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Results 701 - 750 of 1084
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Chimini G - - 2000
Phagocytosis is the uptake of large particles by cells by a mechanism that is based on local rearrangement of the actin microfilament cytoskeleton. In higher organisms, phagocytic cells are essential for host defence against invading pathogens, and phagocytosis contributes to inflammation and the immune response. In addition, engulfment, defined as ...
Labro M T - - 2000
Professional phagocytes (polymorphonuclear neutrophils and monocytes/macrophages) are a main component of the immune system. These cells are involved in both host defenses and various pathological settings characterized by excessive inflammation. Accordingly, they are key targets for immunomodulatory drugs, among which antibacterial agents are promising candidates. The basic and historical concepts ...
Serrander L - - 2000
Phagocytosis and the microbicidal functions of neutrophils require dynamic changes of the actin cytoskeleton. We have investigated the role of gelsolin, a calcium-dependent actin severing and capping protein, in peripheral blood neutrophils from gelsolin-null (Gsn-) mice. The phagocytosis of complement opsonized yeast was only minimally affected. In contrast, phagocytosis of ...
Green T R - - 2000
Polyethylene wear debris generated at the bearing surfaces of total artificial hip joints is thought to play an important role in the periprosthetic osteolysis and ultimately the aseptic loosening of these prostheses. The macrophage is believed to be central to this process by releasing various cytokines and other mediators of ...
Imrich A - - 2000
We sought to characterize the bioactive constituents of concentrated ambient air particles (CAPs) through correlation of alveolar macrophage (AM) biological responses (production of TNF, macrophage inflammatory protein (MIP-2), nitrite; cell viability) to components of particle samples. CAPs samples collected on different days showed a range of bioactivity and a strong ...
Shimoji Y - - 2000
Erysipelothrix rhusiopathiae is the causative agent of erysipelas in animals and erysipeloid in humans. In the absence of specific antibodies, the organism evades phagocytosis by phagocytic cells, but even if phagocytized, it is able to replicate intracellulary in these cells. In this review, recent advances in our understanding of the ...
Shacter E - - 2000
Many antineoplastic drugs kill tumor cells by inducing apoptosis. This highly controlled mechanism of cell death is thought to be physiologically advantageous because apoptotic cells are removed by phagocytosis before they lose their permeability barrier, thus preventing induction of an inflammatory response to the dying cells. In contrast, necrotic cells ...
Callahan M K - - 2000
Cells generally maintain an asymmetric distribution of phospholipids across the plasma membrane bilayer, restricting the phospholipid, phosphatidylserine (PS), to the inner leaflet of the plasma membrane. When cells undergo apoptosis, this asymmetric transbilayer distribution is lost, bringing PS to the surface where it acts as a signal for engulfment by ...
van der Goes A - - 2000
One of the actions of glucocorticoids (GC) in multiple sclerosis (MS) is an inhibitory effect on demyelination. This can be caused by a reduction in the number of infiltrating macrophages and/or by an effect on the phagocytosis of myelin. Here we investigate the effect of GC on the phagocytosis of ...
Ouadrhiri Youssef - - 2000
Phagocytosis and bacterial killing are the primary functions of macrophages. Among the mechanisms involved in the phagocytic process, cytokines, especially those of T-helper 1 profile, appear to influence considerably the internalization and the intracellular fate of the pathogen within the macrophage. In particular, the evidence for a cooperation of cytokines ...
Casey L C - - 2000
In summary, the invasion of bacteria across mucosal surfaces is met with a vigorous host response that includes complement, antibody formation (thymus-independent and eventually thymus-dependent), phagocytosis, production of antibacterial peptides and proteins, the production of cytokines that result in activation of phagocytes and endothelial cells to attract more phagocytes, and ...
Daniels A U - - 2000
Several investigators have suggested that biologic molecules adsorbed onto particles may play a key role in determining macrophage response. Adsorbed endotoxins (bacterial debris) may be of particular importance since they are widely present exogenously and endogenously and adhere strongly to many materials. Murine-transformed peritoneal macrophages (IC-21) were used in this ...
