Displaying publications 1 - 20 of 248 in total

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  1. Goh TB, Koh RY, Yam MF, Azhar ME, Mordi MN, Mansor SM
    Food Chem, 2015 Sep 15;183:208-16.
    PMID: 25863630 DOI: 10.1016/j.foodchem.2015.03.044
    Various 6-methoxytetrahydro-β-carboline derivatives, namely BEN (6-methoxy-1-phenyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole), ANI (6-methoxy-1-(4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole), ACE (6-methoxy-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole) and VAN (2-methoxy-4-(6-methoxy-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-l)phenol), were prepared via the Maillard reaction using food flavours and 5-methoxytryptamine in aqueous medium and were investigated for their in vitro antioxidant and cytotoxicity properties. These derivatives were found to exhibit moderate antioxidant properties, based on a combination of DPPH, ABTS and FRAP assays. The results suggested that the Maillard reaction could be used to generate β-carboline antioxidants. It was beneficial that VAN showed the highest antioxidant activity but the least cytotoxic activities on non-tumourous cell lines of NIH/3T3, CCD18-Co and B98-5 using MTT assay. ACE, ANI and BEN showed mild toxicity at effective antioxidative concentrations derived from DPPH and ABTS assays. Furthermore, they are safer compared to 5-fluorouracil, cisplatin and betulinic acid on NIH/3T3, CCD18-Co and B98-5 cells. In conclusion, the antioxidant and cytotoxicity properties of 6-methoxytetrahydro-β-carbolines were demonstrated for the first time.
    Matched MeSH terms: In Vitro Techniques
  2. Chaisakul J, Rusmili MR, Hodgson WC, Hatthachote P, Suwan K, Inchan A, et al.
    Toxins (Basel), 2017 03 29;9(4).
    PMID: 28353659 DOI: 10.3390/toxins9040122
    Cardiovascular effects (e.g., tachycardia, hypo- and/or hypertension) are often clinical outcomes of snake envenoming. Malayan krait (Bungarus candidus) envenoming has been reported to cause cardiovascular effects that may be related to abnormalities in parasympathetic activity. However, the exact mechanism for this effect has yet to be determined. In the present study, we investigated thein vivoandin vitrocardiovascular effects ofB. candidusvenoms from Southern (BC-S) and Northeastern (BC-NE) Thailand. SDS-PAGE analysis of venoms showed some differences in the protein profile of the venoms.B. candidusvenoms (50 µg/kg-100 µg/kg, i.v.) caused dose-dependent hypotension in anaesthetised rats. The highest dose caused sudden hypotension (phase I) followed by a return of mean arterial pressure to baseline levels and a decrease in heart rate with transient hypertension (phase II) prior to a small decrease in blood pressure (phase III). Prior administration of monovalent antivenom significantly attenuated the hypotension induced by venoms (100 µg/kg, i.v.). The sudden hypotensive effect of BC-NE venom was abolished by prior administration of hexamethonium (10 mg/kg, i.v.) or atropine (5 mg/kg, i.v.). BC-S and BC-NE venoms (0.1 µg/kg-100 µg/ml) induced concentration-dependent relaxation (EC50= 8 ± 1 and 13 ± 3 µg/mL, respectively) in endothelium-intact aorta. The concentration-response curves were markedly shifted to the right by pre-incubation with L-NAME (0.2 mM), or removal of the endothelium, suggesting that endothelium-derived nitric oxide (NO) is likely to be responsible for venom-induced aortic relaxation. Our data indicate that the cardiovascular effects caused byB. candidusvenoms may be due to a combination of vascular mediators (i.e., NO) and autonomic adaptation via nicotinic and muscarinic acetylcholine receptors.
    Matched MeSH terms: In Vitro Techniques
  3. Tang PW, Chua PS, Chong SK, Mohamad MS, Choon YW, Deris S, et al.
    Recent Pat Biotechnol, 2015;9(3):176-97.
    PMID: 27185502
    BACKGROUND: Predicting the effects of genetic modification is difficult due to the complexity of metabolic net- works. Various gene knockout strategies have been utilised to deactivate specific genes in order to determine the effects of these genes on the function of microbes. Deactivation of genes can lead to deletion of certain proteins and functions. Through these strategies, the associated function of a deleted gene can be identified from the metabolic networks.

