The pleomorphic xanthoastrocytoma and its differential diagnosis: A study of five cases

__Abstract__ Five brain tumors with the histopathologic features of pleomorphic xanthoastrocytomas (PXAs) are presented. Computed tomography scans showed a remarkable homology. Two cases had atypical localizations for a PXA, while one 46-year-old patient did not conform to the normal age distribution of this tumor. Nevertheless, in these cases, the histopathology was always characteristic for PXA, a remarkable pleomorphism, in addition to simultaneous expression of glial fibrillary acidic protein and histiocytic markers in the various tumor cells. In one of the presented tumors, however, clusters of neoplastic neuronal cells were also found. In this particular case, differential diagnostic criteria to distinguish between a PXA and a desmoplastic infantile ganglioglioma are lacking

Method for estimating pulsatile wall shear stress from one-dimensional velocity waveforms

Wall shear stress (WSS)—a key regulator of endothelial function—is commonly estimated in vivo using simplified mathematical models based on Poiseuille\u27s flow, assuming a quasi-steady parabolic velocity distribution, despite evidence that more rapidly time-varying, pulsatile blood flow during each cardiac cycle modulates flow-mediated dilation (FMD) in large arteries of healthy subjects. More exact and accurate models based on the well-established Womersley solution for rapidly changing blood flow have not been adopted clinically, potentially because the Womersley solution relies on the local pressure gradient, which is difficult to measure non-invasively. We have developed an open-source method for automatic reconstruction of unsteady, Womersley-derived velocity profiles, and WSS in conduit arteries. The proposed method (available online at https://doi.org/10.5281/zenodo.7576408) requires only the time-averaged diameter of the vessel and time-varying velocity data available from non-invasive imaging such as Doppler ultrasound. Validation of the method with subject-specific computational fluid dynamics and application to synthetic velocity waveforms in the common carotid, brachial, and femoral arteries reveals that the Poiseuille solution underestimates peak WSS 38.5%–55.1% during the acceleration and deceleration phases of systole and underestimates or neglects retrograde WSS. Following evidence that oscillatory shear significantly augments vasodilator production, it is plausible that mischaracterization of the shear stimulus by assuming parabolic flow leads to systematic underestimates of important biological effects of time-varying blood velocity in conduit arteries

The release of wastewater contaminants in the Arctic : a case study from Cambridge Bay, Nunavut, Canada

The treatment of municipal wastewater in the Arctic is challenging due to a variety of financial, operational, climatic and technical issues. To better understand the efficacy of current wastewater treatment in this region and the hazard posed to receiving waters, we assessed the occurrence of contaminants (i.e., pharmaceuticals, antibiotic resistance genes and nutrients) as they moved through a lagoon-based treatment system in Cambridge Bay in Nunavut, Canada. Wastewater treatment in this community is performed by the use of a lagoon-tundra wetland system that is discharged into the marine environment and is representative of current common practices throughout the region. In 2014, samples were collected before and during lagoon discharge from two locations in the main lagoon, one location downstream from the lagoon effluent and three locations offshore. Grab samples were collected to measure nutrients (e.g. total nitrogen and phosphorus) and the presence of antibiotic resistance gene-bearing microbes, and Polar Organic Chemical Integrative Samplers (POCIS) were deployed to collect passively organic contaminants in all locations. A total of six pharmaceuticals were detected from a screen of twenty-eight analytes during the study: atenolol, carbamazepine, clarithromycin, metoprolol, sulfamethoxazole and trimethoprim. The greatest concentrations of nutrients, antibiotic resistance genes (ARGs) and pharmaceuticals were found in sampling locations within the treatment lagoon. Offshore of the release point, we observed limited to no detection of pharmaceuticals and ARGs and no change in total nitrogen and phosphorus from pre-release. We conclude that the current concentrations of monitored pharmaceuticals do not pose a significant hazard at this time to aquatic organisms in Cambridge Bay

Floc formation reduces the pH stress experienced by microorganisms living in alkaline environments

The survival of microorganisms within a cementitious geological disposal facility for radioactive wastes is heavily dependent on their ability to survive the calcium dominated, hyper-alkaline conditions resulting from the dissolution of the cementitious materials. The present study shows that the formation of flocs, composed of a complex mixture of extracellular polymeric substances (EPS), provides protection against alkaline pH values up to pH 13.0. The flocs were dominated by Alishewanella and Dietzia sp, producing a mannose rich carbohydrate fraction incorporating extracellular DNA, resulting in Ca2+ sequestration. EPS provided a ~10 µm thick layer around the cells within the centre of the flocs, which were capable of growth at pH 11.0 and 11.5, maintaining internal pH values of pH 10.4 and 10.7 respectively. Survival was observed at pH 12.0, where an internal floc pH of 11.6 was observed alongside a reduced associated biomass. Limited floc survival (<2 weeks) was observed at pH 13.0.This study demonstrates that flocs are able to maintain a lower internal pH in response to the hyperalkaline conditions expected to occur within a cementitious, geological disposal facility for radioactive wastes and indicates that floc communities within such a facility would be capable of survival up to a pH of 12.0

