Metformin shows anti-neoplastic properties by inhibition of oxidative phosphorylation and glycolysis in epidermolysis bullosa-associated aggressive cutaneous squamous cell carcinoma.

BACKGROUND: While most cutaneous squamous cell carcinomas (cSCCs) are treatable, certain high-risk cSCCs, such as those in recessive dystrophic epidermolysis bullosa (RDEB) patients, are particularly aggressive. Owing to repeated wounding, inflammation and unproductive healing, RDEB patients have a 68% cumulative risk of developing life-threatening cSCCs by the age of 35, and a 70% risk of death by the age of 45. Despite aggressive treatment, cSCC represents the leading cause of premature mortality in these patients, highlighting an unmet clinical need. Increasing evidence points to a role of altered metabolism in the initiation and maintenance of cSCC, making metabolism a potential therapeutic target. OBJECTIVES: We sought to determine the feasibility of targeting tumour cell energetics as a strategy to selectively hinder the growth advantage of aggressive cSCC. METHODS: We evaluated the cell energetics profiles of RDEB-SCC cells by analysing available gene expression data against multiple gene signatures and single-gene targets linked to metabolic reprogramming. Additionally, we employed real-time metabolic profiling to measure glycolysis and respiration in these cells. Furthermore, we investigated the anti-neoplastic properties of the metformin against human and murine high-risk cSCCs in vitro and in vivo. RESULTS: Gene expression analyses highlighted a divergence in cell energetics profiles between RDEB-SCC and non-malignant RDEB keratinocytes, with tumour cells demonstrating enhanced respiration and glycolysis scores. Real-time metabolic profiling supported these data and additionally highlighted a metabolic plasticity of RDEB-SCC cells. Against this background, metformin exerted an anti-neoplastic potential by hampering both respiration and glycolysis, and by inhibiting proliferation in vitro. Metformin treatment in an analogous model of fast-growing murine cSCC resulted in delayed tumour onset and slower tumour growth, translating to a 29% increase in median overall survival. CONCLUSIONS: Our data indicate that metformin exerts anti-neoplastic properties in aggressive cSCCs that exhibit high-risk features by interfering with respiration and glycolytic processes.

Immunotherapeutics for head and neck squamous cell carcinoma stem cells.

Cancer stem cell (CSC)-related therapy resistance has become a new obstacle to the successful application of cancer treatment and head and neck squamous cell carcinoma (HNSCC) is no exception to this finding. Head and neck squamous cell carcinoma is highly immune-suppressive, and recently the immune suppression and invasion of HNSCC-CSCs have been characterized. These characteristics have received research and clinical attention because they would enable the stratification of patients into specific cancer subtypes and, consequently, the establishment of new therapeutic approaches with improved efficacy. This review discusses the feasibility of CSC-targeted strategies and their incorporation with nanotechnology to improve the efficacy of cancer immunotherapy.

Markers of the p53 pathway further refine molecular profiling in high-risk endometrial cancer: A TransPORTEC initiative.

BACKGROUND: The morphological classification of high-risk endometrial cancer is of limited prognostic value. Recent attempts to stratify tumours according to molecular signatures have shown considerable promise. Here we attempted to further refine molecular classifications using markers of the p53 pathway. METHODS: We analysed the expression of p53 as well as three downstream markers of the p53 pathway, p21, mdm2 and phospho-p63 (pp63), by immunohistochemistry in a series of 114 endometrial cancers (86 endometrioid, 28 non-endometrioid subtype) with high-risk features (such as high tumour grade and deep myometrial invasion) and correlated results with clinical outcome. The Cancer Genome Atlas (TCGA) data were used to analyse TP63 mutations and copy-number alterations using cBioPortal. TP53 was silenced in two endometrial cancer cell lines to study its effect on p21 and p63. RESULTS: About half of the tumours showed a p53 mutant phenotype and there was a strong negative correlation with p21 expression. Being marker positive for pp63 or mdm2 was associated with a significantly increased likelihood of dying, [hazard ratios 5.93 (95% CI 2.37-7.27) and 7.48 (95% CI 3.04-9.39), respectively]. These findings were seen in both p53 wildtype and p53 mutant tumours. Only 11% of TCGA endometrial cancers had a functional TP63 alteration. Upon silencing of TP53, p21 expression was decreased in one cell line, but no effects on p63 were observed. CONCLUSION: Markers of the p53 pathway improve stratification of endometrial cancers and provide novel insights into the role of this pathway in the disease.

