Displaying publications 1 - 20 of 52 in total

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  1. Evaluation of variable parameters in neutrophil function test using chemiluminescence assay
    Noah RM, Jais MR, Noh LM
    Malays J Pathol, 1994 Dec;16(2):157-60.
    PMID: 9053565
    Variable parameters in chemiluminescence assay, one of the methods used to assess the functional capacity of neutrophils, were evaluated for suitable adaptation locally. The use of pooled normal human serum as compared to single normal human serum in opsonizing particles for phagocytosis was found to exhibit lower chemiluminescence activity (reduction range of 30%-50%). A similar degree of depression was observed when the particles were opsonized using normal human serum in comparison to that using autologous serum. Different intensity of chemiluminescence was also noted when the opsonized particle used was the Oxford strain of Staphylococcus aureus (NCTC 6571) in contrast to a strain of Staphylococcus aureus isolated from a patient. The results obtained warrant clinicians to deliver appropriate samples as best they can when the chemiluminescence assay is requested.
    Matched MeSH terms: Phagocytosis/physiology*
  2. Effects of aqueous plant extracts on the phagocytic capability and intracellular killing of Staphyococcus aureus by murine peritoneal macrophages in vitro
    Mahmood AA, Khiarul Anwar A, Ansary A, Sidik K, Salmah I, Suzainur KAR
    JUMMEC, 2001;6:30-33.
    Nine local plant species were picked randomly and their aqueous extracts have been screened to know their effects on the phagocytic capability and intracellular killing of StapllylococclIs al/rellS bacteria by mouse peritoneal macrophages. Macrophage cultures were incubated with different concentration of each plant extracts forI hour. Among these aqueous extracts, Ageratum conyzoides and Malastoma melabathricum inhibited the phagocytic capability and intracellular killing of Stapllylococclls aureus compared with controls. Elicited (activated) cells have more phagocytic capability and intracellular killing than the resident (normal) macrophages. There were no differences in the viability of cells between treated cells (with extracts) and controls (without extracts). KEYWORDS: Aqueous plant extracts, murine macrophage, phagocytosis.
    Matched MeSH terms: Phagocytosis
  3. Fulltext Wear Debris Characterization and Corresponding Biological Response: Artificial Hip and Knee Joints
    Nine MJ, Choudhury D, Hee AC, Mootanah R, Osman NAA
    Materials (Basel), 2014 Feb 10;7(2):980-1016.
    PMID: 28788496 DOI: 10.3390/ma7020980
    Wear debris, of deferent sizes, shapes and quantities, generated in artificial hip and knees is largely confined to the bone and joint interface. This debris interacts with periprosthetic tissue and may cause aseptic loosening. The purpose of this review is to summarize and collate findings of the recent demonstrations on debris characterization and their biological response that influences the occurrence in implant migration. A systematic review of peer-reviewed literature is performed, based on inclusion and exclusion criteria addressing mainly debris isolation, characterization, and biologic responses. Results show that debris characterization largely depends on their appropriate and accurate isolation protocol. The particles are found to be non-uniform in size and non-homogeneously distributed into the periprosthetic tissues. In addition, the sizes, shapes, and volumes of the particles are influenced by the types of joints, bearing geometry, material combination, and lubricant. Phagocytosis of wear debris is size dependent; high doses of submicron-sized particles induce significant level of secretion of bone resorbing factors. However, articles on wear debris from engineered surfaces (patterned and coated) are lacking. The findings suggest considering debris morphology as an important parameter to evaluate joint simulator and newly developed implant materials.
    Matched MeSH terms: Phagocytosis
  4. Fulltext Factors influencing phagocytosis of malaria parasites: the story so far
    Chua CLL, Ng IMJ, Yap BJM, Teo A
    Malar J, 2021 Jul 16;20(1):319.
    PMID: 34271941 DOI: 10.1186/s12936-021-03849-1
    There are seven known species of Plasmodium spp. that can infect humans. The human host can mount a complex network of immunological responses to fight infection and one of these immune functions is phagocytosis. Effective and timely phagocytosis of parasites, accompanied by the activation of a regulated inflammatory response, is beneficial for parasite clearance. Functional studies have identified specific opsonins, particularly antibodies and distinct phagocyte sub-populations that are associated with clinical protection against malaria. In addition, cellular and molecular studies have enhanced the understanding of the immunological pathways and outcomes following phagocytosis of malaria parasites. In this review, an integrated view of the factors that can affect phagocytosis of infected erythrocytes and parasite components, the immunological consequences and their association with clinical protection against Plasmodium spp. infection is provided. Several red blood cell disorders and co-infections, and drugs that can influence phagocytic capability during malaria are also discussed. It is hoped that an enhanced understanding of this immunological process can benefit the design of new therapeutics and vaccines to combat this infectious disease.
    Matched MeSH terms: Phagocytosis*
  5. Fulltext Microvascular guidance: a challenge to support the development of vascularised tissue engineering construct
    Sukmana I
    ScientificWorldJournal, 2012;2012:201352.
    PMID: 22623881 DOI: 10.1100/2012/201352
    The guidance of endothelial cell organization into a capillary network has been a long-standing challenge in tissue engineering. Some research efforts have been made to develop methods to promote capillary networks inside engineered tissue constructs. Capillary and vascular networks that would mimic blood microvessel function can be used to subsequently facilitate oxygen and nutrient transfer as well as waste removal. Vascularization of engineering tissue construct is one of the most favorable strategies to overpass nutrient and oxygen supply limitation, which is often the major hurdle in developing thick and complex tissue and artificial organ. This paper addresses recent advances and future challenges in developing three-dimensional culture systems to promote tissue construct vascularization allowing mimicking blood microvessel development and function encountered in vivo. Bioreactors systems that have been used to create fully vascularized functional tissue constructs will also be outlined.
    Matched MeSH terms: Phagocytosis/physiology
  6. Flavonoids of Artocarpus heterophyllus Lam. heartwood inhibit the innate immune responses of human phagocytes
    Septama AW, Jantan I, Panichayupakaranant P
    J Pharm Pharmacol, 2018 Sep;70(9):1242-1252.
    PMID: 29943393 DOI: 10.1111/jphp.12952
    OBJECTIVES: To investigate the effects of flavonoids isolated from Artocarpus heterophyllus. heartwood on chemotaxis, phagocytosis, reactive oxygen species (ROS) production and myeloperoxidase (MPO) activity of human phagocytes.

