Displaying publications 21 - 40 of 340 in total

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  1. Transethosome: An ultra-deformable ethanolic vesicle for enhanced transdermal drug delivery
    Raj A, Dua K, Nair RS, Sarath Chandran C, Alex AT
    Chem Phys Lipids, 2023 Sep;255:105315.
    PMID: 37356610 DOI: 10.1016/j.chemphyslip.2023.105315
    Drug delivery through the skin improves solubility, bioavailability, and unwanted systemic side effects of the drug. The selection of a suitable carrier is a challenging process. The conventional lipid vesicles have some limitations. They deliver the drug in the stratum corneum and have poor colloidal stability. Here comes the need for ultra-deformable lipid vesicles to provide the drug beyond the stratum corneum. Transethosomes are novel ultra-deformable vesicles that can deliver drugs into deeper tissues. The composition of transethosomes includes phospholipid, ethanol and surfactants. Each ingredient has a pivotal role in the properties of the carrier. This review covers the design, preparation method, characterisation, and characteristics of the novel vesicle. Also, we cover the impact of surfactants on vesicular properties and the skin permeation behaviour of novel vesicles.
  2. Fulltext In vitro porcine blood-brain barrier model for permeability studies: pCEL-X software pKa(FLUX) method for aqueous boundary layer correction and detailed data analysis
    Yusof SR, Avdeef A, Abbott NJ
    Eur J Pharm Sci, 2014 Dec 18;65:98-111.
    PMID: 25239510 DOI: 10.1016/j.ejps.2014.09.009
    In vitro blood-brain barrier (BBB) models from primary brain endothelial cells can closely resemble the in vivo BBB, offering valuable models to assay BBB functions and to screen potential central nervous system drugs. We have recently developed an in vitro BBB model using primary porcine brain endothelial cells. The model shows expression of tight junction proteins and high transendothelial electrical resistance, evidence for a restrictive paracellular pathway. Validation studies using small drug-like compounds demonstrated functional uptake and efflux transporters, showing the suitability of the model to assay drug permeability. However, one limitation of in vitro model permeability measurement is the presence of the aqueous boundary layer (ABL) resulting from inefficient stirring during the permeability assay. The ABL can be a rate-limiting step in permeation, particularly for lipophilic compounds, causing underestimation of the permeability. If the ABL effect is ignored, the permeability measured in vitro will not reflect the permeability in vivo. To address the issue, we explored the combination of in vitro permeability measurement using our porcine model with the pKa(FLUX) method in pCEL-X software to correct for the ABL effect and allow a detailed analysis of in vitro (transendothelial) permeability data, Papp. Published Papp using porcine models generated by our group and other groups are also analyzed. From the Papp, intrinsic transcellular permeability (P0) is derived by simultaneous refinement using a weighted nonlinear regression, taking into account permeability through the ABL, paracellular permeability and filter restrictions on permeation. The in vitro P0 derived for 22 compounds (35 measurements) showed good correlation with P0 derived from in situ brain perfusion data (r(2)=0.61). The analysis also gave evidence for carrier-mediated uptake of naloxone, propranolol and vinblastine. The combination of the in vitro porcine model and the software analysis provides a useful tool to better predict BBB permeability in vivo and gain better mechanistic information about BBB permeation.
  3. Fulltext Attitudes of Malaysian general hospital staff towards patients with mental illness and diabetes
    Minas H, Zamzam R, Midin M, Cohen A
    BMC Public Health, 2011;11:317.
    PMID: 21569613 DOI: 10.1186/1471-2458-11-317
    The context of the study is the increased assessment and treatment of persons with mental illness in general hospital settings by general health staff, as the move away from mental hospitals gathers pace in low and middle income countries. The purpose of the study was to examine whether general attitudes of hospital staff towards persons with mental illness, and extent of mental health training and clinical experience, are associated with different attitudes and behaviours towards a patient with mental illness than towards a patients with a general health problem - diabetes.
  4. Chromobacterium violaceum infection
    Tee HP, Francis AL, How SH
    Br J Hosp Med (Lond), 2006 Apr;67(4):208-9.
