Bounding uncertainties around the conceptual representation of species in radiological assessment in the context of routine atmospheric release.

Wildlife protection has become of regulatory interest since the International Commission on Radiological Protection (ICRP) developed an approach to assess the level of radiological protection specifically for animals and plants. For the purpose of demonstrating compliance with regulation to protect the environment against routine authorised discharges from nuclear facilities, the wide variety of biota inhabiting an ecosystem needs to be condensed to a limited set of representative organisms, as proposed by the ICRP with a set of 'reference animals and plants' which can be considered representative of many other species. It is now recommended in the International Atomic Energy Agency Safety Standards, and internationally accepted, that the use of such a limited number of organisms to represent a pool of species is adequate for radiation protection purposes, particularly in planned exposure situations. Adding site-specific species to that set of surrogate species can respond to various interests, such as ensuring a site-specific context to the assessment that addresses stakeholder interests and can aid in stakeholder consultation and risk communication. Moreover, there is a need to question whether the use of the set of surrogate organisms is conservative enough to cover a wider range of biodiversity. Previous studies partially answered this question and this paper adds a range of test cases. A selection of hypothetical representations of possible site-specific species are assessed on the basis of possible variations in size (mass) and occupancy habits. Dose rates are evaluated to determine the greatest difference between hypothetical organisms and those for reference organisms (ROs), considering radionuclides (RNs) potentially discharged in atmospheric routine release from different nuclear facilities. Differences observed in the results between hypothetical organisms and ROs were less than one order of magnitude in all cases, the difference being dependent on the RNs considered. These findings do not preclude the inclusion of site-specific species in environmental radiological assessments if it is considered necessary, but they provide reassurance that using ROs for radiological impact assessments in the case of routine atmospheric discharges is sufficient.

Assessment of dose rates to non-human biota from radioactive discharges from Sellafield Ltd. using PC-CREAM.

PC-CREAM is a tool for assessing the radiological impact of routine discharges of radionuclides to the environment. It can be used for prospective assessments, to calculate doses to members of the public for authorisation of proposed discharges, or for retrospective assessments of previous discharges where doses are compared with dose limits. These types of assessment are a fundamental requirement of regulations governing the control of radioactive discharges. However, the latest publications of the basic safety standards for radiation protection, EU (Council of the European Union, 2014) and the IAEA (IAEA, 2014), now include the requirement to demonstrate protection of the environment as well as members of the public. To this end, a module has been added to PC-CREAM for calculating dose rates to non-human biota (Anderson et al., 2022). The methodology used for this calculation is based on the recommendations contained in ICRP Publication 108 (ICRP, 2008), which provides a general framework for protection of the environment. The additional module means that PC-CREAM can be used to assess doses to humans and dose rates to biota in an integrated way, for the same set of discharges and using the same dispersion models. This paper describes an assessment of dose rates to biota living in the vicinity of the Sellafield nuclear site, carried out using the new biota module of PC-CREAM. Historical discharges from Sellafield to the sea and atmosphere were considered for the period 1951 to 2017, excluding those from the Windscale fire in 1957. Dose rates calculated for marine biota (flatfish, crabs and brown seaweed) are less than 1 mGy d-1 and are below the lower derived consideration reference level (DCRL) for the ICRP marine reference animals and plants (RAPs). Dose rates for terrestrial biota (bees, deer, earthworms, frogs, wild grass, pine trees and rats) are less than the relevant lower DCRL for terrestrial RAPs, ie 0.1 mGy d-1. Dose rates were also calculated for a user defined organism 'seabird' to represent birds which inhabit both marine and terrestrial environments near Sellafield. For seabird, the lower DCRL of 0.1 mGy d-1 is exceeded throughout the 1950s, 1960s and 1970s, when the discharges were at their highest, due to exposures from the marine environment. Since the mid-1980s, no dose rates were calculated that exceeded the lower DCRLs.

Recognizing false ischemic penumbras in CT brain perfusion studies.