Predicting Outcome in Subarachnoid Hemorrhage (SAH) Utilizing the Full Outline of UnResponsiveness (FOUR) Score.

BACKGROUND: Existing scoring systems for aneurysmal subarachnoid hemorrhage (SAH) patients fail to accurately predict patient outcome. Our goal was to prospectively study the Full Outline of UnResponsiveness (FOUR) score as applied to newly admitted aneurysmal SAH patients. METHODS: All adult patients presenting to Health Sciences Center in Winnipeg from January 2013 to July 2015 (2.5 year period) with aneurysmal SAH were prospectively enrolled in this study. All patients were followed up to 6 months. FOUR score was calculated upon admission, with repeat calculation at 7 and 14 days. The primary outcomes were: mortality, as well as dichotomized 1- and 6-month Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) values. RESULTS: Sixty-four patients were included, with a mean age of 54.2 years (range 26-85 years). The mean FOUR score upon admission pre- and post-external ventricular drain (EVD) was 10.3 (range 0-16) and 11.1 (range 3-16), respectively. There was a statistically significant association between pre-EVD FOUR score (total, eye, respiratory and motor sub-scores) with mortality, 1-month GOS, and 6-month GOS/mRS (p < 0.05 in all). The day 7 total, eye, respiratory, and motor FOUR scores were associated with mortality, 1-month GOS/mRS, and 6-month GOS/mRS (p < 0.05 in all). The day 14 total, eye, respiratory, and motor FOUR scores were associated with 6-month GOS (p < 0.05 in all). The day 7 cumulative FOUR score was associated with the development of clinical vasospasm (p < 0.05). CONCLUSIONS: The FOUR score at admission and day 7 post-SAH is associated with mortality, 1-month GOS/mRS, and 6-month GOS/mRS. The FOUR score at day 14 post-SAH is associated with 6-month GOS. The brainstem sub-score was not associated with 1- or 6-month primary outcomes.

Extension of the Q Orbitrap intrascan dynamic range by using a dedicated customized scan.

RATIONALE: The intrascan dynamic range of modern Orbitrap instrumentation is specified to reach 1:5000, while the interscan dynamic range is significantly larger due to the utilization of the automatic gain control feature. There are some applications (e.g. residue analysis in complex matrices, metabolomics or structural elucidation) where a wider intrascan dynamic range is desirable. METHODS: The Application Programming Interface (API) of the Q Exactive Orbitrap mass spectrometer has been used to program a customized scan in order to cover a larger intrascan dynamic range. Different approaches were used, which were all based on the variation of the isolation time of low-abundance versus high-abundance mass range segments. The differently attenuated mass range segments isolated by the quadrupole were sequentially forwarded to the C-trap. Finally, the accumulated mass segments were measured within the Orbitrap analyzer. RESULTS: The spectra obtained by the customized scans show an enlarged dynamic range. This has been demonstrated by monitoring the higher isotope mass peaks (first and second isotope) of a low intensity analyte. Furthermore, a practical application (veterinary drugs in bovine kidney) has been investigated with the proposed customized scan. Analytes eluting within the retention time region of very intense matrix peaks (e.g. peptides) showed improved detectability when utilizing the customized scan. CONCLUSIONS: The extension of the intrascan dynamic range by a customized scan is helpful when analyzing residues which happen to elute together with a dominating matrix peak or within a high ion abundance region (e.g. dead volume). Furthermore, this feature helps in the process of determining the elemental composition of compounds by permitting the investigation of low-abundance ions (e.g. belonging to the isotopic fine structure of the investigated compound).

Product ion isotopologue pattern: A tool to improve the reliability of elemental composition elucidations of unknown compounds in complex matrices.