    PMID: 16681318 DOI: 10.12968/hmed.2006.67.4.20869
  5. The Significance of Tinospora crispa in Treatment of Diabetes Mellitus
    Thomas A, Rajesh EK, Kumar DS
    Phytother Res, 2016 Mar;30(3):357-66.
    PMID: 26749336 DOI: 10.1002/ptr.5559
    Tinospora crispa is a medicinal plant belonging to the botanical family Menispermiaceae. The plant is widely distributed in Southeast Asia and the northeastern region of India. A related species Tinospora cordifolia is used in Ayurveda for treating a large spectrum of diseases. Traditional healers of Thailand, Malaysia, Guyana, Bangladesh and the southern Indian province of Kerala use this plant in the treatment of diabetes. Many diterpenes, triterpenes, phytosteroids, alkaloids and their glycosides have been isolated from T. crispa. Cell culture and animal studies suggest that the herb stimulates secretion of insulin from β-cells. It also causes dose-dependent and time-dependent enhancement of glucose uptake in muscles. However, in view of the reported hepatotoxicity, this herb may be used with caution. This article reviews the animal studies and human clinical trials carried out using this herb. Areas of future research are also identified.
  6. Fulltext Metastatic Thymic Carcinoma on Restaging 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography
    Hoe Khoo AC, Ang SF
    Indian J Nucl Med, 2020 10 21;35(4):364-366.
    PMID: 33642772 DOI: 10.4103/ijnm.IJNM_123_20
    Thymic carcinoma is a rare thymic epithelial cancer which is not only locally invasive but also highly aggressive disease. The prognosis for this cancer is poor and the surgery remains the mainstay of treatment. Thymic carcinomas have been shown to metastasize to the lymph nodes, lung, and liver. A 63-year old male who was successfully treated for thymic cancer in 2015, presented with metastatic disease recurrence to the spinal cord. We share interesting images of the spinal cord lesions as well as pituitary metastases that were incidentally detected on restaging 18F-fluorodeoxyglucose positron emission tomography-computed tomography.
  7. Recurrent Endometrioid Adenocarcinoma of Endometrium With Bone Metastases
    Khoo ACH, Rashid NKA
    Clin Nucl Med, 2017 Aug;42(8):635-636.
    PMID: 28481802 DOI: 10.1097/RLU.0000000000001694
    Endometrial cancer, a common cancer affecting women, has the tendency to metastasize to the lung and liver. Bone metastases in endometrial cancers are rare and accounts for less than 1% of the overall incidence of metastases. We report a case of a 30-year-old single nulliparous woman with metastatic recurrence of endometrioid adenocarcinoma of the endometrium involving the pelvic bone, and the role of bone scintigraphy in detection and staging of the disease.
  8. Impact of capillary flow hydrodynamics on carrier-mediated transport of opioid derivatives at the blood-brain barrier, based on pH-dependent Michaelis-Menten and Crone-Renkin analyses
    Yusof SR, Abbott NJ, Avdeef A
    Eur J Pharm Sci, 2017 Aug 30;106:274-286.
