scholarly journals Measurement of Immunoreactive Angiotensin-(1–7) Heptapeptide in Human Blood

2001 ◽  
Vol 47 (4) ◽  
pp. 726-729 ◽  
Author(s):  
Juerg Nussberger ◽  
Dorette B Brunner ◽  
Juerg A Nyfeler ◽  
Lilly Linder ◽  
Hans R Brunner
Keyword(s):  
Detection Limit ◽  
Human Plasma ◽  
Human Blood ◽  
Plasma Concentrations ◽  
Specific Antiserum ◽  
Clinical Settings ◽  
Physiological Effects ◽  
Reliable Measurement ◽  
Blood Concentrations

Abstract Background: The renal enzyme renin cleaves from the hepatic α2-globulin angiotensinogen angiotensin-(1–10) decapeptide [Ang-(1–10)], which is further metabolized to smaller peptides that help maintain cardiovascular homeostasis. The Ang-(1–7) heptapeptide has been reported to have several physiological effects, including natriuresis, diuresis, vasodilation, and release of vasopressin and prostaglandins. Methods: To investigate Ang-(1–7) in clinical settings, we developed a method to measure immunoreactive (ir-) Ang-(1–7) in 2 mL of human blood and to estimate plasma concentrations by correcting for the hematocrit. A sensitive and specific antiserum against Ang-(1–7) was raised in a rabbit. Human blood was collected in the presence of an inhibitor mixture including a renin inhibitor to prevent peptide generation in vitro. Ang-(1–7) was extracted into ethanol and purified on phenylsilylsilica. The peptide was quantified by radioimmunoassay. Increasing doses of Ang-(1–7) were infused into volunteers, and plasma concentrations of the peptide were measured. Results: The detection limit for plasma ir-Ang-(1–7) was 1 pmol/L. CVs for high and low blood concentrations were 4% and 20%, respectively, and between-assay CVs were 8% and 13%, respectively. Reference values for human plasma concentrations of ir-Ang-(1–7) were 1.0–9.5 pmol/L (median, 4.7 pmol/L) and increased linearly during infusion of increasing doses of Ang-(1–7). Conclusions: Reliable measurement of plasma ir-Ang-(1–7) is achieved with efficient inhibition of enzymes that generate or metabolize Ang-(1–7) after blood sampling, extraction in ethanol, and purification on phenylsilylsilica, and by use of a specific antiserum.

scholarly journals Gene expression–based discovery of atovaquone as a STAT3 inhibitor and anticancer agent

Blood ◽  
2016 ◽  
Vol 128 (14) ◽  
pp. 1845-1853 ◽  
Author(s):  
Michael Xiang ◽  
Haesook Kim ◽  
Vincent T. Ho ◽  
Sarah R. Walker ◽  
Michal Bar-Natan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Retrospective Study ◽  
Human Plasma ◽  
Patient Outcomes ◽  
Anticancer Agent ◽  
Plasma Concentrations ◽  
Anticancer Efficacy ◽  
Key Points

Key PointsThe FDA-approved drug atovaquone is a novel, clinically available inhibitor of STAT3 at standard human plasma concentrations. Atovaquone shows anticancer efficacy in vitro, in vivo, and in a retrospective study of AML patient outcomes after atovaquone treatment.

scholarly journals OLT1177, a β-sulfonyl nitrile compound, safe in humans, inhibits the NLRP3 inflammasome and reverses the metabolic cost of inflammation

2018 ◽  
Vol 115 (7) ◽  
pp. E1530-E1539 ◽  
Author(s):  
Carlo Marchetti ◽  
Benjamin Swartzwelter ◽  
Fabia Gamboni ◽  
Charles P. Neff ◽  
Katrin Richter ◽  
...  
Keyword(s):  
Human Blood ◽  
Nlrp3 Inflammasome ◽  
Inflammatory Diseases ◽  
Plasma Concentrations ◽  
Metabolic Cost ◽  
Inflammasome Activation ◽  
Potassium Efflux ◽  
Caspase 1 ◽  
Healthy Humans

