The Osteogenic Behaviour of Silicon Substituted Hydroxyapatite

2007 ◽  
Vol 361-363 ◽  
pp. 985-988 ◽  
Author(s):  
Serena Best ◽  
Shuo Zou ◽  
Roger A. Brooks ◽  
Jie Huang ◽  
Neil Rushton ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Density Measurement ◽  
Biological Response ◽  
Bone Apposition ◽  
X Ray ◽  
In Vivo Testing ◽  
Scanning Electron

Dense and porous HA and Si-HA discs and granules with varying percentages of silicon substitution have been produced and physically and chemically characterised using scanning electron microscopy, surface area analysis, porosimetry, density measurement, image analysis, Xray diffraction, X-ray fluorescence, FT-infrared spectroscopy and in-vitro and in-vivo testing. Results have shown that cell adhesion in-vitro and bone apposition in-vivo are enhanced by the presence of silicon substitution in the hydroxyapatite structure. The biological response to the materials appears to indicate an optimum outcome for levels of silicon substitution of 0.8wt%.

scholarly journals Low-Level Aflatoxin B1 Promotes Influenza Infection and Modulates a Switch in Macrophage Polarization from M1 to M2

2018 ◽  
Vol 49 (3) ◽  
pp. 1151-1167 ◽  
Author(s):  
Yuhang Sun ◽  
Zixuan Liu ◽  
Dandan Liu ◽  
Jin Chen ◽  
Fang Gan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Influenza Virus ◽  
Matrix Protein ◽  
Macrophage Polarization ◽  
Low Level ◽  
Siv Infection ◽  
Scanning Electron

Background/Aims: Swine influenza virus (SIV) is a major pathogen of both animals and humans. Afatoxin B1 (AFB1) is one of the most common mycotoxins in feed and food. However, the central contribution of AFB1 to SIV infection remains unclear. Methods: Here, TCID50 assays, fluorescence-based quantitative real-time PCR, western blotting, immunofluorescence staining, histopathological examination, flow cytometry and scanning electron microscopy were performed to investigate the involvement and underlying mechanism of AFB1 in SIV infection in vivo and in vitro using mouse models and porcine alveolar macrophage (PAM) models, respectively. Results: The in vivo study showed that low levels of AFB1 promoted SIV infection and increased its severity, as demonstrated by the increased mRNA expression of viral matrix protein (M); by the increased protein expression of nucleoprotein (NP), matrix protein 1 and ion channel protein; and by animal weight loss, lung index and lung histologic damage. In addition, the increased occurrence of SIV infection accompanied by increases in the level of IL-10 in sera and lungs, in the spleen index and in the number of CD206-positive mouse alveolar macrophages but decreases in the level of TNF-α in sera and lungs, in the thymus index and in the number of CD80-positive mouse alveolar macrophages was observed in SIV-infected mice after low-level AFB1 exposure. The in vitro study showed that low concentrations of AFB1 promoted SIV infection, as demonstrated by the increases in viral titers and viral M mRNA and NP expression levels in SIV-infected PAMs as well as by the number of cells positive for NP protein expression. Furthermore, AFB1 promoted the polarization of SIV-infected PAMs to the M1 phenotype at 8 hpi and to the M2 phenotype at 24 hpi, as measured by the increases in IL-10 expression and in the number of CD206-positive PAMs as well as by the morphological changes observed by scanning electron microscopy. The administration of the immune stimulant lipopolysaccharide (LPS) reversed the switch in PAM polarization from M2 to M1 and thereby counteracted the promotion of influenza virus infection induced by AFB1. Conclusion: Our results are the first to confirm that low-level exposure to AFB1 promotes SIV infection and modulates a switch in macrophage polarization from M1 to M2. The work reported here provides important data that point to a role for AFB1 in SIV infection, and it opens a new field of study.

