SIR-Spheres activity measurements reveal systematic miscalibration

2022 ◽  
pp. jnumed.121.262650
Author(s):  
Stephen A Graves ◽  
Molly Martin ◽  
Ashok Tiwari ◽  
Michael J Merrick ◽  
John J Sunderland
1979 ◽  
Vol 41 (04) ◽  
pp. 745-755 ◽  
Author(s):  
Dušan Keber ◽  
Mojca Stegnar ◽  
Irena Keber ◽  
Bojan Accetto

SummaryFibrinolysis was studied in 10 alpinists during regular physical activity of different intensity. Blood was sampled at rest and after exposure to submaximal workload on the treadmill on three occasions: before and after 6 months physical conditioning (moderate physical activity), and after 6 weeks of an alpinistic expedition (strenuous physical activity). Measurements included submaximal working capacity, fibrinogen, euglobulin clot lysis time (ELT), whole plasma clot lysis time, and estimations derived from ELT - percent increase in fibrinolytic activity after exercise (RFS), and absolute increase in fibrinolytic activity after exercise (PAR).Regular moderate activity increased the resting level of ELT, but strenuous activity decreased is. After each treadmill testing, a marked increase in fibrinolytic activity was observed. RFS was unaltered at all three testings. PAR increased after moderate activity, but decreased after strenuous activity.The results indicate that regular physical activity can lead from enhanced to decreased resting activity of plasminogen activator in blood. It is presumed that increased release of activator during prolonged stress causes partial depletion of endothelial stores with the consequence of decreased activator activity in the blood.


1968 ◽  
Vol 20 (03/04) ◽  
pp. 548-554
Author(s):  
J Gajewski ◽  
G Markus

SummaryA method for the standardization of human plasminogen is proposed, based on the stoichiometric interaction between plasminogen and streptokinase, resulting in inhibition of proteolytic activity. Activation of a constant amount of plasminogen with increasing amounts of streptokinase yields linearly decreasing activities, as a function of streptokinase, with a sharp transition to a constant residual level. The point of transition corresponds to complete saturation of plasmin with streptokinase in a 1:1 molar ratio, and is therefore a measure of the amount of plasminogen present initially, in terms of streptokinase equivalents. The equivalence point is independent of the kind of protein substrate used, buffer, pH, length of digestion and, within limits, temperature. The method, therefore, is not subject to the variations commonly encountered in the usual determination based on specific activity measurements.


1985 ◽  
Vol 54 (03) ◽  
pp. 630-634 ◽  
Author(s):  
J Dawes ◽  
C V Prowse ◽  
D D Pepper

SummaryThe competitive binding assay described will specifically and accurately measure concentrations of administered heparin in biological fluids with a sensitivity of 60 ng ml-1. Neither endogenous glycosaminoglycans, nor plasma proteins such as ATIII and PF4 interfere in the assay. Semi-synthetic highly sulphated heparinoids and LMW heparin can also be measured. Using this assay heparin clearance followed simple first-order kinetics over the dose range 100-5,000 units, but the half-life was strongly dose-dependent. There was good correlation with heparin activity measurements by APTT and anti-Xa clotting assays. Plasma concentrations were measurable for at least 5 h following subcutaneous injection of 10,000 units of heparin. Excretion in the urine could be followed after all but the lowest intravenous dose. This assay, used in conjunction with measurements of heparin anticoagulant activity, will be valuable in the elucidation of mechanisms of action of heparin and the heparinoids, and in the assessment and management of problems related to heparin therapy.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Dalton J. Hance ◽  
Katie M. Moriarty ◽  
Bruce A. Hollen ◽  
Russell W. Perry

Abstract Background Studies of animal movement using location data are often faced with two challenges. First, time series of animal locations are likely to arise from multiple behavioral states (e.g., directed movement, resting) that cannot be observed directly. Second, location data can be affected by measurement error, including failed location fixes. Simultaneously addressing both problems in a single statistical model is analytically and computationally challenging. To both separate behavioral states and account for measurement error, we used a two-stage modeling approach to identify resting locations of fishers (Pekania pennanti) based on GPS and accelerometer data. Methods We developed a two-stage modelling approach to estimate when and where GPS-collared fishers were resting for 21 separate collar deployments on 9 individuals in southern Oregon. For each deployment, we first fit independent hidden Markov models (HMMs) to the time series of accelerometer-derived activity measurements and apparent step lengths to identify periods of movement and resting. Treating the state assignments as given, we next fit a set of linear Gaussian state space models (SSMs) to estimate the location of each resting event. Results Parameter estimates were similar across collar deployments. The HMMs successfully identified periods of resting and movement with posterior state assignment probabilities greater than 0.95 for 97% of all observations. On average, fishers were in the resting state 63% of the time. Rest events averaged 5 h (4.3 SD) and occurred most often at night. The SSMs allowed us to estimate the 95% credible ellipses with a median area of 0.12 ha for 3772 unique rest events. We identified 1176 geographically distinct rest locations; 13% of locations were used on > 1 occasion and 5% were used by > 1 fisher. Females and males traveled an average of 6.7 (3.5 SD) and 7.7 (6.8 SD) km/day, respectively. Conclusions We demonstrated that if auxiliary data are available (e.g., accelerometer data), a two-stage approach can successfully resolve both problems of latent behavioral states and GPS measurement error. Our relatively simple two-stage method is repeatable, computationally efficient, and yields directly interpretable estimates of resting site locations that can be used to guide conservation decisions.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Laibin Huang ◽  
Seemanti Chakrabarti ◽  
Jennifer Cooper ◽  
Ana Perez ◽  
Sophia M. John ◽  
...  

AbstractNitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O–N per µg NOx–N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.