Predictors of change in code status from time of admission to death in critically ill surgical patients

Racial and gender disparities in end-of-life decision-making practices have not been well described in surgical patients. We performed an eight-year retrospective analysis of surgical patients within the Cerner Acute Physiology and Chronic Health Evaluation Outcomes database. ICU patients with documented admission code status, and death or ICU discharge code status, respectively, were included. Logistic regression analysis was performed to assess change in code status. Of 468,000 ICU patients, 97,968 (20.9%) were surgical, 63,567 (95%) survived, and 3,343 (5%) died during their hospitalization. Of those, 50,915 (80.1%) and 2,625 (78.5%) had complete code status data on admission and discharge or death, respectively. Women were less likely than men to remain full code at ICU discharge and death (n 5 20,940, 95.6% and n 5 141, 11.9% vs n 5 29,320, 97.4% and n 5 233, 16.3%, P < 0.001). Compared with whites, blacks and other minorities had a 0.46 odds (95% confidence interval [CI]: 0.33–0.64, P < 0.001) and 0.54 odds (95% CI: 0.34–0.85, P 5 0.01) of changing from full code status before death, respectively. Before ICU discharge, blacks and other minorities had a 0.56 odds of changing from full code status when compared with whites (95% CI: 0.40–0.79, P < 0.001 vs 95% CI: 0.36–0.87, P 5 0.01, respectively). Women were more likely to be discharged or die after a change in code status from full code (odds ratio 1.27, 95% CI: 1.06–1.07, P < 0.001 odds ratio 1.39, 95% CI: 1.09–1.79, P 5 0.009). Men and minorities are more likely to be discharged from the ICU or die with a full code status designation

The course of neuropathy after cessation of cisplatin treatment, combined with Org 2766 or placebo

Peripheral neuropathy is an important and disabling side-effect of cisplatin treatment. A new drug, Org 2766, has been found to prevent this neuropathy up to 1 month after treatment. A group of 18 patients with ovarian cancer, who participated in an earlier randomized study with placebo or Org 2766, together with cisplatin and cyclophophamide, were thereafter prospectively followed up to 2 years after discontinuation of treatment to monitor the development of neurological signs and symptoms and vibration perception threshold (VPT). Exploratory, descriptive data analysis shows that between 1 and 4 months after the last cycle the average sum score for neurological signs and symptoms and VPT had deteriorated compared with 1 month after treatment. Thereafter a gradual but incomplete improvement was seen between 4-12 and 12-24 months after treatment. These changes were seen in all patients regardless of previous treatment with Org 2766 or placebo, but deterioration was less pronounced in patients previously treated with Org 2766. These results suggests that treatment with Org 2766 to prevent a cisplatin-induced neuropathy should possibly be continued up to 4 months after the last cycle of cisplatin

Segregation effects on the properties of (AuAg)147

AuAg nanoclusters are promising supported co-catalysts for photocatalytic hydrogen reduction. However, beyond the quantum regime (N > 100) little is known about how the electronic properties of these nanoparticles are affected by chemical ordering. We investigate the effects of chemical ordering on the properties of 147-atom cuboctahedral AuAg nanoclusters, using empirical potentials coupled with an atomic-swap basin-hopping search to optimise the elemental distribution, with the lowest energy arrangements then reminimised using Density Functional Theory (DFT). Force-field calculations show Au atoms preferentially occupy sub-surface positions in the bimetallic structures, which results in the formation of a pseudo-onion structure for Ag-rich compositions. At the DFT-level, however, an Ag core surrounded by an Au shell (Ag@Au) is energetically favoured, as electron density can be drawn more readily when Au atoms are positioned on the nanocluster surface, thus resulting in a partial negative charge. Core@shell configurations are analogous to structures that can be chemically synthesised, and further detailed electronic analysis is discussed in the context of nanocluster applications to co-catalysed photocatalysis

Effect of an ACTH(4-9) analogue on cisplatin neuropathy of longstanding duration: A phase II study

The efficacy of Org 2766, an ACTH(4–9) analogue, on the recovery of cisplatin neuropathy of longstanding duration was investigated in a phase II study. Twenty-two patients were treated with Org 2766 during a period of 4 months and vibration perception threshold (VPT) and sum scores for neuropathic symptoms and signs were compared with pre-treatment values. No change in VPT could be detected. Although there was a small improvement of clinical measures for neuropathy, no clear evidence for repair could be obtained. These results indicate no beneficial effect of Org 2766 on recovery of a longstanding cisplatin neuropathy