Computed tomography (CT) plays a pivotal role in the diagnosis of acute stroke and in treatment decision making. CT perfusion imaging performed with intravenous iodinated contrast material allows calculation of the time to peak enhancement, mean transit time, and cerebral blood volume, important parameters for differentiating between an ischemic penumbra, which might benefit from intravascular therapy with thrombolytic agents, and infarcted tissue, which would not benefit from such therapy. Differentiation between the two entities is important because thrombolytic therapy is associated with an increased risk for intracranial hemorrhage. A finding of delay in peak enhancement or increased mean transit time in a region with normal or only slightly abnormal cerebral blood volume is suggestive of an ischemic penumbra; however, accurate interpretation of the CT perfusion parameters may be difficult in the presence of a cerebrovascular anatomic variant or physiologic condition that produces benign oligemia leading to a false appearance of penumbra. For this reason, CT perfusion parameters must be correlated with the clinical history and findings at unenhanced head CT, angiography or CT angiography, and diffusion-weighted magnetic resonance imaging. The authors identify five possible causes of false penumbras, each of which produces a different pattern at imaging: upstream flow restriction, evolution of ischemic change, vascular dysregulation, positioning of the patient's head at an angle during image acquisition, and variant anatomy in the circle of Willis. Familiarity with the imaging patterns and causes of false penumbras may increase the radiologist's confidence in diagnosis and help avoid costly errors in treatment.

Intraventricular daptomycin and intravenous linezolid for the treatment of external ventricular-drain-associated ventriculitis due to vancomycin-resistant Enterococcus faecium.

OBJECTIVE: To report the successful treatment of external ventricular-drain (EVD)-associated infection due to vancomycin-resistant Enterococcus faecium (VRE) with intraventricular daptomycin and intravenous linezolid. CASE SUMMARY: A 64-year-old white male with a complicated medical history was admitted to the neurosurgical unit with Scedosporium apiospermum meningitis and hydrocephalus requiring management with a right and left EVD. On day 28, cerebrospinal fluid cultures from the right EVD grew VRE. Despite initiation of intravenous linezolid, cultures from the right EVD remained positive. Intraventricular daptomycin 5 mg daily was initiated and administered into the right EVD for 7 days. Cerebrospinal fluid was collected from EVD outputs and analyzed for daptomycin concentrations. VRE in cultures from the EVD cleared after 1 day of therapy and no adverse effects were noted. Right and left EVD daptomycin concentrations were discordant throughout therapy by at least a 3-fold difference. First-dose peak and trough daptomycin concentrations in the cerebrospinal fluid were 112.2 and 1.34 µg/mL, respectively, for the right EVD and 37.4 and 0.37 µg/mL, respectively, for the left EVD. Daptomycin accumulation was evident after 3 days of therapy. DISCUSSION: Varying doses and frequencies of intraventricular daptomycin have been reported effective for VRE ventriculitis. Intraventricular drug distribution may not be homogeneous throughout the central nervous system. Therefore, daptomycin minimum inhibitory concentration for VRE, cerebrospinal fluid communication throughout the central nervous system, EVD output, and the potential for drug accumulation should be considered when selecting a dose and frequency. CONCLUSIONS: Intraventricular daptomycin may be an option for EVD-associated VRE infections that do not respond to conventional therapy. Intraventricular daptomycin 5 mg is a reasonable initial dose in adults with VRE ventriculitis, based on our experience in this patient.

Results From the Perceived Value of Certification Tool-12 Survey: Analysis of the Perceived Value of Certification Among Stroke and Neuroscience Nurses.

