QUANTITATION OF MICROPARTICLES IN PLATELET SUSPENSIONS BY FLOW CYTOMETRY

1987 ◽  
Author(s):  
D T Miller ◽  
A P Bode
Keyword(s):  
Flow Cytometry ◽  
Particle Concentration ◽  
The Other ◽  
Supernatant Fraction ◽  
Becton Dickinson ◽  
Platelet Factor ◽  
Large Particles ◽  
Different Populations ◽  
Number Of Particles

We have examined a platelet-poor, supernatant fraction from fresh and stored platelet suspensions with a FACS 440 (Becton-Dickinson) flow cytometer to study the distribution of small microparticles previously shown to be present in citrated plasma and serum (J. George et al., Blood 60: 834, 1982). Analysis by flow cytometry offers the advantage of discrimination of populations of particles by both light scattering and immunofluorescent properties. We found two distinctly different populations of particles: the predominant one had diameters in the range of 0.1 to 0.4um and was moderately autofluorescent (AF); the other was equally AF with particle diameters of 1.0 to 3.0um and probably included a few intact platelets. By adding a precise quantity of highly fluorescent beads of 0.9um diameter to each sample, relative concentrations of particles (small and/or large) could be quantified in platelet suspensions after various treatments using ratios of particle and bead counts. The lowest concentration of particles was found in samples from whole blood collected into CPDA-1 with PGE-1 and theophylline plus sodium azide (CPT-Az). Blood in CPDA-1 alone had twice the number of small and large particles; serum had a 20X higher particle concentration. A much larger number of particles was found in platelet concentrates (PC) stored for transfusion. Fresh PC had approx. 150X higher particle concentration than CPT-Az, rising to over 200X by the eighth day of storage at 22 C. Also, we noted a shift in distribution between particle populations in stored PC toward the larger size. The concentration of larger particles alone rose from 100X relative to CPT-Az to 350X after 8 days of storage. Similar changes in supernatant platelet factor 3 (PF3) activity were noted in stored PC in another study (A.P. Bode and D.T. Miller, Vox Sanguinis 51: 299, 1986), suggesting that supernatant PF3 activity may be related to one or the other population of particles seen by flow cytometry. This technique of examining and quantifying particles in platelet preparations by flow cytometry will facilitate and expand the characterization of platelet vesiculation and the released particles.

Novel Techniques for Measurement of Variable Sized PF4/H Complexes.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2204-2204
Author(s):  
Benjamin Espinasse ◽  
Manali Joglekar ◽  
Giancarlo Valiente ◽  
Gowthami M. Arepally
Keyword(s):  
Flow Cytometry ◽  
Electrostatic Interactions ◽  
Conflicts Of Interest ◽  
Correlation Spectroscopy ◽  
Size Exclusion ◽  
Size Determination ◽  
Becton Dickinson ◽  
Cationic Protein ◽  
Platelet Factor ◽  
Laser Illumination