RATIONALE: Elucidation of the elemental compositions of unknown compounds (e.g., in metabolomics) generally relies on the availability of accurate masses and isotopic ratios. This study focuses on the information provided by the abundance ratio within a product ion pair (monoisotopic versus the first isotopic peak) when isolating and fragmenting the first isotopic ion (first isotopic mass spectrum) of the precursor. METHODS: This process relies on the capability of the quadrupole within the Q Orbitrap instrument to isolate a very narrow mass window. Selecting only the first isotopic peak (first isotopic mass spectrum) leads to the observation of a unique product ion pair. The lighter ion within such an isotopologue pair is monoisotopic, while the heavier ion contains a single carbon isotope. The observed abundance ratio is governed by the percentage of carbon atoms lost during the fragmentation and can be described by a hypergeometric distribution. RESULTS: The observed carbon isotopologue abundance ratio (product ion isotopologue pattern) gives reliable information regarding the percentage of carbon atoms lost in the fragmentation process. It therefore facilitates the elucidation of the involved precursor and product ions. Unlike conventional isotopic abundances, the product ion isotopologue pattern is hardly affected by isobaric interferences. Furthermore, the appearance of these pairs greatly aids in cleaning up a 'matrix-contaminated' product ion spectrum. CONCLUSIONS: The product ion isotopologue pattern is a valuable tool for structural elucidation. It increases confidence in results and permits structural elucidations for heavier ions. This tool is also very useful in elucidating the elemental composition of product ions. Such information is highly valued in the field of multi-residue analysis, where the accurate mass of product ions is required for the confirmation process. Copyright © 2016 John Wiley & Sons, Ltd.

Persistence of immune responses to the HPV-16/18 AS04-adjuvanted vaccine in women aged 15-55 years and first-time modelling of antibody responses in mature women: results from an open-label 6-year follow-up study.

OBJECTIVE: Evaluation of the long-term HPV-16/18 AS04-adjuvanted vaccine immunogenicity persistence in women. DESIGN: Multicentre, open-label, long-term follow-up (NCT00947115) of a primary phase-III study (NCT00196937). SETTING: Six centres in Germany and Poland. POPULATION: 488 healthy women (aged 15-55 years, age-stratified into groups: 15-25, 26-45, and 46-55 years) who received three vaccine doses in the primary study. METHODS: Immune responses were evaluated in serum and cervicovaginal secretion (CVS) samples 6 years after dose 1. Anti-HPV-16/18 geometric mean titres (GMTs) were measured by enzyme-linked immunosorbent assay (ELISA), and were used to fit the modified power-law and piecewise models, predicting long-term immunogenicity. Serious adverse events (SAEs) were recorded. MAIN OUTCOME MEASURES: Anti-HPV-16/18 seropositivity rates and GMTs 6 years after dose 1. RESULTS: At 6 years after dose 1, all women were seropositive for anti-HPV-16 and ≥97% were seropositive for anti-HPV-18 antibodies. GMTs ranged from 277.7 to 1344.6 EU/ml, and from 97.6 to 438.2 EU/ml, for anti-HPV-16 and anti-HPV-18, respectively. In all age groups, GMTs were higher (anti-HPV-16, 9.3-45.1-fold; anti-HPV-18, 4.3-19.4-fold) than levels associated with natural infection (29.8 EU/ml). A strong correlation between serum and CVS anti-HPV-16/18 levels was observed, with correlation coefficients of 0.81-0.96 (anti-HPV-16) and 0.69-0.84 (anti-HPV-18). Exploratory modelling based on the 6-year data predicted vaccine-induced anti-HPV-16/18 levels above natural infection levels for at least 20 years, except for anti-HPV-18 in the older age group (piecewise model). One vaccine-related and two fatal SAEs were reported. CONCLUSIONS: At 6 years after vaccination, immune responses induced by the HPV-16/18 AS04-adjuvanted vaccine were sustained in all age groups.

Assessing the function of homologous recombination DNA repair in malignant pleural effusion (MPE) samples.