An Experimental Model for the Study of Venous Thrombosis in Vivo

1975 ◽  
Author(s):  
T. K. Day ◽  
K. G. A. Glark ◽  
V. V. Kakkar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Experimental Model ◽  
Femoral Vein ◽  
Total Charge ◽  
Small Current ◽  
Group I ◽  
Scanning Electron

The lack of a satisfactory in vivo experimental model has probably been responsible for the delay in the clinical application of recent advances in in vitro research on thrombosis. This paper describes a model in which thrombosis is initiated by an electrical stimulus. The thrombus produced has the histological and biochemical features of human deep vein thrombosis (DVT).The minimum stimulus necessary to induce thrombosis was first determined by passing a fixed current for timed intervals along the femoral veins of 10 rabbits. Thrombi were seen 24 hours later if the total charge passed exceeded a threshold value of 25 millicoulombes. With this small current, no endothelial changes were visible immediately after the passage of the charge on light or scanning electron microscopy. At 24 hours a mural thrombus formed, which had fully cross-linked fibrin and histological features resembling human DVT.In the second series of experiments, the sequence of changes occurring in thrombus production was investigated in 3 groups of 18 rabbits each. After passage of the critical charge along the femoral vein in each animal, veins were removed at fixed intervals, the contralateral vein acting as a control. The veins were examined by scanning electron-microscopy (Group I), transmission electron-microscopy (Group II) and light microscopy (Group III), The earliest changes were detectable at 5 minutes and consisted of the laying down of an organised structure of criss-crossing fibrin strands with small platelet clumps at fibrin intersections. Later the fibrin structure spread towards the lumen; platelet clumps fused and a coralline thrombus was formed by 24 hours. The significance of these changes will be discussed.

scholarly journals Development and Characterization of an In Vivo Central Venous Catheter Candida albicans Biofilm Model

2004 ◽  
Vol 72 (10) ◽  
pp. 6023-6031 ◽  
Author(s):  
D. Andes ◽  
J. Nett ◽  
P. Oschel ◽  
R. Albrecht ◽  
K. Marchillo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Drug Resistance ◽  
Venous Catheter ◽  
In Vitro Models ◽  
Central Venous ◽  
Biofilm Growth ◽  
Scanning Electron

ABSTRACT Biofilms represent a niche for microorganisms where they are protected from both the host immune system and antimicrobial therapies. Biofilm growth serves as an increasing source of clinical infections. Candida infections are difficult to manage due to their persistent nature and associated drug resistance. Observations made in biofilm research have generally been limited to in vitro models. Using a rat central venous catheter model, we characterized in vivo Candida albicans biofilm development. Time-course quantitative culture demonstrated a progressive increase in the burden of viable cells for the first 24 h of development. Fluorescence and scanning electron microscopy revealed a bilayered architecture. Adjacent to the catheter surface, yeast cells were densely embedded in an extracellular matrix. The layer adjacent to the catheter lumen was less dense. The outermost surface of the biofilm contained both yeast and hyphal forms, and the extracellular material in which they were embedded appeared fibrous. These architectural features were similar in many respects to those described for in vitro models. However, scanning electron microscopy also revealed host cells embedded within the biofilm matrix. Drug susceptibility was determined by using two assays and demonstrated a biofilm-associated drug resistance phenotype. The first assay demonstrated continued growth of cells in the presence of supra-MIC antifungal drug concentrations. The second assay demonstrated reduced susceptibility of biofilm-grown cells following removal from the biofilm structure. Lastly, the model provided sufficient nucleic material for study of differential gene expression associated with in vivo biofilm growth. Two fluconazole efflux pumps, CDR1 and CDR2, were upregulated in the in vivo biofilm-associated cells. Most importantly, the studies described provide a model for further investigation into the molecular mechanisms of C. albicans biofilm biology and drug resistance. In addition, the model provides a means to study novel drug therapies and device technologies targeted to the control of biofilm-associated infections.