Abstract Abstract 2204 Electrostatic interactions between Platelet factor 4 (PF4), a cationic protein, and heparin, an anionic carbohydrate result in the formation of ultra-large complexes (ULCs) that are immunogenic in mice (Suvarna, Blood 2007) and contribute to the immune pathogenesis of Heparin-induced thrombocytopenia (HIT). Previous studies (Rauova, Blood 2005; Greinacher, Arterioscler Thromb Vasc Biol, 2006) have shown that the size of ULCs is determined by the concentration and the molar ratios of PF4:H (PHRs) of each compound. Size determination of PF4/H complexes has been problematic due to technical limitations of two commonly employed methods for sizing complexes, photon correlation spectroscopy (PCS) and size exclusion chromatography (SEC). PCS is a technique for measuring particles in solution using laser illumination is based on principles of Brownian motion. PCS performs optimally with monodisperse populations and is biased by the presence of large aggregates. SEC, a liquid chromatography method, is technically cumbersome, requires sample labeling and not feasible for measuring large numbers of samples. To address these limitations, we examined two novel approaches for measuring a broad range of PF4/H complex size (100–3000 nm) in vitro: Nanosight and flow cytometry (FC). Nanosight (Nanosight Ltd, Wiltshire, United Kingdom),was employed for measuring small-sized complexes using physiologic concentrations of hPF4 (10 ug/mL). Nanosight uses proprietary software to track nanoparticles (range 10–1000nm) in solution by laser illumination with real-time tracking of the motion of individual particles by a camera. Analysis parameters provided by the software include: 1) Particle size distributions displayed as histograms 2) direct visualization of particles 3) particle counting and sizing and 4) particle scatter intensity vs. count and size. For measuring intermediate to large sized particles, formed at high hPF4 concentrations (95 ug/mL), we used flow cytometry calibrated with sizing beads on side scatter channel (SSC). FC was performed using a BD LSRII cell analyzer (Becton Dickinson, Franklin Lakes, NJ), a high throughput flow analyzer with the threshold channel for SSC set to 200 and a flow rate of 1 ul per second. The instrument was calibrated using sizing beads ranging from 0.3–6 μm in size (Figure A). For both techniques, PF4/H ULCs were formed by adding hPF4 (10 or 95 ug/mL)and various UFH concentrations in HBSS to yield the indicated PHRs. Complexes were incubated for 60 minutes and measured by NanoSight or FC. Results of experiments using Nanosight are shown in Table 1 with results showing size and particle counts for each PHR. Results of FC are shown in Figure B and Table 2 (median, 5% and 95% size in nm). Both studies showed reproducibility for measurements for a given concentration and showed changes in complex size as a function of PHR (Figure B). Both methodologies are technically simple and provide complementary approaches to PCS for PF4/H complex size determination. Disclosures: No relevant conflicts of interest to declare.

Mechanism of Formation of Cream in GR-S Latex

1955 ◽  
Vol 28 (2) ◽  
pp. 641-656
Author(s):  
L. H. Howland ◽  
Alfred Nisonoff
Keyword(s):  
Water Level ◽  
The Other ◽  
Cross Linking ◽  
High Solids ◽  
Mechanism Of Formation ◽  
Latex Films ◽  
Ferrous Sulfide ◽  
Other Hand ◽  
Large Particles ◽  
Number Of Particles

Abstract The formation of cream, which occurred in many of the early cold, high-solids GR-S latexes, is undesirable because it results in nonuniformity of the latex and is injurious to the properties of latex films. On the other hand, it is dispersible and, hence, much more tolerable than coagulum. The mechanism of its formation is, therefore, of interest. A cold high-solids latex activated by ferrous sulfide was used as the basis for the study. The giant particles constituting cream begin forming between 18 and 35 per cent conversion in latex stabilized only with the soap present initially, and increase in quantity until the end of polymerization. Their formation can be prevented by the timely addition of sufficient stabilizing soap, or by the use of a soap which initiates a small enough number of particles in relation to its stabilizing capacity. The formation of coagulum, rather than large particles, is favored by decreasing the amount of electrolyte or increasing the amount of water charged, and by the presence of cross-linking in the polymer. The effect of increasing the water level or introducing cross-linking is to increase the size rather than the amount of agglomerates. Methods are suggested for controlling the formation of very large particles.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Rapid Isolation of High Molecular Weight Urokinase from Native Human Urine

1982 ◽  
Vol 47 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Kurt Huber ◽  
Johannes Kirchheimer ◽  
Bernd R Binder
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Human Urine ◽  
Gel Filtration ◽  
Chain Structure ◽  
The Other ◽  
Single Chain ◽  
Apparent Homogeneity ◽  
Sequential Adsorption

SummaryUrokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.

scholarly journals Analysis of the Mechanism by Which Glucose Inhibits Maltose Induction of MAL Gene Expression in Saccharomyces

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 121-132
Author(s):  
Zhen Hu ◽  
Yingzi Yue ◽  
Hua Jiang ◽  
Bin Zhang ◽  
Peter W Sherwood ◽  
...  
Keyword(s):  
Gene Expression ◽  
Glucose Repression ◽  
Protein A ◽  
The Other ◽  
Maltose Permease ◽  
Inducer Exclusion ◽  
Glucose Inhibition ◽  
Independent Mechanism ◽  
Mal Genes

