Displaying publications 121 - 140 of 315 in total

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  1. The impact of long-term in vitro expansion on the senescence-associated markers of human adipose-derived stem cells
    Safwani WK, Makpol S, Sathapan S, Chua KH
    Appl Biochem Biotechnol, 2012 Apr;166(8):2101-13.
    PMID: 22391697 DOI: 10.1007/s12010-012-9637-4
    Human adipose-derived stem cells (ASCs) have generated a great deal of excitement in regenerative medicine. However, their safety and efficacy issue remain a major concern especially after long-term in vitro expansion. The aim of this study was to investigate the fundamental changes of ASCs in long-term culture by studying the morphological feature, growth kinetic, surface marker expressions, expression level of the senescence-associated genes, cell cycle distribution and ß-galactosidase activity. Human ASCs were harvested from lipoaspirate obtained from 6 patients. All the parameters mentioned above were measured at P5, P10, P15 and P20. Data were subjected to one-way analysis of variance with a Tukey post hoc test to determine significance difference (P < 0.05). The data showed that growth of ASCs reduced in long-term culture and the ß-galactosidase activity was significantly increased at later passage (P20). The morphology of ASCs in long-term culture showed the manifestation of senescent feature at P15 and P20. Significant alteration in the senescence-associated genes expression levels was observed in MMP1, p21, Rb and Cyclin D1 at P15 and P20. Significant increase in CD45 and HLA DR DQ DP surface marker was observed at P20. While cell cycle analysis showed significant decrease in percentage of ASCs at S and G2/M phase at later passage (P15). Our data showed ASCs cultured beyond P10 favours the senescence pathway and its clinical usage in cell-based therapy may be limited.
    Matched MeSH terms: Cell Culture Techniques/methods*
  2. Simultaneous 4-chlorophenol and nitrogen removal in moving bed sequencing batch reactors packed with polyurethane foam cubes of various sizes
    Lim JW, Lim PE, Seng CE, Adnan R
    Bioresour Technol, 2013 Feb;129:485-94.
    PMID: 23266850 DOI: 10.1016/j.biortech.2012.11.111
    Moving bed sequencing batch reactors (MBSBRs) packed with 8% (v/v) of 8-, 27- and 64-mL polyurethane (PU) foam cubes, respectively, were investigated for simultaneous 4-chlorophenol (4-CP) and nitrogen removal at increasing 4-CP concentration. When the 4-CP concentration exceeded 300 mg L(-1), the MBSBR with 27-mL foam cubes was observed to outperform the other MBSBRs in removing 4-CP and nitrogen. The reasons were: (1) there were more biomass in inner layer of the 27-mL cubes, compared to that of the 8-mL cubes, which was more shielded from the inhibitory effect of 4-CP and (2) the 27-mL cubes were more mobile than the 64-mL cubes. Although increasing 4-CP concentration to 600 mg L(-1) resulted in incomplete removal of 4-CP in the MBSBRs, results of the batch reactor with 27-mL foam cubes showed that complete 4-CP removal within the REACT period could be achieved by increasing the packing volume to 20%.
    Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
  3. Isolation techniques of murine bone marrow progenitor cells and their adipogenic, neurogenic and osteogenic differentiation capacity
    Ng AM, Kojima K, Kodoma S, Ruszymah BH, Aminuddin BS, Vacanti AC
    Med J Malaysia, 2008 Jul;63 Suppl A:121-2.
    PMID: 19025015
    Bone marrow derived progenitor cells have been widely studied for its multipotent property and have proofed to be an important resource in regenerative medicine. However, the propagation of murine bone marrow appeared to be a great challenge as compared to other mammalian species. In this study, various isolation techniques and the plasticity of the isolated cells were evaluated. Our result shows that magnetic sorting technique yielded the most viable cells and displayed wider differentiation capacity.
    Matched MeSH terms: Cell Culture Techniques/methods
  4. Fulltext Oil palm (Elaeis guineensis Jacq.) tissue culture ESTs: identifying genes associated with callogenesis and embryogenesis
    Low ET, Alias H, Boon SH, Shariff EM, Tan CY, Ooi LC, et al.
    BMC Plant Biol, 2008 May 29;8:62.
