Displaying publications 61 - 80 of 405 in total

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  1. Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene
    Rene ER, Kar S, Krishnan J, Pakshirajan K, López ME, Murthy DV, et al.
    Bioresour Technol, 2015 Aug;190:529-35.
    PMID: 25827361 DOI: 10.1016/j.biortech.2015.03.049
    The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12-0.95g/m(3)), toluene (0.14-1.48g/m(3)) and gas-flow rate (0.024-0.072m(3)/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6-41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects.
    Matched MeSH terms: Models, Biological
  2. The Effect of a Polyvalent Antivenom on the Serum Venom Antigen Levels of Naja sputatrix (Javan Spitting Cobra) Venom in Experimentally Envenomed Rabbits
    Yap MK, Tan NH, Sim SM, Fung SY, Tan CH
    Basic Clin Pharmacol Toxicol, 2015 Oct;117(4):274-9.
    PMID: 25819552 DOI: 10.1111/bcpt.12398
    The treatment protocol of antivenom in snake envenomation remains largely empirical, partly due to the insufficient knowledge of the pharmacokinetics of snake venoms and the effects of antivenoms on the blood venom levels in victims. In this study, we investigated the effect of a polyvalent antivenom on the serum venom antigen levels of Naja sputatrix (Javan spitting cobra) venom in experimentally envenomed rabbits. Intravenous infusion of 4 ml of Neuro Polyvalent Snake Antivenom [NPAV, F(ab')2 ] at 1 hr after envenomation caused a sharp decline of the serum venom antigen levels, followed by transient resurgence an hour later. The venom antigen resurgence was unlikely to be due to the mismatch of pharmacokinetics between the F(ab')2 and venom antigens, as the terminal half-life and volume of distribution of the F(ab')2 in serum were comparable to that of venom antigens (p > 0.05). Infusion of an additional 2 ml of NPAV was able to prevent resurgence of the serum venom antigen level, resulting in a substantial decrease (67.1%) of the total amount of circulating venom antigens over time course of envenomation. Our results showed that the neutralization potency of NPAV determined by neutralization assay in mice may not be an adequate indicator of its capability to modulate venom kinetics in relation to its in vivo efficacy to neutralize venom toxicity. The findings also support the recommendation of giving high initial dose of NPAV in cobra envenomation, with repeated doses as clinically indicated in the presence of rebound antigenemia and symptom recurrence.
    Matched MeSH terms: Models, Biological
  3. Fulltext Quantitation of T lymphocyte subsets helps to distinguish dengue hemorrhagic fever from classic dengue fever during the acute febrile stage
    Fadilah SA, Sahrir S, Raymond AA, Cheong SK, Aziz JA, Sivagengei K
    Southeast Asian J. Trop. Med. Public Health, 1999 Dec;30(4):710-7.
    PMID: 10928365
    Activation of immunoregulatory T lymphocyte subsets has been observed in dengue viral infection, being more evident in dengue hemorrhagic fever (DHF) than in classical dengue fever (DF). There are, however, as yet no well-defined host markers to determine which patients with dengue viral infection will develop severe complications during the acute febrile stage of the disease. A study was performed to compare the cellular immune status in DHF, DF and non-dengue viral infections (NDF) in order to determine the value of these parameters in distinguishing DHF from classic DF and other viral infections during the acute febrile stage of the disease. This study involved 109 febrile patients admitted because of suspected DHF. Fifty patients were serologically confirmed cases of dengue infection, of which 25 had grade 1 or 2 DHF. There was a reduction in total T (CD3), CD4 and CD8 cells in DHF and demonstrated that a low level of CD3, CD4, CD8 and CD5 cells discriminated DHF from DF patients during the febrile stage of the illness. In contrast, B (CD19) cells and natural killer (NK) cells did not appear to be discriminatory in this study. Receiver operating characteristic (ROC) curve analysis showed that a combination of CD3 cell of < or = 45% and CD5 