    METHODS: The main aim of this paper is to review the available techniques in gene knockout strategies for microbial cells. The review is done in terms of their methodology, recent applications in microbial cells. In addition, the advantages and disadvantages of the techniques are compared and discuss and the related patents are also listed as well.

    RESULTS: Traditionally, gene knockout is done through wet lab (in vivo) techniques, which were conducted through laboratory experiments. However, these techniques are costly and time consuming. Hence, various dry lab (in silico) techniques, where are conducted using computational approaches, have been developed to surmount these problem.

    CONCLUSION: The development of numerous techniques for gene knockout in microbial cells has brought many advancements in the study of gene functions. Based on the literatures, we found that the gene knockout strategies currently used are sensibly implemented with regard to their benefits.

    Matched MeSH terms: In Vitro Techniques/methods
  4. Tan NH, Ponnudurai G, Mirtschin PJ
    Toxicon, 1993 Mar;31(3):363-7.
    PMID: 8470140
    The biological properties of adult and juvenile inland taipan (Oxyuranus microlepidotus) snake venoms were examined. The enzymatic activities, intravenous median lethal dose and procoagulant activity of the juvenile venom samples were not significantly different from those of the adult venom samples. Also, the juvenile and adult venoms exhibited similar electrophoretic patterns, indicating that they possessed similar protein composition.
    Matched MeSH terms: In Vitro Techniques
  5. Daood U, Matinlinna JP, Pichika MR, Mak KK, Nagendrababu V, Fawzy AS
    Sci Rep, 2020 07 03;10(1):10970.
    PMID: 32620785 DOI: 10.1038/s41598-020-67616-z
    To study the antimicrobial effects of quaternary ammonium silane (QAS) exposure on Streptococcus mutans and Lactobacillus acidophilus bacterial biofilms at different concentrations. Streptococcus mutans and Lactobacillus acidophilus biofilms were cultured on dentine disks, and incubated for bacterial adhesion for 3-days. Disks were treated with disinfectant (experimental QAS or control) and returned to culture for four days. Small-molecule drug discovery-suite was used to analyze QAS/Sortase-A active site. Cleavage of a synthetic fluorescent peptide substrate, was used to analyze inhibition of Sortase-A. Raman spectroscopy was performed and biofilms stained for confocal laser scanning microscopy (CLSM). Dentine disks that contained treated dual-species biofilms were examined using scanning electron microscopy (SEM). Analysis of DAPI within biofilms was performed using CLSM. Fatty acids in bacterial membranes were assessed with succinic-dehydrogenase assay along with time-kill assay. Sortase-A protein underwent conformational change due to QAS molecule during simulation, showing fluctuating alpha and beta strands. Spectroscopy revealed low carbohydrate intensities in 1% and 2% QAS. SEM images demonstrated absence of bacterial colonies after treatment. DAPI staining decreased with 1% QAS (p 
    Matched MeSH terms: In Vitro Techniques
  6. Ponnampalam JT, Musa J
    Med J Malaya, 1965 Dec;20(2):144-5.
    PMID: 4221975
    Matched MeSH terms: In Vitro Techniques
  7. Subrahmanyam C
    Med J Malaya, 1966 Mar;20(3):234-9.
    PMID: 4223073
    Matched MeSH terms: In Vitro Techniques
  8. Singh RB
    Med J Malaya, 1966 Mar;20(3):215-20.
    PMID: 4223129
    Matched MeSH terms: In Vitro Techniques
  9. Chapple PJ
    Bull World Health Organ, 1966;34(2):243-8.
    PMID: 5296130
    Studies have recently been published of surveys of antibodies to common respiratory viruses in human sera from several parts of the world. The present article reports the findings of a survey of antibodies to two more viruses (adenovirus type 8 and coxsackievirus type A21) in human sera mainly collected from six widely separated geographical regions (Alaska, England, Marshall Islands, Sarawak, South-West Africa and Tunisia).A world-wide geographical distribution of infection with these two viruses was found. However, antibodies to individual viruses were not found with the same frequency in all countries; and, in marked contrast to the findings in the earlier surveys of antibodies to the common respiratory viruses, the frequency of antibodies was not the same for each virus in sera from the same country. It was not possible to draw any final conclusions as to the reasons for the observed differences.
    Matched MeSH terms: In Vitro Techniques
  10. Perumal R, Bhattathiry EP
    Med J Malaya, 1970 Mar;24(3):208-11.
    PMID: 4246803
    Matched MeSH terms: In Vitro Techniques
  11. Jin LZ, Ho YW, Ali MA, Abdullah N, Ong KB, Jalaludin S
    Lett Appl Microbiol, 1996 Mar;22(3):229-32.
    PMID: 8852352
    A total of 46 Lactobacillus isolates obtained from chicken intestine were assessed on their ability to adhere to the chicken ileal epithelial cell (IEC) in vitro. Twelve out of the 46 isolates showed moderate to good ability to adhere to the IEC. Temperature (between 4 degrees C and 42 degrees C) did not affect attachment. Incubation (contact) time of 30 min was found to be insufficient for the attachment of bacteria to the IEC, but contact time beyond 1 h did not increase this ability. The pH values (4-7) of the suspending buffer did not have any significant effect on the attachment of bacteria to the IEC, but at pH 8 it was reduced significantly (P < 0.05).
    Matched MeSH terms: In Vitro Techniques
  12. Muir CK, Lim YM
    Med J Malaysia, 1980 Jun;34(4):387-90.
    PMID: 7219269
    The effects of phentolamine and propranolol on contractural responses of guinea-pig superior mesenteric-portal vein to adrenaline and isoprenaline were investigated. Phentolamine was capable of completely abolishing the response to adrenaline and to isoprenaline while propranolol had no effect on responses to either agonist. It is suggested that Alpha receptors are the only type of adrenoceptor involved in adrenergic control of contraction of this vein and that isoprenaline is capable of stimulating these receptors.
    Matched MeSH terms: In Vitro Techniques
  13. Loh LC, Rosdara Masayuni MS, Nor Izran Hanim AS, Raman S, Thayaparan T, Kumar S
    Ann Acad Med Singap, 2007 Aug;36(8):642-6.
    PMID: 17767334
    INTRODUCTION: In Malaysia, Klebsiella pneumoniae ranks high as a cause of adult pneumonia requiring hospitalisation.

