Versailles Project on Advanced Materials and Standards interlaboratory study on intensity calibration for x-ray photoelectron spectroscopy instruments using low-density polyethylene

We report the results of a Versailles Project on Advanced Materials and Standards interlaboratory study on the intensity scale calibration of x-ray photoelectron spectrometers using low-density polyethylene (LDPE) as an alternative material to gold, silver, and copper. An improved set of LDPE reference spectra, corrected for different instrument geometries using a quartz-monochromated Al Kα x-ray source, was developed using data provided by participants in this study. Using these new reference spectra, a transmission function was calculated for each dataset that participants provided. When compared to a similar calibration procedure using the NPL reference spectra for gold, the LDPE intensity calibration method achieves an absolute offset of ∼3.0% and a systematic deviation of ±6.5% on average across all participants. For spectra recorded at high pass energies (≥90 eV), values of absolute offset and systematic deviation are ∼5.8% and ±5.7%, respectively, whereas for spectra collected at lower pass energies (<90 eV), values of absolute offset and systematic deviation are ∼4.9% and ±8.8%, respectively; low pass energy spectra perform worse than the global average, in terms of systematic deviations, due to diminished count rates and signal-to-noise ratio. Differences in absolute offset are attributed to the surface roughness of the LDPE induced by sample preparation. We further assess the usability of LDPE as a secondary reference material and comment on its performance in the presence of issues such as variable dark noise, x-ray warm up times, inaccuracy at low count rates, and underlying spectrometer problems. In response to participant feedback and the results of the study, we provide an updated LDPE intensity calibration protocol to address the issues highlighted in the interlaboratory study. We also comment on the lack of implementation of a consistent and traceable intensity calibration method across the community of x-ray photoelectron spectroscopy (XPS) users and, therefore, propose a route to achieving this with the assistance of instrument manufacturers, metrology laboratories, and experts leading to an international standard for XPS intensity scale calibration.

Comparing the effects of endogenous and synthetic cannabinoid receptor agonists on survival of gastric cancer cells

AIMS

Anti-neoplastic activity induced by cannabinoids has been extensively documented for a number of cancer cell types; however, this topic has been explored in gastric cancer cells only in a limited number of approaches. Thus, the need of integrative and comparative studies still persists.

MATERIALS AND METHODS

In this study we tested and compared the effects of three different cannabinoid receptor agonists-anandamide (AEA), (R)-(+)-methanandamide (Meth-AEA) and CP 55,940 (CP)- on gastric cancer cell morphology, viability and death events in order to provide new insights to the use of these agents for therapeutic purposes.

KEY FINDINGS

The three agents tested exhibited similar concentration-dependent effects in the induction of changes in cell morphology and cell loss, as well as in the decrease of cell viability and DNA laddering in the human gastric adenocarcinoma cell line (AGS). Differences among the cannabinoids tested were mostly observed in the density of cells found in early and late apoptosis and necrosis, favoring AEA and CP as the more effective inducers of apoptotic mechanisms, and Meth-AEA as a more effective inducer of necrosis through transient and rapid apoptosis.

SIGNIFICANCE

Through a comparative approach, our results support and confirm the therapeutic potential that cannabinoid receptor agonists exert in gastric cancer cells and open possibilities to use cannabinoids as part of a new gastric cancer therapy.

Atomic force acoustic microscopy: Influence of the lateral contact stiffness on the elastic measurements

Atomic force acoustic microscopy is a dynamic technique where the resonances of a cantilever, that has its tip in contact with the sample, are used to quantify local elastic properties of surfaces. Since the contact resonance frequencies (CRFs) monotonically increase with the tip-sample contact stiffness, they are used to evaluate the local elastic properties of the surfaces through a suitable contact mechanical model. The CRFs depends on both, normal and lateral contact stiffness, kN and kS respectively, where the last one is taken either as constant (kS<1), or as zero, leading to uncertainty in the estimation of the elastic properties of composite materials. In this work, resonance spectra for free and contact vibration were used in a finite element analysis of cantilevers to show the influence of kS in the resonance curves due to changes in the kS/kN ratio. These curves have regions for the different vibrational modes that are both, strongly and weakly dependent on kS, and they can be used in a selective manner to obtain a precise mapping of elastic properties.