Activation of the NLRP3 inflammasome induces maturation of IL-1β and IL-18, both validated targets for treating acute and chronic inflammatory diseases. Here, we demonstrate that OLT1177, an orally active β-sulfonyl nitrile molecule, inhibits activation of the NLRP3 inflammasome. In vitro, nanomolar concentrations of OLT1177 reduced IL-1β and IL-18 release following canonical and noncanonical NLRP3 inflammasome activation. The molecule showed no effect on the NLRC4 and AIM2 inflammasomes, suggesting specificity for NLRP3. In LPS-stimulated human blood-derived macrophages, OLT1177 decreased IL-1β levels by 60% and IL-18 by 70% at concentrations 100-fold lower in vitro than plasma concentrations safely reached in humans. OLT1177 also reduced IL-1β release and caspase-1 activity in freshly obtained human blood neutrophils. In monocytes isolated from patients with cryopyrin-associated periodic syndrome (CAPS), OLT1177 inhibited LPS-induced IL-1β release by 84% and 36%. Immunoprecipitation and FRET analysis demonstrated that OLT1177 prevented NLRP3-ASC, as well as NLRP3-caspase-1 interaction, thus inhibiting NLRP3 inflammasome oligomerization. In a cell-free assay, OLT1177 reduced ATPase activity of recombinant NLRP3, suggesting direct targeting of NLRP3. Mechanistically, OLT1177 did not affect potassium efflux, gene expression, or synthesis of the IL-1β precursor. Steady-state levels of phosphorylated NF-κB and IkB kinase were significantly lowered in spleen cells from OLT1177-treated mice. We observed reduced IL-1β content in tissue homogenates, limited oxidative stress, and increased muscle oxidative metabolism in OLT1177-treated mice challenged with LPS. Healthy humans receiving 1,000 mg of OLT1177 daily for 8 d exhibited neither adverse effects nor biochemical or hematological changes.

Improvement and assessment of enzyme-linked immunosorbent assay to detect low FK506 concentrations in plasma or whole blood within 6 hours

1993 ◽  
Vol 39 (6) ◽  
pp. 1045-1049 ◽  
Author(s):  
P E Wallemacq ◽  
I Firdaous ◽  
A Hassoun
Keyword(s):  
Detection Limit ◽  
Whole Blood ◽  
Clinical Investigation ◽  
Plasma Concentrations ◽  
Original Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pharmacokinetic Studies ◽  
Blood Concentrations ◽  
Blood Temperature ◽  
Biological Variables

Abstract FK506, a promising new immunosuppressant, is currently under clinical investigation. Because dose-dependent toxicity is possible, blood concentrations of FK506 should be monitored. We improved the original ELISA of FK506 by shortening the incubation time. With some modification of materials, results are obtained within 6 h instead of 2 days, with similar or even better precision. Internal and external quality-control programs showed that our results correlated satisfactorily both with values determined by the original method and the theoretical expected values. Either plasma (detection limit 0.1 microgram/L) or whole-blood (detection limit 1 microgram/L) samples can be used. The sensitivity of the method makes it particularly useful for accurate pharmacokinetic studies or measurement of low blood concentrations. Twenty-four drugs and nine biological variables showed no significant interference on the assay. Study of the concentration- and temperature-dependent distribution of FK506 shows that the drug is largely bound to erythrocytes (ratio of blood to plasma concentrations is 10-40); as the erythrocytes become saturated, more of the drug is found in the plasma. Plasma concentrations may vary according to the blood temperature. We conclude that whole blood should be used for FK506 monitoring, as it is for monitoring cyclosporine.

scholarly journals Studies on the interactions of human pancreatic elastase 2 with human α1-proteinase inhibitor and α1-antichymotrypsin

1987 ◽  
Vol 245 (3) ◽  
pp. 699-704 ◽  
Author(s):  
M Davril ◽  
A Laine ◽  
A Hayem
Keyword(s):  
Human Plasma ◽  
Proteinase Inhibitor ◽  
Plasma Concentrations ◽  
Electrophoretic Method ◽  
Pancreatic Elastase ◽  
Normal Plasma ◽  
Order Of Magnitude ◽  
Normal Human ◽  
Slow Dissociation

The interactions of human pancreatic elastase 2 with alpha 1-proteinase inhibitor and alpha 1-antichymotrypsin were compared by studies in vitro. The equimolar complexes obtained between the enzyme and either inhibitor were relatively stable at 25 degrees C since they could be visualized for up to 5 days by an electrophoretic method. However, in both cases, a slow dissociation occurred with release of active enzyme. As the kass. rate constants are of the same order of magnitude, with a slightly lower value for alpha 1-proteinase inhibitor when compared with alpha 1-antichymotrypsin [(5.6 +/- 1.2) X 10(5) and (8.9 +/- 1.3) X 10(5) M-1.s-1 respectively], partition of human pancreatic elastase 2 between both inhibitors in human plasma is mainly dependent on their respective concentrations. A comparative study by crossed immunoelectrophoresis of the interactions of this enzyme with the two inhibitors contained in normal human plasma and in a mimetic mixture of pure inhibitors was carried out. This allowed the visualization of complexes with either inhibitor. Formation of such a complex with alpha 1-antichymotrypsin had never been demonstrated previously. The patterns obtained are similar when working with normal plasma or with the synthetic mixture, suggesting that, in the conditions used, alpha 1-proteinase inhibitor and alpha 1-antichymotrypsin are the main inhibitors of human pancreatic elastase 2 in the plasma sample. However, it is also shown that part of the enzyme may be taken up by alpha 2-macroglobulin, which is responsible for the remaining enzyme activity on a synthetic substrate. The present work suggests that, according to the delay times of inhibition of human pancreatic elastase 2 calculated from the normal plasma concentrations of alpha 1-proteinase inhibitor and alpha 1-antichymotrypsin, a significant role can be assigned to both inhibitors. Moreover, the role of alpha 1-antichymotrypsin would be enhanced in alpha 1-proteinase-inhibitor deficiency.

scholarly journals Activities of Cefiderocol with Simulated Human Plasma Concentrations against Carbapenem-Resistant Gram-Negative Bacilli in an In Vitro Chemostat Model

2020 ◽  
Vol 64 (11) ◽  
Author(s):  
Shuhei Matsumoto ◽  
Sachi Kanazawa ◽  
Takafumi Sato ◽  
Yoshinori Yamano
Keyword(s):  
Human Plasma ◽  
Plasma Concentrations ◽  
Bactericidal Effect ◽  
Dosing Regimen ◽  
Chemostat Model ◽  
Gram Negative ◽  
Content Type ◽  
Sustained Efficacy ◽  
Carbapenem Resistant

ABSTRACT Activities of cefiderocol under simulated human plasma concentrations at the recommended dosing regimen of 2 g every 8 h with a 3-h infusion were evaluated using an in vitro chemostat model. Against a total of 6 meropenem-resistant Gram-negative strains with cefiderocol MICs of 0.5 to 4 μg/ml, including metallo-β-lactamase producers and carbapenem-resistant Acinetobacter baumannii, cefiderocol treatment showed a bactericidal effect within 8 h and sustained efficacy with no marked bacterial regrowth over 24 h.

scholarly journals An in vitro study on factors affecting endotoxin neutralization in human plasma using the Limulus amebocyte lysate test

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephan Harm ◽  
Claudia Schildböck ◽  
Karin Strobl ◽  
Jens Hartmann
Keyword(s):  
Human Plasma ◽  
Human Blood ◽  
Divalent Cations ◽  
In Vitro Study ◽  
Serum Levels ◽  
Content Type ◽  
Factors Affecting ◽  
Endotoxin Activity ◽  
The Individual

AbstractEndotoxin neutralization, caused by plasma components, makes it difficult to detect endotoxins in human blood. In this study, we investigated which factors influence the recovery of endotoxins using limulus ameobocyte lysate (LAL)-based assays. The individual factors that were examined in more detail were lipoprotein content, type of blood anticoagulation, kinetics and serum levels of divalent cations. Furthermore, it was investigated whether there is a direct correlation between LAL activity and monocyte activation. We could show that polyanionic heparin increases endotoxin recovery in blood, while citrate anticoagulation promotes endotoxin neutralization. Furthermore, we could show that the endotoxin activity in human plasma and serum decreases strongly over time. Time-dependent endotoxin neutralization reaches its maximum after 4–6 h incubation. By means of filtration tests we could determine that endotoxins in the plasma bind to lipoproteins but do not influence their activity. Comparative measurements have shown that high LAL activity of endotoxins in plasma simultaneously possesses high monocyte activating properties in whole blood. For the maximum recovery of endotoxins in human blood the physiological calcium and magnesium concentrations are sufficient. In this study, it was shown that the endotoxin neutralizing plasma components have a molecular weight similar to β2-microglobulin (11.7 kDa). For the exact identification of the endotoxin neutralizing plasma components, which caused a modulation of the immunostimulating endotoxin activity, further investigations have to be carried out in the future.

Fibrinogen-Fibrin-Related Antigen Pattern in Human Blood

1974 ◽  
Vol 32 (02/03) ◽  
pp. 266-276
Author(s):  
Carl D. Jacobsen ◽  
John C. Hoak ◽  
Kenneth K. WU ◽  
Glenna L. Fry
Keyword(s):  
Human Blood ◽  
Plasma Samples

SummaryIn serum from patients with DIC at least 3 different FR-antigenic components could be found. It was difficult to demonstrate these components in the corresponding plasma samples. It is possible that a portion of these antigens formed as a result of in vitro clotting despite the presence of proteolytic inhibitors. These results suggest that the interpretation of “increased split products in serum” may be more complex than current concepts indicate.

Sign in / Sign up

Export Citation Format

Share Document