    PATIENTS AND METHODS: With concern over its rising microbial resistance, we explored the association of empiric antibiotics choices with the hospital outcomes of patients treated for microbial proven K. pneumoniae pneumonia in an urban-based teaching hospital.

    RESULTS: In 313 eligible cases reviewed retrospectively, hospital mortality and requirement for ventilation were 14.3% and 10.8% respectively. Empiric regimes that had in vitro resistance to at least one empiric antibiotic (n = 90) were associated with higher hospital mortality (23.3% vs. 10.8%, P = 0.004) with risk increased by about two-fold [Odds ratio (OR), 2.5; 95% confidence interval (CI), 1.3 to 4.8]. Regimes (n = 84) other than the commonly recommended "standard" regimes (a beta-lactam stable antibiotic with or without a acrolide) were associated with higher ventilation rates (16.7% vs. 8.8%, P = 0.047) with similar increased risk [OR, 2.0; 95% CI, 1.0 to 4.3].

    CONCLUSIONS: Our findings reiterate the clinical relevance of in vitro microbial resistance in adult K. pneumoniae pneumonia and support empiric regimes that contain beta-lactam stable antibiotics.

    Matched MeSH terms: In Vitro Techniques
  14. Chong YH, Beng CG
    Med J Malaya, 1965 Sep;20(1):49-50.
    PMID: 4221413
    Matched MeSH terms: In Vitro Techniques
  15. Khan MA, Sattar MA, Abdullah NA, Johns EJ
    Acta Pharmacol Sin, 2008 Feb;29(2):193-203.
    PMID: 18215348 DOI: 10.1111/j.1745-7254.2008.00727.x
    This study examined whether alpha1B-adrenoceptors are involved in mediating adrenergically-induced renal vasoconstrictor responses in rats with pathophysiological and normal physiological states.
    Matched MeSH terms: In Vitro Techniques
  16. Safwani WK, Makpol S, Sathapan S, Chua KH
    Cell Tissue Bank, 2013 Jun;14(2):289-301.
    PMID: 22476937 DOI: 10.1007/s10561-012-9309-1
    Adipose tissue is a source of multipotent stem cells and it has the ability to differentiate into several types of cell lineages such as neuron cells, osteogenic and adipogenic cells. Most studies on human adipose-derived stem cells (ASCs) have been carried out at the early passages. For clinical usage, ASCs need to be expanded in vitro for a period of time to get sufficient cells for transplantation into patients. However, the impact of long-term culture on ASCs molecular characteristics has not been established yet. Several studies have also shown that osteogenic and adipogenic cells have the ability to switch pathways during in vitro culture as they share the same progenitor cells. This data is important to ensure their functionality and efficacy before being used clinically in the treatment of bone diseases. Therefore, we aim to investigate the effect of long-term culture on the adipogenic, stemness and osteogenic genes expression during osteogenic induction of ASCs. In this study, the molecular characteristics of ASCs during osteogenic induction in long-term culture was analysed by observing their morphological changes during induction, analysis of cell mineralization using Alizarin Red staining and gene expression changes using quantitative RT-PCR. Morphologically, cell mineralization at P20 was less compared to P5, P10 and P15. Adipogenesis was not observed as negative lipid droplets formation was recorded during induction. The quantitative PCR data showed that adipogenic genes expression e.g. LPL and AP2 decreased but PPAR-γ was increased after osteogenic induction in long-term culture. Most stemness genes decreased at P5 and P10 but showed no significant changes at P15 and P20. While most osteogenic genes increased after osteogenic induction at all passages. When compared among passages after induction, Runx showed a significant increased at P20 while BSP, OSP and ALP decreased at later passage (P15 and P20). During long-term culture, ASCs were only able to differentiate into immature osteogenic cells.
