The Application of LC-ICP-MS to Study Metal Ion Homeostasis in Biological Systems

Eukaryotic cells contain low-molecular-mass metal complexes (LMMMCs), defined as having masses between 200 – 10,000 Da, but these so-called labile or chelatable metal pools are poorly defined in terms of structures and functions. LMMMCs are thought to participate in metal-ion regulation, trafficking, storage and/or signaling in cells. These cellular processes are often dysfunctional in metal-associated diseases. The objective of these studies was to detect and characterize LMMMCs in eukaryotic cells, organelles and tissues. A novel liquid chromatography system in a cold inert-atmosphere glove box was interfaced with an in-line inductively coupled plasma mass spectrometer, and this LC-ICP-MS system was used to detect LMMMCs in yeast cells, mitochondria, and vacuoles as well as in mouse brain and liver cells and mitochondria. In each biological system, this separations technique was applied to detect numerous LMMMCs. The molecular mass and concentration of such species were estimated. In yeast, the previously reported mismetallation of MnSOD2 was examined in the mutant strain Δmtm1. A combination of SEC and AEX chromatography revealed that the degree of mismetallation of the SOD2 protein, in which Fe replace Mn in the active site, was no greater in Δmtm1 cells than in WT cells. The mitochondria of such mutant cells did exhibit an intense chromatography peak of Mn corresponding to at mass of 2000 – 3000 Da. Mitochondria from WT cells exhibited a similar species, but at much lower intensity. This was the only Mn species present, suggesting that it was the used to metallate apo-SOD2. Mitochondria isolated from WT yeast cells contained 6 Co, 3 Cu, 2 Mn, 5 Fe and 3 Zn LMMMCs and approximately 6 P- and S- LLM species. Some of the P- and S- LMMCs probably arose from compounds like ATP, ADP, etc. Molecular masses of the LMM Cu peaks were higher (> 5 kDa) than for the LMM complexes of other transition metals. Zinc, Mn, and Fe had multiple species of interest which demonstrate the presence and labiality of the metals in pools. The same separation system was utilized to examine mice brain LMM extracts were found to contain > 30 LMMMCs. Eleven Co, 2 Cu, 5 Mn, 4 Mo, 3 Fe and 2 Zn LLM complexes were detected. Most Cu and Zn complexes appeared to be protein-bound with masses ranging from 4–20 kDa. In these systems, Co was the only metal for which the aqueous complex was reproducibly observed. A second mouse study used the LC-ICP-MS system to examine the forms of iron present in mouse plasma. Chromatograms exhibited ~6 Fe-associated peaks that were assigned to ferritin, transferrin, and hemopexin, respectively; the other 3 peaks could not be assigned. The LC-ICP-MS experiment demonstrates that numerous Fe-containing species coexist with transferrin in healthy WT mouse plasma

Life stress, social problem solving and asthma

Asthma is an immuno‐inflammatory condition of the respiratory system. Clinical wisdom and previous scientific research suggest that life stress negatively impacts asthma. However, the nature of the stress‐asthma relationship remains largely unclear. One hypothesis is that stress plays a multifaceted role, affecting asthma through the nervous and immune systems, and through behavioral pathways, such as disease selfmanagement. Social problem‐solving ability has been shown to play an important role in mediating the connections between stress and other chronic diseases, such as heart disease, diabetes and cancer. The coping abilities of individuals with asthma may also play a role as mediators of the stress‐asthma relationship. The presented research is the first to examine the life stress and social problem‐solving abilities of asthma patients in relation to their asthma control and asthma‐related quality of life. The hypothesis that negative stressful life events would be associated with poor asthma control and asthmarelated quality of life was not supported. Likewise, tests of the hypothesis that social problem‐solving would mediate the stress‐asthma relationship could not be conducted due to lack of statistical power. However, a statistically significant correlation was found between social problem‐solving and asthma control and asthma‐related quality of life. Problem‐solving styles and asthma‐related quality of life exhibited the strongest correlation. These results suggest that the social problem‐solving framework is a potentially important factor in asthma morbidity and may be potentially fruitful avenues for improving patient’s capacity for successful asthma self‐management.M.S., Psychology -- Drexel University, 201

Modelling arterial wall drug concentrations following the insertion of a drug-eluting stent