cell of < or = 55% was the best marker to identify DHF patients (sensitivity = 84% and specificity = 52% for CD3 cell of < or = 45%; sensitivity = 92% and specificity = 71% for CD5 cell of < or = 55%). CD4 cell of < or = 25% and CD8 cell < or = 30% were equally good in discriminating DHF from DF patients. On the other hand, the ROC curves indicated no clear difference between the immunoregulatory cell counts in DF from NDF Lymphopenia, atypical lymphocytosis and thrombocytopenia were significantly more evident in dengue compared to non-dengue infection but did not appear to be discriminatory among DHF and DF patients. The reduction in CD3, CD4, CD8, CD5 cells correlated with the degree of thrombocytopenia in DHF (p < 0.05) which suggests that these cells probably participate in a common pathogenetic mechanism.
    Matched MeSH terms: Models, Biological
  4. Microcalcification clustering parameters in breast disease: a morphometric analysis of radiographs of excision specimens
    Ng KH, Looi LM, Bradley DA
    Br J Radiol, 1996 Apr;69(820):326-34.
    PMID: 8665132
    X-ray microradiography of surgically excised breast specimens offers the possibility of morphological characterization of calcifications. When combined with digital imaging techniques there exists added potential for obtaining valuable basic quantitative morphometric information regarding differences between microcalcifications in tissues exhibiting evidence of fibrocystic change, benign and malignant tumours. A total of 157 excised breast specimens from 84 patients were microradiographed using a Softex Super Soft X-ray unit and Kodak AA high resolution industrial film. A Quantimet 570C image analysis system was used to digitize and analyse the microradiographs. Of the 157 microradiographs, 51 (from 30 patients) revealed microcalcification clusters. The existence of significant differences between the three identified categories of tissue were indicated by clustering parameters. These included the number of particles per cluster, area of clusters, maximum distance to nearest neighbour, and geometric mean distance to nearest neighbour. The distribution pattern index (DPI), another of the clustering parameters used in this study, has been observed to be a particularly powerful discriminator. The value for fibrocystic change was found to be significantly smaller (0.514) than that for benign tumour (0.796) whilst that for benign tumour was observed to be significantly larger than that for malignant tumour (0.604) at a p-value of less than 0.05 (Kruskal-Wallis one-way analysis of variance).
    Matched MeSH terms: Models, Biological
  5. Fulltext Fibrillary deposits: amyloids and tactoids
    Looi LM
    Malays J Pathol, 1995 Jun;17(1):1-10.
    PMID: 8906998
    Two forms of abnormal fibrillary protein deposition are considered: amyloidosis and fibrillary (immunotactoid) glomerulonephritis. Amyloid is characterised by an antiparallel, beta-pleated configuration which imparts to it a unique apple-green birefringence after Congo red staining. Inspite of its fairly constant physical properties, the chemical composition of amyloid fibrils is amazingly diverse, encomposing AA protein, light chain fragments, transthyretin, procalcitonin, islet amyloid polypeptide, atrial natriuretic peptides, beta-amyloid protein, beta-2-microglobulin, cystatin C, gelsolin, apolipoprotein A1, lyzozyme and their mutant variants. Amyloid P component and heparan sulphate proteoglycan are ubiquitous non-fibrillary amyloid components which have significant roles in the amyloidogenetic process, as do also precursor fibril proteins. Different amyloid fibril proteins relate to different amyloidosis syndromes and different histological patterns, and provide the basis for new diagnostic approaches to this disorder. Glomerular deposits in fibrillary glomerulonephritis (FGN), although often mistaken for amyloid, differ from it in its negative Congophilia, wider fibril width and highly organised, microtubular-tactoidal appearance ultrastructurally. FGN is essentially a primary glomerulopathy resulting in progressive renal failure. Despite certain differences, intriguing similarities between both entities of fibrillary deposition pose a challenge to researchers as to the mechanisms of abnormal protein crystallization and fibril formation in tissues.