Author(s):  
Zoe Del Fante ◽  
Nicola Di Fazio ◽  
Adriano Papale ◽  
Paola Tomao ◽  
Fabio Del Duca ◽  
...  

Physical risk assessments allow us to understand work-related critical issues, thus representing a useful tool in risk management strategies. In particular, our study focuses on the identification of already known and emerging physical risks related to necropsy and morgue activities, as well as crime scene investigations. The aim of our study is, therefore, to identify objective elements in order to quantify exposure to such risk factors among healthcare professionals and working personnel. For the research of potentially at-risk activities, data from the Morgue of Policlinico Umberto I Hospital in Rome were used. The scientific literature has been reviewed in order to assess the risks associated with morgue activity. Measurements were performed on previously scheduled days, in collaboration with the activities of different research units. The identified areas of risk were: microclimate; exposure to noise and vibrations; postural and biomechanical aspects of necropsy activities. The obtained results make it possible to detect interindividual variability in exposure to many of the aforementioned risk factors. In particular, the assessment of microclimate did not show significant results. On the contrary, exposure to vibrations and biomechanical aspects of load handling have shown potential risk profiles. For this reason, both profiles have been identified as possible action targets for risk management strategies.


2021 ◽  
Vol 13 ◽  
pp. 1759720X2110337
Author(s):  
Iván Ferraz-Amaro ◽  
Javier Rueda-Gotor ◽  
Fernanda Genre ◽  
Alfonso Corrales ◽  
Ricardo Blanco ◽  
...  

Background: Axial spondyloarthritis (axSpA) patients are known to have a higher prevalence of several comorbidities, including, among others, an increased risk of atherosclerosis, hypertension, dyslipidemia, and diabetes. The purpose of the present study was to determine whether the sum of traditional cardiovascular (CV) risk factors is related to disease characteristics, such as disease activity, in patients with axSpA. Methods: A cross-sectional study that encompassed 804 patients with axSpA was conducted. Patients were assessed for the presence of five traditional CV risk factors (diabetes mellitus, dyslipidemia, hypertension, obesity, and smoking status), and disease activity measurements. A multivariable regression analysis was performed to evaluate whether the number of classic CV risk factors was independently associated with specific features of the disease, to include disease activity. Results: A multivariable analysis showed that Ankylosing Spondylitis Disease Activity Score–C reactive protein (ASDAS-CRP) activity score was significantly higher in patients with 1 [beta coefficient 0.3 (95% confidence interval (CI) 0.1–0.5), p = 0.001] and ⩾2 [beta coefficient 0.5 (95% CI 0.3–0.7), p = 0.000] CV risk factors compared with those without CV risk factors. Similarly, patients with 1 [OR 2.00 (95%CI 0.99–4.02), p = 0.053] and ⩾2 [OR 3.39 (95%CI 1.82–6.31), p = 0.000] CV risk factors had a higher odds ratio for the presence of high disease activity compared with the zero CV category. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) activity score was significantly associated with the number of CV risk factors, being higher in patients with more CV risk factors. These relationships showed a CV risk factor-dependent effect being beta coefficients and ORs higher for the effect of ⩾2 over 1 CV risk factor. Conclusion: Among patients with axSpA, as the number of traditional CV risk factors increased, disease activity similarly increases in an independent manner.


2021 ◽  
Vol 10 (6) ◽  
pp. 1190
Author(s):  
Victoria Alcaraz-Serrano ◽  
Ane Arbillaga-Etxarri ◽  
Patricia Oscanoa ◽  
Laia Fernández-Barat ◽  
Leticia Bueno ◽  
...  

Background: Low physical activity and high sedentary behaviour in patients with bronchiectasis are associated with hospitalisation over one year. However, the factors associated with longitudinal changes in physical activity and sedentary behaviour have not been explored. We aimed to identify clinical and sociodemographic characteristics related to a change in physical activity and sedentary behaviour in patients with bronchiectasis after one year. Methods: This was a prospective observational study during which physical activity measurements were recorded using a SenseWear Armband for one week at baseline and at one year. At each assessment point, patients were classified as active or inactive (measured as steps per day) and as sedentary or not sedentary (measured as sedentary time). Results: 53 patients with bronchiectasis were analysed, and after one year, 18 (34%) had worse activity and sedentary levels. Specifically, 10 patients became inactive and sedentary. Multivariable analysis showed that the number of exacerbations during the follow-up period was the only outcome independently associated with change to higher inactivity and sedentary behaviour (odds ratio (OR), 2.19; 95% CI, 1.12 to 4.28). Conclusions: The number of exacerbations in patients with bronchiectasis was associated with changes in physical activity and sedentary behaviour. Exacerbation prevention may appear as a key factor in relation to physical activity and sedentary behaviour in patients with bronchiectasis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroshi Ishida ◽  
Ryosuke S. Isono ◽  
Jun Kita ◽  
Yutaka W. Watanabe

AbstractThis study examines long-term ocean pH data to evaluate ocean acidification (OA) trends at two coastal research institutions located on the Sea of Japan and the Pacific Ocean. These laboratories are located away from the influences of large rivers and major industrial activity. Measurements were performed daily for the past 30 years (1980s–2010s). The average annual ocean pH for both sites showed generally negative trends. These trends were – 0.0032 and – 0.0068 year–1 (p < 0.001) at the Sea of Japan and Pacific Ocean sites, respectively. The trends were superimposed onto approximately 10-year oscillations, which appear to synchronize with the ocean current periodicity. At the Sea of Japan site, the ocean pH in the summer was higher, and the rate of OA was higher than during other seasons. Our results suggest that seasonality and ocean currents influence OA in the coastal areas of open oceans and can affect the coastal regions of marginal seas.


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