scholarly journals THE ROLE OF OPSONINS IN THE CLEARANCE OF LIVING AND INERT PARTICLES BY CELLS OF THE RETICULOENDOTHELIAL SYSTEM

1961 ◽  
Vol 114 (3) ◽  
pp. 363-374 ◽  
Author(s):  
Charles R. Jenkin ◽  
Derrick Rowley
Keyword(s):  
Large Dose ◽  
Reticuloendothelial System ◽  
Blood Stream ◽  
Phagocytic Cells ◽  
Serum Factors ◽  
Inert Particles ◽  
Reduced Rate ◽  
Living Bacteria

An investigation of the clearance of bacteria and colloids from the blood stream of mice has shown that both living and inert particles require serum factors (opsonins) in order that they may be phagocytosed by the macrophages of the reticuloendothelial system. It has been demonstrated that after the injection of a large dose of colloid there is a depletion of these serum opsonins which appears to account for the reduced rate of clearance of a second dose of colloid or living bacteria, since replacement of these factors leads to normal clearance. The significance of these results is discussed and it is suggested that in "blockaded" animals there is a depletion of serum opsonins rather than a saturation of phagocytic cells.

Interaction of Monocytes, Platelets, and Bacteria in Vitro

1970 ◽  
Vol 28 ◽  
pp. 68-69
Author(s):  
C. C. Clawson ◽  
J. G. White ◽  
R. A. Good
Keyword(s):  
Platelet Count ◽  
Reticuloendothelial System ◽  
Intimate Relationship ◽  
Mononuclear Phagocytes ◽  
Living Animal ◽  
Serum Factors ◽  
Sequential Evaluation ◽  
Living Bacteria

The injection of inert colloidal material or bacteria into the circulating blood of a living animal induces platelet aggregation and a fall in platelet count. This interaction of particulates with circulating platelets appears to have an intimate relationship with the subsequent clearance of the foreign particles from the circulation by the reticuloendothelial system Most previous investigations of this phenomenon have employed inert colloids in vivo. An in vitro system has been designed which allows close sequential evaluation of the interactions of living bacteria, platelets, serum factors and mononuclear phagocytes (monocytes).

Perspective – Escape from destruction: how cancer-derived EVs are protected from phagocytosis

2020 ◽  
Vol 2 (1) ◽  
pp. 60-64
Author(s):  
Peter Altevogt ◽  
Marei Sammar ◽  
Laura Hüser ◽  
Viktor Umansky ◽  
Jochen Utikal
Keyword(s):  
Extracellular Vesicles ◽  
Immune Suppression ◽  
Blood Circulation ◽  
Blood Stream ◽  
Phosphatidyl Serine ◽  
The Body ◽  
Hostile Environment ◽  
Phagocytic Cells ◽  
The Stability

There is evidence that cancer-derived extracellular vesicles (EVs) have nearby and distant effects in the body. In order to reach distant sites, EVs need to travel through the blood stream and organs where they encounter a hostile environment in the form or phagocytic cells. However, the stability and homeostasis in the blood circulation and in the tumor microenvironment are not well understood. Phagocytosis is an important mechanism for the clearance of apoptotic and necrotic cells. As exosomes (small EV) express “eat-me” signals such as phosphatidyl-serine, it is likely that they are cleared similar to dead cells. Here we discuss measures that cancer cells have developed to protect their EVs from rapid depletion. The expression of “don’t eat me” signals such as CD47 and CD24 on the tumor cell surface and in released exosomes is of vital importance. We will focus on the role of the CD24-Siglec-10 binding axis as a stop signal at the interface between tumor cells and phagocytic cells. Extending the lifetime of EVs is essential for the cancer to achieve systemic immune suppression and to prepare metastatic niches for spreading. Keywords: CD24, CD47, Extracellular vesicles, Siglecs, carbohydrates, phagocytosis

Studies on the reticuloendothelial system of the dogfish Scyliorhinus canicula. Endocytic activity of fixed cells in the spleen and liver

1987 ◽  
Vol 65 (7) ◽  
pp. 1759-1769 ◽  
Author(s):  
Timothy C. Hunt ◽  
Andrew F. Rowley
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Reticuloendothelial System ◽  
Phagocytic Cells ◽  
Scyliorhinus Canicula ◽  
Sheep Red Blood Cells ◽  
Latex Beads ◽  
Endocytic Activity ◽  
Red Pulp

The role of the spleen and liver of the lesser spotted dogfish, Scyliorhinus canicula, in the clearance of a range of materials, including colloidal carbon, latex beads, sheep red blood cells, bacteria, and dextran, was examined. The spleen was particularly important in the clearance process. Smaller particulates, such as carbon, were sequestered by the highly endocytic macrophages of the ellipsoids, while larger particles, for example, bacteria and sheep red blood cells, were mainly taken up by the fixed macrophages of the red pulp. An increase in the numbers of the eosinophilic G1 granulocytes in the red pulp of the spleen was observed following injection of the particulates. In the liver, fixed cells, probably homologous to mammalian Kupffer cells, were involved in clearance and participated in endocytosis of carbon and latex. Additionally, all of the injected particulates were internalized by cells (frequently seen to also contain melanin granules) lying within nonsinusoidal blood vessels in the hepatic parenchyma. Often, but especially in fish injected with bacteria, these phagocytic cells appeared trapped along with free bacteria, within large clumps of circulatory blood cells in the vessels. The presence of the injected materials in the spleen and liver was evident at 30 min and increased up to 1 week. The ultimate localization and differential uptake of the injected materials, and the relative importance of the spleen and liver in the clearance of these materials are discussed.

