Prehospital Evaluation of the FAST-ED as a Secondary Stroke Screen to Identify Large Vessel Occlusion Strokes

Introduction: The Field Assessment Stroke Triage for Emergency Destination (FAST-ED) was developed to identify Large Vessel Occlusion Strokes (LVOS) presenting out of hospital, although there is limited prospective research validating its use in this setting. This study evaluated the test characteristics of the FAST-ED to identify LVOS when used as a secondary stroke screen in the prehospital environment. Secondary analysis compared the performance of the CPSS and the FAST-ED in identifying an LVOS. Methods: This prospective, observational study was conducted from April 2018 to December 2019 in a municipal EMS system with all ALS ambulance response. The FAST-ED was implemented as a secondary screening tool for emergent stroke patients who had at least one positive Cincinnati Prehospital Stroke Screen (CPSS) item. CPSS and FAST-ED scores were extracted from prehospital electronic care reports, while the presence of LVOS was extracted from hospital records. Results: A total 1,359 patients were enrolled; 55.3% female, 47.5% white, with a mean age of 69.4 (SD 15.8). In this cohort, 11.3% of patients experienced an LVOS. The mean FAST-ED for a patient experiencing an LVOS was 5.33 (95%CI 4.97-5.69) compared to 3.06 (95%CI 2.95-3.12) (p < 0.001). A score of greater or equal to 4 yielded the highest combination of sensitivity (77.78%) and specificity (65.34%) with positive likelihood ratio 2.24 (95% CI 2.00-2.52) and negative likelihood ratio 0.34 (95% CI 0.25-0.46). Area under the ROC curve was 0.77 (95%CI 0.73, 0.81). A CPSS with all three items positive demonstrated a sensitivity of 73.20% and 69.57% specificity, with an ROC area of 0.73 (95% CI 0.70-0.77). When comparing a FAST-ED ≥4 to a CPSS of all positive items, there was no significant difference in sensitivity (p > 0.05), and the FAST-ED had a significantly lower specificity than the CPSS (p < 0.005). Conclusion: As stroke care advances, EMS agencies must consider their destination triage needs. This study suggests agencies must consider the use of single versus secondary scales, and to determine the ideal sensitivity and specificity for their system.

Inter-Rater Reliability of the FAST-ED in the Out-of-Hospital Setting

Introduction: Patients experiencing a large vessel occlusion stroke (LVOS) may require endovascular-capable centers and benefit from direct transport to such facilities, creating a need for an accurate prehospital assessment. The Field Assessment Stroke Triage for Emergency Destination (FAST-ED) is a secondary scale to identify LVOS. Currently, there is limited prospective evidence validating the use of the FAST-ED in the prehospital environment. This study aimed to evaluate the inter-rater reliability of the FAST-ED between patient care providers in the prehospital setting.Methods: This prospective study was conducted between 4/1/2018 and 7/1/2018 in a single municipal EMS agency that staffs two providers per ambulance with at least one being a paramedic. Patients were included based on paramedic impression that the patient was both having a stroke and greater than 18 years old. Each provider independently performed and documented a FAST-ED assessment on eligible patients. Data analysis consisted of performing inter-rater reliability using Cohen's Kappa on the FAST-ED score between primary and secondary providers. The FAST-ED was analyzed on an item level, an aggregate level (cumulative of all items), and using the defined cut point of ≥4. A sub-analysis determined if inter-rater reliability changed across provider certification.Results: There were 231 patients included in this analysis with an average age of 68.5 years and 135 (58.4%) female. Inter-rater reliability varied across individual items in the scale from 90.1% agreement to 82.5%. When analyzing inter-rater reliability of the aggregate FAST-ED score, the scale demonstrated 70.1% agreement (Kappa 0.66), considered substantial agreement. FAST-ED scores were analyzed using a cut point of ≥4. When using this cut point, there was 92.2% (Kappa 0.81) agreement between primary and secondary caregiver, demonstrating almost perfect agreement. Agreement was substantial across provider certifications including paramedics and EMTS.Conclusion: This study demonstrated high inter-rater reliability of the FAST-ED scale when performed in the prehospital setting on patients suspected of having a stroke. There were minimal differences in reliability based on provider certification, and item level analysis indicated substantial inter-rater reliability.

