Displaying publications 1 - 20 of 93 in total

Abstract:
Sort:
  1. Vairimorpha imperfecta n.sp., a microsporidian exhibiting an abortive octosporous sporogony in Plutella xylostella L. (Lepidoptera: Yponomeutidae)
    Canning EU, Curry A, Cheney S, Lafranchi-Tristem NJ, Haque MA
    Parasitology, 1999 Sep;119 ( Pt 3):273-86.
    PMID: 10503253
    The microsporidian genus Nosema is characterized by development in direct control with host cell cytoplasm, diplokaryotic nuclei throughout development and disporous sporogony. The genus Vairimorpha exhibits the same features plus an octoporous sporogony producing uninucleate spores in a sporophorous vesicle. A microsporidium from diamondback moth, Plutella xylostella, falls between Nosema and Vairimorpha in that it initiates but fails to complete the octosporous sequence in this host. The name Vairimorpha imperfecta n.sp. is proposed. Merogony is mainly by formation of buds from multinucleate meronts, the buds remaining attached in chains. Diplokaryotic spores measure 4.3 x 2.0 microns (fresh) and have 15.5 coils of the polar tube in 1 rank. The octosporous sporogony is aborted owing to irregular formation of nuclear spindles, incomplete cytoplasmic fission and bizarre deposition of electron-dense episporontal secretions. Phylogenetic analyses of the sequences of the small subunit rRNA genes of V. imperfecta and of several Nosema and Vairimorpha spp. place V. imperfecta in a clade with Nosema spp. from Lepidoptera rather than in the clade containing the more typical species of Vairimorpha. It is suggested that the ancestors of the Vairimorpha/Nosema complex of species exhibited both disporous and octosporous sporogonies, as does the type species of Vairimorpha, Vairimorpha necatrix. It would follow that true Nosema spp. have lost the ability to express an octosporous sequence and that V. imperfecta is in the process of losing it. It is proposed that the genera Nosema and Vairimorpha be placed in the same family Nosematidae Labbé 1899, rather than in separate families and orders as at present.
    Matched MeSH terms: Microspheres
  2. Use of superparamagnetic beads for the isolation of a peptide with specificity to cymbidium mosaic virus
    Ooi DJ, Dzulkurnain A, Othman RY, Lim SH, Harikrishna JA
    J Virol Methods, 2006 Sep;136(1-2):160-5.
    PMID: 16781785
    A modified method for the rapid isolation of specific ligands to whole virus particles is described. Biopanning against cymbidium mosaic virus was carried out with a commercial 12-mer random peptide display library. A solution phase panning method was devised using streptavidin-coated superparamagnetic beads. The solution based panning method was more efficient than conventional immobilized target panning when using whole viral particles of cymbidium mosaic virus as a target. Enzyme-linked immunosorbent assay of cymbidium mosaic virus-binding peptides isolated from the library identified seven peptides with affinity for cymbidium mosaic virus and one peptide which was specific to cymbidium mosaic virus and had no significant binding to odontoglossum ringspot virus. This method should have broad application for the screening of whole viral particles towards the rapid development of diagnostic reagents without the requirement for cloning and expression of single antigens.
    Matched MeSH terms: Microspheres
  3. Fulltext Ultrasound-assisted encapsulation of Pandan (Pandanus amaryllifolius) extract
    Omer N, Choo YM, Ahmad N, Mohd Yusof NS
    Ultrason Sonochem, 2021 Nov;79:105793.
    PMID: 34673338 DOI: 10.1016/j.ultsonch.2021.105793
    Pandan (Pandanus amaryllifolius) is commonly used as a food ingredient in Southeast Asia due to its delicious flavor, appetizing aroma and bright green colour. Pandan plant is uniquely found only in certain parts of the world. Despite its increasing popularity worldwide, its export market is limited by practical issues. One of the main problems for exporting Pandan to global market is its stability during transport. Due to the volatility of its active constituent, the functional properties of Pandan are lost during storage and shipment. In this study, we explored the ability of ultrasound processing technology to encapsulate the aromatic Pandan extract using lysozyme or chitosan as a shell material. 20 kHz ultrasonicator was used to encapsulate the pandan extract at 150 W of applied power. Two parameters, the ultrasonic probe tip and the core-to-shell ratio were varied to control the properties of the encapsulates. The diameters of the probe tip used were 0.3 and 1.0 cm. The core-to-shell volume ratios used were 1:160 and 1:40. The size distribution and the stability of the synthesized microspheres were characterized to understand and explore the possible parameters variation impact. Both size and size distribution of the microspheres were found to be influenced by the parameters varied to certain extent. The results showed that the mean size of the microspheres was generally smallest when using 1 cm probe tip with lower core-to-shell volume ratio but largest when using the 3 mm tip with higher core-to-shell volume ratio. This indicates that the sonication parameters could be fine-tuned to achieve the encapsulation of Pandan extract for storage and export. The pandan-encapsulated microspheres were also found to be stable during storage at least for one month.