BACKGROUND: Patients with malignant pleural effusions (MPEs) generally have advanced disease with poor survival and few therapeutic options. Cells within MPEs may be used to stratify patients for targeted therapy. Targeted therapy with poly(ADP ribose) polymerase inhibitors (PARPi) depends on identifying homologous recombination DNA repair (HRR)-defective cancer cells. We aimed to determine the feasibility of assaying HRR status in MPE cells. METHODS: A total of 15 MPE samples were collected from consenting patients with non-small-cell lung cancer (NSCLC), mesothelioma and ovarian and breast cancer. Primary cultures were confirmed as epithelial by pancytokeratin, and HRR status was determined by the detection of γH2AX and RAD51 foci following a 24-h exposure to rucaparib, by immunofluorescence microscopy. Massively parallel next-generation sequencing of DNA repair genes was performed on cultured MPE cells. RESULTS: From 15 MPE samples, 13 cultures were successfully established, with HRR function successfully determined in 12 cultures. Four samples - three NSCLC and one mesothelioma - were HRR defective and eight samples - one NSCLC, one mesothelioma, one sarcomatoid, one breast and four ovarian cancers - were HRR functional. No mutations in DNA repair genes were associated with HRR status, but there was probable loss of heterozygosity of FANCG, RPA1 and PARP1. CONCLUSIONS: HRR function can be successfully detected in MPE cells demonstrating the potential to stratify patients for targeted therapy with PARPi.

Elastic modulus and fracture strength evaluation on the nanoscale by scanning force microscope experiments.

This work first reviews the capability of scanning force microscopy (SFM) to perform experiments with forces in a wide range, from low non-contact forces to high contact forces which induce mechanical deformations in the substrate. In analogy to fracture strength evaluation, as established in materials science, SFM is used to exert forces on pillars with nanometer dimensions while the cantilever deformations are monitored quantitatively. Hence, it is possible to bend the pillars until the threshold for triggering fracture is reached, and to determine the mechanical properties at the different stages of this process. Using this novel approach, in combination with 'state of the art' nanofabrication to produce nanopillar arrays on silicon and silicon dioxide substrates, a number of experiments are performed. Furthermore, quantitative measurements of the fracture strength of Si and of the SiO2/Si interface and E-modulus are presented. To analyze the experimental data obtained in the different experimental procedures and modes, finite element method calculations were used. The methods introduced herein provide a versatile toolbox for addressing a wide range of scientific problems and for applications in materials science and technology.

Technical aspects of botulinum toxin type A injection in the bladder to treat urinary incontinence: reviewing the procedure.

AIMS: Standardise the injection technique with botulinum toxin type A (BoNT A) in the bladder of patients with overactive bladder (OAB) [idiopathic overactive bladder (iOAB) or neurogenic overactive bladder (nOAB) with urinary incontinence], using a literature review and a survey of an International expert panel. METHODS: PubMed literature searches of BoNT A in adults with iOAB/nOAB together with a survey of 13 experts from 10 countries. RESULTS: Data from 21 articles and completed questionnaires were collated. The procedure can be carried out in an out-/inpatient setting. Dose used in clinical studies vs. clinical practice was 300 and 200 U for nOAB and 200 and 100 U for iOAB. Recent studies have also demonstrated that there are no clinically relevant benefits between 100 and 150 U in iOAB or between 300 and 200 U in nOAB, though adverse effects are increased with higher doses. Usually, 30 sites for nOAB (range: 6.7-10 U/ml) and 20-30 sites for iOAB (range: 5-10 U/ml) are injected in clinical studies vs. 20-30 sites of 1 ml/injection for 200 U in nOAB and 10-20 sites of 0.5-1 ml/injection for 100 U in iOAB in clinical practice. BoNT A is usually injected directly into the detrusor, sparing the trigone. Flexible or rigid cystoscopes are used. The needle should be typically 22-27 gauge and 4 mm in length and should have a stopper to avoid any leakage or perforation of the bladder wall while ensuring a targeted injection. CONCLUSION: Based on the literature and survey analysis, recommendations are proposed for the standardisation of the injection procedure.