    Matched MeSH terms: Models, Biological
  6. Fulltext TRPC3-Nox2 axis mediates nutritional deficiency-induced cardiomyocyte atrophy
    Sudi SB, Tanaka T, Oda S, Nishiyama K, Nishimura A, Sunggip C, et al.
    Sci Rep, 2019 07 05;9(1):9785.
    PMID: 31278358 DOI: 10.1038/s41598-019-46252-2
    Myocardial atrophy, characterized by the decreases in size and contractility of cardiomyocytes, is caused by severe malnutrition and/or mechanical unloading. Extracellular adenosine 5'-triphosphate (ATP), known as a danger signal, is recognized to negatively regulate cell volume. However, it is obscure whether extracellular ATP contributes to cardiomyocyte atrophy. Here, we report that ATP induces atrophy of neonatal rat cardiomyocytes (NRCMs) without cell death through P2Y2 receptors. ATP led to overproduction of reactive oxygen species (ROS) through increased amount of NADPH oxidase (Nox) 2 proteins, due to increased physical interaction between Nox2 and canonical transient receptor potential 3 (TRPC3). This ATP-mediated formation of TRPC3-Nox2 complex was also pathophysiologically involved in nutritional deficiency-induced NRCM atrophy. Strikingly, knockdown of either TRPC3 or Nox2 suppressed nutritional deficiency-induced ATP release, as well as ROS production and NRCM atrophy. Taken together, we propose that TRPC3-Nox2 axis, activated by extracellular ATP, is the key component that mediates nutritional deficiency-induced cardiomyocyte atrophy.
    Matched MeSH terms: Models, Biological
  7. Obesity, metabolic syndrome, adipocytes and vascular function: A holistic viewpoint
    Achike FI, To NH, Wang H, Kwan CY
    Clin Exp Pharmacol Physiol, 2011 Jan;38(1):1-10.
    PMID: 21083697 DOI: 10.1111/j.1440-1681.2010.05460.x
    1. Obesity is a metabolic disease of pandemic proportions largely arising from positive energy balance, a consequence of sedentary lifestyle, conditioned by environmental and genetic factors. Several central and peripheral neurohumoral factors (the major ones being the anorectic adipokines leptin and adiponecin and the orexigenic gut hormone ghrelin) acting on the anorectic (pro-opiomelanocortin and cocaine- and amphetamine-regulated transcript) and orexigenic (neuropeptide Y and agouti gene-related protein) neurons regulate energy balance. These neurons, mainly in the arcuate nucleus of the hypothalamus, project to parts of the brain modulating functions such as wakefulness, autonomic function and learning. A tilt in the anorectic-orexigenic balance, perhaps determined genetically, leads to obesity. 2. Excess fat deposition requires space, created by adipocyte (hypertrophy and hyperplasia) and extracellular matrix (ECM) remodelling. This process is regulated by several factors, including several adipocyte-derived Matrix metalloproteinases and the adipokine cathepsin, which degrades fibronectin, a key ECM protein. Excess fat, also deposited in visceral organs, generates chronic low-grade inflammation that eventually triggers insulin resistance and the associated comorbidities of metabolic syndrome (hypertension, atherosclerosis, dyslipidaemia and diabetes mellitus). 3. The perivascular adipose tissue (PVAT) has conventionally been considered non-physiological structural tissue, but has recently been shown to serve a paracrine function, including the release of adipose-derived relaxant and contractile factors, akin to the role of the vascular endothelium. Thus, PVAT regulates vascular function in vivo and in vitro, contributing to the cardiovascular pathophysiology of the metabolic syndrome. Defining the mechanism of PVAT regulation of vascular reactivity requires more and better controlled investigations than currently seen in the literature.
    Matched MeSH terms: Models, Biological
  8. Fulltext Modelling the Effect of a Novel Autodissemination Trap on the Spread of Dengue in Shah Alam and Malaysia
    Liang Y, Ahmad Mohiddin MN, Bahauddin R, Hidayatul FO, Nazni WA, Lee HL, et al.