    PMID: 18507865 DOI: 10.1186/1471-2229-8-62
    BACKGROUND: Oil palm (Elaeis guineensis Jacq.) is one of the most important oil bearing crops in the world. However, genetic improvement of oil palm through conventional breeding is extremely slow and costly, as the breeding cycle can take up to 10 years. This has brought about interest in vegetative propagation of oil palm. Since the introduction of oil palm tissue culture in the 1970s, clonal propagation has proven to be useful, not only in producing uniform planting materials, but also in the development of the genetic engineering programme. Despite considerable progress in improving the tissue culture techniques, the callusing and embryogenesis rates from proliferating callus cultures remain very low. Thus, understanding the gene diversity and expression profiles in oil palm tissue culture is critical in increasing the efficiency of these processes.

    RESULTS: A total of 12 standard cDNA libraries, representing three main developmental stages in oil palm tissue culture, were generated in this study. Random sequencing of clones from these cDNA libraries generated 17,599 expressed sequence tags (ESTs). The ESTs were analysed, annotated and assembled to generate 9,584 putative unigenes distributed in 3,268 consensi and 6,316 singletons. These unigenes were assigned putative functions based on similarity and gene ontology annotations. Cluster analysis, which surveyed the relatedness of each library based on the abundance of ESTs in each consensus, revealed that lipid transfer proteins were highly expressed in embryogenic tissues. A glutathione S-transferase was found to be highly expressed in non-embryogenic callus. Further analysis of the unigenes identified 648 non-redundant simple sequence repeats and 211 putative full-length open reading frames.

    CONCLUSION: This study has provided an overview of genes expressed during oil palm tissue culture. Candidate genes with expression that are modulated during tissue culture were identified. However, in order to confirm whether these genes are suitable as early markers for embryogenesis, the genes need to be tested on earlier stages of tissue culture and a wider range of genotypes. This collection of ESTs is an important resource for genetic and genome analyses of the oil palm, particularly during tissue culture development.

    Matched MeSH terms: Tissue Culture Techniques/methods
  5. Fulltext Effects of feeding and induction strategy on the production of BmR1 antigen in recombinant E. coli
    Norsyahida A, Rahmah N, Ahmad RM
    Lett Appl Microbiol, 2009 Nov;49(5):544-50.
    PMID: 19832937 DOI: 10.1111/j.1472-765X.2009.02694.x
    To investigate the effects of feeding and induction strategies on the production of BmR1 recombinant antigen.
    Matched MeSH terms: Culture Techniques/methods*
  6. Human amnion as a novel cell delivery vehicle for chondrogenic mesenchymal stem cells
    Tan SL, Sulaiman S, Pingguan-Murphy B, Selvaratnam L, Tai CC, Kamarul T
    Cell Tissue Bank, 2011 Feb;12(1):59-70.
    PMID: 19953328 DOI: 10.1007/s10561-009-9164-x
    This study investigates the feasibility of processed human amnion (HAM) as a substrate for chondrogenic differentiation of mesenchymal stem cells (MSCs). HAM preparations processed by air drying (AD) and freeze drying (FD) underwent histological examination and MSC seeding in chondrogenic medium for 15 days. Monolayer cultures were used as control for chondrogenic differentiation and HAMs without cell seeding were used as negative control. Qualitative observations were made using scanning electron microscopy analysis and quantitative analyses were based on the sulfated glycosaminoglycans (GAG) assays performed on day 1 and day 15. Histological examination of HAM substrates before seeding revealed a smooth surface in AD substrates, while the FD substrates exhibited a porous surface. Cell attachment to AD and FD substrates on day 15 was qualitatively comparable. GAG were significantly highly expressed in cells seeded on FD HAM substrates. This study indicates that processed HAM is a potentially valuable material as a cell-carrier for MSC differentiation.
    Matched MeSH terms: Cell Culture Techniques/methods*
  7. Production of cell culture (MDCK) derived live attenuated influenza vaccine (LAIV) in a fully disposable platform process
    George M, Farooq M, Dang T, Cortes B, Liu J, Maranga L
    Biotechnol Bioeng, 2010 Aug 15;106(6):906-17.