    METHODS: Chemotaxis was evaluated using a modified Boyden chamber and phagocytosis was determined by flowcytometer. Respiratory burst was investigated by luminol-based chemiluminescence assay while MPO activity was determined by colorimetric assay.

    KEY FINDINGS: Artocarpanone and artocarpin strongly inhibited all steps of phagocytosis. Artocarpanone and artocarpin showed strong chemotactic activity with IC50 values of 6.96 and 6.10 μm, respectively, which were lower than that of ibuprofen (7.37 μm). Artocarpanone was the most potent compound in inhibiting ROS production of polymorphonuclear leucocytes and monocytes with IC50 values comparable to those of aspirin. Artocarpin at 100 μg/ml inhibited phagocytosis of opsonized bacteria (28.3%). It also strongly inhibited MPO release with an IC50 value (23.3 μm) lower than that of indomethacin (69 μm). Structure-activity analysis indicated that the number of hydroxyl group, the presence of prenyl group and variation of C-2 and C-3 bonds might contribute towards their phagocytosis.

    CONCLUSIONS: Artocarpanone and artocarpin were able to suppress strongly the phagocytosis of human phagocytes at different steps and have potential to be developed into potent anti-inflammatory agents.

    Matched MeSH terms: Phagocytosis/drug effects; Phagocytosis/immunology
  7. Fulltext Chlamydia and Its Many Ways of Escaping the Host Immune System
    Wong WF, Chambers JP, Gupta R, Arulanandam BP
    J Pathog, 2019;2019:8604958.
    PMID: 31467721 DOI: 10.1155/2019/8604958
    The increasing number of new cases of Chlamydia infection worldwide may be attributed to the pathogen's ability to evade various host immune responses. Summarized here are means of evasion utilized by Chlamydia enabling survival in a hostile host environment. The pathogen's persistence involves a myriad of molecular interactions manifested in a variety of ways, e.g., formation of membranous intracytoplasmic inclusions and cytokine-induced amino acid synthesis, paralysis of phagocytic neutrophils, evasion of phagocytosis, inhibition of host cell apoptosis, suppression of antigen presentation, and induced expression of a check point inhibitor of programmed host cell death. Future studies could focus on the targeting of these molecules associated with immune evasion, thus limiting the spread and tissue damage caused by this pathogen.
    Matched MeSH terms: Phagocytosis
  8. Fulltext Maternal and umbilical cord blood polymorphonuclear leukocytes showed moderate oxidative burst at phagocytosis of Gardnerella vaginalis
    Swaminathan A, Abd Aziz NH, Ayub NA, Wong KK, Cheah FC
    BMC Res Notes, 2021 Nov 22;14(1):420.
    PMID: 34809696 DOI: 10.1186/s13104-021-05842-y
    OBJECTIVE: Pregnant women with bacterial vaginosis due to Gardnerella vaginalis (GV) infection presents with a wide-ranging disease symptomatology. We speculate this may be due to interaction that varies between host immune response and the pathogen. We studied the oxidative burst in polymorphonuclear leukocytes (PMNL)s from maternal blood (MB) and cord blood (CB) upon phagocytosis of GV and compared against E. coli and Group B Streptococcus (GBS).

    RESULTS: The PHAGOBURST™ assay detects fluorescence from oxidized dihydrorhodamine during oxidative burst. The average percentage of PMNL showing oxidative burst was almost two-fold greater with GBS (99.5%) and E. coli (98.2%) than GV (56.9%) (p 