On the effects of CP 55-940 and other cannabinoid receptor agonists in C6 and U373 cell lines

Cannabinoid receptor (CBs) agonists affect the growth of tumor cells via activation of deadly cascades. The spectrum of action of these agents and the precise role of the endocannabinoid system (ECS) on oncogenic processes remain elusive. Herein we compared the effects of synthetic (CP 55-940 and WIN 55,212-2) and endogenous (anandamide or AEA) CBs agonists (10-20 μM) on morphological changes, cell viability, and induction of apoptosis in primary astrocytes and in two glioblastoma cell lines (C6 and U373 cells) in order to characterize their possible differential actions on brain tumor cells. None of the CBs agonist tested induced changes in cell viability or morphology in primary astrocytes. In contrast, CP 55-940 significantly decreased cell viability in C6 and U373 cells at 5 days of treatment, whereas AEA and WIN 55,212-2 moderately decreased cell viability in both cell lines. Treatment of U373 and C6 for 3 and 5 days with AEA or WIN 55,212-2 produced discrete morphological changes in cell bodies, whereas the exposure to CP 55-940 induced soma degradation. CP 55-940 also induced apoptosis in both C6 and U373 cell lines. Our results support a more effective action of CP 55-940 to produce cell death of both cell lines through apoptotic mechanisms. Comparative aspects between cannabinoids with different profiles are necessary for the design of potential treatments against glial tumors.

[Colorectal surgery in patients over 65 years of age]

BACKGROUND

There is a limited functional reserve in patients over 65 years of age which is conducive to more frequent postoperative complications. Disease extension at the time of diagnosis (clinical stage) and complete tumor resection are two independent risk factors that have a direct influence on survival.

AIMS

To describe the factors that influence morbidity and mortality in patients over 65 years of age after colorectal surgery.

MATERIAL AND METHODS

A retrospective, observational, descriptive study was carried out within the time frame of January 2004 and December 2009 on 105 colon cancer patients after colorectal surgery. They were divided into two groups, one under 65 years of age and the other over 65 years of age, in order to compare preoperative comorbidity, as well as morbidity and mortality 30 days after surgery.

RESULTS

Of the 105 patient total (53,3%), 56 were ≤ 65 years of age. There were complications in 42,8% of the patients, and those of early and less severe presentation were the most frequent; late complications were more frequent in patients ≤ 65 vs > 65 years of age (16,0% vs 10,2%). Overweight (BMI > 25 kg/m(2)) was observed in 35,0% of the study population. Patients > 65 years of age had fewer comorbidities. The most common causes of reintervention were anastomosis dehiscence and postoperative hemorrhage. Mortality in the group was 6,6% and sepsis was the most frequent cause of death.

CONCLUSIONS

Colorectal surgery in patients over 65 years of age has an acceptable complication frequency and a low mortality rate. Our results suggest that patients older than 65 years of age be treated with the same prospects for cure as younger patients.

Clinical characteristics and outcomes of critically ill cancer patients with septic shock

OBJECTIVE

To evaluate the clinical characteristics and outcomes of critically ill cancer patients with septic shock.

DESIGN

Prospective, observational cohort study.

METHODS

Medical-surgical intensive care unit (ICU) at the Instituto Nacional de Cancerología located in Mexico City from January 2008 to February 2010. There were no interventions. Eighty-two consecutive cancer patients with septic shock aged over 18 years were prospectively included and evaluated.

RESULTS

During the study period, 620 critically ill cancer patients were admitted to ICU. Ninety-four patients were evaluated for septic shock at the request of ward onco-hematologists or surgeon oncologist responsible for the patient. After being evaluated by the intensivists, 82 patients were admitted to the ICU. Of the 82 patients, 56 (68.3%) had solid tumours and 26 (31.7%) had hematological malignancy. The most frequent sites of infection were: abdominal (57.3%) and respiratory (35.8%). Cultures were positive in 41 (50%) patients. The 63.4% of the patients had three or more organ dysfunctions on the day of their admission to the ICU. Cox multivariate analysis identified the Sequential Organ Failure Assessment (SOFA) score [hazard ratio (HR): 1.11; 95% confidence interval (95% CI): 1.02-1.19, P=0.008) and performance status (PS)≥2 (HR: 1.84; 95% CI: 1.03-3.29, P=0.040) as independent predictors of death to 3 months. The ICU mortality rate was 41.5% (95% CI: 31-52%).

CONCLUSION

The variables associated with increased mortality were the degree of organ dysfunction determined by SOFA score at ICU admission and PS≥2.

Prognostic Factors in Critically Ill Patients with Solid Tumours Admitted to an Oncological Intensive Care Unit

The mortality and prognostic factors for patients admitted to the intensive care unit (ICU) with solid tumours are unclear. The aim of this study was to describe demographic, clinical and survival data and to identify factors associated with mortality in critically ill patients with solid tumours. A prospective observational cohort study of 177 critically ill patients with solid tumours admitted to a medical-surgical oncological ICU was undertaken. There were no interventions. Among the admissions, 66% were surgical, 79.7% required mechanical ventilation during their stay in the ICU and 31.6% presented with severe sepsis or septic shock. In a multivariate analysis, independent prognostic factors for in-ICU death were the need for vasopressors (OR: 22.66, 95% confidence interval: 6.09 to 82.22, P <0.001) and the acute physiology and chronic health evaluation (APACHE) II score (OR: 1.92, 95% confidence interval: 1.43 to 2.58, P <0.001). Cox multivariate analysis identified the length of stay in the ICU, Charlson comorbidity index score greater than 2, and the need for vasopressors as independent predictors of death after ICU discharge. The mortality rate in the ICU was 21.4%. Improved outcomes in critically ill cancer patients extended to the subgroup of patients with solid tumours. Independent prognostic factors for in-ICU death were the need for vasopressors and the APACHE II score, while the length of stay in the ICU, Charlson comorbidity index score >2, and the need for vasopressors were independent predictors of death after ICU discharge.

