227 results on '"Sathasivam S"'
Search Results
202. PbO-modified TiO2 thin films: a route to visible light photocatalysts.
- Author
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Bhachu DS, Sathasivam S, Carmalt CJ, and Parkin IP
- Subjects
- Catalysis, Particle Size, Photochemical Processes, Surface Properties, Lead chemistry, Light, Oxides chemistry, Titanium chemistry
- Abstract
PbO clusters were deposited onto polycrystalline titanium dioxide (anatase) films on glass substrates by aerosol-assisted chemical vapor deposition (AACVD). The as-deposited PbO/TiO2 films were then tested for visible light photocatalysis. This was monitored by the photodegradation of stearic acid under visible light conditions. PbO/TiO2 composite films were able to degrade stearic acid at a rate of 2.28 × 10(15) molecules cm(-2) h(-1), which is 2 orders of magnitude greater than what has previously been reported. The PbO/TiO2 composite film demonstrated UVA degradation of resazurin redox dye, with the formal quantum yield (FQY) and formal quantum efficiency (FQE) exceeding that of a TiO2 film grown under the same conditions and Pilkington Activ, a commercially available self-cleaning glass. This work correlates with computational studies that predicted PbO nanoclusters on TiO2 form active visible light photocatalysts through new electronic states through PbO/TiO2 interfacial bonds resulting in new electronic states above the valence band maximum in TiO2, shifting the valence band upward as well as more efficient electron/hole separation with hole localization on PbO particles and electron on the TiO2 surface.
- Published
- 2014
- Full Text
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203. Aerosol-Assisted Chemical Vapour Deposition of a Copper Gallium Oxide Spinel.
- Author
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Knapp CE, Prassides ID, Sathasivam S, Parkin IP, and Carmalt CJ
- Abstract
Copper-based spinel oxide CuGa
2 O4 films have been deposited by means of a simple one-pot solution-based chemical vapour deposition (CVD) method. Aerosol-assisted (AA) CVD of copper(II) 2,2,6,6,-tetramethylheptan-3,5-dionate (thd), Cu(thd)2 and gallium(III) acetylacetonate, Ga(acac)3 , in toluene resulted in the formation of transparent films with a slight yellow tinge at 300-500 °C. Scanning electron microscopy (SEM) indicated that the films had grown by means of an island growth mechanism. Energy-dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS) showed that CuGa2 O4 had formed along with copper(I) oxide and gallium(III) oxide was observed at the surface of the film. Annealing the films under a range of conditions (air, N2 , vacuum) resulted in oxidation and the formation of CuGa2 O4 and copper(II) oxide, as shown by powder X-ray diffraction (XRD). The films were further analysed by UV/Vis spectroscopy and atomic force microscopy. Similar AACVD depositions using copper(II) acetylacetonate, Cu(acac)2 , and Ga(acac)3 in a range of solvents only resulted in the formation of gallium oxide owing to the lower solubility of the copper precursor than the gallium complex. AACVD is dependent on the precursor solubility hence Cu(thd)2 is a superior precursor to Cu(acac)2 owing to its increased solubility., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2014
- Full Text
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204. Immunodeficiency, centromeric region instability and facial anomalies (ICF) syndrome diagnosed in an adult who is now a long-term survivor.
- Author
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Sathasivam S, Selvakumaran A, Jones QC, and Wathen CG
- Subjects
- Adult, Humans, Male, Primary Immunodeficiency Diseases, Face abnormalities, Immunologic Deficiency Syndromes diagnosis, Survivors
- Abstract
We describe a 42-year-old British man of Indo-Caribbean origin with immunodeficiency, centromeric region instability and facial anomalies (ICF) syndrome. Most patients with ICF syndrome die of infection at a young age, usually in the first or second decade of life. The patient was born 3.5 weeks premature to non-consanguineous parents. He had a mild bird-like face abnormality, but had no other congenital malformations, cognitive impairment or developmental delays. He had recurrent ear and chest infections during childhood and developed bronchiectasis. Investigations revealed IgG, IgA and IgM deficiencies with a normal lymphocyte count and normal T cell proliferation to in vitro mitogenic stimulation. Following several unsuccessful attempts to make a diagnosis during childhood, a recent chromosomal analysis showed centromeric region instability of chromosomes 1 and 16, diagnosing ICF syndrome. The patient receives immunoglobulin replacement for hypogammaglobulinameia and has chest physiotherapy and antibiotics for bronchiectasis. Recently, he developed liver cirrhosis of unknown cause.