    Matched MeSH terms: Phagocytosis
  9. An electronmicroscopic study of the interaction of Burkholderia pseudomallei and human macrophages
    Nathan SA, Puthucheary SD
    Malays J Pathol, 2005 Jun;27(1):3-7.
    PMID: 16676686
    B. pseudomallei has been shown to persist intracellularly in melioidosis patients until reactivated by decreasing immunocompetence. We have shown by transmission electron microscopy the internalization of B. pseudomallei by human macrophages via conventional phagocytosis enclosed within membrane-bound vacuoles or phagosomes. Ferritin labeled lysosomes provided evidence of phagosome-lysosome fusion. Ingested bacilli were designated as "intact" or "damaged" on the basis of their ultrastructural features. An intact bacterium was seen with low electron opaque central nuclear region surrounded by dense bacterial cytoplasm, bounded externally by bacterial plasma membrane and cell wall. In contrast, B. pseudomallei were considered damaged when seen with cavitation within the central nuclear region, separation of bacterial cytoplasm from the cell wall, herniation of cytoplasmic contents and lamination of bacterial cell wall and its surrounding electron transparent zone. Our observations indicate that the microbicidal mechanism(s) in B. pseudomallei-infected macrophages failed to ensure complete clearance of the organism and this failure probably facilitates intracellular persistence and proliferation, and this may be one of the survival strategies adopted by this organism.
    Matched MeSH terms: Phagocytosis*
  10. Phagocytosis of malaria-infected erythrocytes in rodent malaria
    Rain AN, Roxas CC, Mak JW
    Southeast Asian J. Trop. Med. Public Health, 1993 Jun;24(2):388-90.
    PMID: 8266248
    Matched MeSH terms: Phagocytosis*
  11. Time-Lapse 2D Imaging of Phagocytic Activity in M1 Macrophage-4T1 Mouse Mammary Carcinoma Cells in Co-cultures
    Zaidi NE, Shazali NAH, Chor ALT, Osman MA, Ibrahim K, Jaoi-Edward M, et al.
    J Vis Exp, 2019 12 14.
    PMID: 31885381 DOI: 10.3791/60281
    Tumor-associated macrophages (TAMs) have been identified as an important component for tumor growth, invasion, metastasis, and resistance to cancer therapies. However, tumor-associated macrophages can be harmful to the tumor depending on the tumor microenvironment and can reversibly alter their phenotypic characteristics by either antagonizing the cytotoxic activity of immune cells or enhancing anti-tumor response. The molecular actions of macrophages and their interactions with tumor cells (e.g., phagocytosis) have not been extensively studied. Therefore, the interaction between immune cells (M1/M2-subtype TAM) and cancer cells in the tumor microenvironment is now a focus of cancer immunotherapy research. In the present study, a live cell coculture model of induced M1 macrophages and mouse mammary 4T1 carcinoma cells was developed to assess the phagocytic activity of macrophages using a time-lapse video feature using phase-contrast, fluorescent, and differential interference contrast (DIC) microscopy. The present method can observe and document multipoint live-cell imaging of phagocytosis. Phagocytosis of 4T1 cells by M1 macrophages can be observed using fluorescent microscopy before staining 4T1 cells with carboxyfluorescein succinimidyl ester (CFSE). The current publication describes how to coculture macrophages and tumor cells in a single imaging dish, polarize M1 macrophages, and record multipoint events of macrophages engulfing 4T1 cells during 13 h of coculture.
    Matched MeSH terms: Phagocytosis/physiology*
