Higher Resolution Charge Detection Mass Spectrometry

Charge detection mass spectrometry is a single particle technique where the masses of individual ions are determined from simultaneous measurements of each ion's m/z ratio and charge. The ions pass through a conducting cylinder, and the charge induced on the cylinder is detected. The cylinder is usually placed inside an electrostatic linear ion trap so that the ions oscillate back and forth through the cylinder. The resulting time domain signal is analyzed by fast Fourier transformation; the oscillation frequency yields the m/z, and the charge is determined from the magnitudes. The mass resolving power depends on the uncertainties in both quantities. In previous work, the mass resolving power was modest, around 30-40. In this work we report around an order of magnitude improvement. The improvement was achieved by coupling high-accuracy charge measurements (obtained with dynamic calibration) with higher resolution m/z measurements. The performance was benchmarked by monitoring the assembly of the hepatitis B virus (HBV) capsid. The HBV capsid assembly reaction can result in a heterogeneous mixture of intermediates extending from the capsid protein dimer to the icosahedral T = 4 capsid with 120 dimers. Intermediates of all possible sizes were resolved, as well as some overgrown species. Despite the improved mass resolving power, the measured peak widths are still dominated by instrumental resolution. Heterogeneity makes only a small contribution. Resonances were observed in some of the m/z spectra. They result from ions with different masses and charges having similar m/z values. Analogous resonances are expected whenever the sample is a heterogeneous mixture assembled from a common building block.

Revision of Alberta's Provincial Insulin Pump Therapy Criteria for Adults and Children With Type 1 Diabetes: Process, Rationale and Framework for Evaluation

OBJECTIVES

Insulin pump therapy is a valuable, but costly approach, with public funding in Alberta for eligible individuals since 2013. The Provincial Insulin Pump Therapy Program Clinical Advisory Committee has revised and updated the clinical criteria, integrating current literature, best practice and feedback from clinicians. The objective was to develop criteria that would: 1) optimize safety and effectiveness of insulin pump therapy, while 2) carefully stewarding resources available to care for people with type 1 diabetes.

METHODS

The Clinical Advisory Committee comprised health-care professionals with expertise in pump therapy and included adult and pediatric endocrinologists, an internist, a pediatrician, certified pump trainers, diabetes educators and clinic managers. The group meets regularly by teleconference. Decisions are made by consensus.

RESULTS

Indications for insulin pump therapy for adults and children with insulin-deficient diabetes were divided into 4 hierarchical levels: 1) problematic hypoglycemia, inability to achieve acceptable control or progressive complications; 2) unpredictable activity, dawn phenomenon or children for whom use of multiple daily injections is not appropriate; 3) individual preference and 4) clinical exception, with priority given to indications with clear evidence of benefit. The criteria emphasize the importance of: 1) adequate education in diabetes self-management; 2) adequate trial of flexible insulin therapy with modern analogues and 3) evidence of active, safe diabetes self-management. Tools to facilitate effective and efficient annual review and surveillance were developed incorporating biological, behavioural evaluation and self-reflection to provide a framework for program evaluation. The recommendations were implemented in January 2019.

CONCLUSIONS

The process and revised criteria may be valuable for jurisdictions considering how to develop and implement a publicly funded insulin pump program.

Ecological drivers of female lion (Panthera leo) reproduction in the Kruger National Park

The role of social cues in the reproduction of social mammals, particularly carnivores, has been thoroughly studied and documented in literature. However, environmental cues such as resources of water, food, and shelter have been identified to a lesser extent. Pregnant lions (Panthera leo) are notoriously secretive during the final stages of pregnancy and postpartum. Behavioral indicators depicted by movement patterns obtained by remote detection of collared female lions in the Kruger National Park were necessary for the monitoring of birth timing. Over the study period, eight plus a potential three parturition incidences of collared females were recorded. Of the variables measured (step length, range size, duration, prey biomass, and rainfall), range size during the month of parturition was the most indicative movement pattern of a successful birth. By backdating the potential birth month of the litters, date of conception was calculated and our results revealed a correlation between the birthing peaks of preferred prey during the month of conception. Birth timing in conjunction with remote sensing and ecological factors were thus identified behaviors associated with denning.