    Matched MeSH terms: Microspheres
  4. Fulltext Tunable Microfluidic Devices for Hydrodynamic Fractionation of Cells and Beads: A Review
    Alvankarian J, Majlis BY
    Sensors (Basel), 2015 Nov 24;15(11):29685-701.
    PMID: 26610519 DOI: 10.3390/s151129685
    The adjustable microfluidic devices that have been developed for hydrodynamic-based fractionation of beads and cells are important for fast performance tunability through interaction of mechanical properties of particles in fluid flow and mechanically flexible microstructures. In this review, the research works reported on fabrication and testing of the tunable elastomeric microfluidic devices for applications such as separation, filtration, isolation, and trapping of single or bulk of microbeads or cells are discussed. Such microfluidic systems for rapid performance alteration are classified in two groups of bulk deformation of microdevices using external mechanical forces, and local deformation of microstructures using flexible membrane by pneumatic pressure. The main advantage of membrane-based tunable systems has been addressed to be the high capability of integration with other microdevice components. The stretchable devices based on bulk deformation of microstructures have in common advantage of simplicity in design and fabrication process.
    Matched MeSH terms: Microspheres
  5. Fulltext The modulation of PPARγ1 and PPARγ2 mRNA expression by ciglitazone in CD3/CD28-activated naïve and memory CD4+ T cells
    Norazmi MN, Mohamed R, Nurul AA, Yaacob NS
    Clin. Dev. Immunol., 2012;2012:849195.
    PMID: 22548115 DOI: 10.1155/2012/849195
    Given their roles in immune regulation, the expression of the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) 1 and 2 isoforms was investigated in human naïve (CD45RA+) and memory (CD45RO+) CD4+ T cells. Stimulation of both types of cells via the CD3/CD28 pathway resulted in high expression of both PPARγ receptors as measured by real-time PCR. Treatment with the PPARγ agonist, ciglitazone, increased PPARγ1 expression but decreased PPARγ2 expression in stimulated naïve and memory cells. Furthermore, when present, the magnitude of both PPARγ receptors expression was lower in naïve cells, perhaps suggesting a lower regulatory control of these cells. Similar profiles of selected proinflammatory cytokines were expressed by the two cell types following stimulation. The induction of PPARγ1 and suppression of PPARγ2 expressions in naïve and memory CD4+ T cells in the presence of ciglitazone suggest that the PPARγ subtypes may have different roles in the regulation of T-cell function.
    Matched MeSH terms: Microspheres
  6. Synthesis and characterization of carbon cryogel microspheres from lignin-furfural mixtures for biodiesel production
    Zainol MM, Amin NA, Asmadi M
    Bioresour Technol, 2015 Aug;190:44-50.
    PMID: 25919936 DOI: 10.1016/j.biortech.2015.04.067
    The aim of this work was to study the potential of biofuel and biomass processing industry side-products as acid catalyst. The synthesis of carbon cryogel from lignin-furfural mixture, prepared via sol-gel polycondensation at 90°C for 0.5h, has been investigated for biodiesel production. The effect of lignin to furfural (L/F) ratios, lignin to water (L/W) ratios and acid concentration on carbon cryogel synthesis was studied. The carbon cryogels were characterized and tested for oleic acid conversion. The thermally stable amorphous spherical carbon cryogel has a large total surface area with high acidity. Experimental results revealed the optimum FAME yield and oleic acid conversion of 91.3wt.% and 98.1wt.%, respectively were attained at 65°C for 5h with 5wt.% catalyst loading and 20:1 methanol to oleic acid molar ratio. Therefore, carbon cryogel is highly potential for heterogeneous esterification of free fatty acid to biodiesel.