A mathematical model of a drug-eluting stent is proposed. The model considers a polymer region, containing the drug initially, and a porous region consisting of smooth muscle cells embedded in an extracellular matrix. An analytical solution is obtained for the drug concentration both in the target cells and the interstitial region of the tissue in terms of the drug release concentration at the interface between the polymer and the tissue. When the polymer region and the tissue region are considered as a coupled system it can be shown, under certain assumptions, that the drug release concentration satisfies a Volterra integral equation which must be solved numerically in general. The drug concentrations, both in the cellular and extracellular regions, are then determined from the solution of this integral equation and used in deriving the mass of drug in the cells and extracellular space

Thermal Analysis of Potted Litz Wire for High-Power-Density Aerospace Electric Machines

Increasing the power density and efficiency of electric machines (motors and generators) is integral to bringing Electrified Aircraft (EA) to commercial realization. To that end an effort to create a High Efficiency Megawatt Motor (HEMM) with a goal of exceeding 98% efficiency and 1.46 MW of power has been undertaken at the NASA Glenn Research Center. Of the motor components the resistive losses in the stator windings are by far the largest contributor (34%) to total motor loss. The challenge is the linear relationship between resistivity and temperature, making machine operation sensitive to temperature increases. In order to accurately predict the thermal behavior of the stator the thermal conductivity of the Litz wire-potting-electrical insulation system must be known. Unfortunately, this multi material system has a wide range of thermal conductivities (0.1 W/m-K 400 W/m-K) and a high anisotropy (axial vs transverse) making the prediction of the transverse thermal conductivity an in turn the hot spot temperatures in the windings is difficult. In order to do this a device that simulates the thermal environment found in the HEMM stator was designed. This device is not unlike the motorettes (little motors) that are described in IEEE standards for testing electrical insulation lifetimes or other electric motor testing. However, because the HEMM motor design includes significant rotor electrical and thermal considerations the term motorette was not deemed appropriate. Instead statorette (or little stator) was adopted as the term for this test device. This paper discussed the design, thermal heat conjugate analysis (thermal model), manufacturing and testing of HEMM's statorette. Analysis of the results is done by thermal resistance network model and micro thermal model and is compared to analytical predictions of thermal conductivity of the insulated and potted Litz wire system

A multinational randomized, controlled, clinical trial of etoricoxib in the treatment of rheumatoid arthritis [ISRCTN25142273]

BACKGROUND: Etoricoxib is a highly selective COX-2 inhibitor which was evaluated for the treatment of rheumatoid arthritis (RA). METHODS: Double-blind, randomized, placebo and active comparator-controlled, 12-week study conducted at 67 sites in 28 countries. Eligible patients were chronic NSAID users who demonstrated a clinical worsening of arthritis upon withdrawal of prestudy NSAIDs. Patients received either placebo, etoricoxib 90 mg once daily, or naproxen 500 mg twice daily (2:2:1 allocation ratio). Primary efficacy measures included direct assessment of arthritis by counts of tender and swollen joints, and patient and investigator global assessments of disease activity. Key secondary measures included the Stanford Health Assessment Questionnaire, patient global assessment of pain, and the percentage of patients who achieved ACR20 responder criteria response (a composite of pain, inflammation, function, and global assessments). Tolerability was assessed by adverse events and routine laboratory evaluations. RESULTS: 1171 patients were screened, 891 patients were randomized (N = 357 for placebo, N = 353 for etoricoxib, and N = 181 for naproxen), and 687 completed 12 weeks of treatment (N = 242 for placebo, N = 294 for etoricoxib, and N = 151 for naproxen). Compared with patients receiving placebo, patients receiving etoricoxib and naproxen showed significant improvements in all efficacy endpoints (p<0.05). Treatment responses were similar between the etoricoxib and naproxen groups for all endpoints. The percentage of patients who achieved ACR20 responder criteria response was 41% in the placebo group, 59% in the etoricoxib group, and 58% in the naproxen group. Etoricoxib and naproxen were both generally well tolerated. CONCLUSIONS: In this study, etoricoxib 90 mg once daily was more effective than placebo and similar in efficacy to naproxen 500 mg twice daily for treating patients with RA over 12 weeks. Etoricoxib 90 mg was generally well tolerated in RA patients

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Genetic mechanisms of critical illness in COVID-19.

Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 ×  10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice