Viscum album agglutinin-induced aggregation of blood cells and the lectin effects on neutrophil function

SummaryThe effect of red blood cells, rbc, and shear rate on the ADPinduced aggregation of platelets in whole blood, WB, flowing through polyethylene tubing was studied using a previously described technique (1). Effluent WB was collected into 0.5% glutaraldehyde and the red blood cells removed by centrifugation through Percoll. At 23°C the rate of single platelet aggregtion was upt to 9× greater in WB than previously found in platelet-rich plasma (2) at mean tube shear rates Ḡ = 41.9,335, and 1,920 s−1, and at both 0.2 and 1.0 µM ADP. At 0.2 pM ADP, the rate of aggregation was greatest at Ḡ = 41.9 s−1 over the first 1.7 s mean transit time through the flow tube, t, but decreased steadily with time. At Ḡ ≥335 s−1 the rate of aggregation increased between t = 1.7 and 8.6 s; however, aggregate size decreased with increasing shear rate. At 1.0 µM ADP, the initial rate of single platelet aggregation was still highest at Ḡ = 41.9 s1 where large aggregates up to several millimeters in diameter containing rbc formed by t = 43 s. At this ADP concentration, aggregate size was still limited at Ḡ ≥335 s−1 but the rate of single platelet aggregation was markedly greater than at 0.2 pM ADP. By t = 43 s, no single platelets remained and rbc were not incorporated into aggregates. Although aggregate size increased slowly, large aggregates eventually formed. White blood cells were not significantly incorporated into aggregates at any shear rate or ADP concentration. Since the present technique did not induce platelet thromboxane A2 formation or cause cell lysis, these experiments provide evidence for a purely mechanical effect of rbc in augmenting platelet aggregation in WB.

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Physico-Chemical Explanation of Blood Cell Adhesion in Thrombus Formation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648058 ◽

1976 ◽

Vol 36 (02) ◽

pp. 430-440 ◽

Cited By ~ 5

Author(s):

A Marmur ◽

E Ruckenstein ◽

S. R Rakower

Keyword(s):

Blood Cells ◽

Thrombus Formation ◽

Experimental Information ◽

Deposition Surface ◽

Physico Chemical ◽

Quantitative Results ◽

Energy Of Interaction ◽

Induced Aggregation ◽

Adhesion Of Platelets ◽

Hydrodynamic Factors

SummaryA model is suggested which assumes that the rate of deposition of cells is determined both by hydrodynamic factors and by Brownian motion over the potential barrier caused by London and double-layer forces in the immediate vicinity of the deposition surface. The height of the barrier in the potential energy of interaction between blood cells and various surfaces is analyzed in relation to the physical properties of the cells, surfaces, and solutions. Based on this analysis, the adhesion of platelets to injured blood vessel walls and to non-biologic materials, the lack of adhesion of red blood cells under the same conditions, the mechanism of ADP induced aggregation and the interaction with blood flow are explained. The qualitative predictions of the model are substantiated by available experimental information. Quantitative results are presented in terms of a time constant, which typifies a period of contact with a surface, during which appreciable deposition occurs.

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EFFECTS OF BLOOD CELLS ON PLATELET AGGREGATION BY IMPEDANCE METHOD

10.1055/s-0038-1644870 ◽

1987 ◽

Author(s):

L Mannucci ◽

R Redaelli ◽

E Tremoll

Keyword(s):

Platelet Aggregation ◽

Whole Blood ◽

Blood Cells ◽

White Blood Cells ◽

Normal Subjects ◽

Impedance Method ◽

Induced Aggregation ◽

Vitro Data ◽

In Vitro Data

To evaluate the effects of blood cells on the response of platelets to aggregating agents using whole blood impedance aggregometer, studies were carried out on whole blood (WB) of normal subjects and of patients with: polycythemia vera (PV), iatrogenic anemia (IA), primary thrombocytosis (PT), idiopathic thrombotic purpura (ITP), myeloid chronic leukemia (MCL), iatrogenic leukopenia (IL). The in vitro effects of red blood cells (RBC) and of white blood cells (WBC) on platelet rich plasma (PRP) aggregation were also evaluated. WB, PRP, WBC and RBC were prepared by conventional methods. Aggregation was performed using the impedance aggregometer (mod. 540, Chrono Log Corp). In normal subjects the concentration of collagen giving 50 % aggregation (AC50 ) found in PRP did not differ from that of WB, indicating that hematocrit values within the normal range did not appreciably affect platelet aggregation. The results obtained in WB of patients are summarized in the table: In vitro data showed that aggregation in prp in wb of normal subjects was related to the number of platelets present in the sample. RBC added to PRP significant reduced aggregation only when the RBC number was greater than 4.101 cells. No effect of WBC on collagen induced aggregation of PRP was observed, whereas significant inhibition was detected after ADP. It is concluded that the aggregation evaluated in WB with impedance method is dependent on the platelet number. Also, in vitro data and studies in WB of patients indicate that aggregation is significantly affected by the presence of cells other than platelets only in conditions of changes of the ratio between platelets and leukocytes and/or red cells.

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The structural and functional changes of blood cells and molecular components in diabetes mellitus

Biological Chemistry ◽

10.1515/hsz-2016-0196 ◽

2017 ◽

Vol 398 (4) ◽

pp. 411-423 ◽

Cited By ~ 12

Author(s):

Leszek Szablewski ◽

Anna Sulima

Keyword(s):

Diabetes Mellitus ◽

Red Blood Cells ◽

Blood Cells ◽

White Blood Cells ◽

Neutrophil Function ◽

Cardiovascular Complications ◽

Oxygen Binding ◽

Functional Changes ◽

Coronary Syndrome ◽

Patients With Diabetes

Abstract It is known fact that diabetes mellitus (DM) affects blood cells. Changes in the erythrocyte membrane, disorder in hemoglobin oxygen-binding and modification in mechanical characteristics, are effects of hyperglycemia on red blood cells. Altered susceptibility infection of patients with diabetes has been ascribed to a depression in the function of polymorphonuclear leukocytes. Neutrophil function in patients with diabetes with good glucose control is slightly different than in healthy ones. DM causes significant changes in lymphocytes metabolism and their functions. Patients with diabetes, presenting with acute coronary syndrome, are at higher risk of cardiovascular complications and recurrent ischemic events in comparison to non-diabetic counterparts. Various mechanisms, including endothelial dysfunction, platelet hyperactivity, and abnormalities in coagulation and fibrynolysis have been implicated for this increased atherothrombotic risk. There are many other alterations of blood cells due to DM. In the present review we focused on modifications of blood cells due to DM. Then, as a second point, we explored how the changes affect functions of red blood cells, white blood cells and platelets.

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Observed differences in dextran and polyvinylpyrrolidone as rouleaux-inducing agents

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y80-046 ◽

1980 ◽

Vol 58 (3) ◽

pp. 271-274 ◽

Cited By ~ 5

Author(s):

Lionel S. Sewchand ◽

Dieter Bruckschwaiger

Keyword(s):

Red Blood Cells ◽

Blood Cells ◽

Animal Species ◽

Critical Concentration ◽

Rbc Membrane ◽

Low Concentrations ◽

High Concentrations ◽

Induced Aggregation ◽

Do So

The effectiveness of dextran fractions (Dx-500, Dx-100, Dx-70) and polyvinylpyrrolidone (PVP-360, PVP-40) in inducing aggregation of red blood cells (RBC) was studied in a nonflowing environment. The Dx fractions, at low concentrations, induced aggregation of human RBC but failed to do so at high concentrations (concentrations greater than 70 g/L). The effect was different on RBC from animal species (cat and rabbit); aggregation increased steadily with the Dx concentration and there was no critical concentration beyond which Dx failed to induce aggregation. The PVP was found to be very effective, at all concentrations, in inducing aggregation of RBC from both human and the animal species. These results have a twofold significance: (1) they suggest that Dx and PVP, both neutral polymers, interact differently with the human RBC membrane; and (2) the association of Dx with the human RBC membrane is different from that with cat and rabbit RBC membranes.

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Paricalcitol Effects on Activities and Metabolism of Platelet Activating Factor and on Inflammatory Cytokines in Hemodialysis Patients

The International Journal of Artificial Organs ◽

10.5301/ijao.5000187 ◽

2013 ◽

Vol 36 (2) ◽

pp. 87-96 ◽

Cited By ~ 18

Author(s):

Sophia N. Verouti ◽

Alexandros B. Tsoupras ◽

Fotini Alevizopoulou ◽

Constantinos A. Demopoulos ◽

Christos Iatrou

Keyword(s):

Vitamin D ◽

Blood Cells ◽

Platelet Activating Factor ◽

Inhibitory Effect ◽

Hemodialysis Patients ◽

Inflammatory Status ◽

Tnf Α ◽

Induced Aggregation

Purpose Paricalcitol improves the inflammatory status of hemodialysis patients. PAF is a strong inflammatory mediator which is produced during hemodialysis. We studied the effects of paricalcitol on PAF and other inflammatory mediators implicated in chronic kidney disease (CKD). Methods We examined the in vitro effects of paricalcitol on PAF/thrombin-induced aggregation as well as on the activities of PAF-basic metabolic enzymes, lyso-PAF acetyltransferase (Lyso-PAF-AT), DTT-insensitive CDP-choline: 1-alkyl-2-acetyl-sn-glycerol cholinephospho-transferase (PAF-CPT) and PAF-acetylhydrolase (PAF-AH) in blood cells from healthy volunteers. In addition, the in vivo effects of paricalcitol on the above these enzymes were examined in plasma and blood cells of hemodialysis patients who had not received any type of vitamin D treatment during the last three months before and after receiving paricalcitol for a month. Finally, IL-12p70, IL-1β, IL-6, IL-8 and TNF-α were measured. Results Paricalcitol inhibited in vitro PAF/thrombin-induced platelet aggregation and the inhibitory effect was comparable with that of PAF/thrombin antagonists. In addition, paricalcitol inhibited in vitro PAF-CPT activity in platelets and leukocytes and increased PAF-AH activity in leukocytes, while much higher concentrations of paricalcitol were needed to inhibit Lyso-PAF-AT activity. Similarly, in hemodialysis patients, paricalcitol treatment reduced PAF-CPT activity in platelets and leukocytes and increased PAF-AH activity in leukocytes, while it could not influence Lyso-PAF-AT activity. On the other hand, paricalcitol therapy reduced IL-8, IL-1β, and TNF-α. Conclusions These results further support the beneficial effects of vitamin D treatment in hemodialysis patients, since it strongly affects PAF/thrombin activities, PAF-metabolism, and IL-8, IL-1β and TNF-α circulating levels.

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Cathelicidin Antimicrobial Peptide Expression Is Inversely Associated with Absolute Neutrophil Counts in Pediatric HCT Recipients

Blood ◽

10.1182/blood-2019-131471 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3294-3294

Author(s):

Jos Domen ◽

Hung-Wen Yeh ◽

Nancy L Shreve ◽

Lei Sun ◽

Yongwu Li ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Hydrogen Peroxide ◽

Membrane Potential ◽

Antimicrobial Peptide ◽

Host Defense ◽

Blood Cells ◽

White Blood Cells ◽

Neutrophil Function ◽

Oxygen Species ◽

Continuous Variables

BACKGROUND: Neutropenia is a major risk factor for infectious complications in hematopoietic cell transplantation (HCT) recipients. However, much less is understood about neutrophil function in the posttransplant period. Cathelicidins are multifunctional host defense peptides. The sole human homolog, Cathelicidin Antimicrobial Peptide (CAMP, OMIM * 600474) is secreted by invading leukocytes, especially neutrophils and plays an important and pleiotropic role in host defense. It acts both as a direct bactericidal agent, but also affects the activity of many immune cells, including prolonging the lifespan of neutrophils. Another critical step in the microbicidal function of neutrophils is the generation of reactive oxygen species. OBJECTIVE: To characterize neutrophil function and CAMP expression over time in children following HCT. METHODS: A prospective study of children undergoing HCT was conducted. Blood samples were collected at 3 months, 6 mo., and 1 y post-HCT timepoints. White blood cells were purified using a PolymorphPrep gradient (Axis-Shield Diagnostics Ltd., Scotland). CAMP expression was measured using Clone H7 antibody (Santa Cruz Biotechnology Inc., USA) in fixed and permeabilized cells. Neutrophil activation was measured as reduction in membrane potential following stimulation with phorbol 12-myristate 13-acetate (PMA) using fluorescence staining with 3,3'-dipentyloxacarbocyanine iodide (DiOC5). Neutrophil hydrogen peroxide generation was measured by oxidation, and resultant increased staining of the probe 2',7' dichlorohydrofluorescein diacetate (DCFH-DA) following PMA stimulation. STATISTICS: Categorical variables were summarized by frequency and percent, and continuous variables were summarized by median and inter-quartile range (IQR). Distributions of continuous variables were examined and were log-transformed if skewed. Linear mixed-effects model was used to evaluate temporal trends and correlations between pairs of variables across time. points. The Bayesian Information Criterion was used to identify the optimal model that balanced model goodness-of-fit and complexity. RESULTS: Sixty-three patients were enrolled, median age 6.1 y (0.4 - 20.5 y). A majority of transplants (69%) were allogeneic. Patient and transplant characteristics are described in Table 1. CAMP was expressed in 95.8% of white blood cells (IQR 80.3 - 99.0%) (Figure 1). CAMP expression in neutrophils, measured as fold-increase above background staining, showed a median value of 474 (IQR 355 - 623). CAMP expression was inversely corelated with absolute neutrophil counts, with 37 folds increase (95% CI 11 to 63 folds, p = 0.006; Figure 2) for every 106 per milliliter reduction in neutrophil counts. Neutrophil activation measured as reduction in membrane potential was expressed as % decrease in DiOC5 staining following PMA stimulation with a median value of 41% (IQR 31 - 56%). Peroxide generation expressed as % increase in DCFH-DA staining following PMA stimulation showed a median value of 304% (IQR 170 - 630%). The reduction in membrane potential was correlated with peroxide generation. For every 1% reduction in membrane potential, hydrogen peroxide production increased by 2% (95% CI 1 to 3%, Figure 3). CAMP expression in neutrophils was not associated with neutrophil function measured by change in membrane potential or peroxide generation. None of the covariates examined (age, transplant type, and timepoints posttransplant) was found to be associated with CAMP expression or measures of neutrophil function. CONCLUSIONS: We have demonstrated that neutrophils, as characterized by changes in membrane potential and reactive oxygen species generation in response to PMA stimulation, are functional in children as early as 3 months following HCT. Of the parameters assessed in this study the increase in CAMP expression in neutrophils in patients with lower numbers of neutrophils in circulation after HCT stands out and this finding may potentially be of importance. Further studies will be necessary to determine if this is specific to HCT setting or if this can also be observed in normal individuals. It will also be important to study if this is reflected in the serum levels of the CAMP-derived active peptides. Disclosures No relevant conflicts of interest to declare.

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The Effect of Antihuman Platelet Antibodies on Human Platelets

10.1055/s-0039-1684377 ◽

1979 ◽

Author(s):

E.F. Ali-Briggs ◽

E.F. van Leeuwen ◽

A.E.G. von dem Borne ◽

C.S.P. Jenkit

Keyword(s):

Blood Cells ◽

Human Platelets ◽

Prostaglandin Synthesis ◽

Antigenic Determinants ◽

Platelet Antibodies ◽

Indirect Antiglobulin Test ◽

Antiglobulin Test ◽

Immunofluorescence Studies ◽

Immunological Approach ◽

Induced Aggregation

The influence of an heterologous antihuman platelet serum (AS) was examined an immunological approach to investigate platelet function, as induces aggregation and release from platelets in citrate plasma. Neither thrombin nor complement were requirements, and inhibitors of ADP-(adenosine) and collagen-induced (aspirin) aggregation were only slightly inhibitory. EDTA-P and four-times washed platelets were also aggregated by as. These data sugf AS-induced aggregation proceeds, at least in part, by a mechanism independer of adp and does not involve platelet prostaglandin synthesis. The active orinciple of the as was found to be associated with the IgG fraction. as fo ipmunoprecipitates (by immunodiffusion) with platelets, fibrinogen and facte VIII; absorbtion with cryoprecipitate did not influence the aggregation resf Since platelets have common antigenic determinants with other blood cells, absorbtion studies with such cells were performed. Absorbtion of as with cells (until negative in the indirect antiglobulin test) had little effect of AS–induced aggregation and release. Following absorbtion with leucocytes, immunofluorescence studies revealed that lymphocyte reactive antibodies were almost totally removed while those of the granulocyte and platelet were stil present. This absorbed as retained the ability to induce both platelet aggregation and release.

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