Evaluation of internal standards for inductively coupled plasma-mass spectrometric analysis of arsenic in soils.

Arsenic (As) is a common contaminant in soils, and analysis of soils by inductively coupled plasma-mass spectrometry (ICP-MS) is often used to detect As in soil extracts. Internal standards (ISs) are part of ICP-MS analyses to enhance precision and accuracy by compensating for instrument variability; however, an improper choice of IS can result in negative analytical bias. The goal of this study was to develop a protocol for evaluating ISs commonly used in ICP-MS. Three soils of varying clay content and total As were extracted with a dilute electrolyte [0.005 mol L-1 Mg(NO3 )2 ] and an acid digest. Arsenic concentrations were quantified by ICP-MS using typical ISs: 6 Li, 45 Sc, 69 Ga, 89 Y, 103 Rh, 115 In, 159  Tb, and 209 Bi. Standard addition was used as a benchmark for As quantification. The most consistent IS was 115 In. Elevated, naturally occurring concentrations were detected for several of the ISs, particularly in the total digests, emphasizing the necessity for screening soils prior to analysis.

Solvent-Free Synthesis of Nano Zirconium Phenylphosphonates with Molten Phenylphosphonic Acid.

Nanosized α-zirconium phenylphosphonate particles were successfully prepared by the reaction between different zirconium sources and molten phenylphosphonic acid in the absence of solvent. The resultant nanoplates exhibit particle sizes in the range of 15 to 30 nm. The use of a topotactic anion exchange method starting from α-zirconium phosphate instead resulted in the generation of 15 to 180 nm plates, while also resulting in nanoparticles with a higher degree of crystallinity. The topotactic anion exchange of the phosphate groups by phenylphosphonate groups could be performed to completion when performed in molten phenylphosphonic acid. Characterization of both the final products as well as the individual steps in the anion exchange were performed by powder XRD, fast neutron activation analysis, TGA, FTIR spectroscopy, TEM, solid-state NMR and XPS.

Molecular Colocalization Using Massive Gold Cluster Secondary Ion Mass Spectrometry.

We report on the ion emission from impacts of hypervelocity massive gold clusters for use in secondary ion mass spectrometry. Two massive gold clusters are considered, 520 keV Au4004+ and 1040 keV Au28008+. The emission of fragment ions and molecular ions is evaluated for a series of neat samples, glycine, phenylalanine, arginine, and gramicidin S. A 2 to 4-fold increase of molecular ion emission is observed from impacts of 1040 keV Au28008+ versus 520 keV Au4004+. Compared to impacts of 20 keV Ar2000+ and 20 keV (H2O)7000+ in static conditions, impacts of 1040 keV Au28008+ display a 6 to 9-fold increase in the number of detected molecular ions per projectile impact. To explain the increased emission of molecular species, we examine the size of the impact craters and calculate the ratio of molecular ions to fragment ions. The characterization of Au28008+ and the operating conditions of the gold liquid metal ion source are presented.

Comprehensive Molecular Profiling Identifies FOXM1 as a Key Transcription Factor for Meningioma Proliferation.

Meningioma is the most common primary intracranial tumor, but the molecular drivers of aggressive meningioma are incompletely understood. Using 280 human meningioma samples and RNA sequencing, immunohistochemistry, whole-exome sequencing, DNA methylation arrays, and targeted gene expression profiling, we comprehensively define the molecular profile of aggressive meningioma. Transcriptomic analyses identify FOXM1 as a key transcription factor for meningioma proliferation and a marker of poor clinical outcomes. Consistently, we discover genomic and epigenomic factors associated with FOXM1 activation in aggressive meningiomas. Finally, we define a FOXM1/Wnt signaling axis in meningioma that is associated with a mitotic gene expression program, poor clinical outcomes, and proliferation of primary meningioma cells. In summary, we find that multiple molecular mechanisms converge on a FOXM1/Wnt signaling axis in aggressive meningioma.

Resection and brain brachytherapy with permanent iodine-125 sources for brain metastasis.

OBJECTIVE Stereotactic radiosurgery (SRS) with or without whole-brain radiotherapy can be used to achieve local control (> 90%) for small brain metastases after resection. However, many brain metastases are unsuitable for SRS because of their size or previous treatment, and whole-brain radiotherapy is associated with significant neurocognitive morbidity. The purpose of this study was to investigate the efficacy and toxicity of surgery and iodine-125 (125I) brachytherapy for brain metastases. METHODS A total of 95 consecutive patients treated for 105 brain metastases at a single institution between September 1997 and July 2013 were identified for this analysis retrospectively. Each patient underwent MRI followed by craniotomy with resection of metastasis and placement of 125I sources as permanent implants. The patients were followed with serial surveillance MRIs. The relationships among local control, overall survival, and necrosis were estimated by using the Kaplan-Meier method and compared with results of log-rank tests and multivariate regression models. RESULTS The median age at surgery was 59 years (range 29.9-81.6 years), 53% of the lesions had been treated previously, and the median preoperative metastasis volume was 13.5 cm3 (range 0.21-76.2 cm3). Gross-total resection was achieved in 81% of the cases. The median number of 125I sources implanted per cavity was 28 (range 4-93), and the median activity was 0.73 mCi (range 0.34-1.3 mCi) per source. A total of 476 brain MRIs were analyzed (median MRIs per patient 3; range 0-22). Metastasis size was the strongest predictor of cavity volume and shrinkage (p < 0.0001). Multivariable regression modeling failed to predict the likelihood of local progression or necrosis according to metastasis volume, cavity volume, or the rate of cavity remodeling regardless of source activity or previous SRS. The median clinical follow-up time in living patients was 14.4 months (range 0.02-13.6 years), and crude local control was 90%. Median overall survival extended from 2.1 months in the shortest quartile to 62.3 months in the longest quartile (p < 0.0001). The overall risk of necrosis was 15% and increased significantly for lesions with a history of previous SRS (p < 0.05). CONCLUSIONS Therapeutic options for patients with large or recurrent brain metastases are limited. Data from this study suggest that resection with permanent 125I brachytherapy is an effective strategy for achieving local control of brain metastasis. Although metastasis volume significantly influences resection cavity size and remodeling, volumetric parameters do not seem to influence local control or necrosis. With careful patient selection, this treatment regimen is associated with minimal toxicity and can result in long-term survival for some patients. ▪ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: retrospective case series; evidence: Class IV.