Mercury intake by inflammatory phagocytes: in vivo cytology of mouse macrophages and neutrophils by X-ray elemental microanalysis coupled with scanning electron microscopy

2004 ◽  
Vol 23 (9) ◽  
pp. 447-453 ◽  
Author(s):  
Elisabete M Cunha ◽  
Maria João R Oliveira ◽  
Paula G Ferreira ◽  
Artur P Águas
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Peritoneal Cavity ◽  
The Body ◽  
Air Pouch ◽  
X Ray ◽  
Elemental Microanalysis ◽  
Short Period ◽  
Scanning Electron

Phagocytes remove and store mercury (Hg) that enters the body. Macrophages and granulocytes respond in opposite ways to Hg: macrophages loose cell viability, and neutrophils become protected from apoptosis. We have investigated the cytology of early intake of Hg by macrophages and neutrophils after a short period (2-4 min) of in vivo exposure to HgCl2. The two types of phagocytes were attracted either to a subcutaneous air pouch or to the peritoneal cavity of BALB/c mice by in situ BSA injection. BSA caused, 72 hours later, inflammatory exudates where neutrophils (air-pouch cavity) or macrophages (peritoneal cavity) were the predominant cell type. A lethal dose of HgCl2 (25 mg) was then injected in the two inflammatory cavities. The mice died 2-4 min later and the cell exudates were harvested and studied by scanning electron microscopy coupled with X-ray elemental microanalysis (SEM-XRM). More than half of the phagocytes showed ingested Hg; a higher percentage of macrophages (around 70%) than neutrophils (around 50%) were positive for the metal. Intracellular particles of Hg were spheroid and presented a small diameter (less than 20 nm). They could be seen in large numbers inside phagocytes (up to 20-30 Hg dots per cell); they were scattered throughout the cytoplasm of the cells. The ability of phagocytes to ingest Hg increased as the BSA-induced inflammation progressed. We conclude that (i) Hg is quickly ingested as small particles by phagocytes; (ii) endocytosis of Hg increases with the degree of activation of phagocytes; and (iii) phagocytes internalize Hg by pinocytosis.

scholarly journals Synergistic effect of combination chemotherapy with praziquantel and DW-3-15 for Schistosoma japonicum in vitro and in vivo

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Zi-Yin Yang ◽  
Zi-Hao Liu ◽  
Ya-Nan Zhang ◽  
Chen Li ◽  
Lei Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Synergistic Effect ◽  
Schistosoma Japonicum ◽  
Combination Chemotherapy ◽  
Combination Index ◽  
First Choice ◽  
Scanning Electron

Abstract Background Schistosomiasis is a debilitating and neglected tropical disease for which praziquantel (PZQ) remains the first-choice drug for treatment and control of the disease. In our previous studies, we found that the patented compound DW-3-15 (patent no. ZL201110142538.2) displayed significant and stabilized antiparasitic activity through a mechanism that might be distinct from PZQ. Here, we investigated the antischistosomal efficacy of PZQ combined with DW-3-15 against schistosomula and adult worms of Schistosoma japonicum in vitro and in vivo, to verify whether there was a synergistic effect of the two compounds. Methods The antischistosomal efficacy of PZQ combined with DW-3-15 in comparison with an untreated control and monotherapy group against schistosomula and adult worms was assessed both in vitro and in vivo. Parasitological studies, scanning electron microscopy, combination index, and histopathological analysis were used for the assessment. Results The results showed significantly reduced viability of schistosomes, achieving 100% viability reduction for juveniles and males by combination chemotherapy using PZQ together with DW-3-15 in vitro. The combination index was 0.28, 0.27, and 0.53 at the higher concentration of PZQ combined with DW-3-15 against juveniles, males, and females, respectively, indicating that the two compounds display strong synergism. Scanning electron microscopy observations also demonstrated that the compound combination induced more severe and extensive alterations to the tegument and subtegument of S. japonicum than those with each compound alone. In vivo, compared with the single-compound-treated group, the group treated with the higher-dose combination demonstrated the best schistosomicidal efficacy, with significantly reduced worm burden, egg burden, and granuloma count and area, which was evident against schistosomula and adult worms. Conclusions Our study provides a potential novel chemotherapy for schistosomiasis caused by S. japonicum. It would improve the antischistosomal effect on schistosomula and adult worms of S. japonicum, and decrease individual dosages. Graphical Abstract

scholarly journals Silver Nanoparticles: Green Synthesis, Characterization, Blood Compatibility and Protoscolicidal Efficacy against Echinococcus granulosus