Abstract Expression of the MAL genes required for maltose fermentation in Saccharomyces cerevisiae is induced by maltose and repressed by glucose. Maltose-inducible regulation requires maltose permease and the MAL-activator protein, a DNA-binding transcription factor encoded by MAL63 and its homologues at the other MAL loci. Previously, we showed that the Mig1 repressor mediates glucose repression of MAL gene expression. Glucose also blocks MAL-activator-mediated maltose induction through a Mig1p-independent mechanism that we refer to as glucose inhibition. Here we report the characterization of this process. Our results indicate that glucose inhibition is also Mig2p independent. Moreover, we show that neither overexpression of the MAL-activator nor elimination of inducer exclusion is sufficient to relieve glucose inhibition, suggesting that glucose acts to inhibit induction by affecting maltose sensing and/or signaling. The glucose inhibition pathway requires HXK2, REG1, and GSF1 and appears to overlap upstream with the glucose repression pathway. The likely target of glucose inhibition is Snf1 protein kinase. Evidence is presented indicating that, in addition to its role in the inactivation of Mig1p, Snf1p is required post-transcriptionally for the synthesis of maltose permease whose function is essential for maltose induction.

scholarly journals On a New Geometric Constant Related to the Euler-Lagrange Type Identity in Banach Spaces

Mathematics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 116
Author(s):  
Qi Liu ◽  
Yongjin Li
Keyword(s):  
Banach Spaces ◽  
Product Space ◽  
Sufficient Conditions ◽  
Normal Structure ◽  
The Other ◽  
Inner Product ◽  
Equivalent Characterization ◽  
Geometric Constant ◽  
Geometric Constants

In this paper, we will introduce a new geometric constant LYJ(λ,μ,X) based on an equivalent characterization of inner product space, which was proposed by Moslehian and Rassias. We first discuss some equivalent forms of the proposed constant. Next, a characterization of uniformly non-square is given. Moreover, some sufficient conditions which imply weak normal structure are presented. Finally, we obtain some relationship between the other well-known geometric constants and LYJ(λ,μ,X). Also, this new coefficient is computed for X being concrete space.

The development of body and organ shape

BMC Zoology ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ansa E. Cobham ◽  
Christen K. Mirth
Keyword(s):  
Relative Position ◽  
Body Shape ◽  
Single Cells ◽  
The Other ◽  
Geometric Features ◽  
Main Text ◽  
Size Characterization ◽  
Organ Shape ◽  
The Many

Abstract Background Organisms show an incredibly diverse array of body and organ shapes that are both unique to their taxon and important for adapting to their environment. Achieving these specific shapes involves coordinating the many processes that transform single cells into complex organs, and regulating their growth so that they can function within a fully-formed body. Main text Conceptually, body and organ shape can be separated in two categories, although in practice these categories need not be mutually exclusive. Body shape results from the extent to which organs, or parts of organs, grow relative to each other. The patterns of relative organ size are characterized using allometry. Organ shape, on the other hand, is defined as the geometric features of an organ’s component parts excluding its size. Characterization of organ shape is frequently described by the relative position of homologous features, known as landmarks, distributed throughout the organ. These descriptions fall into the domain of geometric morphometrics. Conclusion In this review, we discuss the methods of characterizing body and organ shape, the developmental programs thought to underlie each, highlight when and how the mechanisms regulating body and organ shape might overlap, and provide our perspective on future avenues of research.

scholarly journals Development of a New Pasta Product by the Incorporation of Chestnut Flour and Bee Pollen

2021 ◽  
Vol 11 (14) ◽  
pp. 6617
Author(s):  
Maëlys Brochard ◽  
Paula Correia ◽  
Maria João Barroca ◽  
Raquel P. F. Guiné
Keyword(s):  
Wheat Flour ◽  
Nutritional Composition ◽  
Cooking Time ◽  
The Other ◽  
Physical Characterization ◽  
Chemical Analyses ◽  
High Fiber ◽  
Chestnut Flour ◽  
Cooking Yield