    PMID: 28614733 DOI: 10.1016/j.ejps.2017.06.016
    Most studies of blood-brain barrier (BBB) permeability and transport are conducted at a single pH, but more detailed information can be revealed by using multiple pH values. A pH-dependent biophysical model was applied to the mechanistic analysis of published pH-dependent BBB luminal uptake data from three opioid derivatives in rat: pentazocine (Suzuki et al., 2002a, 2002b), naloxone (Suzuki et al., 2010a), and oxycodone (Okura et al., 2008). Two types of data were processed: in situ brain perfusion (ISBP) and brain uptake index (BUI). The published perfusion data were converted to apparent luminal permeability values, Papp, and analyzed by the pCEL-X program (Yusof et al., 2014), using the pH-dependent Crone-Renkin equation (pH-CRE) to determine the impact of cerebrovascular flow on the Michaelis-Menten transport parameters (Avdeef and Sun, 2011). For oxycodone, the ISBP data had been measured at pH7.4 and 8.4. The present analysis indicates a 7-fold lower value of the cerebrovascular flow velocity, Fpf, than that expected in the original study. From the pyrilamine-inhibited data, the flow-corrected passive intrinsic permeability value was determined to be P0=398×10-6cm·s-1. The uptake data indicate that the neutral form of oxycodone is affected by a transporter at pH8.4. The extent of the cation uptake was less certain from the available data. For pentazocine, the brain uptake by the BUI method had been measured at pH5.5, 6.5, and 7.4, in a concentration range 0.1-40mM. Under similar conditions, ISBP data were also available. The pH-CRE determined values of Fpf from both methods were nearly the same, and were smaller than the expected value in the original publication. The transport of the cationic pentazocine was not fully saturated at pH5.5 at 40mM. The transport of the neutral species at pH7.4 appeared to reach saturation at 40mM pentazocine concentration, but not at 12mM. In the case of naloxone, a pH-dependent Michaelis-Menten equation (pH-MME) analysis of the data indicated a smooth sigmoidal transition from a higher capacity uptake process affecting cationic naloxone (pH5.0-7.0) to a lower capacity uptake process affecting the neutral drug (pH8.0-8.5), with cross-over point near pH7.4. Evidently, measurements at multiple pH values can reveal important information about both cerebrovascular flow and BBB transport kinetics.
  9. Incidental Sclerosing Pneumocytoma Detected on Bone Scintigraphy
    Khoo AC, Hamzah F, Ong CK
    Clin Nucl Med, 2016 Oct 5.
    PMID: 27749415
    Nonosseous uptake in Tc-hydroxymethylene bone scintigraphy should always be evaluated for any possibility of pathological changes. We share interesting images of a 60-year-old woman initially investigated for suspected osteomyelitis of the left femur but found to have an extraosseous uptake in the right hemithorax on bone scintigraphy. Plain chest radiograph followed by contrast-enhanced CT of the thorax revealed the presence of a lung mass in the right lower lobe with no lymphadenopathy. CT-guided biopsy yielded fibrocollagenous tissue, partly lined by benign pneumocytes. The F-FDG-avid lung mass was confirmed to be sclerosing pneumocytoma postlobectomy.
  10. Fulltext Incidental Finding of Lipomatous Hypertrophy of the Interatrial Septum during 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography for Cervical Cancer
    Khoo ACH, Nasir SMBM
    Indian J Nucl Med, 2018 11 6;33(4):374-375.
    PMID: 30386070 DOI: 10.4103/ijnm.IJNM_89_18
    Lipomatous hypertrophy of the interatrial septum is a benign but less recognized pathology of the heart caused by benign fatty infiltration of the interatrial septum which most often spares the fossa ovalis. We share images of the incidentally detected fluorodeoxyglucose (FDG) uptake in the interatrial septum during the restaging of 18F-FDG positron emission tomography/computed tomography scan of cervical cancer.
  11. Fulltext A Review of TENIS Syndrome in Hospital Pulau Pinang
    Khoo ACH, Fong LY, Hamzah F
    Indian J Nucl Med, 2018 11 6;33(4):284-289.
    PMID: 30386048 DOI: 10.4103/ijnm.IJNM_65_18
    Introduction: The treatment for differentiated thyroid cancers (DTCs) has always been radioactive iodine 131I therapy after definitive surgical management. Clinicians are faced with therapeutic challenges when dealing with patients having thyroglobulin-elevated negative iodine scintigraphy (TENIS) syndrome (elevated serum thyroglobulin [Tg] levels but negative whole-body scans [WBSs]).

    Objective: The aim of the study was to determine the prevalence of TENIS syndrome in our local setting and to evaluate the use of 18-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) in the management.

    Methodology: The data from DTC patients treated in the Department of Nuclear Medicine, Hospital Pulau Pinang from December 1, 2010, to November 30, 2016, with negative WBS and elevated Tg were reviewed. These patients should have undergone 18F-FDG PET-CT to be included in the study.