Nanoparticle-Delivered HIV Peptides to Dendritic Cells a Promising Approach to Generate a Therapeutic Vaccine

Finding a functional cure for HIV-1 infection will markedly decrease the social and economic burden of this disease. In this work, we have taken advantage of the antigen presenting cell role of human dendritic cells (DCs) to try to induce an immune response to HIV-derived peptide delivered to DCs using two different polycationic nanoparticles: a G4 PAMAM dendrimer modified to a 70/30 ratio of hydroxyl groups/amines and a cyclodextrin derivative. We have studied peptide delivery using a fluorescence peptide and have studied the immune response generation by cytokine determination and flow cytometry. We have found a robust delivery of the antigenic peptide to DCs and activated dendritic cell-mediated peripheral blood mononuclear cells (PBMCs) proliferation using the mixed lymphocyte reaction. However, no expression of markers indicating activation of either B or T lymphocytes was observed. Moreover, the release of the pro-inflammatory cytokine TNF-α or IL-2 was only observed when DCs treated with either the dendrimer or the dendriplex containing the peptide. Antigenic peptide delivery to DCs is a promising approach to generate a vaccine against HIV-1 infection. However, more studies, including the simultaneous delivery of several antigenic peptides from different viral proteins, can markedly improve the immune response.

Analysis of polyamidoamine dendrimers by isoelectric focusing

Polyamidoamine dendrimers have been studied extensively for their potential applications in nanomedicine. Their uses as imaging, drug, and nucleic acid delivery agents are nearing clinical trials. As such, characterization of polyamidoamine dendrimers and their nano-devices is of immense importance for monitoring the efficiency of their synthesis, purity, and quality control of manufactured products as well as their in vivo behavior. We report here the analysis of polyamidoamine dendrimers possessing various cores and surface groups with a simple and inexpensive isoelectric focusing method. The isoelectric points of the dendrimers were readily determined from a calibration plot generated by running proteins with known pI values. The isoelectric points for various surface-modified polyamidoamine dendrimers ranged from 4 to 9. Polyamidoamine dendrimers possessing terminal hydroxyl groups gave a pI > 7, while those with terminal carboxyl groups exhibit a pI < 7. Generation number and cores of the dendrimers did not significantly affect their isoelectric points. Isoelectric focusing thus offers another important tool for characterizing these nanomolecules.

Preparation of fullerene-shell dendrimer-core nanoconjugates

Generation 4 amine-terminated polyamidoamine dendrimer (PAMAM G4) was allowed to react with an excess of buckminsterfullerene (C60) to form a nanoconjugate containing a PAMAM core and C60 shell. The PAMAM-C60 conjugate was characterized by MALDI-TOF, TGA, UV-vis, and IR spectroscopy. Approximately thirty shell fullerenes surround each dendrimer core. The conjugates catalyze photooxidation of thioanisole by generation of singlet oxygen (1O2). The oxidation reactions occur in both organic and aqueous solvents, but the reactivity is enhanced in aqueous solution, possibly due to a nanoreactor effect resulting from diffusion of hydrophobic reactant molecules into dendrimer cavities.

Partial shell-filled core-shell tecto(dendrimers): a strategy to surface differentiated nano-clefts and cusps

Poly(amidoamine) (PAMAM) dendrimer shell reagents possessing either nucleophilic (i.e., primary amines) or electrophilic (i.e., carboxymethyl esters) functional groups have been covalently assembled around appropriate electrophilic or nucleophilic dendrimer core reagents to produce partial shell filled/core-shell tecto(dendrimers). Partial shell-filled products with saturation levels ranging from 28% to 66% were obtained. These metastable, remarkably monodispersed assemblies possess functionally differentiated nano-cusps and clefts that exhibit "autoreactive" behavior. Pacification of these autoreactive products with appropriate alkanolamine reagents produced robust, nonreactive, "hydroxy-amine-differentiated" surfaces that exhibit very active self-assembly properties. Based on the monodispersity, dimensional scaling, and electrophoretic similarities of PAMAM dendrimers to globular proteins, these assemblies may be viewed as crude biomimetics of classical core shell-type protein aggregates. These dimensionally larger, but analogous PAMAM core-shell tecto(dendrimer) architectures extend and complete a similar pattern of autoreactivity and pacification that was observed earlier for traditional mono PAMAM dendrimer core-shell modules possessing unsaturated shell levels.