    Matched MeSH terms: Microspheres
  7. Synthesis and characterization of a new vertebroplasty cement based on gold-containing PMMA microspheres
    Jacobs E, Saralidze K, Roth AK, de Jong JJ, van den Bergh JP, Lataster A, et al.
    Biomaterials, 2016 Mar;82:60-70.
    PMID: 26751820 DOI: 10.1016/j.biomaterials.2015.12.024
    There are a number of drawbacks to incorporating large concentrations of barium sulfate (BaSO4) as the radiopacifier in PMMA-based bone cements for percutaneous vertebroplasty. These include adverse effects on injectability, viscosity profile, setting time, mechanical properties of the cement and bone resorption. We have synthesized a novel cement that is designed to address some of these drawbacks. Its powder includes PMMA microspheres in which gold particles are embedded and its monomer is the same as that used in commercial cements for vertebroplasty. In comparison to one such commercial cement brand, VertaPlex™, the new cement has longer doughing time, longer injection time, higher compressive strength, higher compressive modulus, and is superior in terms of cytotoxicity. For augmentation of fractured fresh-frozen cadaveric vertebral bodies (T6-L5) using simulated vertebroplasty, results for compressive strength and compressive stiffness of the construct and the percentage of the volume of the vertebral body filled by the cement were comparable for the two cements although the radiopacity of the new cement was significantly lower than that for VertaPlex™. The present results indicate that the new cement warrants further study.
    Matched MeSH terms: Microspheres*
  8. Surfactant protein A and stable microbubble formation in tracheal aspirates
    Cheong KB, Cheong SK, Boo NY
    Malays J Pathol, 1996 Dec;18(2):101-5.
    PMID: 10879230
    This study aimed to determine the role of surfactant protein A (SP-A) in the formation of stable microbubble in tracheal aspirates. Our results showed that as the concentration of anti SP-A antibodies added to tracheal aspirate specimens increased, the number of stable microbubble formed in the specimen decreased. The correlation between stable microbubble counts and the SP-A levels in the tracheal aspirates was good, r = 0.85, p < 0.05. This study suggests that SP-A plays an important role in stable microbubble formation. Measurement of small stable microbubbles is thus a useful bedside test for predicting the SP-A activity in the tracheal aspirates and in indirect measurement of lung maturity.
    Matched MeSH terms: Microspheres
  9. Fulltext Surface Modification of SPIONs in PHBV Microspheres for Biomedical Applications
    Idris MI, Zaloga J, Detsch R, Roether JA, Unterweger H, Alexiou C, et al.
    Sci Rep, 2018 May 08;8(1):7286.
    PMID: 29739955 DOI: 10.1038/s41598-018-25243-9
    Surface modification of superparamagnetic iron oxide nanoparticles (SPIONs) has been introduced with lauric acid and oleic acid via co-precipitation and thermal decomposition methods, respectively. This modification is required to increase the stability of SPIONs when incorporated in hydrophobic, biodegradable and biocompatible polymers such as poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). In this work, the solid-in-oil-in-water (S/O/W) emulsion-solvent extraction/evaporation method was utilized to fabricate magnetic polymer microspheres incorporating SPIONs in PHBV. The prepared magnetic PHBV microspheres exhibited particle sizes <1 µm. The presence of functional groups of lauric acid, oleic acid and iron oxide in the PHBV microspheres was confirmed by Fourier Transform Infrared spectroscopy (FTIR). X-ray diffraction (XRD) analysis was performed to further confirm the success of the combination of modified SPIONs and PHBV. Thermogravimetric analysis (TGA) indicated that PHBV microspheres were incorporated with SPIONsLauric as compared with SPIONsOleic. This was also proven via magnetic susceptibility measurement as a higher value of this magnetic property was detected for PHBV/SPIONsLauric microspheres. It was revealed that the magnetic PHBV microspheres were non-toxic when assessed with mouse embryotic fibroblast cells (MEF) at different concentrations of microspheres. These results confirmed that the fabricated magnetic PHBV microspheres are potential candidates for use in biomedical applications.