  12. The effect of L-arginine on Porphyromonas gingivalis-induced phagocytosis of a murine macrophage-like RAW264.7 cell line
    Sosroseno W
    Immunopharmacol Immunotoxicol, 2004 May;26(2):309-13.
    PMID: 15209366
    The aim of this study was to determine the effect of L-arginine on Porphyromonas gingivalis-induced phagocytosis by RAW264.7 cells. The cells were pretreated with L-arginine or D-arginine prior to incubation with either unopsonized or opsonized P. gingivalis. In other experiments, the cells were pretreated with L-arginine and various concentrations of NMLA (N(G)-monomethyl-L-arginine) prior to incubation with the bacteria. The phagocytosis was microscopically assessed and determined by the phagocytic index. The results showed that L-arginine, but not D-arginine enhances the ability of RAW264.7 cells to engulf the bacteria. The upregulatory effect of L-arginine on P. gingivalis-induced phagocytosis was abolished by NMLA. The results of the present study suggest that L-arginine may upregulate the P. gingivalis-induced phagocytic activity of RAW264.7 cells, perhaps, via modulation of nitric oxide synthase.
    Matched MeSH terms: Phagocytosis/drug effects*
  13. Role of interleukin-1beta and tumour necrosis factor-alpha on hydroxyapatite-induced phagocytosis by murine macrophages (RAW264.7 cells)
    Gopinath VK, Musa M, Samsudin AR, Sosroseno W
    Br J Biomed Sci, 2006;63(4):176-8.
    PMID: 17201208
    Matched MeSH terms: Phagocytosis/immunology*
  14. Fulltext Standardized ethanol extract, essential oil and zerumbone of Zingiber zerumbet rhizome suppress phagocytic activity of human neutrophils
    Akhtar NMY, Jantan I, Arshad L, Haque MA
    BMC Complement Altern Med, 2019 Nov 21;19(1):331.
    PMID: 31752812 DOI: 10.1186/s12906-019-2748-5
    BACKGROUND: Zingiber zerumbet rhizome and its bioactive metabolites have previously been reported to exhibit innumerable pharmacological properties particularly anti-inflammatory activities. In the present study, the 80% ethanol extract, essential oil and zerumbone of Z. zerumbet rhizomes were explored for their in vitro immunosuppressive properties on chemotaxis, CD11b/CD18 expression, phagocytosis and chemiluminescence of isolated human polymorphonuclear neutrophils (PMNs).

    METHODS: The extract was analyzed quantitatively by performing a validated reversed phase high performance liquid chromatography (RP-HPLC). Zerumbone was isolated by chromatographic technique while the essential oil was acquired through hydro-distillation of the rhizomes and further analyzed by gas chromatography (GC) and GC-MS. Chemotaxis assay was assessed by using a 24-well cell migration assay kit, while CD18 integrin expression and phagocytic engulfment were measured using flow cytometry. The reactive oxygen species (ROS) production was evaluated by applying lucigenin- and luminol-enhanced chemiluminescence assays.

    RESULTS: Zerumbone was found to be the most abundant compound in the extract (242.73 mg/g) and the oil (58.44%). Among the samples tested, the oil revealed the highest inhibition on cell migration with an IC50 value of 3.24 μg/mL. The extract, oil and zerumbone showed moderate inhibition of CD18 integrin expression in a dose-dependent trend. Z. zerumbet extract showed the highest inhibitory effect on phagocytic engulfment with percentage of phagocytizing cells of 55.43% for PMN. Zerumbone exhibited strong inhibitory activity on oxidative burst of zymosan- and PMA-stimulated neutrophils. Zerumbone remarkably inhibited extracellular ROS production in PMNs with an IC50 value of 17.36 μM which was comparable to that of aspirin.