Specific heat of helium confined to a 57- &mgr;m planar geometry near the lambda point

We report measurements of the specific heat of liquid helium confined to 57-&mgr;m planar gaps extending to within a few nanokelvin of the bulk lambda transition. The data are in fair agreement with Monte Carlo estimates for finite-size effects and with renormalization-group-theory predictions above the transition. Far from the transition, we find surface specific heat exponents, alpha(s) = 0.64+/-0.05 below, and 0.65+/-0.2 above, which compare well with the prediction of 0.658. Comparison with other recent data on small length scales shows some areas of agreement.

Using ARROWSMITH: a computer-assisted approach to formulating and assessing scientific hypotheses

Conventional computer searches of the biomedical literature (e.g. MEDLINE) allow investigators to retrieve much of the information that has already been published on a given topic. However, these searches are of limited utility at the frontier of scientific discovery, when one wishes to identify and assess new, untested scientific hypotheses, or to uncover biologically significant relations between two previously disparate fields of inquiry. We have designed a set of interactive software and database search strategies, collectively called ARROWSMITH, that facilitate the discovery of plausible hypotheses linking findings across specialties (Artif. Intell. 91 (1997) 183-203). In the simplest implementation of ARROWSMITH, the user begins with an experimental finding or hypothesis that two items A and C are related in some way. The titles of papers indexed in MEDLINE which contain the word 'A' (or synonyms) are downloaded into a file A, and similarly a file C is created. The software constructs a list of words and phrases B common to files A and C; automatic and manual editing are used to filter out uninteresting B-terms. For each B-term, the software generates an AB file of titles containing both 'A' and 'B', and a BC file of titles containing both 'B' and 'C'; these titles are juxtaposed to facilitate the user judging whether there is likely to be a biologically significant relation among A, B and C. ARROWSMITH has been employed to analyze research problems relating to oxidative stress, brain damage, Alzheimer's disease and schizophrenia. Applications of ARROWSMITH include: anticipating adverse drug reactions, identifying mechanisms by which agents modulate cellular or organismal responses, suggesting new therapeutic approaches, identifying possible risk factors for diseases, and identifying potential animal models for human conditions. A simplified experimental version of ARROWSMITH is now freely accessible on the World Wide Web (http:@kiwi.uchicago.edu).

Linking estrogen to Alzheimer's disease: an informatics approach

Epidemiologic studies suggest that estrogen protects against AD. We employ ARROWSMITH, a novel computer-assisted approach, to identify possible links between estrogen and AD that are not explicit in the biomedical literature, by searching for substances or processes that are known targets of estrogen action and that have also been separately studied in relation to AD. Several links appear particularly promising (e.g., estrogen's antioxidant activity) and merit attention by neuroscientists.

Medical literature as a potential source of new knowledge

Specialized biomedical literatures have been found that are implicitly linked by arguments that they respectively contain, but which nonetheless do not cite or refer to each other. The combined arguments lead to new inferences and conclusions that cannot be drawn from the separate literatures. One such analysis identified one set of articles showing that dietary fish oils lead to certain blood and vascular changes, and a second set containing evidence that similar changes might benefit patients with Raynaud's syndrome. Yet these two literatures had no articles in common and had never before been cited together; neither literature mentioned the other or suggested that dietary fish oil might benefit Raynaud patients. Two years after publication of that analysis, the first clinical trial demonstrating such a beneficial effect was reported independently by others. A second example of literature synthesis, based on eleven indirect connections, led to an inference that magnesium deficiency might be a causal factor in migraine headache. A third example calls attention to implicit connections between arginine intake and blood levels of somatomedins, a potentially fruitful but neglected area of research with implications for the decline with age of thymic function and protein synthesis. A model and an online search strategy to aid in identifying other logically related noninteractive literatures is described. Such structures are probably not rare and may provide the foundation for a literature-based approach to scientific discovery.