Clinical Validation of Targeted and Untargeted Metabolomics Testing for Genetic Disorders: A 3 Year Comparative Study

Global untargeted metabolomics (GUM) has entered clinical diagnostics for genetic disorders. We compared the clinical utility of GUM with traditional targeted metabolomics (TM) as a screening tool in patients with established genetic disorders and determined the scope of GUM as a discovery tool in patients with no diagnosis under investigation. We compared TM and GUM data in 226 patients. The first cohort (n = 87) included patients with confirmed inborn errors of metabolism (IEM) and genetic syndromes; the second cohort (n = 139) included patients without diagnosis who were undergoing evaluation for a genetic disorder. In patients with known disorders (n = 87), GUM performed with a sensitivity of 86% (95% CI: 78–91) compared with TM for the detection of 51 diagnostic metabolites. The diagnostic yield of GUM in patients under evaluation with no established diagnosis (n = 139) was 0.7%. GUM successfully detected the majority of diagnostic compounds associated with known IEMs. The diagnostic yield of both targeted and untargeted metabolomics studies is low when assessing patients with non-specific, neurological phenotypes. GUM shows promise as a validation tool for variants of unknown significance in candidate genes in patients with non-specific phenotypes.

The synergy of TLR and STING in cancer immunity

Adjuvants are essential components of cancer vaccine formulations to promote effective immune responses. We initially screened multiple immune-activating targets, including TLR and STING adjuvants using in-vitro assays to test their ability to activate bone marrow DC (BMDC) and showed STING had the most potent activation (i.e., MHC and co-stimulatory molecules) on DCs. Since STING and TLR signaling is non-redundant, TLR and STING adjuvants were combined to enhance DC activation. We utilized the multidimensional synergy of combinations (MuSyc), a novel synergy algorithm, to assess molecular synergy in combining STING and TLR adjuvants, and we noted that the combination of R848 (TLR7-8) plus STING agonists provided a synergistic efficacious and potent response on BMDCs. From this data-set, we generated a MuSYC synergy strategy where we will utilize max signal dose for STING adjuvant and ten times less of max signal dose for R848 (TLR7-8) to determine synergy for other assays. We tested this same MuSYC strategy for activation of human monocytic cell line THP-1 and determined that the synergy strategy induced similar or better activation effects compared to the max signal dose for both adjuvants. Finally, we tested the in-vivo anti-tumor immune response for the B16 melanoma and MOC2 head/neck tumor-bearing vaccination models that resulted in an improved anti-tumor response for the combinatorial STING-TLR adjuvanted vaccines compared to the single agents.

Metabolic barriers imposed on tumor associated macrophages

Macrophages comprise a broad spectrum of heterogeneous cell population with diverse functions in immune responses in pathological conditions including cancer, inflammation and infection. Macrophages are extremely plastic in nature and highly specialized in sensing their microenvironment which governs their functional phenotype. Simplistically, macrophages can be categorized into classical inflammatory or M1 type and anti-inflammatory or M2 type. While the M1 macrophages play a crucial role in activating immune responses and release a wide array of pro-inflammatory and cytotoxic molecules, M2 macrophages facilitate resolution of inflammation by secreting immunosuppressive anti-inflammatory factors, phagocytosing and clearing apoptotic debris and promoting sustainability of regulatory T cells while suppressing effector T cells. Emerging evidences indicate an intimate connection between a robust switch in metabolic adaptations and different classes of macrophages. Tumor associated macrophages (TAM) are abundantly present in tumor microenvironments and can account for up to 50% of myeloid infiltrate in some types of human solid malignancies and contribute to disease progression, therapy resistance and clinical outcome. However, the metabolic circuitries in TAM underlying their ability to sustain tumor evolution and influence their own functional polarization is complicated and less characterized in many tumor types. In the current study, using multi-prong approaches like bulk myeloid as well as single cell RNA sequencing as well as functional assays, we highlight the metabolic pattern of TAMs in head and neck cancer and melanoma and propose immunometabolic strategies to harness TAM for controlling tumor growth.