[Cancer stem cell phenotypes and miRNA: therapeutic targets in head and neck squamous cell carcinoma]. / Tumorstammzellphänotypen und miRNA : Therapietargets bei Kopf-Hals-Plattenepithelkarzinomen.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. HNSCC is caused by persistent high-risk human papillomavirus (HR-HPV) infection or excessive consumption of alcohol or tobacco. The persistently low survival rates result from local recurrences and metastases, which are probably caused by so-called tumor stem cells (TSCs). The epithelial-mesenchymal transition (EMT) or transformation is a key event in metastasis initiation and is being increasingly associated with TSCs. OBJECTIVES: This review describes new therapeutic targets in HNSCC, focusing on the TSC hypothesis and EMT regulation. MATERIALS AND METHODS, RESULTS: TSCs and EMT are regulated directly and indirectly via transcription factors and microRNAs (miRNAs). These miRNAs regulate multiple cellular processes and may serve as new therapeutic targets, whose modulation could increase the effectiveness of HNSCC treatments. Post-transcriptionally, miRNAs regulate transcription factors associated with EMT (ZEB1/2, EZH2, Bmi-1), tumor suppressors (p53), TSC markers (ALDH, CD44, EpCAM, p63) and both epithelial (E-cadherin) and mesenchymal markers (vimentin). CONCLUSION: Alterations in HNSSC TSC miRNA expression before and after chemotherapy could potentially serve as a therapeutic control. In the long term, knowledge of a patient's individual protein expression pattern may permit application of specific chemotherapy. Such individualized therapy might prohibit the development of metastases and potentially unresectable recurrences with a high resistance to radiation and chemotherapy, thus improving the prognosis in HNSCC patients.

[Role of miRNA in malignoma of the head and neck]. / Die Rolle von miRNA bei Kopf-Hals-Malignomen.

Despite optimized therapeutic strategies, the long-term survival of head and neck squamous cell carcinomas (HNSCC) has improved in recent years only slightly. Most studies on the tumor cell genome focus on protein-coding genes (exons). Data on changes within the non-coding sequences (introns) are limited. miRNAs (microRNA, miR) are small non-coding single-stranded RNAs that control gene expression at the posttranscriptional level by interacting with the mRNA. miRNA functions include many biological processes and control up to 50 % of human genes. They can have oncogenic or tumor suppressive functions. Altered expression patterns of miRNAs are involved in carcinogenesis and tumor progression even in HNSCC, or those processes (increased resistance to radiation or chemotherapy) that could be responsible for the poor long-term prognosis by forming metastases and inoperable local recurrences. Therefore, we here present miRNA groups, which are involved in these processes and may serve as new potential therapeutic treatment targets. miRNAs may also serve as biomarkers for early diagnosis, evaluation and monitoring of treatment and tumor recurrence. Alterations in miRNA expression before and after chemotherapy are therefore of high interest. In the long run, this knowledge could lead to more effective therapies with improved therapeutic outcome of HNSCC.

Feasibility and acceptance of cervicovaginal self-sampling within the German National Cohort (Pretest 2).