    Results: Only forty (10.4%) out of a total of 386 patients treated in Hospital Pulau Pinang during the study fulfilled the inclusion criteria. There were 28 women (70%) with median age of 59 years old. Thirty-four patients (85%) had papillary thyroid cancer (PTC) and six patients had follicular thyroid cancer. The use of 18F-FDG PET-CT revealed 23 patients (57.5%) with 18F-FDG avid metastases suggesting dedifferentiation of thyroid cancers. Based on this study, the probability of detecting FDG-avid disease is higher (P = 0.03) if 18F-FDG PET-CT was performed when Tg ≥15 ng/mL.

    Conclusion: TENIS syndrome constitutes a significant number of cases in our setting. Our data suggest a cutoff Tg ≥15 ng/mL for performing 18F-FDG PET-CT for these patients would be more beneficial than the currently American Thyroid Association recommended cutoff of 10 ng/mL.

  12. A red-shifted Bioluminescence Resonance Energy Transfer (BRET) biosensing system for rapid measurement of plasmin activity in human plasma
    Weihs F, Peh A, Dacres H
    Anal Chim Acta, 2020 Mar 15;1102:99-108.
    PMID: 32044001 DOI: 10.1016/j.aca.2019.12.044
    Proteases are key signalling molecules for many physiological processes and their dysregulation is implicated in the progression of a range of diseases. Sensitive methods to measure protease activities in complex biological samples are critical for rapid disease diagnoses. The proteolytic activity of plasmin reflects the fibrinolysis state of blood and its deregulation can indicate pathologies such as bleeding events. While Bioluminescence Resonance Energy Transfer (BRET) is a powerful and sensitive method for the detection of protease activity, the commonly applied blue-shifted BRET2 system, consisting of the Renilla luciferase Rluc2 and the large-stokes shift fluorescent protein GFP2, suffers from light absorption and light scattering in human plasma samples. To address this challenge, we developed a red-shifted BRET-based plasmin sensor by substituting BRET2 with the BRET6 system. BRET6 is composed of the red-shifted RLuc8.6 luciferase linked to the red light emitting fluorescent protein TurboFP635. The BRET6 biosensor exhibited 3-fold less light absorption in plasma samples compared to the BRET2 sensor leading to an up to a 5-fold increase in sensitivity for plasmin detection in plasma. The limits of detection for plasmin were determined to be 11.90 nM in 7.5% (v/v) plasma with a 10 min assay which enables biologically relevant plasmin activities of thrombolytic therapies to be detected. While a colorigenic plasmin activity assay achieved a similar detection limit of 10.91 nM in 7.5% (v/v) human plasma, it required a 2 h incubation period. The BRET6 sensor described here is faster and more specific than the colorigenic assay as it did not respond to unspiked human plasma samples.
  13. Cigarette price level and variation in five Southeast Asian countries
    Liber AC, Ross H, Ratanachena S, Dorotheo EU, Foong K
    Tob Control, 2015 Jun;24(e2):e137-41.
    PMID: 24500266 DOI: 10.1136/tobaccocontrol-2013-051184
    OBJECTIVES: To monitor and analyse impacts of the interaction between tobacco excise tax policy and industry price strategy, on the price level and variation of cigarettes sold in five Southeast Asian countries (Indonesia, Cambodia, Lao PDR, the Philippines and Vietnam).
    METHODS: Prices of cigarette sold by sticks and packs were collected through an in-person survey of retailers during 2011. Mean cigarette prices and price variation were calculated in each study country for single cigarettes, whole packs and brand groups.
    RESULTS: Price variation of whole packs was greater in countries with ad-valorem excise tax structures (Cambodia, Lao PDR and Vietnam) than in countries with multitiered specific excise taxes (Indonesia and the Philippines). The price variation for single sticks appeared to be driven by local currency denomination. Cigarettes sold individually cost more per stick than cigarettes sold in whole packs in every brand group except for Indonesia's domestic brands.
    CONCLUSIONS: Tobacco industry strategy and excise tax structure drove the price level and variation of cigarettes sold in packs, while currency denominations influence the selling price of single sticks. To maximise the effectiveness of tobacco tax policies, countries should adopt specific excise tax structures to decrease cigarette price variation, which would minimise opportunities for smokers to 'trade down' to a cheaper brand to avoid a tax-driven price increase.