    CONCLUSION: The strong inhibition on the phagocytosis of neutrophils by Z. zerumbet extract and its essential oil might be due the presence of its chemical components particularly zerumbone which was capable of impeding phagocytosis at different stages.

    Matched MeSH terms: Phagocytosis/drug effects*
  15. Fulltext Plasmodium-infected erythrocytes induce secretion of IGFBP7 to form type II rosettes and escape phagocytosis
    Lee WC, Russell B, Sobota RM, Ghaffar K, Howland SW, Wong ZX, et al.
    Elife, 2020 Feb 18;9.
    PMID: 32066522 DOI: 10.7554/eLife.51546
    In malaria, rosetting is described as a phenomenon where an infected erythrocyte (IRBC) is attached to uninfected erythrocytes (URBC). In some studies, rosetting has been associated with malaria pathogenesis. Here, we have identified a new type of rosetting. Using a step-by-step approach, we identified IGFBP7, a protein secreted by monocytes in response to parasite stimulation, as a rosette-stimulator for Plasmodium falciparum- and P. vivax-IRBC. IGFBP7-mediated rosette-stimulation was rapid yet reversible. Unlike type I rosetting that involves direct interaction of rosetting ligands on IRBC and receptors on URBC, the IGFBP7-mediated, type II rosetting requires two additional serum factors, namely von Willebrand factor and thrombospondin-1. These two factors interact with IGFBP7 to mediate rosette formation by the IRBC. Importantly, the IGFBP7-induced type II rosetting hampers phagocytosis of IRBC by host phagocytes.
    Matched MeSH terms: Phagocytosis*
  16. Role of protein kinase C in hydroxyapatite- induced phagocytosis by a murine macrophage cell line (RAW264.7)
    Gopinath VK, Musa M, Samsudin AR, Sosroseno W
    Immunopharmacol Immunotoxicol, 2006;28(3):485-9.
    PMID: 16997796
    The role of protein kinase C (PKC) in hydroxyapatite (HA)-induced phagocytosis by RAW 264.7 cells was investigated. The cells were incubated with HA particles at various incubation time and the levels of PKC activity were determined from the cell lysate. To determine the role of PKC, particles were incubated with the cells pretreated with the various concentrations of bisindolylmaleimide, a PKC inhibitor, and phagocytosis was then assessed at 60 min. Latex beads were used as a control. Our results showed that following incubation with HA particles, the levels of PKC activity in RAW264.7 cells was highest at 7 min and then decreased to reach the baseline levels of the controls at 30 min. Pretreatment of the cells with bisindolylmaleimide significantly reduced phagocytosis of HA particles in a dose-dependent pattern. The results of our present study suggest therefore that ingestion of HA by RAW264.7 cells may depend on PKC activity that may act in the early stages of phagocytosis.
    Matched MeSH terms: Phagocytosis/drug effects*; Phagocytosis/immunology
  17. Haemophagocytosis in dengue haemorrhagic fever: a case report
    Ramanathan M, Duraisamy G
    Ann Acad Med Singap, 1991 Nov;20(6):803-4.
    PMID: 1803975
    Virus associated haemophagocytic syndrome (VAHS), a distinct clinico-pathologic entity, is characterised by systemic proliferation of non-neoplastic histotiocytes showing haemophagocytosis resulting in blood cytopaenia. It has been described in relation to several viruses earlier. Here we describe a young girl who developed this reactive process during the course of dengue haemorrhagic fever (DHF).
    Matched MeSH terms: Phagocytosis
  18. Fulltext Major cellular events in peripheral nerve regeneration: A brief overview
    Naidu, M., David, P.
    International Medical Journal Malaysia, 2009;8(1):61-64.
    MyJurnal
    Injury to a peripheral nerve leads to degeneration of the segment distal to the site of lesion, a process referred to as Wallerian degeneration. During Wallerian degeneration, axons and myelin sheaths undergo degeneration and are phagocytosed by macrophages and Schwann cells. The Schwann cells proliferate and the endoneurial tubes persist, together the whole structure is known as the band of Büngner. Within few hours, the damaged axons in the proximal stump initiate a regeneration response, with formation of new growth cones. During Wallerian degeneration, neurotrophins, neural cell adhesion molecules, cytokines and other soluble factors are upregulated to facilitate regeneration. The recovery of the target in mammals is often variable, but almost never complete. In humans, scar tissue forms at the site of lesion and this often results in poor recovery of the target. The major events underlying this regenerative process is highlighted and discussed in this review.