Salman H - - 2000
To examine the effect of hypothermia on the phagocytic capacity of rat peritoneal macrophages for latex particles, male Wistar rats were exposed to 4 degrees C for 8 and 72 h. While the shorter exposure to cold did not affect body temperature and macrophage function, animals exposed to 4 degrees ...
Gold E S - - 2000
Phagocytosis of pathogens by macrophages initiates the innate immune response, which in turn orchestrates the adaptive immune response. Amphiphysin II participates in receptor-mediated endocytosis, in part, by recruiting the GTPase dynamin to the nascent endosome. We demonstrate here that a novel isoform of amphiphysin II associates with early phagosomes in ...
Walenkamp A M - - 2000
Macrophages and monocytes are adherent phagocytic cells which play an important role in host defence against the yeast-like fungus Cryptococcus neoformans. Before, phagocytosis by adherent phagocytes could only be measured by means of microscopy or by a radioactive assay, which both have obvious disadvantages. We have developed a new, rapid ...
Lázaro M I - - 2000
Proneness of addicts to infections may be partially due to opiate effects on immune cells. We find that acute morphine inhibits phagocytosis in murine peritoneal macrophages in vitro with apparent desensitization at high concentrations, whereas chronic exposure results in a state akin to tolerance/dependence where macrophages seem to require morphine ...
Gregory C D - - 2000
Until very recently, the function of CD14 was thought to be limited to innate immune responses to bacterial and other microbial structures. It is now known that macrophage CD14 serves an additional unexpected function, namely as a receptor involved in the recognition and phagocytosis of cells undergoing apoptosis. In stark ...
Fietta A - - 2000
BACKGROUND AND OBJECTIVE: The role of mycobacterial lipoarabinomannan (LAM) in regulating the granulomatous response and its effects on cells involved in early responses to tuberculosis have not been clearly defined. The aim of this study was to acquire further evidence about the mechanisms by which LAM takes part in the ...
Sandler S G - - 2000
The benefits of surgical splenectomy in patients with immune (Idiopathic) thrombocytopenia purpura (ITP) probably reflect the combined effects of eliminating a source of antiplatelet antibody synthesis as well as the primary site of platelet destruction. The recent availability of intravenous Rho(D) Immune globulin (WinRho SDF; Nabi, Boca Raton, FL) presents ...
Richards E H. - - 2000
Although many endoparasitic wasps suppress the haemocyte-mediated immune defences of their insect hosts, the effects of ectoparasitoids are virtually unknown. In view of this, a study has been made of the ectoparasitic wasp, Eulophus pennicornis, and its host, the tomato moth, Lacanobia oleracea. For unparasitized insects, in vitro assays indicated ...
Dahlgren C - - 1999
During phagocytosis of microbial intruders, professional phagocytes of our innate immune system increase their oxygen consumption through the activity of an NADPH-oxidase that generates superoxide anion (O(2)(-)) and hydrogen peroxide (H(2)O(2)). These oxygen metabolites give rise to yet other reactive oxygen species that are strongly anti-microbial but which may also ...
Hiura T S - - 1999
There is increasing evidence that particulate air pollutants, such as diesel exhaust particles (DEP), potentiate chronic inflammatory processes as well as acute symptomatic responses in the respiratory tract. The mechanisms of action as well as the cellular targets for DEP remain to be elucidated. We show in this paper that ...
A. The Skin,Mucous Membranes,B. ...
imentary immune system OBJECTIVES After reading this chapter and attending lecture, the student should be able to: 1. Explain what is meant by nonspecific defense and list the nonspecific lines of defense in the vertebrate body. 2. Explain how the physical barrier of skin is reinforced by chemical defenses. 3. ...
Correa R - - 1999
Previous studies have shown that several immune functions were improved in mice after the ingestion of a thioproline (thiazolidine-4-carboxylic acid) enriched diet. In the present work, we have studied the in vitro effects of several concentrations of this thiol compound (0.1, 0.5, 1, 2.5 and 5 mM) on the most ...
Mondal S - - 1999
The splenic macrophages of wall lizards exhibited marked sex-related difference in their phagocytic activity. The percentage phagocytosis and phagocytic index in females was considerably higher than that of males. Gonadectomy resulted in significant increase in percentage phagocytosis and phagocytic index in both male as well as female lizards, suggesting that ...