Longitudinal optic neuritis-unrelated visual evoked potential changes in NMO spectrum disorders

OBJECTIVE

To investigate if patients with neuromyelitis optica spectrum disorder (NMOSD) develop subclinical visual pathway impairment independent of acute attacks.

METHODS

A total of 548 longitudinally assessed full-field visual evoked potentials (VEP) of 167 patients with NMOSD from 16 centers were retrospectively evaluated for changes of P100 latencies and P100-N140 amplitudes. Rates of change in latencies (RCL) and amplitudes (RCA) over time were analyzed for each individual eye using linear regression and compared using generalized estimating equation models.

RESULTS

The rates of change in the absence of optic neuritis (ON) for minimal VEP intervals of ≥3 months between baseline and last follow-up were +1.951 ms/y (n = 101 eyes; SD = 6.274; p = 0.012) for the P100 latencies and -2.149 µV/y (n = 64 eyes; SD = 5.013; p = 0.005) for the P100-N140 amplitudes. For minimal VEP intervals of ≥12 months, the RCL was +1.768 ms/y (n = 59 eyes; SD = 4.558; p = 0.024) and the RCA was -0.527 µV/y (n = 44 eyes; SD = 2.123; p = 0.111). The history of a previous ON >6 months before baseline VEP had no influence on RCL and RCA. ONs during the observational period led to mean RCL and RCA of +11.689 ms/y (n = 16 eyes; SD = 17.593; p = 0.003) and -1.238 µV/y (n = 11 eyes; SD = 3.708; p = 0.308), respectively.

CONCLUSION

This first longitudinal VEP study of patients with NMOSD provides evidence of progressive VEP latency delay occurring independently of acute ON. Prospective longitudinal studies are needed to corroborate these findings and help to interpret the clinical relevance.

Virtual Student Collaboration: Connecting Student Health Professionals

This pilot study aimed to provide students with a learning activity to develop a global perspective of health care. Senior nursing students from New Zealand and the United Kingdom (n=15) were allocated to eNetwork small-groups. Students met weekly for one month via audio/video-conferencing for discussions. Students reported that this collaborative activity enabled them to engage purposefully with other students. While cultural differences were noted, similarities were also found and multiplestudents expressed interest in working overseas.

Should individuals use influenza vaccine effectiveness studies to inform their decision to get vaccinated?

Studies on the effectiveness of seasonal influenza vaccine can affect an individual's perception of the ability of this vaccine to protect against influenza. However, vaccine effectiveness studies are designed to inform public health decisions rather than for individual decision-making. This overview explains what vaccine effectiveness means and why vaccine effectiveness estimates can vary. Individual variation in the response to seasonal influenza vaccine is based upon risk factors such as age, underlying health conditions, immune status and risk of infection and complications. Therefore, an individual's decision to get vaccinated should be primarily informed by their risk of influenza illness and their risk of transmitting influenza to vulnerable people.

Decision-centred design in healthcare: The process of identifying a decision support tool for airway management

Current decision support interventions for airway management in anaesthesia lack the application of Human Factors Engineering; leading to interventions that can be disruptive, inefficient and error-inducing. This study followed a decision-centred design process to identify decision support that can assist anaesthesia teams with challenging airway management situations. Field observations, Critical Decision Method interviews and focus groups were conducted to identify the most difficult decisions and their requirements. Data triangulation narrowed the focus to key decisions related to preparation and planning, and the transitioning between airway techniques during difficulties. Five decision-support interventions were identified and positively rated by anaesthesia team members in relation to their perceived effectiveness. An organized airway equipment trolley was chosen as the most beneficial decision support intervention. This study reiterated the key importance of both Human Factors Engineering and data triangulation when designing for healthcare.