    KEYWORDS: Low/Middle Income Country; Packaging and Labelling; Price; Surveillance and Monitoring; Taxation
  14. Fulltext A Severe Case of Arthrographis kalrae Keratomycosis
    Ramli SR, Francis AL, Yusof Y, Khaithir TM
    Case Rep Infect Dis, 2013;2013:851875.
    PMID: 24377053 DOI: 10.1155/2013/851875
    A 52-year-old man with diabetes developed a unilateral central corneal ulcer after accidental foreign body inoculation. He complained of pain and loss of visual acuity in the injured eye, which displayed redness and edema and eventually discharged pus. A corneal scraping from the left eye orbit revealed fungal elements, and cultures of the material grew a fungus. The isolate was identified as Arthrographis kalrae based on gross and microscopic morphologies. The patient received amphotericin B intravenously and itraconazole orally. The wound healed following surgical intervention, but the patient lost the use of his left eye.
  15. Fulltext In vitro antibacterial and antibiofilm activities of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia including the trimethoprim/sulfamethoxazole resistant strain
    Karunanidhi A, Thomas R, van Belkum A, Neela V
    Biomed Res Int, 2013;2013:392058.
    PMID: 23509719 DOI: 10.1155/2013/392058
    The in vitro antibacterial and antibiofilm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. The inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16  μg mL(-1) and 16 to 32  μg mL(-1). Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h. In vitro antibiofilm testing showed a 4-fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085 < 0.397 A 490 nm) of chlorogenic acid. The data from this study support the notion that the chlorogenic acid has promising in vitro antibacterial and antibiofilm activities against S. maltophilia.
  16. A novel pathogenic variant of the LDLR gene in the Asian population and its clinical correlation with familial hypercholesterolemia
    Chahil JK, Lye SH, Bagali PG, Alex L
    Mol Biol Rep, 2012 Jul;39(7):7831-8.
    PMID: 22544571 DOI: 10.1007/s11033-012-1626-8
    Familial hypercholesterolemia (FH) is a disease implicated with defects in either, Low density lipoprotein receptor gene (LDLR), Apolipoprotein B-100 gene (APOB), the Proprotein convertase subtilisin/kexin type 9 gene (PCSK9) or other related genes of the lipid metabolism pathway. The general characterization of heterozygous FH is by elevated low-density lipoprotein (LDL) cholesterol and early-onset cardiovascular diseases, while the more severe type, the homozygous FH results in extreme elevated levels of LDL cholesterol and usually death of an affected individual by early twenties. We present here a novel non-synonymous, missense mutation in exon 14 of the LDLR gene in two siblings of the Malay ethnicity discovered during an in-house genetic test. We postulate that their elevated cholesterol is due to this novel mutation and they are positive for homozygous FH. This is the first report of a C711Y mutation in patients with elevated cholesterol in Asia.
  17. A finite element analysis of ceramic restorations in endodontically treated premolars
    Seow LL, Toh CG, Fok AS, Wilson NH
    Am J Dent, 2008 Oct;21(5):331-6.
    PMID: 19024261
    PURPOSE: To investigate the level and distribution of stresses in endodontically treated maxillary premolar teeth restored using various cavity designs of bonded all-ceramic restorations. The hypothesis tested was that the various all-ceramic approaches, including incorporating a pulp chamber extension in the restoration, had no influence on the stresses in the restored tooth unit.
    METHODS: Finite element packages Patran and Abaqus were used for the stress analysis. The cavity designs investigated include: (1) inlay (I); (2) inlay with palatal cusp coverage (IPC); (3) onlay (O); (4) inlay with pulp chamber extension (IPE); (5) inlay with palatal cusp coverage and pulp chamber extension (IPCPE); and (6) onlay with pulp chamber extension (OPE).
    RESULTS: In each case, tensile stresses were found to be concentrated subjacent to the occlusal fossa. Peak tensile stress and peak shear stress values along the tooth/restoration interface for IPC, O IPCPE and OPE cavity designs were found to be associated with the axiogingival line angle. Overall, the order of the various forms of restoration investigated in terms of the maximum principal stress (from greatest to lowest) was as follows: IPE > IPCPE > OPE > I > IPC > O.