Rader C P - - 1999
The aim of this study was to establish a human macrophage cell culture system to examine the effect of polyethylene (PE) and titanium particles on cytokine release by macrophage-like cells (MLC) and to quantify this response with respect to the nature and concentration of particles. Human monocytic leukemia cells were ...
Hubbard A K - - 1999
Macrophages participate in a variety of inflammatory and immunologic functions (e.g., phagocytosis, cytokine production, killing of microbes and tumor cells, and processing and presentation of antigen to T lymphocytes). Because these cells are widely distributed in the circulation and throughout tissue, the effects of xenobiotics on macrophage function can be ...
Franc N C - - 1999
Macrophages in the Drosophila embryo are responsible for the phagocytosis of apoptotic cells and are competent to engulf bacteria. Croquemort (CRQ) is a CD36-related receptor expressed exclusively on these macrophages. Genetic evidence showed that crq was essential for efficient phagocytosis of apoptotic corpses but was not required for the engulfment ...
Moffatt O D - - 1999
Cells undergoing apoptosis are cleared rapidly by phagocytes, thus preventing tissue damage caused by loss of plasma membrane integrity. In this study, we show that the surface of leukocytes is altered during apoptosis such that the first Ig-like domain of ICAM-3 (CD50) can participate in the recognition and phagocytosis of ...
Schlegel R A - - 1999
Expression of the aminophospholipid phosphatidylserine (PS) on the surface of apoptotic lymphocytes and lipid-symmetric erythrocytes triggers their phagocytosis by macrophages. Phagocytosis by both activated and unactivated macrophages, which utilize different recognition systems, can be blocked by certain monoclonal antibodies directed against the LPS receptor, CD14. Here we investigate the requirement ...
Chang M K - - 1999
Apoptosis is recognized as important for normal cellular homeostasis in multicellular organisms. Although there have been great advances in our knowledge of the molecular events regulating apoptosis, much less is known about the receptors on phagocytes responsible for apoptotic cell recognition and phagocytosis or the ligands on apoptotic cells mediating ...
Nakashima Y - - 1999
BACKGROUND: Loosening of the implant after total joint arthroplasty remains a serious problem. The activation of macrophages by wear debris from implants, mediated by the release of cytokines that elicit bone resorption, may lead to loosening. The purpose of the present study was to elucidate the mechanisms of macrophage activation ...
Fadok V A - - 1999
Engulfment by a phagocyte is the final common event in the life of most apoptotic cells. Phagocytosis of apoptotic bodies prior to their lysis prevents the release of potentially toxic or immunogenic intracellular contents and activates an anti-inflammatory response, at least in macrophages. We are beginning to understand the mechanisms ...
Boland S - - 1999
The involvement of diesel exhaust particles (DEPs) in respiratory diseases was evaluated by studying their effects on two in vitro models of human airway epithelial cells. The cytotoxicity of DEPs, their phagocytosis, and the resulting immune response were investigated in a human bronchial epithelial cell line (16HBE14o-) as well as ...
Monn C - - 1999
Increased incidence of mortality and morbidity due to cardiopulmonary complications has been found to associate with elevated levels of particulate air pollution (particulate matter with an aerodynamic diameter < 10 microm, PM10 and <2.5 microm, PM2. 5). Lung injury and an imbalance of inflammatory mediators are proposed causative mechanisms, while ...
Baeza-Squiban A - - 1999
PM10, the commonly used indicator of respirable environmental suspended particulate matter with a mean aerodynamic diameter of less than 10 microm, is composed of organic or elemental carbon aggregates containing various metals, acid salts, organic pollutants (polyaromatic hydrocarbons, quinones, nitroaromatic hydrocarbons, etc.), and biological contaminants. In urban and industrial areas, ...
Prabhu A - - 1998
Wear debris from orthopedic joint implants have been postulated to initiate a cascade of complex cellular events that results in aseptic loosening of the prosthesis and eventually in loss of function of the device. The impact of biomaterials used in these devices on host inflammatory response has not been examined ...
Bainbridge J - - 1998
The response to wear particles from orthopaedic implants can lead to inflammation, osteolytic lesions, and aseptic loosening. To gain an insight into the development of this pathogenetic process, immunohistochemical techniques were used to identify the expression and tissue distribution of the potent cell mitogen epidermal growth factor (EGF), and the ...