Nifedipine gastrointestinal therapeutic system

Convenient once-a-day dosage regimens are highly desirable in general, and especially for the treatment of asymptomatic diseases such as essential hypertension. Nifedipine is an insoluble, short-acting calcium channel blocker that presents a difficult technical challenge for formulation in a constant 24-hour delivery dosage form. Once-a-day dosage forms have been developed based on the gastrointestinal therapeutic system (GITS) push-pull osmotic pump configuration in three strengths with different drug delivery rates (mg/hour) per dose (mg), as 1.7/30, 3.4/60, and 5.1/90. The delivery rates of drug from these systems are controlled by their drug loading, composition of osmotic components, membrane properties, and dimensions. The release rates are independent of pH in the range from gastric pH = 1.2 to intestinal pH = 7.5. The release rates are independent of stirring rate and therefore unlikely to be influenced by motility in the gastrointestinal tract. The drug release rate from the nifedipine GITS dosage form in vivo in the gastrointestinal tract of dogs has been found to be equal to the release rate in vitro, indicating that the in vitro test is predictive of in vivo delivery. Following administration of the nifedipine GITS dosage forms to human subjects, absorption rates, calculated from resulting plasma concentrations, indicate that the cumulative amount of drug absorbed in humans over 24 hours is proportional to the amounts of drug delivered in vitro. Plasma concentrations are therefore predictable and remain relatively constant throughout the 24-hour dosing interval.

Evaluation of oxprenolol and metoprolol Oros systems in the dog: comparison of in vivo and in vitro drug release, and of drug absorption from duodenal and colonic infusion sites

The performance of oxprenolol and metoprolol Oros systems has been evaluated in the dog. One study compared in vivo and in vitro release from both systems over 2-14 h. The other compared the systemic availabilities of both drugs after 3 h infusion at a constant rate into the cephalic and hepatic portal veins, and into the lumen of the duodenum and colon. In the in vivo release studies, Oros systems were recovered throughout the gut from the stomach to the colon. The amounts of drug remaining in the systems corresponded closely to those measured in a parallel in vitro release experiment. In vitro testing is thus a reliable indicator of in vivo system performance. In the absorption studies, both metoprolol and oxprenolol were shown to be subject to substantial first-pass metabolism. Additionally, for metoprolol the data indicated a significant loss during transport from the gut lumen into the portal circulation. For both drugs the availability from the colon was equal to that from the duodenum. These results provide some justification for the development of oral dosage forms with extended durations of release even for drugs which undergo significant first-pass metabolism.

Osmotic delivery systems for the beta-adrenoceptor antagonists metoprolol and oxprenolol: design and evaluation of systems for once-daily administration

The essential features and mode of action of oral osmotic drug delivery systems (Oros) for metoprolol fumarate and oxprenolol succinate are described. Critical aspects in the development of systems for once-daily administration of both drugs are discussed, and methods for evaluating in vitro release characteristics are presented. In vitro testing confirmed that drug delivery corresponded closely to the theoretical release behaviour predicted from the physicochemical and membrane permeability characteristics for both oxprenolol and metoprolol systems. In vitro release rates were also shown to be unaffected by pH, in vitro test procedures, dissolution media and long-term storage at different temperatures.

Toxicity of anticholinesterases: interactions of pyridostigmine and physostigmine with soman

This investigation was conducted to assess the potential of carbamate pretreatment to exacerbate the ill effects of low doses of soman. Ambulatory Activity in a photocell cage (AA) and performance time on an accelerating rotarod (ARR) were used to test for interactions between pyridostigmine or physostigmine and soman. ED50s (i.e., dosages sufficient to reduce ARR time and AA to 50% of control level) of each carbamate (IM) and soman (SC) were determined. The ED50 values (mg/kg) in the ARR test were 3.2, 0.21, and 0.072 for pyridostigmine, physostigmine and soman, respectively, while in the AA test the corresponding values were 1.8, 0.072 and 0.060. The matrix of 16 combinations of 0, 1, 2/3, and 1/3 ED50 each of carbamate and soman was studied in each test system, as well as the effect of behavioral deficit free (BDF) dosages of each carbamate on the ED50s of soman. In both the AA and ARR tests the matrix of combinations of pyridostigmine and soman indicated an additive effect. In contrast, physostigmine produced one instance of potentiation in each test system and anatagonism in two combinations in the AA procedure. A BDF dosage of each carbamate (0.056 mg/kg of pyridostigmine and 0.026 mg/kg of physostigmine) gave no evidence of adding to the deficit in AA induced by soman. In the ARR test, the ED50 of soman was lower by 11% with pyridostigmine pretreatment and by 14% with physostigmine; the latter just reached statistical significance (p less than 0.05). Although additivity was most often found at higher dosages of pyridostigmine and physostigmine, at the BDF dosages little or no adverse interaction was found between Pyridostigmine or Physostigmine and low levels of soman.