The role of microRNA-33 as a key regulator in hepatic lipogenesis signaling and a potential serological biomarker for NAFLD with excessive dietary fructose consumption in C57BL/6N mice

2021 ◽  
Author(s):  
Jeong Hoon Pan ◽  
Hanvit Cha ◽  
Jingsi Tang ◽  
Seoyoon Lee ◽  
Suk Hee Lee ◽  
...  
Keyword(s):  
Fatty Liver ◽  
Blood Stream ◽  
Hepatic Lipogenesis ◽  
Dietary Fructose

Fructose-induced hepatic miR-33 suppression lead to fatty liver via upregulation of SREBP1. Additionally, fructose-induced hepatic ferroptosis may cause a spill-over of miR-33 into blood stream, which could be a potential serological biomarker for fructose-induced NAFLD.

scholarly journals Evaluation of the role of CD47 in sickle cell disease

2021 ◽  
Author(s):  
Basmah Eldakhakhny ◽  
Hadeel Al Sadoun ◽  
Nehal Bin Taleb ◽  
Dunya Ahmed Nori ◽  
Nawal Helmi ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Annexin V ◽  
Cell Disease ◽  
Phagocytic Cells ◽  
Surface Marker Expression ◽  
Inflammatory Phenotype ◽  
Healthy Control ◽  
Cell Surface Marker Expression ◽  
Pro Inflammatory Cytokines

AbstractCD47 is a self-marker expressed on the surface of RBCs and work to prevent the process of phagocytosis. SIRPα is the ligand of CD47 that is expressed on the surface of phagocytic cells, such as macrophages, to control the removal of dead/diseased cells. This study aimed to examine the expression of CD47 on RBCs and SIRPα on PBMC cells in SCD patients and the apoptosis of SCD RBCs. We also measured the levels of pro-inflammatory cytokines in SCD patients and correlated it with the cell surface marker expression of CD47 and SIRPα to determine whether CD47 and/or SIRPα played a role in promoting the pro-inflammatory phenotype in SCD. Whole blood samples were drawn from SCD patients, and healthy control and PBMC were isolated and stained with SIRPα. Change in CD47, apoptosis by annexin V marker, and pro-inflammatory cytokines were measured and correlation among these variants was determined. The expression of CD47 was significantly decreased and the apoptosis was increased in RBCs of SCD patients. A higher level of pro-inflammatory cytokines, IL-6 and IL-1β, was found in SCD patients and IL-1β was found to be inversely correlated with SIRPα expression. Our data showed that CD47 of erythrocytes of SCD samples is reduced and that the apoptosis is increased in those patients. Based on the role of CD47, we suggest that increased apoptosis in SCD would be impacted by the reduced level of CD47. An inverse relationship was found between SIRPα marker on PBMC and the increased production of pro-inflammatory cytokines in SCD.

scholarly journals Potential Role of Vitamins and Zinc on Acute Respiratory Infections Including Covid-19

2021 ◽  
Vol 8 ◽  
pp. 2333794X2110217
Author(s):  
Indah K. Murni ◽  
Endy P. Prawirohartono ◽  
Rina Triasih
Keyword(s):  
Vitamin A ◽  
Vitamin C ◽  
Large Dose ◽  
Common Cold ◽  
Potential Role ◽  
Respiratory Infections ◽  
Acute Respiratory Infections ◽  
Under Five ◽  
Short Period

Background. Vitamin C, E, D, A, zinc are considered to be essential in preventing and treating of acute respiratory infections (ARI) including COVID-19. Methods. We reviewed published studies evaluating the potential roles of these vitamin and zinc for ARIs and COVID-19 using Medline database, medRxiv, and bibliographic references. Results. Vitamins C, D, and E did not reduce incidence of common cold in general, but vitamin C reduced by half in population with physical and environment stresses. Vitamins C and E shortened duration and reduced severity of common cold. A large-dose vitamin A had no effect on recovery from pneumonia. Zinc improved clinical deterioration and pneumonia duration in under five. The effect on preventing COVID-19 morbidity and related-death was lacking. Conclusions. Although the effects of vitamins and zinc on ARIs including COVID-19 were inconclusive, taking these for a short period during pandemic may be beneficial when there is risks of deficiency.

scholarly journals Centromere Protein B Null Mice are Mitotically and Meiotically Normal but Have Lower Body and Testis Weights