Kurosaka K - - 1998
Because it is generally believed that apoptosis is not associated with inflammation, we hypothesized that the interaction of phagocytes with apoptotic cells provides a negative or null signal for inflammation. However, we recently found that the interaction led to the production of proinflammatory cytokines but not antiinflammatory cytokines, although the ...
Fadok V A - - 1998
In vivo, apoptotic cells are efficiently removed by professional or nonprofessional phagocytes, a process thought to be essential for tissue remodeling and resolution of inflammation. Macrophages recognize apoptotic cells by several mechanisms, including recognition of exposed phosphatidylserine (PS); however, PS recognition on apoptotic cells has not been identified as a ...
Mulero V - - 1998
The phagocytic cell function is an important factor of resistance to infection in fish. Although it is known that several nutritional factors affect phagocyte function and that vitamins C and E modulate the vertebrate immune system, there are no data on the direct effect of these vitamins or on their ...
McCutcheon J C - - 1998
The potential for leukocyte-mediated host tissue damage during resolution of inflammatory responses is influenced by the rate at which extravasated apoptotic leukocytes are cleared from inflammatory sites. Regulation of macrophage capacity for clearance of apoptotic granulocytes is likely to be an important factor determining whether inflammation ultimately resolves or progresses ...
Qureshi M A - - 1998
4 beta, 15 Diacetoxyscirpenol (DAS) mycotoxin produced by Fusarium species was tested for detrimental effects on macrophage viability, phagocytosis, and Fc-receptor expression. Sephadex-elicited chicken abdominal cells were harvested to establish adherent macrophage monolayers on glass coverslips. Coverslips were then assigned randomly to treatment groups (0, 12.5 and 25 micrograms/mL DAS). ...
Madl A K - - 1998
Individuals with preexisting cardiopulmonary disease are thought to be more susceptible to acute episodes of particulate pollution resulting in increased morbidity and mortality. Our study was designed to evaluate particle fate and macrophage function in an animal model of monocrotaline (MCT)-induced pulmonary hypertension. Two weeks following a single MCT injection, ...
Smith M E - - 1998
Certain cytokines are believed to play a key role in the development of autoimmune demyelinating diseases. Little is known, however, about the effects of these cytokines in the regulation of the key event in myelin destruction, the phagocytosis of myelin by phagocytic cells. We investigated the effects of certain cytokines ...
Piperski V - - 1998
Tiazofurin, an anticancer drug which inhibits IMP dehydrogenase activity and decreases GTP concentration in various malignant cells, induced inhibition of growth and apoptosis in C6 rat glioma in vitro. The effects of tiazofurin were significantly blocked by addition of exogenous guanosine, suggesting the role of decreased GTP in triggering specific ...
Maloney W J - - 1998
This study tested whether macrophages respond differently to retrieved titanium-alloy particles than they do to machined titanium-alloy particles and assessed whether pretreatment of machined titanium-alloy particles with human serum would influence macrophage activation and cytokine release in vitro. Human monocyte/macrophages were isolated from normal healthy donors and exposed to increasing ...
Sandhu J - - 1998
OBJECTIVE: To investigate the role of T lymphocytes in ultra-high molecular weight polyethylene (UHMWPE) induced inflammation in joint arthroplasty. METHOD: We address the role of T cells in wear induced inflammation by injecting the knee joints of both immune competent rats and mice and severe combined immunodeficient (SCID) mice with ...
Ren Y - - 1998
In vivo, cells undergoing apoptosis are usually recognised and swiftly ingested by macrophages or neighbouring cells acting as semi-professional phagocytes. This review debates evidence that the contents of apoptotic cells represent a danger to the organism, being capable of injuring tissue directly or triggering autoimmune responses, concluding that phagocytic clearance ...
Haas A - - 1998
Phagocytic immune cells (particularly macrophages and neutrophils) take up and digest particles that have invaded our bodies. In doing so, they represent a very early line of defence against a microbial attack. During uptake, the particles are wrapped by a portion of the phagocyte's plasma membrane, and a new endocytic ...
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