    PMID: 20589670 DOI: 10.1002/bit.22753
    The majority of influenza vaccines are manufactured using embryonated hens' eggs. The potential occurrence of a pandemic outbreak of avian influenza might reduce or even eliminate the supply of eggs, leaving the human population at risk. Also, the egg-based production technology is intrinsically cumbersome and not easily scalable to provide a rapid worldwide supply of vaccine. In this communication, the production of a cell culture (Madin-Darby canine kidney (MDCK)) derived live attenuated influenza vaccine (LAIV) in a fully disposable platform process using a novel Single Use Bioreactor (SUB) is presented. The cell culture and virus infection was maintained in a disposable stirred tank reactor with PID control of pH, DO, agitation, and temperature, similar to traditional glass or stainless steel bioreactors. The application of this technology was tested using MDCK cells grown on microcarriers in proprietary serum free medium and infection with 2006/2007 seasonal LAIV strains at 25-30 L scale. The MDCK cell growth was optimal at the agitation rate of 100 rpm. Optimization of this parameter allowed the cells to grow at a rate similar to that achieved in the conventional 3 L glass stirred tank bioreactors. Influenza vaccine virus strains, A/New Caledonia/20/99 (H1N1 strain), A/Wisconsin/67/05 (H3N2 strain), and B/Malaysia/2506/04 (B strain) were all successfully produced in SUB with peak virus titers > or =8.6 log(10) FFU/mL. This result demonstrated that more than 1 million doses of vaccine can be produced through one single run of a small bioreactor at the scale of 30 L and thus provided an alternative to the current vaccine production platform with fast turn-around and low upfront facility investment, features that are particularly useful for emerging and developing countries and clinical trial material production.
    Matched MeSH terms: Cell Culture Techniques/methods
  8. Nitrogen removal in moving bed sequencing batch reactor using polyurethane foam cubes of various sizes as carrier materials
    Lim JW, Seng CE, Lim PE, Ng SL, Sujari AN
    Bioresour Technol, 2011 Nov;102(21):9876-83.
    PMID: 21890353 DOI: 10.1016/j.biortech.2011.08.014
    The performance of moving bed sequencing batch reactors (MBSBRs) added with 8 % (v/v) of polyurethane (PU) foam cubes as carrier media in nitrogen removal was investigated in treating low COD/N wastewater. The results indicate that MBSBR with 8-mL cubes achieved the highest total nitrogen (TN) removal efficiency of 37% during the aeration period, followed by 31%, 24% and 19 % for MBSBRs with 27-, 64- and 125-mL cubes, respectively. The increased TN removal in MBSBRs was mainly due to simultaneous nitrification and denitrification (SND) process which was verified by batch studies. The relatively lower TN removal in MBSBR with larger PU foam cubes was attributed to the observation that larger PU foam cubes were not fully attached by biomass. Higher concentrations of 8-mL PU foam cubes in batch reactors yielded higher TN removal.
    Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
  9. Fulltext Extrinsic factors involved in the differentiation of stem cells into insulin-producing cells: an overview
    Wong RS
    Exp Diabetes Res, 2011;2011:406182.
    PMID: 21747828 DOI: 10.1155/2011/406182
    Diabetes mellitus is a chronic disease with many debilitating complications. Treatment of diabetes mellitus mainly revolves around conventional oral hypoglycaemic agents and insulin replacement therapy. Recently, scientists have turned their attention to the generation of insulin-producing cells (IPCs) from stem cells of various sources. To date, many types of stem cells of human and animal origins have been successfully turned into IPCs in vitro and have been shown to exert glucose-lowering effect in vivo. However, scientists are still faced with the challenge of producing a sufficient number of IPCs that can in turn produce sufficient insulin for clinical use. A careful choice of stem cells, methods, and extrinsic factors for induction may all be contributing factors to successful production of functional beta-islet like IPCs. It is also important that the mechanism of differentiation and mechanism by which IPCs correct hyperglycaemia are carefully studied before they are used in human subjects.
    Matched MeSH terms: Cell Culture Techniques/methods*
  10. Physical factors affecting the production of organic solvent-tolerant protease by Pseudomonas aeruginosa strain K
    Rahman RN, Geok LP, Basri M, Salleh AB
    Bioresour Technol, 2005 Mar;96(4):429-36.