    Comput Math Methods Med, 2019;2019:1923479.
    PMID: 31481976 DOI: 10.1155/2019/1923479
    In this paper, we will start off by introducing the classical Ross-Macdonald model for vector-borne diseases which we use to describe the transmission of dengue between humans and Aedes mosquitoes in Shah Alam, which is a city and the state capital of Selangor, Malaysia. We will focus on analysing the effect of using the Mosquito Home System (MHS), which is an example of an autodissemination trap, in reducing the number of dengue cases by changing the Ross-Macdonald model. By using the national dengue data from Malaysia, we are able to estimate λ, which represents the initial growth rate of the dengue epidemic, and this allows us to estimate the number of mosquitoes in Malaysia. A mathematical expression is also constructed which allows us to estimate the potential number of breeding sites of Aedes mosquitoes. By using the data available from the MHS trial carried out in Section 15 of Shah Alam, we included the potential effect of the MHS into the dengue model and thus modelled the impact MHS has on the spread of dengue within the trial area. We then extended our results to analyse the effect of the MHSs on reducing the number of dengue cases in the whole of Malaysia. A new model was constructed with a basic reproduction number, R0,MalaMHS, which allows us to identify the required MHSs coverage needed to achieve extinction in Malaysia. Numerical simulations and tables of results were also produced to illustrate our results.
    Matched MeSH terms: Models, Biological
  9. Wheat mitochondrial respiration shifts from the tricarboxylic acid cycle to the GABA shunt under salt stress
    Che-Othman MH, Jacoby RP, Millar AH, Taylor NL
    New Phytol, 2020 02;225(3):1166-1180.
    PMID: 30688365 DOI: 10.1111/nph.15713
    Mitochondrial respiration and tricarboxylic acid (TCA) cycle activity are required during salt stress in plants to provide ATP and reductants for adaptive processes such as ion exclusion, compatible solute synthesis and reactive oxygen species (ROS) detoxification. However, there is a poor mechanistic understanding of how salinity affects mitochondrial metabolism, particularly respiratory substrate source. To determine the mechanism of respiratory changes under salt stress in wheat leaves, we conducted an integrated analysis of metabolite content, respiratory rate and targeted protein abundance measurements. Also, we investigated the direct effect of salt on mitochondrial enzyme activities. Salt-treated wheat leaves exhibit higher respiration rate and extensive metabolite changes. The activity of the TCA cycle enzymes pyruvate dehydrogenase complex and the 2-oxoglutarate dehydrogenase complex were shown to be directly salt-sensitive. Multiple lines of evidence showed that the γ-aminobutyric acid (GABA) shunt was activated under salt treatment. During salt exposure, key metabolic enzymes required for the cyclic operation of the TCA cycle are physiochemically inhibited by salt. This inhibition is overcome by increased GABA shunt activity, which provides an alternative carbon source for mitochondria that bypasses salt-sensitive enzymes, to facilitate the increased respiration of wheat leaves.
    Matched MeSH terms: Models, Biological
  10. Fulltext The possible potential therapeutic targets for drug induced gingival overgrowth
    Subramani T, Rathnavelu V, Alitheen NB
    Mediators Inflamm, 2013;2013:639468.
    PMID: 23690667 DOI: 10.1155/2013/639468
