has the advantages of greater primary stability and decreased likelihood of screw loosening.

Polycephalin B and C: Unusual Tetramic Acids from Plasmodia of the Slime Mold Physarum polycephalum (Myxomycetes).

Illumination results in increased formation of metabolites 1 and 2 in the plasmodia of the slime mold Physarum polycephalum. This was determined from HPLC studies undertaken in the search for the photoactive substances involved in the "blue-light phenomenon". The isolation and structure elucidation of 1 and 2 is described.