    Matched MeSH terms: Phagocytosis
  19. Enhanced phagocytosis of Aggregatibacter actinomycetemcomitans cells by macrophages activated by a probiotic Lactobacillus strain
    Jaffar N, Okinaga T, Nishihara T, Maeda T
    J Dairy Sci, 2018 Jul;101(7):5789-5798.
    PMID: 29680655 DOI: 10.3168/jds.2017-14355
    The activation of phagocytosis is one important approach to clearing pathogenic cells in a host. This study evaluated the ability of probiotic lactobacilli to induce phagocytic activity as well as the clearance of a periodontal pathogen, Aggregatibacter actinomycetemcomitans. First, the activation of phagocytosis was found by using lyophilized dead cells. Probiotic Lactobacillus strains significantly enhanced the phagocytic activity of macrophage cells, indicating that the probiotic lactobacilli have a remarkable ability to stimulate the macrophages. Essentially, 3 Lactobacillus strains tested did not have any critical toxic effect on the murine macrophage, and Lactobacillus johnsonii NBRC 13952 showed the least cytotoxic effect on the RAW264.7 macrophages. The expression of classically activated macrophage markers, IL-1β, and cluster of differentiation 80 increased by L. johnsonii NBRC 13952; however, there was no significant difference for IL-18. The highest phagocytic activity by macrophages was found in a condition in which the macrophage activated by L. johnsonii NBRC 13952 functions to kill the cells of A. actinomycetemcomitans. Correlating with the result, a high amount of hypodiploid DNA (SubG1) was detected from the macrophage cells stimulated by L. johnsonii NBRC 13952. Taken together, the results suggest that macrophages activated by the Lactobacillus strain can facilitate the phagocytosis of A. actinomycetemcomitans cells by linking with enhanced apoptotic activities. In conclusion, L. johnsonii NBRC 13952 has a certain role in activating the RAW264.7 macrophages, thereby counteracting the infection of A. actinomycetemcomitans.
    Matched MeSH terms: Phagocytosis
  20. Fulltext Cell surface proteins of cryptococcus neoformans mediate adherence and internalisation into mammalian cells
    Choo, K.K., Chin, V.K., Chong, P.P., Ho, S.H., Yong, V.C.
    JUMMEC, 2019;22(2):24-30.
    MyJurnal
    Cryptococcus neoformans is an encapsulated fungal pathogen that causes severe disease primarily in
    immunocompromised patients. Adherence and internalisation of microbial pathogens into host cells often
    begin with engagement of microbes to the surface receptors of host. However, the mechanisms involved
    remain poorly understood. In this study, we investigated the association of cell surface determinants of C.
    neoformans with mammalian cells. Our results showed that treatment with trypsin, but not paraformaldehyde
    or heat killing, could reduce host-cryptococci interaction, suggesting the involvement of cell surface proteins
    (CSPs) of C. neoformans in the interaction. We extended our investigations to determine the roles of CSPs
    during cryptococci-host cells interaction by extracting and conjugating CSPs of C. neoformans to latex beads.
    Conjugation of CSPs with both encapsulated and acapsular C. neoformans increased the association of latex
    beads with mammalian alveolar epithelial cells, alveolar macrophages and monocyte-derived macrophages.
    Further examination on the actin organisation of the host cells implied the involvement of actin-dependent
    phagocytosis in the internalisation of C. neoformans in CSP-conjugated latex beads. We hypothesised that
    CSPs present on the cell wall of C. neoformans mediate the adherence and actin-dependent phagocytosis
    of cryptococci by mammalian cells. Our results warrant further studies on the exact role of CSPs in the
    pathogenesis of cryptococcosis.
    Matched MeSH terms: Phagocytosis
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