    Gingival overgrowth is a side effect of certain medications. The most fibrotic drug-induced lesions develop in response to therapy with phenytoin, the least fibrotic lesions are caused by cyclosporin A, and the intermediate fibrosis occurs in nifedipine-induced gingival overgrowth. Fibrosis is one of the largest groups of diseases for which there is no therapy but is believed to occur because of a persistent tissue repair program. During connective tissue repair, activated gingival fibroblasts synthesize and remodel newly created extracellular matrix. Proteins such as transforming growth factor (TGF), endothelin-1 (ET-1), angiotensin II (Ang II), connective tissue growth factor (CCN2/CTGF), insulin-like growth factor (IGF), and platelet-derived growth factor (PDGF) appear to act in a network that contributes to the development of gingival fibrosis. Since inflammation is the prerequisite for gingival overgrowth, mast cells and its protease enzymes also play a vital role in the pathogenesis of gingival fibrosis. Drugs targeting these proteins are currently under consideration as antifibrotic treatments. This review summarizes recent observations concerning the contribution of TGF-β, CTGF, IGF, PDGF, ET-1, Ang II, and mast cell chymase and tryptase enzymes to fibroblast activation in gingival fibrosis and the potential utility of agents blocking these proteins in affecting the outcome of drug-induced gingival overgrowth.
    Matched MeSH terms: Models, Biological
  11. Fulltext Synthesis of diindolylmethane (DIM) bearing thiadiazole derivatives as a potent urease inhibitor
    Taha M, Rahim F, Khan AA, Anouar EH, Ahmed N, Shah SAA, et al.
    Sci Rep, 2020 05 14;10(1):7969.
    PMID: 32409737 DOI: 10.1038/s41598-020-64729-3
    The current study describes synthesis of diindolylmethane (DIM) derivatives based-thiadiazole as a new class of urease inhibitors. Diindolylmethane is natural product alkaloid reported to use in medicinal chemistry extensively. Diindolylmethane-based-thiadiazole analogs (1-18) were synthesized and characterized by various spectroscopic techniques 1HNMR, 13C-NMR, EI-MS and evaluated for urease (jack bean urease) inhibitory potential. All compounds showed excellent to moderate inhibitory potential having IC50 value within the range of 0.50 ± 0.01 to 33.20 ± 1.20 µM compared with the standard thiourea (21.60 ± 0.70 µM). Compound 8 (IC50 = 0.50 ± 0.01 µM) was the most potent inhibitor amongst all derivatives. Structure-activity relationships have been established for all compounds. The key binding interactions of most active compounds with enzyme were confirmed through molecular docking studies.
    Matched MeSH terms: Models, Biological
  12. Correlating gastric emptying of amphotericin B and paracetamol solid lipid nanoparticles with changes in particle surface chemistry
    Amekyeh H, Billa N, Roberts C
    Int J Pharm, 2017 Jan 30;517(1-2):42-49.
    PMID: 27923696 DOI: 10.1016/j.ijpharm.2016.12.001
    Oral delivery of pharmaceuticals requires that they retain their physical and chemical attributes during transit within the gastrointestinal (GI) tract, for the manifestation of desired therapeutic profiles. Solid lipid nanoparticles (SLNs) are used as carriers to improve the absorption of hydrophobic drugs. In this study, we examine the stability of amphotericin B (AmB) and paracetamol (PAR) SLNs in simulated GI fluids during gastric emptying. On contact with the simulated fluids, the particles increased in size due to ingress of the dissolution media into the particles. Simulated gastric emptying revealed that the formulations had mean sizes <350nm and neutral surface charges, both of which are optimal for intestinal absorption of SLNs. There was ingress of the fluids into the SLNs, followed by diffusion of the dissolved drug, whose rate depended on the solubility of the loaded-drug in the particular medium. Time-of-flight secondary ion mass spectrometry analyses indicated that drug loading followed the core-shell model and that the AmB SLNs have a more drug-enriched core than the PAR SLNs do. The AmB SLNs are therefore a very suitable carrier of AmB for oral delivery. The stability of the SLNs in the simulated GI media indicates their suitability for oral delivery.
    Matched MeSH terms: Models, Biological
  13. Fulltext Acacia honey accelerates in vitro corneal ulcer wound healing model
    Abd Ghafar N, Ker-Woon C, Hui CK, Mohd Yusof YA, Wan Ngah WZ
    BMC Complement Altern Med, 2016 Jul 29;16:259.
    PMID: 27473120 DOI: 10.1186/s12906-016-1248-0
    BACKGROUND: The study aimed to evaluate the effects of Acacia honey (AH) on the migration, differentiation and healing properties of the cultured rabbit corneal fibroblasts.