2021 ◽  
Vol 41 (03) ◽  
pp. 393-399
Author(s):  
Parwin Jalal Jalil
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Echinococcus Granulosus ◽  
Blood Compatibility ◽  
Ag Nps ◽  
X Ray ◽  
Hydatid Fluid ◽  
Scanning Electron

Spillage of protoscoleces within hydatid fluid during surgery for hydatid cyst is the main reason for its recurrence. Therefore, to inactivate the protoscoleces, various scolicidal substances have been tested. However, novel and more efficient agents are needed owing to several associated complications. This study focused on the effects of green synthetic Silver Nanoparticles (AgNPs) from Zizyphus spina- christi leaves on Echinococcus granulosus protoscoleces. Also, to evaluate the blood compatibility of Ag NPs. The Ag NPs were identified by ultraviolet-visible (UV-Visible) spectrophotometer, X-ray diffraction (XRD), Scanning electron microscopy imaging, and Energy-dispersive X-ray spectroscopy (EDX). Hydatid fluid was aspirated aseptically from cysts of infected sheep liver. The protoscoleces were exposed to Ag NPs at several concentrations. Also, scanning electron microscopy for ultrastructural changes and in vitro erythrocytes lysis was performed. The Ag NPs were spherical; the particles' size reached 50 nm, and presented a surface plasmon peak around 460 nm. The current study's findings indicated the powerful in vitro scolicidal efficacy of the green biosynthesized AgNPs. Several morphological alterations were observed on the protoscoleces by optical and scanning electron microscopy. Lysis of RBCs at different doses of Ag NPs was significantly (P≤0.05) less than the positive control value, thus proposing its biocompatibility. This work suggests that chemicals like polyphenols present in the extract of Z. spina- christi act as reducing and stabilizers agents to create Ag NPs Nevertheless, further investigations are needed to investigate the Ag NPs scolicidial effects in animal models.

Applications of Soft X-Ray and other Microscopy Techniques to Elucidate the Structure of Parasitic Metazoa

1998 ◽  
Vol 4 (S2) ◽  
pp. 1156-1157
Author(s):  
W. J. Kozek ◽  
J. Brown ◽  
W. Meyer-Ilse ◽  
C. Larabell ◽  
M. Moronne
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Trichinella Spiralis ◽  
National Laboratory ◽  
Confocal Laser ◽  
X Ray ◽  
New Information ◽  
Microscopy Techniques ◽  
Scanning Electron

The small size of many parasitic organisms requires the use of election microscopy for adequate elucidation of their structure. While both transmission and scanning electron microscopy can provide complementary results which allow considerable degree of structural correlation, each technique has its inherent limitations. Since previous studies have demonstrated that soft X-ray microscopy could be used to study parasitic protozoa and provide new information, the objective of this study was to determine whether soft X-ray microscopy could also be used to elucidate the morphology of small metazoa to complement the data obtained by other microscopy techniques.Newborn larvae, approximately 7 μm × 110 μm in size, of parasitic nematode Trichinella spiralis were used as a model system. Some of the larvae, deposited by adult females maintained in vitro, were isolated and processed for examination by transmission and scanning electron microscopy as described in our previous studies, others were fixed in 4% glutaraldehyde (Millonig's buffer) and examined in the X-ray microscope XM-1, and in the BioRad MRC 1024 confocal laser (krypton/argon) microscope of the Advanced Light Source, Berkeley National Laboratory.

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