BACKGROUND AND OBJECTIVES: Within the German National Cohort (GNC) 100,000 adult women in Germany will be comprehensively interviewed and examined. While women's health is addressed in the basic interview, direct detection of cervicovaginal microbial colonisation or infection is not part of the examination protocol. In a pilot project the feasibility of female study participants of the GNC collecting a cervicovaginal lavage at home without having to involve a gynecologist or other medical personnel was thus investigated. The ability of the procedure to detect vaginal microbes and conditions including human papillomavirus (HPV), Chlamydia trachomatis and bacterial vaginosis (BV) were also explored. METHODS: This cross-sectional study was conducted in two study centers (Hamburg and Hanover) of the GNC during Pretest 2 in 2012 as an add-on module to the main program of the National Cohort. Participants were randomly selected through the population registration office. After providing written informed consent at the study center, participants self-collected a cervicovaginal lavage (Delphi Screener™) at home following written instructions. Participants mailed samples and acceptability questionnaires to the laboratory and the study center, respectively. Acceptability of self-sampling was categorized as consent, partial consent and rejection. The samples were analyzed by multiplex HPV genotyping for the presence of 27 mucosal HPV subtypes. To detect other pathogens "Sexually Transmitted Infection Profiling" (STIP) was used, a novel multiplex polymerase chain reaction (PCR) for various vaginally occurring pathogens/conditions coupled with subsequent bead-based Luminex(®) hybridization. Human beta-globin and DNA polymerase alpha (PolA) sequences were used as positive controls for the detection of human DNA during HPV detection and STIP, respectively. RESULTS: The participation based on the proportion of all women in Pretest 2 who could take part in the add-on Pretest 2 was 67.3 % (109 out of 162). The age of participants ranged from 20 to 69 years. The self-reported median duration of the collection of the lavage was 5 min. Analysis of the questionnaires (n = 108) revealed that the self-sampling of a cervicovaginal lavage was acceptable to 98 % of women (106 out of 108), and considered to be easy by 89 % (96 out of 108) as well as user-friendly by 96 % of the women (104 out of 108). Human beta-globin and PolA as markers for human DNA and sample quality were detected in all samples analyzed while HPV as a marker for pathogen detectability was identified in 18 out of 109 samples. Of the 107 samples tested with STIP as a second marker for pathogen detectability, 5 samples were excluded from statistical analyses on bacterial colonization because of signs in the laboratory results of the use of antibiotics. For the computation of the possible occurrence of bacterial vaginosis and candidiasis 7 and 8 samples, respectively, were excluded because of low signal intensities resulting in an evaluation of 95 or 94 samples, respectively. Ureaplasma parvum was detected in 22 out of 102 samples, BV in 14 out of 95 samples and candidiasis in 13 out of 94 samples. Chlamydia trachomatis was not detected in any sample. CONCLUSION: The feasibility study on cervicovaginal self-sampling indicates that this form of biosampling was very well accepted within the framework of the GNC and feasible in terms of pathogen detection. Its further application in the GNC would allow investigation of transience and persistence, or long-term effects of vaginal (co)infections and colonization.

Improved method robustness and ruggedness in liquid chromatography-mass spectrometry by increasing the acid content of the mobile phase.

A routine multiresidue method developed for the detection and quantification of veterinary drug residues in animal-based food was used to analyze sheep (ovine) liver. Unlike when working with previously validated matrices (e.g., bovine liver), some of the analytes of interest chromatographed in the form of split- or even fully baseline separated peaks. In other cases a significantly longer retention times (tR) was observed. A detailed investigation led to the elucidation of taurocholic acid as the causative agent. This compound is present in sheep liver at significantly higher concentrations than in most other animal tissues. Taurocholic acid is a zwitterionic compound and likely acts as an ion pairing agent, which modifies the selectivity of the stationary phase in a highly spatial and dynamic way. Injecting smaller volumes of matrix extract or the use of a significantly higher formic acid concentration in the mobile phase reduced or even completely eliminated the peak splitting. A more detailed examination led to the observation that the problem is not restricted to this particular matrix and extraction procedure or the used stationary phase. In fact, a higher formic acid concentration (e.g., 1.0 % versus 0.1 %) significantly improves the peak shape of many analytes present in fortified matrix samples as well as in pure standard solutions. In addition, analytical column aging was observed as being slower with a higher formic acid concentration. Finally the peak shape of analytes interacting with the metallic parts along the flow path of the liquid chromatograph was also significantly improved. Use of 0.1 % acid in mobile phases is often taken for granted in LC-MS. Regardless of the stationary phase, a higher ionic strength better stabilizes the pH and reduces unwanted interactions, which ultimately improves the method robustness. Flow injection experiments often show that 0.1 % acid concentrations produce the highest analyte signals. Yet, the use of 1 % acid in the mobile phase often leads to narrower and therefore taller chromatographic peaks, which may lead to lower detection limits for many analytes and to an improved separation efficiency.

Evaluation of the interrelationship between mass resolving power and mass error tolerances for targeted bioanalysis using liquid chromatography coupled to high-resolution mass spectrometry.