    METHODS: Stromal derived corneal fibroblasts from New Zealand White rabbit (n = 6) were isolated and cultured until passage 1. In vitro corneal ulcer was created using a 4 mm corneal trephine onto confluent cultures and treated with basal medium (FD), medium containing serum (FDS), with and without 0.025 % AH. Wound areas were recorded at day 0, 3 and 6 post wound creation. Genes and proteins associated with wound healing and differentiation such as aldehyde dehydrogenase (ALDH), vimentin, alpha-smooth muscle actin (α-SMA), collagen type I, lumican and matrix metalloproteinase 12 (MMP12) were evaluated using qRT-PCR and immunocytochemistry respectively.

    RESULTS: Cells cultured with AH-enriched FDS media achieved complete wound closure at day 6 post wound creation. The cells cultured in AH-enriched FDS media increased the expression of vimentin, collagen type I and lumican genes and decreased the ALDH, α-SMA and MMP12 gene expressions. Protein expression of ALDH, vimentin and α-SMA were in accordance with the gene expression analyses.

    CONCLUSION: These results demonstrated AH accelerate corneal fibroblasts migration and differentiation of the in vitro corneal ulcer model while increasing the genes and proteins associated with stromal wound healing.

    Matched MeSH terms: Models, Biological
  14. In utero Exposure to Germinated Brown Rice and Its GABA Extract Attenuates High-Fat-Diet-Induced Insulin Resistance in Rat Offspring
    Adamu HA, Imam MU, Der-Jiun O, Ismail M
    J Nutrigenet Nutrigenomics, 2017;10(1-2):19-31.
    PMID: 28399529 DOI: 10.1159/000469663
    BACKGROUND: Numerous studies have reported on the influence of diet on insulin resistance. Our study provides insight into the effect of germinated brown rice (GBR) and γ-aminobutyric acid (GABA) on early environment-driven programming and susceptibility to insulin resistance in rat offspring.

    METHODS: Male rat offspring from female Sprague-Dawley rats fed with a high-fat diet (HFD) alone, HFD + GBR, or HFD + GABA extract throughout pregnancy and lactation were weaned 4 weeks after delivery and followed up for 8 weeks. A biochemical analysis and an assessment of the hepatic expression of insulin signaling genes were performed.

    RESULTS: The results showed that intrauterine exposure to HFD caused metabolic perturbations in rat offspring which gravitated towards insulin resistance even though the rat offspring did not consume an HFD. GBR and GABA attenuated the HFD-induced changes by underlying regulation of the insulin signaling genes.

    CONCLUSIONS: The results suggest that intake of GBR and GABA during pregnancy and lactation can influence the programming of genes in rat offspring, thereby enhancing insulin sensitivity.

    Matched MeSH terms: Models, Biological
  15. The role of bevacizumab on tumour angiogenesis and in the management of gynaecological cancers: A review
    Chellappan DK, Leng KH, Jia LJ, Aziz NABA, Hoong WC, Qian YC, et al.
    Biomed Pharmacother, 2018 Jun;102:1127-1144.
    PMID: 29710531 DOI: 10.1016/j.biopha.2018.03.061
    OBJECTIVE: The study aims to analyze the effectiveness of bevacizumab in addressing the complications associated with gynecological cancers and evaluates effective treatments for various gynecological cancers.

    METHODS: The study follows a systematic review approach that has been implemented to analyze the qualitative published data from previous studies. Studies related with the trials of angiogenesis and bevacizumab were selected in the review.

    RESULTS: In general, the management of gynecological cancers include chemotherapy, surgery and radiation therapy. Results suggest bevacizumab as an effective treatment modality for cervical and several other cancers. Overall, bevacizumab showed promising results in improving the overall survival rate of gynecological cancer patients through the combination of bevacizumab with other chemotherapeutic agents.

    CONCLUSION: Bevacizumab possess less documented adverse effects when compared to other chemotherapeutic agents. The manifestation and severity of adverse effects reported varied according to the chemotherapeutic agent(s) that were used with bevacizumab in combination therapy. Overall, bevacizumab effectively improved the survival rate in patients with several gynaecological cancers.