This work aimed at developing fortified pastas incorporating chestnut flour (25–55%) and powdered pollen (5–20%), either separately or in combination, as well as the characterization of the products obtained. To this, a physical characterization was carried out (analyzing texture and color), complemented with chemical analyses to determine the nutritional composition. Results showed that adding chestnut flour over 40% to wheat-flour pasta shortened optimum cooking time and lowered cooking yield, and the addition to pasta prepared with wheat flour and eggs maintained approximately constant the cooking yield. Additionally, the incorporation of pollen powder (up to 20%) in pasta prepared with wheat flour and water or fresh egg shortened the cooking time and cooking yield, in both fresh and dried pasta. The most suitable percentages of the new ingredients were 50% for chestnut and 10% for pollen. Comparing with the control pasta recipe (wheat flour and egg), the addition of chestnut flour (50%) or pollen powder (10%) increased stickiness, adhesiveness and the darkening of the final product (fresh or dried) but maintained the firmness of the pasta. The cooking of fresh or dried pasta enriched with both ingredients turned the pasta clearer and slightly stickier. On the other hand, the addition of chestnut flour and pollen powder in pasta formulation delivered a nutritionally balanced product with high fiber, vitamins and minerals. Overall, chestnut flour and powdered pollen represent promising ingredients for the development of functional fresh and dried pasta formulations.

scholarly journals Evaluating Latency in Multiprocessing Embedded Systems for the Smart Grid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3322
Author(s):  
Sara Alonso ◽  
Jesús Lázaro ◽  
Jaime Jiménez ◽  
Unai Bidarte ◽  
Leire Muguira
Keyword(s):  
Operating System ◽  
Smart Grid ◽  
Real Time ◽  
Processing System ◽  
The Other ◽  
Programmable Logic ◽  
Detailed Characterization ◽  
Timing Constraint ◽  
Time Part

Smart grid endpoints need to use two environments within a processing system (PS), one with a Linux-type operating system (OS) using the Arm Cortex-A53 cores for management tasks, and the other with a standalone execution or a real-time OS using the Arm Cortex-R5 cores. The Xen hypervisor and the OpenAMP framework allow this, but they may introduce a delay in the system, and some messages in the smart grid need a latency lower than 3 ms. In this paper, the Linux thread latencies are characterized by the Cyclictest tool. It is shown that when Xen hypervisor is used, this scenario is not suitable for the smart grid as it does not meet the 3 ms timing constraint. Then, standalone execution as the real-time part is evaluated, measuring the delay to handle an interrupt created in programmable logic (PL). The standalone application was run in A53 and R5 cores, with Xen hypervisor and OpenAMP framework. These scenarios all met the 3 ms constraint. The main contribution of the present work is the detailed characterization of each real-time execution, in order to facilitate selecting the most suitable one for each application.

Characterization of Different Deoxyribonucleases in Human Lymphocytes

1975 ◽  
Vol 30 (11-12) ◽  
pp. 781-784 ◽  
Author(s):  
E. Jürgen Zöllner ◽  
Hans Störger ◽  
Hans-Joachim Breter ◽  
Rudolf Zahn
Keyword(s):  
Human Lymphocytes ◽  
Disc Electrophoresis ◽  
The Other ◽  
Lower Activity ◽  
Nuclear Fraction ◽  
Polyacrylamide Gels ◽  
Cytoplasmic Fraction ◽  
Acid Deoxyribonuclease ◽  
Deoxyribonuclease Activity

Abstract Deoxyribonucleases, Disc Electrophoresis, Lymphocytes Four groups of deoxyribonuclease activities from human lymphocytes have been characterized by deoxyribonuclease assay in DNA-containing polyacrylamide gels following their separation by disc-electrophoresis. All activities hydrolyse DNA endonucleolytically. One neutral deoxyribo­ nuclease found in the cytoplasmic fraction prefers native or UV-irradiated DNA over denatured DNA as substrate and is a 5′-monoester former. Two groups of acid deoxyribonuclease activities are detectable in the nuclear fraction. Both are 3′-monoester formers. One is as well active with denatured DNA as with native DNA, the other one shows the same activity with native and UV-irradiated DNA but lower activity with denatured DNA. An alkaline deoxyribonuclease activity, also localized in the nucleus, is a 5′ -monoester DNA as substrate.

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