    Matched MeSH terms: Microspheres
  10. Fulltext Supramolecular Nested Microbeads as Building Blocks for Macroscopic Self-Healing Scaffolds
    Yu Z, Liu J, Tan CSY, Scherman OA, Abell C
    Angew Chem Int Ed Engl, 2018 03 12;57(12):3079-3083.
    PMID: 29377541 DOI: 10.1002/anie.201711522
    The ability to construct self-healing scaffolds that are injectable and capable of forming a designed morphology offers the possibility to engineer sustainable materials. Herein, we introduce supramolecular nested microbeads that can be used as building blocks to construct macroscopic self-healing scaffolds. The core-shell microbeads remain in an "inert" state owing to the isolation of a pair of complementary polymers in a form that can be stored as an aqueous suspension. An annealing process after injection effectively induces the re-construction of the microbead units, leading to supramolecular gelation in a preconfigured shape. The resulting macroscopic scaffold is dynamically stable, displaying self-recovery in a self-healing electronic conductor. This strategy of using the supramolecular assembled nested microbeads as building blocks represents an alternative to injectable hydrogel systems, and shows promise in the field of structural biomaterials and flexible electronics.
    Matched MeSH terms: Microspheres
  11. Stomach specific polymeric low density microballoons as a vector for extended delivery of rabeprazole and amoxicillin for treatment of peptic ulcer
    Choudhary S, Jain A, Amin MCIM, Mishra V, Agrawal GP, Kesharwani P
    Colloids Surf B Biointerfaces, 2016 May 01;141:268-277.
    PMID: 26859118 DOI: 10.1016/j.colsurfb.2016.01.048
    The study was intended to develop a new intra-gastric floating in situ microballoons system for controlled delivery of rabeprazole sodium and amoxicillin trihydrate for the treatment of peptic ulcer disease. Eudragit S-100 and hydroxypropyl methyl cellulose based low density microballoons systems were fabricated by employing varying concentrations of Eudragit S-100 and hydroxypropyl methyl cellulose, to which varying concentrations of drug was added, and formulated by stirring at various speed and time to optimize the process and formulation variable. The formulation variables like concentration and ratio of polymers significantly affected the in vitro drug release from the prepared floating device. The validation of the gastro-retentive potential of the prepared microballoons was carried out in rabbits by orally administration of microballoons formulation containing radio opaque material. The developed formulations showed improved buoyancy and lower ulcer index as compared to that seen with plain drugs. Ulcer protective efficacies were confirmed in ulcer-bearing mouse model. In conclusion, greater compatibility, higher gastro-retention and higher anti-ulcer activity of the presently fabricated formulations to improve potential of formulation for redefining ulcer treatment are presented here. These learning exposed a targeted and sustained drug delivery potential of prepared microballoons in gastric region for ulcer therapeutic intervention as corroborated by in vitro and in vivo findings and, thus, deserves further attention for improved ulcer treatment.
    Matched MeSH terms: Microspheres*
  12. Fulltext Screening of Electrospray-operating Parameters in the Production of Alginate-Royal Jelly Microbeads Using Factorial Design
    Shaiqah MR, Salahuddin HM, Afiful Huda AYA, Izzuddin M, Nur Shafiq NIM, Nur Hakimah MA, et al.
    J Pharm Bioallied Sci, 2020 Nov;12(Suppl 2):S703-S706.
    PMID: 33828364 DOI: 10.4103/jpbs.JPBS_249_19
    Introduction: Royal jelly (RJ) has been consumed as food or as a supplement because of its high nutritional and medicinal values. A fresh harvested RJ is yellowish to whitish in color and contains proteins, free amino acids, lipids, vitamins, and sugar. Without proper storage conditions, such as at 4°C, the color of RJ changes to much darker yellow and produces a rancid smell. To prolong its shelf life, RJ is usually mixed with honey. Alginate, a natural and edible polymer derived from seaweed, is commonly used to encapsulate drugs and food due to its ability to form gels by reacting with divalent cations. However, there is a lack of research on the microencapsulation of RJ in alginate using electrospray. The electrospray technique has the advantage in producing consistent size and shape of alginate microbeads under optimum parameters.

    Aim: This research aimed to optimize electrospray-operating parameters in producing alginate-RJ microbeads.