    Matched MeSH terms: Models, Biological
  16. Incorporation of dietary fibre-rich oyster mushroom (Pleurotus sajor-caju) powder improves postprandial glycaemic response by interfering with starch granule structure and starch digestibility of biscuit
    Ng SH, Robert SD, Wan Ahmad WA, Wan Ishak WR
    Food Chem, 2017 Jul 15;227:358-368.
    PMID: 28274444 DOI: 10.1016/j.foodchem.2017.01.108
    The purpose of this study was to determine the effects of Pleurotus sajor-caju (PSC) powder addition at 0, 4, 8 and 12% levels on the nutritional values, pasting properties, thermal characteristics, microstructure, in vitro starch digestibility, in vivo glycaemic index (GI) and sensorial properties of biscuits. Elevated incorporation levels of PSC powder increased the dietary fibre (DF) content and reduced the pasting viscosities and starch gelatinisation enthalpy value of biscuits. The addition of DF-rich PSC powder also interfered with the integrity of the starch granules by reducing the sizes and inducing the uneven spherical shapes of the starch granules, which, in turn, resulted in reduced starch susceptibility to digestive enzymes. The restriction starch hydrolysis rate markedly reduced the GI of biscuits. The incorporation of 8% PSC powder in biscuits (GI=49) could be an effective way of developing a nutritious and low-GI biscuit without jeopardizing its desirable sensorial properties.
    Matched MeSH terms: Models, Biological
  17. Molecular characterization of glycation-associated skin ageing: an alternative skin model to study in vitro antiglycation activity of topical cosmeceutical and pharmaceutical formulations
    Lee KH, Ng YP, Cheah PS, Lim CK, Toh MS
    Br J Dermatol, 2017 Jan;176(1):159-167.
    PMID: 27363533 DOI: 10.1111/bjd.14832
    BACKGROUND: Glycation is a nonenzymatic reaction that cross-links a sugar molecule and protein macromolecule to form advanced glycation products (AGEs) that are associated with various age-related disorders; thus glycation plays an important role in skin chronological ageing.

    OBJECTIVES: To develop a novel in vitro skin glycation model as a screening tool for topical formulations with antiglycation properties and to further characterize, at the molecular level, the glycation stress-driven skin ageing mechanism.

    METHODS: The glycation model was developed using human reconstituted full-thickness skin; the presence of N(ε) -(carboxymethyl) lysine (CML) was used as evidence of the degree of glycation. Topical application of emulsion containing a well-known antiglycation compound (aminoguanidine) was used to verify the sensitivity and robustness of the model. Cytokine immunoassay, quantitative real-time polymerase chain reaction and histological analysis were further implemented to characterize the molecular mechanisms of skin ageing in the skin glycation model.

    RESULTS: Transcriptomic and cytokine profiling analyses in the skin glycation model demonstrated multiple biological changes, including extracellular matrix catabolism, skin barrier function impairment, oxidative stress and subsequently the inflammatory response. Darkness and yellowness of skin tone observed in the in vitro skin glycation model correlated well with the degree of glycation stress.

    CONCLUSIONS: The newly developed skin glycation model in this study has provided a new technological dimension in screening antiglycation properties of topical pharmaceutical or cosmeceutical formulations. This study concomitantly provides insights into skin ageing mechanisms driven by glycation stress, which could be useful in formulating skin antiageing therapy in future studies.