(18)F-FDG PET/CT for discrimination between tumor extension and blood thrombus in pancreatic adenocarcinoma associated with portal vein thrombosis

Pancreatic cancer is a malignancy with an extremely poor prognosis. Less than 3 % of patients are alive 5 years after diagnosis. Pancreatic neoplasms represent a possible but uncommon etiology of portal venous invasion. It is important to differentiate the nature of the thrombus, if it is a bland thrombus or is a direct tumor extension. Intense uptake of 18F-fluorodeoxyglucose ((18)F-FDG) has been reported in portal vein tumor thrombus. We present a case of pancreatic adenocarcinoma and clinical findings of portal hypertension due to portal vein thrombosis. (18)F-FDG positron emission tomography (PET)/computed tomography (CT) evaluation discarded a tumor thrombus; imaging findings of the pancreatic tumor and the bland thrombus are presented.

Craniofacial resection for sinunasal tumors

INTRODUCTION

Malignant sinonasal tumors are very rare in Mexico. They ussually present as advanced disease because it is extremely difficult to make an early diagnosis; in addition, its treatment is complicated by a variety of lesions. Surgical resection remains the mainstay of treatment, but its relative therapeutic value compared with alternative treatments is controversial.

OBJECTIVE

We undertook a retrospective analysis in order to evaluate results of craniofacial resections for sinonasal tumors.

MATERIALS AND METHODS

A total of 20 patients, 11 men and 9 women were considered, median age was 49 years (18-74). Eleven had received previous treatment elsewhere. In 13 patients tumor was limited to maxillo-ethmoid complex, but in 6 cases tumor involved anteroinferior aspect of sphenoid sinus, in 7 extended to the orbit, in 3 to dura and two to the brain. One had cervical metastases. Median tumoral size was 5.8 cm (1-10).

RESULTS

Overall complication rate was 50%. Major surgical complications occurred in 4 patients (20%): one patient developed isolated cerebrospinal fluid leakage (CEFL), 1 developed deterioration of mental status, and two developed meningitis associated with CEFL. Late complications occurred in 30% of the patients. There was not any operative death. Eleven patients received postoperative radiotherapy. Fifteen patients recurred. There were 11 local relapses, although one associated with a regional relapse, and another with regional and distant relapse. There were four isolated regional fails and six isolated distant failures. Three year overall survival was 65%, and 3-year disease free survival was 50%. Patients without previous treatment median survival was 28.3 months, meanwhile with previous treatment was 18.2 months.

CONCLUSIONS

Craniofacial resection is a safe and valuable tool in the treatment of advanced sinonasal tumors involving cranial base.

Phase II trial of gemcitabine concurrent with radiation for locally advanced squamous cell carcinoma of the head and neck

BACKGROUND

Concurrent chemoradiation is the current standard of treatment for patients with advanced unresectable head and neck squamous cell carcinoma (HNSCC). Due to the potent radiosensitizing properties of gemcitabine, we decided to assess its efficacy and toxicity with concurrent radiation in patients with advanced HNSCC.

PATIENTS AND METHODS

From January 1997 to December 2001, 27 patients with locally advanced HNSCC (stage III, 37%; stage IV, 63%) were enrolled. All received a course of radiotherapy (70 Gy over 7 weeks) concurrent with weekly infusions of gemcitabine at 100 mg/m2 or 50 mg/m2.

RESULTS

All patients were assessable for toxicity and 26 for response. Severe mucositis (grade 3-4) was observed in 74% of patients (grade 4, 41%). Severe hematological toxicity was uncommon. Mild and moderate xerostomy was the most common late toxicity in 23 patients (85%). The median radiation dose delivered was 70 Gy (40-80 Gy), 25 patients (93%) received > or = 80% of the intended dose. Gemcitabine dose intensity was > or = 80% in only 13 (48%) patients. The rate of complete and partial responses were 61% and 27%, respectively, for an overall response rate of 88%. At a median follow-up of 13 months (range 6-62), the actuarial 3-year progression-free survival (PFS) and overall survival (OS) were 37% and 33%, respectively. The only variable associated with prolonged survival (P = 0.0001) was the degree of response. No difference was observed in response or toxicity with either gemcitabine 50 or 100 mg/m2.

CONCLUSIONS

The concurrent use of radiotherapy and gemcitabine is effective but produces manageable severe mucositis in a high percentage of patients.