    Matched MeSH terms: In Vitro Techniques
  17. Roselan MA, Ashari SE, Faujan NH, Mohd Faudzi SM, Mohamad R
    Molecules, 2020 Jun 04;25(11).
    PMID: 32512808 DOI: 10.3390/molecules25112616
    Tyrosinase inhibitors have become increasingly important targets for hyperpigmentation disease treatment. Kojic monooleate (KMO), synthesized from the esterification of kojic acid and oleic acid, has shown a better depigmenting effect than kojic acid. In this study, the process parameters include the speed of high shear, the time of high shear and the speed of the stirrer in the production of nanoemulsion containing KMO was optimized using Response Surface Methodology (RSM), as well as evaluated in terms of its physicochemical properties, safety and efficacy. The optimized condition for the formulation of KMO nanoemulsion was 8.04 min (time of high shear), 4905.42 rpm (speed of high shear), and 271.77 rpm (speed of stirrer), which resulted in a droplet size of 103.97 nm. An analysis of variance (ANOVA) showed that the fitness of the quadratic polynomial fit the experimental data with large F-values (148.79) and small p-values (p < 0.0001) and an insignificant lack of fit. The optimized nanoemulsion containing KMO with a pH value of 5.75, showed a high conductivity value (3.98 mS/cm), which indicated that the nanoemulsion containing KMO was identified as an oil-in-water type of nanoemulsion. The nanoemulsion remains stable (no phase separation) under a centrifugation test and displays accelerated stability during storage at 4, 25 and 45 °C over 90 days. The cytotoxicity assay showed that the optimized nanoemulsion was less toxic, with a 50% inhibition of cell viability (IC50) > 500 μg/mL, and that it can inhibit 67.12% of tyrosinase activity. This study reveals that KMO is a promising candidate for the development of a safe cosmetic agent to prevent hyperpigmentation.
    Matched MeSH terms: In Vitro Techniques
  18. Rahman HS, Tan BL, Othman HH, Chartrand MS, Pathak Y, Mohan S, et al.
    Biomed Res Int, 2020;2020:8857428.
    PMID: 33381591 DOI: 10.1155/2020/8857428
    Angiogenesis is a crucial area in scientific research because it involves many important physiological and pathological processes. Indeed, angiogenesis is critical for normal physiological processes, including wound healing and embryonic development, as well as being a component of many disorders, such as rheumatoid arthritis, obesity, and diabetic retinopathies. Investigations of angiogenic mechanisms require assays that can activate the critical steps of angiogenesis as well as provide a tool for assessing the efficacy of therapeutic agents. Thus, angiogenesis assays are key tools for studying the mechanisms of angiogenesis and identifying the potential therapeutic strategies to modulate neovascularization. However, the regulation of angiogenesis is highly complex and not fully understood. Difficulties in assessing the regulators of angiogenic response have necessitated the development of an alternative approach. In this paper, we review the standard models for the study of tumor angiogenesis on the macroscopic scale that include in vitro, in vivo, and computational models. We also highlight the differences in several modeling approaches and describe key advances in understanding the computational models that contributed to the knowledge base of the field.
    Matched MeSH terms: In Vitro Techniques
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