    Materials and Methods: Optimization of alginate-RJ microbeads electrospray parameters was carried out using 24 factorial design with three center points (19 runs). The studied parameters were flow rate, high voltage, nozzle size, and tip-to-collector distance, whereas the responses were particle size, particle size distribution, and sphericity factor. The responses of each run were analyzed using Design-Expert software.

    Results: Nozzle size is a significant parameter that influences the particle size. Flow rate is a significant parameter influencing the sphericity factor.

    Conclusion: Screening of the electrospray-operating parameters paves the way in determining the significant parameters and their design space to produce consistent alginate-RJ microbeads.

    Matched MeSH terms: Microspheres
  13. Fulltext Sandwich-Type DNA Micro-Optode Based on Gold-Latex Spheres Label for Reflectance Dengue Virus Detection
    Jeningsih, Tan LL, Ulianas A, Heng LY, Mazlan NF, Jamaluddin ND, et al.
    Sensors (Basel), 2020 Mar 25;20(7).
    PMID: 32218202 DOI: 10.3390/s20071820
    A DNA micro-optode for dengue virus detection was developed based on the sandwich hybridization strategy of DNAs on succinimide-functionalized poly(n-butyl acrylate) (poly(nBA-NAS)) microspheres. Gold nanoparticles (AuNPs) with an average diameter of ~20 nm were synthesized using a centrifugation-based method and adsorbed on the submicrometer-sized polyelectrolyte-coated poly(styrene-co-acrylic acid) (PSA) latex particles via an electrostatic method. The AuNP-latex spheres were attached to the thiolated reporter probe (rDNA) by Au-thiol binding to functionalize as an optical gold-latex-rDNA label. The one-step sandwich hybridization recognition involved a pair of a DNA probe, i.e., capture probe (pDNA), and AuNP-PSA reporter label that flanked the target DNA (complementary DNA (cDNA)). The concentration of dengue virus cDNA was optically transduced by immobilized AuNP-PSA-rDNA conjugates as the DNA micro-optode exhibited a violet hue upon the DNA sandwich hybridization reaction, which could be monitored by a fiber-optic reflectance spectrophotometer at 637 nm. The optical genosensor showed a linear reflectance response over a wide cDNA concentration range from 1.0 × 10-21 M to 1.0 × 10-12 M cDNA (R2 = 0.9807) with a limit of detection (LOD) of 1 × 10-29 M. The DNA biosensor was reusable for three consecutive applications after regeneration with mild sodium hydroxide. The sandwich-type optical biosensor was well validated with a molecular reverse transcription polymerase chain reaction (RT-PCR) technique for screening of dengue virus in clinical samples, e.g., serum, urine, and saliva from dengue virus-infected patients under informed consent.
    Matched MeSH terms: Microspheres
  14. SIRveNIB: Selective Internal Radiation Therapy Versus Sorafenib in Asia-Pacific Patients With Hepatocellular Carcinoma
    Chow PKH, Gandhi M, Tan SB, Khin MW, Khasbazar A, Ong J, et al.
    J Clin Oncol, 2018 07 01;36(19):1913-1921.
    PMID: 29498924 DOI: 10.1200/JCO.2017.76.0892
    Purpose Selective internal radiation therapy or radioembolization (RE) shows efficacy in unresectable hepatocellular carcinoma (HCC) limited to the liver. This study compared the safety and efficacy of RE and sorafenib in patients with locally advanced HCC. Patients and Methods SIRveNIB (selective internal radiation therapy v sorafenib), an open-label, investigator-initiated, phase III trial, compared yttrium-90 (90Y) resin microspheres RE with sorafenib 800 mg/d in patients with locally advanced HCC in a two-tailed study designed for superiority/detriment. Patients were randomly assigned 1:1 and stratified by center and presence of portal vein thrombosis. Primary end point was overall survival (OS). Efficacy analyses were performed in the intention-to-treat population and safety analyses in the treated population. Results A total of 360 patients were randomly assigned (RE, 182; sorafenib, 178) from 11 countries in the Asia-Pacific region. In the RE and sorafenib groups, 28.6% and 9.0%, respectively, failed to receive assigned therapy without significant cross-over to either group. Median OS was 8.8 and 10.0 months with RE and sorafenib, respectively (hazard ratio, 1.1; 95% CI, 0.9 to 1.4; P = .36). A total of 1,468 treatment-emergent adverse events (AEs) were reported (RE, 437; sorafenib, 1,031). Significantly fewer patients in the RE than sorafenib group had grade ≥ 3 AEs (36 of 130 [27.7%]) v 82 of 162 [50.6%]; P < .001). The most common grade ≥ 3 AEs were ascites (five of 130 [3.8%] v four of 162 [2.5%] patients), abdominal pain (three [2.3%] v two [1.2%] patients), anemia (zero v four [2.5%] patients), and radiation hepatitis (two [1.5%] v zero [0%] patients). Fewer patients in the RE group (27 of 130 [20.8%]) than in the sorafenib group (57 of 162 [35.2%]) had serious AEs. Conclusion In patients with locally advanced HCC, OS did not differ significantly between RE and sorafenib. The improved toxicity profile of RE may inform treatment choice in selected patients.