1998 ◽  
Vol 141 (2) ◽  
pp. 309-319 ◽  
Author(s):  
Damien F. Hudson ◽  
Kerry J. Fowler ◽  
Elizabeth Earle ◽  
Richard Saffery ◽  
Paul Kalitsis ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Mammalian Species ◽  
Experimental Studies ◽  
Conflicting Evidence ◽  
Body Weights ◽  
Reduced Rate ◽  
And Function ◽  
Centromere Assembly ◽  
Mitosis And Meiosis

CENP-B is a constitutive centromere DNA-binding protein that is conserved in a number of mammalian species and in yeast. Despite this conservation, earlier cytological and indirect experimental studies have provided conflicting evidence concerning the role of this protein in mitosis. The requirement of this protein in meiosis has also not previously been described. To resolve these uncertainties, we used targeted disruption of the Cenpb gene in mouse to study the functional significance of this protein in mitosis and meiosis. Male and female Cenpb null mice have normal body weights at birth and at weaning, but these subsequently lag behind those of the heterozygous and wild-type animals. The weight and sperm content of the testes of Cenpb null mice are also significantly decreased. Otherwise, the animals appear developmentally and reproductively normal. Cytogenetic fluorescence-activated cell sorting and histological analyses of somatic and germline tissues revealed no abnormality. These results indicate that Cenpb is not essential for mitosis or meiosis, although the observed weight reduction raises the possibility that Cenpb deficiency may subtly affect some aspects of centromere assembly and function, and result in reduced rate of cell cycle progression, efficiency of microtubule capture, and/or chromosome movement. A model for a functional redundancy of this protein is presented.

The role of Staphylococcus lugdunensis as a pathogen in children: a multicentre retrospective study

2021 ◽  
Vol 70 (5) ◽  
Author(s):  
Noa Hurvitz ◽  
Lea Ohana Sarna Cahan ◽  
Itai Gross ◽  
Daniel Grupel ◽  
Orli Megged ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Blood Culture ◽  
Otitis Media ◽  
Paediatric Population ◽  
Blood Stream ◽  
Staphylococcus Lugdunensis ◽  
Content Type ◽  
Link Type ◽  
Putative Role

Introduction: Staphylococcus lugdunensis (SL), a tube coagulase negative Staphylococcus , is known to be pathogenic in adults, causing mainly skin infections. Gap Statement: Previous studies assessing SL's role in paediatric populations are sparse and are mainly limited to case reports. Aim: Present the clinical characteristics consistent with SL infections and its putative role as a pathogen in the paediatric population. Methodology: A retrospective multicentre study was conducted in four paediatric medical centres in Israel. Patients with isolates of SL presenting between 2009–2019 were included. Results: SL was isolated from 40 patients. Average (±SD) age at presentation was 5.9 (±6.2) years, with 22 (55 %) being female. Skin, soft tissue and musculoskeletal infections were the most common (n=20, 50%) followed by ear infections (n=13, 32.5%). Five cases of urine isolates and two isolates from blood culture samples were also reported. Skin abscess was the most common infection among skin and soft tissue isolates, reported in 17 children (85%) with SL being the only pathogen in 15 (75%). Otitis media was the most common ear infection accounting for 12 (92%) of all cases with SL as the only isolate reported in 6 (46%). Five cases of SL isolates from urine specimens were reported, all of which with poor growth of bacteria and normal urinalysis. Two cases of SL growth in blood culture were found in children presenting with signs and symptoms consistent with invasive blood stream infection. Conclusions: In the paediatric population, studied infections caused by SL are increasingly observed. The results of this study highlight its role as a pathogen in soft tissue infections and its putative role in otitis media and invasive blood stream infections. However, the role of SL as an uropathogen was not established.

The cell biology and pathogenic role of pulmonary intravascular macrophages

1990 ◽  
Vol 258 (2) ◽  
pp. L1-L12 ◽  
Author(s):  
A. E. Warner ◽  
J. D. Brain
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Cell Biology ◽  
Morphological Characteristics ◽  
Laboratory Animals ◽  
Capillary Endothelium ◽  
Phagocytic Cells ◽  
Pulmonary Uptake ◽  
Pulmonary Intravascular Macrophages

Pulmonary intravascular macrophages (PIMs) are an extensive population of mature phagocytic cells adherent to the pulmonary capillary endothelium in selected species. They are not prevalent in lungs of commonly studied laboratory animals, such as rodents, and thus have only been recently appreciated. However, their potential role in host defense and acute lung injury has attracted interest, since a number of studies have demonstrated pulmonary localization of circulating particles, microbes, and endotoxin by PIMs. Those animal species, such as ruminants, that provide useful models of pathogen (or endotoxin)-induced acute lung injury demonstrate rapid pulmonary uptake of bacteria by PIMs. Inflammatory mediators released by activated PIMs may initiate the process and provoke accumulation of neutrophils and platelets. This review summarizes the morphological characteristics of PIMs and their species distribution. The role of these members of the mononuclear phagocyte system, both beneficial and potentially pathogenic, is reviewed. The question of whether PIMs have a role in acute lung injury in humans is also discussed.

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