    PMID: 15491823
    The physical factors affecting the production of an organic solvent-tolerant protease from Pseudomonas aeruginosa strain K was investigated. Growth and protease production were detected from 37 to 45 degrees C with 37 degrees C being the optimum temperature for P. aeruginosa. Maximum enzyme activity was achieved at static conditions with 4.0% (v/v) inoculum. Shifting the culture from stationary to shaking condition decreased the protease production (6.0-10.0% v/v). Extracellular organic solvent-tolerant protease was detected over a broad pH range from 6.0 to 9.0. However, the highest yield of protease was observed at pH 7.0. Neutral media increased the protease production compared to acidic or alkaline media.
    Matched MeSH terms: Cell Culture Techniques/methods*
  11. Coral--polyhydroxybutrate composite scaffold for tissue engineering: prefabrication properties
    Al-Salihi KA, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:202-3.
    PMID: 15468888
    In this study the surface properties of two particulate coral and polyhydroxybutrate (PHB) were studied in order to characterize them prior to use in composite production. Coral powder and PHB particle were evaluated using scanning electron microscopy and confocal laser scanning microscopy, to measure surface porosity and pores size. The results showed that coral powder has multiple pleomorphic micropores cross each others give appearance of micro-interconnectivity. Some pore reached to 18 microm with an average porosity of 70%. PHB revealed multiple different size pores extended to the depth, with an average some times reach 25 microm and porosity 45%. These findings demonstrate that both coral and PHB have excellent pores size and porosity that facilitate bone in growth, vascular invasion and bone development. We believe that incorporation of coral powder into PHB will make an excellent composite scaffold for tissue engineering.
    Matched MeSH terms: Organ Culture Techniques/methods
  12. Evaluation of suitable biodegradable scaffolds for engineered bone tissue
    Phang MY, Ng MH, Tan KK, Aminuddin BS, Ruszymah BH, Fauziah O
    Med J Malaysia, 2004 May;59 Suppl B:198-9.
    PMID: 15468886
    Tricalcium phosphate/hydroxyapatite (TCP/HA), hydroxyapatite (HA), chitosan and calcium sulphate (CaSO4) were studied and evaluated for possible bone tissue engineered construct acting as good support for osteogenic cells to proliferate, differentiate, and eventually spread and integrate into the scaffold. Surface morphology visualized by SEM showed that scaffold materials with additional fibrin had more cell densities attached than those without, depicting that the presence of fibrin and collagen fibers were truly a favourite choice of cells to attach. In comparison of various biomaterials used incorporated with fibrin, TCP/HA had the most cluster of cells attached.
    Matched MeSH terms: Organ Culture Techniques/methods*
  13. Design and fabrication of scaffolds for anatomic bone reconstruction
    Hollister SJ, Lin CY, Lin CY, Schek RD, Taboas JM, Flanagan CL, et al.
    Med J Malaysia, 2004 May;59 Suppl B:131-2.
    PMID: 15468853
    Matched MeSH terms: Organ Culture Techniques/methods*
  14. Bone marrow mesenchymal stem cells differentiation and proliferation on the surface of coral implant
    Al-Salihi KA, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:45-6.
    PMID: 15468811
    This study was designed to evaluate the ability of natural coral implant to provide an environment for marrow cells to differentiate into osteoblasts and function suitable for mineralized tissue formation. DNA content, alkaline phosptatase (ALP) activity, calcium (Ca) content and mineralized nodules, were measured at day 3, day 7 and day 14, in rat bone marrow stromal cells cultured with coral discs glass discs, while cells alone and coral disc alone were cultured as control. DNA content, ALP activity, Ca content measurements showed no difference between coral, glass and cells groups at 3 day which were higher than control (coral disc alone), but there were higher measurement at day 7 and 14 in the cell cultured on coral than on glass discs, control cells and control coral discs. Mineralized nodules formation (both in area and number) was more predominant on the coral surface than in control groups. These results showed that natural coral implant provided excellent and favorable situation for marrow cell to differentiate to osteoblasts, lead to large amount of mineralized tissue formation on coral surface. This in vitro result could explain the rapid bone bonding of coral in vivo.