Survival after chemotherapy and stem cell transplant followed by delayed craniospinal irradiation is comparable to upfront craniospinal irradiation in pediatric embryonal brain tumor patients.

Pediatric embryonal brain tumor patients treated with craniospinal irradiation (CSI) are at risk for adverse effects, with greater severity in younger patients. Here we compare outcomes of CSI vs. high-dose chemotherapy (HD), stem cell transplant (SCT) and delayed CSI in newly diagnosed patients. Two hundred one consecutive patients treated for medulloblastoma (72 %), supratentorial primitive neuroectodermal tumor (sPNET; 18 %) or pineoblastoma (10 %) at two institutions between 1988 and 2014 were retrospectively identified. Progression free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared by log-rank tests. Adjuvant CSI regimens were used for 56 % of patients (upfront-CSI), and HD/SCT regimens were used in 32 % of patients. HD/SCT patients were significantly younger than those receiving upfront-CSI (2.9 vs. 7.8 years; P < 0.0001). There were no differences in metastases, extent of resection, or CSI dose between upfront-CSI and HD/SCT patients, but median follow-up was shorter in the HD/SCT group (6.2 vs. 3.9 years; P = 0.007). There were no significant outcome differences between upfront-CSI and HD/SCT patients who received CSI as a prophylaxis or following relapse (OS 66 % vs. 61 %, P = 0.13; PFS 67 % vs. 62 %, P = 0.12). Outcomes were equivalent when restricting analyses to HD/SCT patients who received prophylactic CSI prior to relapse (OS 66 % vs. 65 %, P = 0.5; PFS 67 % vs. 74 %, P = 0.8). At last follow-up, 48 % of HD/SCT patients had received neither definitive nor salvage radiotherapy. In this retrospective cohort, outcomes with adjuvant HD/SCT followed by delayed CSI are comparable to upfront-CSI for carefully surveyed pediatric embryonal brain tumor patients. Future prospective studies are required to validate this finding, and also to assess the impact of delayed CSI on neurocognitive outcomes.

Patient- and treatment-specific predictors of genitourinary function after high-dose-rate monotherapy for favorable prostate cancer.

PURPOSE: High-dose-rate (HDR) brachytherapy alone is an effective treatment option for patients with early-stage prostate cancer. The purpose of this study was to quantify patient-reported short- and long-term toxicity and quality of life (QOL) after HDR monotherapy. METHODS AND MATERIALS: Thirty-nine consecutive men between May 2001 and January 2012 were identified for this analysis. All patients underwent definitive HDR monotherapy for favorable prostate cancer to a total dose of 3150 cGy in three fractions, 3800 cGy in four fractions, or 3850 in five fractions. Patient-reported genitourinary function was assessed before HDR, during an acute period after treatment (within 90 days of HDR), and on long-term followup using the American Urological Association International Prostate Symptom Score, a urinary QOL Likert questionnaire, and the Sexual Health Inventory for Men questionnaire. Regression analyses were performed using the ordinary least squares method. RESULTS: With median followup of 57 months, biochemical progression-free survival was 100%. There were no grade ≥3 toxicities. Dose to the urethra and bladder, as well as prostate size and intraprostatic urethra length were predictive for short-term changes in QOL. Advanced patient age was predictive for worse sexual function on both acute and long-term followup. CONCLUSIONS: Toxicity after HDR monotherapy for prostate cancer is acceptable. Patients with larger prostates, longer intraprostatic urethras, and greater doses to the bladder and urethra may experience worse acute urinary QOL. Older patients may experience greater impairment in sexual function in the short and long terms.

Improvements in determinations using the Cu-64 annihilation gamma rays.

The method of gammagamma coincidence counting has been applied to the determination of Cu via the (64)Cu annihilation gamma rays. Preliminary experiments show that at least an order of magnitude reduction in (24)Na interference may be obtained by employing the 511-511 keV coincidence peak rather than the singles 511-keV peak. The effect of the sample matrix on the yield of (24)Na pair-production events was investigated by a combination of experimental measurements and Monte Carlo calculations.