The determination of acceptable mass error tolerances for high-resolution mass spectrometry based signals has been evaluated in a comprehensive way. This was achieved by using a technical approach which is based on the post-column infusion of an analyte containing solution. This well-known experimental setup was not used to spot signal suppression regions of a particular analyte, but to spot regions of the chromatogram where a systematic mass drift of the analyte ion can be observed (isobaric interference plot). Not the changing signal intensity but the stability of the measured analyte mass was observed. A wide range of different analytes in combinations with potentially interfering matrices has been evaluated. Furthermore, different mass resolving power settings were evaluated. Isobaric interferences between matrix compounds and analytes were common at mass resolving powers <50,000 full width at half maximum. The proposed post-column infusion technique is a useful tool for the determination of the assay and matrix-specific mass error tolerances. It aims to ensure the highest possible selectivity, at the same time preventing the encounter of detrimental mass error related peak deformations as well as false negative findings. Unlike conventional matrix spiking approaches, isobaric interference plots provide information of potential interferences across the whole chromatographic time range. This becomes relevant when there is a relative retention time shift between the analyte and potential interfering matrix compounds. Furthermore, the described setup can be used to study how the mass accuracy of any mass spectrometer is affected by a widely varying total ion current.

Gamma knife radiosurgery for large vestibular schwannomas: a Canadian experience.

OBJECT: To review our institutional experience with Gamma Knife (GK) stereotactic radiosurgery in treating large vestibular schwannomas (VS) of 3 to 4 cm diameter. METHODS: We conducted a retrospective cohort review of all patients treated with GK for VS at our institution between November 2003 and March 2012. Data on age, sex, VS volume, location and maximal diameter, House-Brackmann (HB) facial nerve scores pre and post-GK, Gardner-Robertson (GR) hearing score pre and post-GK, GK treatment parameters, VS response time, complications and clinical outcome was recorded RESULTS: A total of 28 patients during the defined time period were identified. Three patients were lost to follow-up. Mean follow-up was 34.5 months. Tumor control occurred in 92%, and was maintained in 85.7% at two years. Facial nerve or hearing preservation occurred in all treated compared to pre-GK status, as per HB and GR grading. Transient complications occurred in 80%. Temporary vestibular dysfunction occurred in seven patients (28%). One patient (4%) had the permanent complication of worsening pre-GK hemifacial spasm. Four patients (16%) developed hydrocephalus post-GK. CONCLUSION: GK stereotactic radiosurgery as a primary treatment modality for large VS can provide acceptable tumor control rates with good facial nerve and hearing preservation, and low complication rates.

Gamma knife in the treatment of pituitary adenomas: results of a single center.

INTRODUCTION: Gamma Knife (GK) radiosurgery for pituitary adenomas can offer a means of tumor and biologic control with acceptable risk and low complication rates. METHODS: Retrospective review of all the patients treated at our center with GK for pituitary adenomas from Nov 2003 to June 2011. RESULTS: We treated a total of 86 patients. Ten were lost to follow-up. Mean follow was 32.8 months. There were 21 (24.4%) growth hormone secreting adenomas (GH), 8 (9.3%) prolactinomas (PRL), 8 (9.3%) adrenocorticotropic hormone secreting (ACTH) adenomas, 2 (2.3%) follicle stimulating hormone/luteinizing hormone secreting (FSH/LH) adenomas, and 47 (54.7%) null cell pituitary adenomas that were treated. Average maximum tumor diameter and volume was 2.21cm and 5.41cm³, respectively. The average dose to the 50% isodose line was 14.2 Gy and 23.6 Gy for secreting and non-secreting adenomas respectively. Mean maximal optic nerve dose was 8.87 Gy. Local control rate was 75 of 76 (98.7%), for those with followup. Thirty-three (43.4%) patients experienced arrest of tumor growth, while 42 (55.2%) patients experienced tumor regression. Of the 39 patients with secreting pituitary tumors, 6 were lost to follow-up. Improved endocrine status occurred in 16 (50.0%), while 14 (43.8%) demonstrated stability of hormone status on continued pre-operative medical management. Permanent complications included: panhypopituitarism (4), hypothyroidism (4), hypocortisolemia (1), diabetes insipidus (1), apoplexy (1), visual field defect (2), and diplopia (1). CONCLUSIONS: Gamma Knife radiosurgery is a safe and effective means of achieving tumor growth control and endocrine remission/stability in pituitary adenomas.