    Matched MeSH terms: Organ Culture Techniques*
  15. Higher β-HCG concentrations and higher birthweights ensue from single vitrified embryo transfers
    Keane KN, Mustafa KB, Hinchliffe P, Conceicao J, Yovich JL
    Reprod Biomed Online, 2016 Aug;33(2):149-60.
    PMID: 27209497 DOI: 10.1016/j.rbmo.2016.04.014
    To examine the effect of cryopreservation on developmental potential of human embryos, this study compared quantitative β-HCG concentrations at pregnancy test after IVF-fresh embryo transfer (IVF-ET) with those arising after frozen embryo transfer (FET). It also tracked outcomes of singleton pregnancies resulting from single-embryo transfers that resulted in singleton live births (n = 869; with 417 derived from IVF-ET and 452 from FET). The initial serum β-HCG concentration indicating successful implantation was measured along with the birthweight of the ensuing infants. With testing at equivalent luteal phase lengths, the median pregnancy test β-HCG was significantly higher following FET compared with fresh IVF-ET (844.5 IU/l versus 369 IU/l; P < 0.001). Despite no significant difference in the average period of gestation (38 weeks 5 days for both groups), the mean birthweight of infants born following FET was significantly heavier by 161 g (3370 g versus 3209 g; P < 0.001). Furthermore, more infants exceeded 4000 g (P < 0.001) for FET although there was no significant difference for the macrosomic category (≥4500 g). We concluded that FET programme embryos lead to infants with equivalent (if not better) developmental potential compared with IVF-ET, demonstrated by higher pregnancy β-HCG concentrations and ensuing birthweights.
    Matched MeSH terms: Embryo Culture Techniques/methods
  16. Anaerobic Probiotics: The Key Microbes for Human Health
    El Enshasy H, Malik K, Malek RA, Othman NZ, Elsayed EA, Wadaan M
    Adv. Biochem. Eng. Biotechnol., 2016;156:397-431.
    PMID: 26907552
    Human gastrointestinal microbiota (HGIM) incorporate a large number of microbes from different species. Anaerobic bacteria are the dominant organisms in this microbial consortium and play a crucial role in human health. In addition to their functional role as the main source of many essential metabolites for human health, they are considered as biotherapeutic agents in the regulation of different human metabolites. They are also important in the prevention and in the treatment of different physical and mental diseases. Bifidobacteria are the dominant anaerobic bacteria in HGIM and are widely used in the development of probiotic products for infants, children and adults. To develop bifidobacteria-based bioproducts, therefore, it is necessary to develop a large-scale biomass production platform based on a good understanding of the ideal medium and bioprocessing parameters for their growth and viability. In addition, high cell viability should be maintained during downstream processing and storage of probiotic cell powder or the final formulated product. In this work we review the latest information about the biology, therapeutic activities, cultivation and industrial production of bifidobacteria.
    Matched MeSH terms: Batch Cell Culture Techniques/methods*
  17. Fulltext Comparison of invasion by human microvascular endothelial cell lines in response to vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in a threedimensional (3D) cell culture system
    Ng CT, Yip WK, Mohtarrudin N, Seow HF
    Malays J Pathol, 2015 Dec;37(3):219-25.
    PMID: 26712666 MyJurnal
    Immortalized human endothelial cells are widely used as in vitro models for debilitating conditions such as cancer, cardiovascular and ocular diseases. Human microvascular endothelial cell (HMEC-1) is immortalized via stable transfection with a gene encoding SV40 large antigen whilst telomerase-immortalized human microvascular endothelial (TIME) cells is immortalized by engineering the human telomerase catalytic protein (hTERT) into primary microvascular endothelial cells. Here, we established a three-dimensional (3D) spheroid invasion assay with HMEC-1 and TIME and compared the difference in their ability to invade through the collagen matrix in response to exogenous growth factors, namely vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF).
    Matched MeSH terms: Cell Culture Techniques/methods*
  18. Cation dependence, pH tolerance, and dosage requirement of a bioflocculant produced by Bacillus spp. UPMB13: flocculation performance optimization through kaolin assays
    Zulkeflee Z, Aris AZ, Shamsuddin ZH, Yusoff MK
    ScientificWorldJournal, 2012;2012:495659.