ABSTRACT: AIM: The purpose of this study was to explore the perceived value of certification among those with a neuroscience or stroke nursing certification. METHODS: The Perceived Value of Certification Tool-12 (PVCT-12) consists of 12 value statements related to the benefits of certification, using a 4-point Likert scale ranging from strongly disagree to strongly agree. Descriptive statistics were used to determine the percentage of agreement among respondents with each of the PVCT-12 items. A generalized linear model approach was then used to estimate the associations between age, sex, race, experience, certification, highest degree earned, primary responsibility, and primary work setting with intrinsic and extrinsic values. An exploratory factor analysis was performed to identify factors on which related variables were found. RESULTS: The 632 certificants were predominantly female (90%) with a mean age of 54 years. Approximately 80% were White, followed by Asian (11%), Hispanic (4%), and Black (3%). Certification included certified neuroscience registered nurse (34%), stroke certified registered nurse (47%), or both (20%). Approximately 57% of the certificants work in critical care/medical-surgical units. Work setting included academic (46%) and community (42%). Responses indicated lower levels of agreement with the value statements regarding certification challenges, professional autonomy, being listened to, and monetary gain. Those in administration had statistically significant higher intrinsic and extrinsic value scores ( P = .005) as compared with those in nonadministrative roles. There was no significant difference on perceived intrinsic or extrinsic values for those who work in an academic environment versus those who work in a community environment ( P = .25). After factor analysis, the PVCT-12 was found to have 3 factors that accounted for 53.4% of the total variation in the data: recognition of specialization, personal achievement, and professional accomplishment. CONCLUSION: The PVCT-12 incorporated a Likert-type scale to provide levels of agreement for intrinsic and extrinsic values among stroke certified registered nurses and certified neuroscience registered nurses. To complement these findings, further research using open-ended questions is needed to improve our understanding of participant responses regarding complex values such as "autonomy" and the "extent of being listened to."

Stroke alert program improves recognition and evaluation time of in-hospital ischemic stroke.

An inpatient stroke alert program is effective in decreasing evaluation time for in-hospital strokes, although response times remain significantly longer than those in the emergency department. It is capable of increasing the percentage of ischemic strokes identified by the hospital's stroke team, at the cost of an increased percentage of false alarms.

Promoting cardiovascular health: from individual goals to social environmental change.

A conceptual model of the relationship between well-known individual-level behavioral and biomedical risk factors for heart disease and stroke and community-level social environmental risk factors, which may be less familiar to professionals working in cardiovascular health promotion, is presented. The social environment paradigm holds that programs and interventions should focus "upstream" and attempt to directly modify social environmental conditions in order to positively influence human behaviors, and consequently disability and disease. For each of the "big five" cardiovascular risk factors (poor diet, physical inactivity, cigarette smoking, high blood pressure, and high blood cholesterol), social environmental barriers and promoters are described. This conceptual model should be a useful tool in explaining and justifying the ways in which social environmental change can improve risk factor distributions for entire populations, and subsequently reduce disability and death from heart disease and stroke.

Current and evolving management of subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a catastrophic event that carries a mortality rate of 25% to 50%, with 10% to 15% of patients dying before reaching a hospital. Approximately 30,000 aneurysms rupture each year in the United States. Aneurysmal SAH accounts for 2% to 5% of all new strokes each year. Unlike other types of strokes, the incidence of SAH has not declined over time. As many as 46% of SAH survivors have long-term cognitive impairment, with impact on functional status and quality of life. Modern therapy offers the opportunity to reduce the morbidity of SAH by reducing secondary injury, preventing complications, and reducing the risk of future bleeding events. For most people, an aneurysmal rupture is a life-changing event.

Comparing recovering efficiency of immunomagnetic separation and centrifugation of mycobacteria in metalworking fluids.

The accurate detection and enumeration of Mycobacterium immunogenum in metalworking fluids (MWFs) is imperative from an occupational health and industrial fluids management perspective. We report here a comparison of immunomagnetic separation (IMS) coupled to flow-cytometric enumeration, with traditional centrifugation techniques for mycobacteria in a semisynthetic MWF. This immunolabeling involves the coating of laboratory-synthesized nanometer-scale magnetic particles with protein A, to conjugate a primary antibody (Ab), specific to Mycobacterium spp. By using magnetic separation and flow-cytometric quantification, this approach enabled much higher recovery efficiency and fluorescent light intensities in comparison to the widely applied centrifugation technique. This IMS technique increased the cell recovery efficiency by one order of magnitude, and improved the fluorescence intensity of the secondary Ab conjugate by 2-fold, as compared with traditional techniques. By employing nanometer-scale magnetic particles, IMS was found to be compatible with flow cytometry (FCM), thereby increasing cell detection and enumeration speed by up to two orders of magnitude over microscopic techniques. Moreover, the use of primary Ab conjugated magnetic nanoparticles showed better correlation between epifluorescent microscopy counts and FCM analysis than that achieved using traditional centrifugation techniques. The results strongly support the applicability of the flow-cytometric IMS for microbial detection in complex matrices.