    Matched MeSH terms: Microspheres
  15. 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: Microspheres
  16. 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: Microspheres
  17. Fulltext Radionuclide therapy of hepatocellular carcinoma
    Sundram F
    Biomed Imaging Interv J, 2006 Jul;2(3):e40.
    PMID: 21614248 MyJurnal DOI: 10.2349/biij.2.3.e40
    Hepatocellular carcinoma (HCC) is a malignant tumour of the hepatocyte. It is a common malignancy worldwide and causes almost half a million deaths annually. Asia is a high risk area. Although surgery (hepatectomy or liver transplantation) is the main form of curative treatment, the majority of patients are not eligible for surgery due to extent of tumour and dysfunction of liver. Radiopharmaceuticals used for transarterial treatment of HCC were Yttrium-90 microspheres, Iodine-131 lipiodol, Rhenium-188 lipiodol, and Holmium-166 Chitosan complex. Yittrium-90 microspheres are glass or resin microspheres of mean sphere diameter of 20 to 30 micrometre. The activity administered was about 4 GBq. Reported response rate was about 20%, and median survival was 54 weeks. On inoperable tumours, reported objective response of I-131 lipiodol was 40 to 70%, and median survival was six to nine months. It showed efficacy similar to TACE. In adjuvant treatment following curative resection of HCC, reported three year survival was 86% compared with 46% for the control group. The administered activity in both adjuvant and inoperable HCC was about 2 GBq (55 mCi). Rhenium-188 lipiodol is a new radioconjugate, and using it we treated 70 patients with inoperable HCC. This treatment was a part of a multi-centre trial sponsored by the International Atomic Energy Agency. Partial response was obtained in 17% of cases, while 49% had stable disease at three months, and 34% showed disease progression. In terms of survival, 19% survived one year, 60% for six months, and 90% for three months. The mean activity was about 4.6 GBq (124 mCi). This method was safe and free from adverse effects.
    Matched MeSH terms: Microspheres
  18. Fulltext Production of Newcastle disease virus by Vero cells grown on cytodex 1 microcarriers in a 2-litre stirred tank bioreactor
    Arifin MA, Mel M, Abdul Karim MI, Ideris A
    J Biomed Biotechnol, 2010;2010:586363.
    PMID: 20625497 DOI: 10.1155/2010/586363
    The aim of this study is to prepare a model for the production of Newcastle disease virus (NDV) lentogenic F strain using cell culture in bioreactor for live attenuated vaccine preparation. In this study, firstly we investigated the growth of Vero cells in several culture media. The maximum cell number was yielded by culture of Vero cells in Dulbecco's Modified Eagle Medium (DMEM) which was 1.93 x 10(6) cells/ml. Secondly Vero cells were grown in two-litre stirred tank bioreactor by using several commercial microcarriers. We achieved the maximum cell concentration about 7.95 x 10(5) cells/ml when using Cytodex 1. Later we produced Newcastle Disease virus in stirred tank bioreactor based on the design developed using Taguchi L4 method. Results reveal that higher multiplicity of infection (MOI) and size of cell inoculums can yield higher virus titer. Finally, virus samples were purified using high-speed centrifugation based on 3( * *)(3-1) Fractional Factorial Design. Statistical analysis showed that the maximum virus titer can be achieved at virus sample concentration of 58.45% (v/v), centrifugation speed of 13729 rpm, and centrifugation time of 4 hours. As a conclusion, high yield of virus titer could be achieved through optimization of cell culture in bioreactor and separation by high-speed centrifugation.