    Matched MeSH terms: Models, Biological
  18. Fulltext Real-time acquisition of transendothelial electrical resistance in an all-human, in vitro, 3-dimensional, blood-brain barrier model exemplifies tight-junction integrity
    Maherally Z, Fillmore HL, Tan SL, Tan SF, Jassam SA, Quack FI, et al.
    FASEB J, 2018 01;32(1):168-182.
    PMID: 28883042 DOI: 10.1096/fj.201700162R
    The blood-brain barrier (BBB) consists of endothelial cells, astrocytes, and pericytes embedded in basal lamina (BL). Most in vitro models use nonhuman, monolayer cultures for therapeutic-delivery studies, relying on transendothelial electrical resistance (TEER) measurements without other tight-junction (TJ) formation parameters. We aimed to develop reliable, reproducible, in vitro 3-dimensional (3D) models incorporating relevant human, in vivo cell types and BL proteins. The 3D BBB models were constructed with human brain endothelial cells, human astrocytes, and human brain pericytes in mono-, co-, and tricultures. TEER was measured in 3D models using a volt/ohmmeter and cellZscope. Influence of BL proteins-laminin, fibronectin, collagen type IV, agrin, and perlecan-on adhesion and TEER was assessed using an electric cell-substrate impedance-sensing system. TJ protein expression was assessed by Western blotting (WB) and immunocytochemistry (ICC). Perlecan (10 µg/ml) evoked unreportedly high, in vitro TEER values (1200 Ω) and the strongest adhesion. Coculturing endothelial cells with astrocytes yielded the greatest resistance over time. ICC and WB results correlated with resistance levels, with evidence of prominent occludin expression in cocultures. BL proteins exerted differential effects on TEER, whereas astrocytes in contact yielded higher TEER values and TJ expression.-Maherally, Z., Fillmore, H. L., Tan, S. L., Tan, S. F., Jassam, S. A., Quack, F. I., Hatherell, K. E., Pilkington, G. J. Real-time acquisition of transendothelial electrical resistance in an all-human, in vitro, 3-dimensional, blood-brain barrier model exemplifies tight-junction integrity.
    Matched MeSH terms: Models, Biological
  19. The role of neuron-glia interactions in the emergence of ultra-slow oscillations
    Chan SC, Mok SY, Ng DW, Goh SY
    Biol Cybern, 2017 Dec;111(5-6):459-472.
    PMID: 29128889 DOI: 10.1007/s00422-017-0740-z
    Ultra-slow cortical oscillatory activity of 1-100 mHz has been recorded in human by electroencephalography and in dissociated cultures of cortical rat neurons, but the underlying mechanisms remain to be elucidated. This study presents a computational model of ultra-slow oscillatory activity based on the interaction between neurons and astrocytes. We predict that the frequency of these oscillations closely depends on activation of astrocytes in the network, which is reflected by oscillations of their intracellular calcium concentrations with periods between tens of seconds and minutes. An increase of intracellular calcium in astrocytes triggers the release of adenosine triphosphate from these cells which may alter transmission at nearby synapses by increasing or decreasing neurotransmitter release. These results provide theoretical support for the emerging awareness of astrocytes as active players in the regulation of neural activity and identify neuron-astrocyte interactions as a potential primary mechanism for the emergence of ultra-slow cortical oscillations.
    Matched MeSH terms: Models, Biological
  20. Design and validation of a bi-axial loading bioreactor for mechanical stimulation of engineered cartilage
    Yusoff N, Abu Osman NA, Pingguan-Murphy B
    Med Eng Phys, 2011 Jul;33(6):782-8.
    PMID: 21356602 DOI: 10.1016/j.medengphy.2011.01.013
    A mechanical-conditioning bioreactor has been developed to provide bi-axial loading to three-dimensional (3D) tissue constructs within a highly controlled environment. The computer-controlled bioreactor is capable of applying axial compressive and shear deformations, individually or simultaneously at various regimes of strain and frequency. The reliability and reproducibility of the system were verified through validation of the spatial and temporal accuracy of platen movement, which was maintained over the operating length of the system. In the presence of actual specimens, the system was verified to be able to deliver precise bi-axial load to the specimens, in which the deformation of every specimen was observed to be relatively homogeneous. The primary use of the bioreactor is in the culture of chondrocytes seeded within an agarose hydrogel while subjected to physiological compressive and shear deformation. The system has been designed specifically to permit the repeatable quantification and characterisation of the biosynthetic activity of cells in response to a wide range of short and long term multi-dimensional loading regimes.
    Matched MeSH terms: Models, Biological
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