  18. Fulltext Role of electron microscopy in Nipah virus outbreak investigation and control
    Chua KB, Wong EM, Cropp BC, Hyatt AD
    Med J Malaysia, 2007 Jun;62(2):139-42.
    PMID: 18705447 MyJurnal
    In 1998, a novel paramyxovirus (order Mononegavirales, family Paramyxoviridae, subfamily Paramyxovirinae, genus Henipavirus) emerged in peninsular Malaysia causing fatal encephalitis in humans and severe respiratory illness with encephalitis in pigs. The virus was successfully isolated in cultured mammalian cells. Transmission electron microscopy of infected tissue culture cells played a crucial role in the early preliminary identification of the causative agent of the outbreak. This in turn was pivotal to determine the correct direction of control measures that subsequently brought the epidemic under control. In light of this investigation, and indeed identification of infectious agents associated with other disease episodes, electron microscopy will remain an important frontline method for rapid diagnostic virology and investigation of any future outbreak of new and unusual cases of illness suspected of an infectious aetiology.
  19. An improved selective and differential medium for the isolation of Burkholderia pseudomallei from clinical specimens
    Francis A, Aiyar S, Yean CY, Naing L, Ravichandran M
    Diagn Microbiol Infect Dis, 2006 Jun;55(2):95-9.
    PMID: 16626918
    Isolation and culture of Burkholderia pseudomallei remains the main stay in the diagnosis of melioidosis. Thus, the search for selective and differential media for B. pseudomallei has been ongoing. A number of such media have been reported with varying efficacy. Ashdown medium is the most established selective medium for the isolation of B. pseudomallei. There are no reports of differential media differentiating B. pseudomallei from Burkholderia cepacia. This report documents such a selective and differentiating medium for B. pseudomallei. Of a total of 1042 clinical specimens containing mixed flora and gram-negative isolates that were tested on this medium, 16 of the specimens yielded B. pseudomallei. The isolation rate was found to be 1.5%. This medium was found to be simple and inexpensive, can be made by small laboratories, and called as Francis medium. Based on the colony morphology and color, a preliminary report can be made within 18-24 h for the presence of B. pseudomallei. Our study showed that this medium had an overall sensitivity of 78.4% with a specificity of 92.2%. The use of this medium as an early diagnostic tool will help to reduce mortality and morbidity of melioidosis patients.
  20. Fulltext A Terrestrial Single Chamber Microbial Fuel Cell-based Biosensor for Biochemical Oxygen Demand of Synthetic Rice Washed Wastewater
    Logroño W, Guambo A, Pérez M, Kadier A, Recalde C
    Sensors (Basel), 2015;16(1).
    PMID: 26784197 DOI: 10.3390/s16010101
    Microbial fuel cells represent an innovative technology which allow simultaneous waste treatment, electricity production, and environmental monitoring. This study provides a preliminary investigation of the use of terrestrial Single chamber Microbial Fuel Cells (SMFCs) as biosensors. Three cells were created using Andean soil, each one for monitoring a BOD concentration of synthetic washed rice wastewater (SRWW) of 10, 100, and 200 mg/L for SMFC1, SMFC2 and SMFC3, respectively. The results showed transient, exponential, and steady stages in the SMFCs. The maximum open circuit voltage (OCV) peaks were reached during the elapsed time of the transient stages, according to the tested BOD concentrations. A good linearity between OCV and time was observed in the increasing stage. The average OCV in this stage increased independently of the tested concentrations. SMFC1 required less time than SMFC2 to reach the steady stage, suggesting the BOD concentration is an influencing factor in SMFCs, and SMFC3 did not reach it. The OCV ratios were between 40.6-58.8 mV and 18.2-32.9 mV for SMFC1 and SMFC2. The reproducibility of the SMFCs was observed in four and three cycles for SMFC1 and SMFC2, respectively. The presented SMFCs had a good response and reproducibility as biosensor devices, and could be an alternative for environmental monitoring.
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