    Matched MeSH terms: Microspheres*
  19. Prevention of Hypercholesterolemia with "Liposomes in Microspheres" Composite Carriers: A Promising Approach for Intestinal-Targeted Oral Delivery of Astaxanthin
    Liu A, He M, Liu C, Ye Z, Tan CP, Liu Y, et al.
    J Agric Food Chem, 2024 Mar 27;72(12):6118-6132.
    PMID: 38477232 DOI: 10.1021/acs.jafc.3c08697
    Cardiovascular diseases are caused by hypercholesterolemia. Astaxanthin (AST) has been reported to exhibit antioxidant and anti-inflammatory properties. However, its bioavailability is poor because of low solubility and instability. In order to improve the bioavailability of AST, we developed an intestinal-responsive composite carrier termed as "liposomes in micropheres" incorporating N-succinyl-chitosan (NSC)-poly(ethylene glycol) (PEG) liposomes that functionalized by neonatal Fc receptors (FcRn) into hydrogels of sodium alginate (SA) and carboxymethyl chitosan (CMCS). In the AST NSC/HSA-PEG liposomes@SA/CMCS microspheres, the AST's encapsulation efficiency (EE) was 96.26% (w/w) and its loading capacity (LC) was 6.47% (w/w). AST NSC/HSA-PEG liposomes had stability in the gastric conditions and achieved long-term release of AST in intestinal conditions. Then, AST NSC/HSA-PEG liposomes@SA/CMCS bind to intestinal epithelial cell targets by the neonatal Fc receptor. In vitro permeation studies show that there was a 4-fold increase of AST NSC/HSA-PEG liposomes@SA/CMCS in AST permeation across the intestinal epithelium. Subsequent in vivo experiments demonstrated that the composite carrier exhibited a remarkable mucoadhesive capacity, allowing for extended intestinal retention of up to 12 h, and it displayed deep penetration through the mucus layer, efficiently entering the intestinal villi epithelial cells, and enhancing the absorption of AST and its bioavailability in vivo. And oral administration of AST NSC/HSA-PEG liposomes@SA/CMCS could effectively prevent hypercholesterolemia caused by a high-fat, high-cholesterol diet (HFHCD). These advancements highlight the potential of NSC/HSA-PEG liposomes@SA/CMCS composite carriers for targeted and oral uptake of hydrophobic bioactives.
    Matched MeSH terms: Microspheres
  20. Preparation, characterization, and in vivo evaluation of insulin-loaded PLA-PEG microspheres for controlled parenteral drug delivery
    Sheshala R, Peh KK, Darwis Y
    Drug Dev Ind Pharm, 2009 Nov;35(11):1364-74.
    PMID: 19832637 DOI: 10.3109/03639040902939213
    AIM: The aim of this study was to prepare insulin-loaded poly(lactic acid)-polyethylene glycol microspheres that could control insulin release at least for 1 week and evaluate their in vivo performance in a streptozotocin-induced diabetic rat model.
    METHODS: The microspheres were prepared using a water-in-oil-in-water double emulsion solvent evaporation technique. Different formulation variables influencing the yield, particle size, entrapment efficiency, and in vitro release profiles were investigated. The pharmacokinetic study of optimized formulation was performed with single dose in comparison with multiple dose of Humulin 30/70 as a reference product in streptozotocin-induced diabetic rats.
    RESULTS: The optimized formulation of insulin microspheres was nonporous, smooth-surfaced, and spherical in structure under scanning electron microscope with a mean particle size of 3.07 microm and entrapment efficiency of 42.74% of the theoretical amount incorporated. The in vitro insulin release profiles was characterized by a bimodal behavior with an initial burst release because of the insulin adsorbed on the microsphere surface, followed by slower and continuous release corresponding to the insulin entrapped in polymer matrix.
    CONCLUSIONS: The optimized formulation and reference were comparable in the extent of absorption. Consequently, these microspheres can be proposed as new controlled parenteral delivery system.
    Matched MeSH terms: Microspheres
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links