Gamma knife radiosurgery for high grade glial neoplasms: a Canadian experience.

OBJECT: To review our institutional experience with Gamma Knife (GK) stereotactic radiosurgery in treating focally recurrent high grade glial neoplasms of World Health Organization (WHO) grade III or IV. METHODS: We conducted a retrospective cohort review of all patients treated with GK for focally recurrent high grade gliomas at our institution between November 2003 and April 2013. Data on age, sex, tumor volume, location and maximal diameter, presenting clinical status, complications and clinical outcome was recorded. RESULTS: A total of 33 patients were identified. Four were lost to follow-up. Average post-GK and overall survival was 20.4 months (range: 3­72) and 63.3 months (range: 10­214) respectively. For WHO grade IV gliomas, the average post-GK and overall survival was 15.8 months (range: 3­77) and 40.1 months (range: 13­148) respectively. Similarily, for WHO grade III gliomas, the average post-GK and overall survival was 34.9 months (range: 6­72) and 136.4 months (range: 22­214) respectively. Twenty-two patients (75.9%) had post-GK edema, with 14 requiring dexamethasone and eight being asymptomatic. Four patients (13.8%) had imaging defined radiation necrosis. CONCLUSIONS: Gamma Knife SRS affords an extension of local tumor control, acceptable morbidity, and potentially prolonged survival, for highly selected patients with focally recurrent high grade glial neoplasms.Radiochirurgie par scalpel gamma pour les néoplasies gliales de haut grade de malignité : une expérience canadienne.

Ketamine for medically refractory status epilepticus after elective aneurysm clipping.

BACKGROUND: Medically refractory status epilepticus, without an identifiable cause, post elective aneurysm clipping is a rare event. OBJECTIVE: To describe the two cases of refractory status epilepticus post elective aneurysm clipping, without an identifiable cause, and discuss the potential role for early consideration of ketamine. METHODS: Retrospectively reviewed two patients at our institution who developed refractory status epilepticus post elective aneurysm clipping, without a defined cause. RESULTS: Two patients who underwent elective aneurysm clipping developed medically refractory status epilepticus post-craniotomy. No structural, vascular, infectious, or metabolic cause was identified. Seizure control failed with multiple medications and intravenous sedatives over the period of weeks in both. Ketamine was instituted at 20 and 40 mg/kg/min in these patients. Within hours of starting ketamine, burst suppression was obtained in both. Medications were all tapered over the next month, and both the patients recovered to be cognitively normal, with mild residual morbidity secondary to critical care polyneuropathy. CONCLUSIONS: Refractory status epilepticus, in the absence of an identifiable etiology, in elective aneurysm clipping is a rare event. Consideration should be given for the early use of ketamine in refractory status epilepticus.

Accuracy of relative isotopic abundance and mass measurements in a single-stage orbitrap mass spectrometer.

Orbitrap technology offers a combination of different technical specifications which have not yet been achieved by other high-resolution mass spectrometry instrumentation. This refers to the combination of sensitivity, dynamic range, mass accuracy, resolution and speed. The high stability of the mass axis and the general ease of use made the orbitrap instrumentation attractive for routine laboratories. However, there are circumstances where significantly deviating relative isotopic abundance (RIA) and shifting accurate masses can be observed. RIA becomes biased at low ion counts. Furthermore, two adjacent, only partially resolved near-isobaric ions are detected with a deviating RIA. The presence of a very intensive mass peak does not only induce Fourier transformation related artefacts (side-lobes) but can cause mass shifts of small adjacent near-isobaric mass peaks. These effects are not as drastic as known for Fourier transform ion cyclotron resonance instruments. Still, users trying to identify or quantify trace level compounds should be aware about such limitations in order to avoid possible pitfalls.