    PMID: 22997497
    A bioflocculant-producing bacterial strain with highly mucoid and ropy colony morphological characteristics identified as Bacillus spp. UPMB13 was found to be a potential bioflocculant-producing bacterium. The effect of cation dependency, pH tolerance and dosage requirement on flocculating ability of the strain was determined by flocculation assay with kaolin as the suspended particle. The flocculating activity was measured as optical density and by flocs formation. A synergistic effect was observed with the addition of monovalent and divalent cations, namely, Na⁺, Ca²⁺, and Mg²⁺, while Fe²⁺ and Al³⁺ produced inhibiting effects on flocculating activity. Divalent cations were conclusively demonstrated as the best cation source to enhance flocculation. The bioflocculant works in a wide pH range, from 4.0 to 8.0 with significantly different performances (P < 0.05), respectively. It best performs at pH 5.0 and pH 6.0 with flocculating performance of above 90%. A much lower or higher pH would inhibit flocculation. Low dosage requirements were needed for both the cation and bioflocculant, with only an input of 50 mL/L for 0.1% (w/v) CaCl₂ and 5 mL/L for culture broth, respectively. These results are comparable to other bioflocculants produced by various microorganisms with higher dosage requirements.
    Matched MeSH terms: Batch Cell Culture Techniques/methods; Batch Cell Culture Techniques/standards*
  19. Combined use of in ovo electroporation and cultured neurons for gene function analysis of embryogenesis in the chicken optic tectum
    Yang C, Li X, Li Q, Zhang B, Li H, Lin J
    Neuroreport, 2017 Dec 06;28(17):1180-1185.
    PMID: 28953094 DOI: 10.1097/WNR.0000000000000903
    Chicken embryos are used widely in the fields of developmental biology and neurobiology. The chicken embryo also serves as a model to analyze gene expression and function using in ovo electroporation. Plasmids may be injected into the spinal cord or tectum of the chicken central nervous system by microinjection for electroporation. Here, we developed a novel method that combines in ovo electroporation and neuronal culturing to study gene function in the chicken tectum during embryo development. Our method can be used to study in-vivo and in-vitro exogenous genes' function. In addition, live cell imaging microscopy, immunostaining, and transfection can be used with our method to study neuronal growth, development, neurite growth and retraction, and axonal pathfinding. Our result showed that axons were present in isolated neurons after culturing for 24 h, and cell debris was low after replacing the media at 48 h. Many GFP-expressing neurons were observed in the cultured cells after 48 h. We successfully cultured the neurons for 3 weeks. Together, this method combines in ovo electroporation and neuronal culturing advantages and is more convenient for the gene function analysis.
    Matched MeSH terms: Cell Culture Techniques*
  20. Production of bio-hydrogen from dairy wastewater using pretreated landfill leachate sludge as an inoculum
    Wong YM, Show PL, Wu TY, Leong HY, Ibrahim S, Juan JC
    J Biosci Bioeng, 2019 Feb;127(2):150-159.
    PMID: 30224189 DOI: 10.1016/j.jbiosc.2018.07.012
    Bio-hydrogen production from wastewater using sludge as inoculum is a sustainable approach for energy production. This study investigated the influence of initial pH and temperature on bio-hydrogen production from dairy wastewater using pretreated landfill leachate sludge (LLS) as an inoculum. The maximum yield of 113.2 ± 2.9 mmol H2/g chemical oxygen demand (COD) (12.8 ± 0.3 mmol H2/g carbohydrates) was obtained at initial pH 6 and 37 °C. The main products of volatile fatty acids were acetate and butyrate with the ratio of acetate:butyrate was 0.4. At optimum condition, Gibb's free energy was estimated at -40 kJ/mol, whereas the activation enthalpy and entropy were 65 kJ/mol and 0.128 kJ/mol/l, respectively. These thermodynamic quantities suggest that bio-hydrogen production from dairy wastewater using pretreated LLS as inoculum was effective and efficient. In addition, genomic and bioinformatics analyses were performed in this study.
    Matched MeSH terms: Batch Cell Culture Techniques/methods
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