- Published
- 2013
- Full Text
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205. Design optimization of pin fin geometry using particle swarm optimization algorithm.
- Author
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Hamadneh N, Khan WA, Sathasivam S, and Ong HC
- Subjects
- Reproducibility of Results, Algorithms, Computer Simulation, Models, Theoretical
- Abstract
Particle swarm optimization (PSO) is employed to investigate the overall performance of a pin fin.The following study will examine the effect of governing parameters on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The idea of entropy generation minimization, EGM is employed to combine the effects of thermal resistance and pressure drop within the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters.
- Published
- 2013
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206. Aluminium and radiation cross-linked carboxymethyl sago pulp beads for colon targeted delivery.
- Author
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Thenapakiam S, Kumar DG, Pushpamalar J, and Saravanan M
- Subjects
- Aluminum Chloride, Anti-Inflammatory Agents, Non-Steroidal chemistry, Cross-Linking Reagents chemistry, Drug Carriers chemistry, Hydrogels chemistry, Kinetics, Mesalamine chemistry, Microspheres, Particle Size, Spectroscopy, Fourier Transform Infrared, Surface Properties, X-Ray Diffraction, Aluminum Compounds chemistry, Arecaceae chemistry, Cellulose chemistry, Chlorides chemistry
- Abstract
The carboxymethyl sago pulp (CMSP) with a degree of substitution of 0.4% was synthesized from sago waste. The CMSP beads with an average diameter of 3.1-4.8 mm were formed by aluminium chloride gelation as well as further cross-linked by irradiation. To evaluate colon targeted release, a model drug, 5-aminosalicylic acid (5-ASA) was encapsulated in CMSP beads. Fourier-transform infrared spectroscopy and X-ray diffraction studies indicated intact and amorphous nature of entrapped drug. A pH dependent drug release was observed, and about 90% of the drug was released only at pH 7.4 over 9 h. Irradiated beads were resisted the drug release in an acidic environment at a higher extent than non-irradiated beads. The drug release from 6% (w/w) of 5-ASA loaded bead followed zero order, whereas, 15 and 22% loaded beads followed first order. The release exponent n value suggests non-fickian transport of 5-ASA from the beads., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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207. Patent foramen ovale and migraine: what is the relationship between the two?
- Author
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Sathasivam S and Sathasivam S
- Subjects
- Clinical Trials as Topic, Foramen Ovale, Patent physiopathology, Foramen Ovale, Patent surgery, Humans, Migraine Disorders therapy, Foramen Ovale, Patent complications, Migraine Disorders etiology
- Abstract
There is conflicting evidence on the causal relationship of patent foramen ovale (PFO) in migraine. This review will examine the pathophysiological relevance of PFO in migraine, the epidemiological evidence of PFO causing migraine, and the existing evidence on the effectiveness of closure of PFO on the symptomatology of migraine. From the current available evidence, the role of PFO in migraine is debatable, and interventions such as closure of PFO cannot yet be considered routine treatment of migraine., (Copyright © 2013 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2013
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208. Darunavir is a good third-line antiretroviral agent for HIV type 1-infected patients failing second-line protease inhibitor-based regimens in South India.
- Author
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Saravanan S, Madhavan V, Balakrishnan P, Smith DM, Solomon SS, Sivamalar S, Poongulali S, Kumarasamy N, Schooley RT, Solomon S, and Kantor R
- Subjects
- Cross-Sectional Studies, Darunavir, HIV Protease genetics, HIV Protease Inhibitors therapeutic use, HIV-1 isolation & purification, Humans, India, Mutation, Missense, Anti-HIV Agents therapeutic use, Drug Resistance, Viral, HIV Infections drug therapy, HIV Infections virology, HIV-1 drug effects, Sulfonamides therapeutic use
- Abstract
Eleven protease mutations have been associated with reduced susceptibility to darunavir. In this study of 87 HIV-1-infected patients experiencing virological failure to second-line regimens containing protease inhibitors boosted with ritonavir (viral load >1,000 HIV RNA copies/ml), we observed a low prevalence (3%) of ≥3 darunavir resistance-associated mutations, indicating that this drug may be a good option for third-line antiretroviral therapy in southern India.
- Published
- 2013
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209. Unusual insertion and deletion at codon 67 and 69 of HIV type 1 subtype C reverse transcriptase among first-line highly active antiretroviral treatment-failing South Indian patients: association with other resistance mutations.
- Author
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Saravanan S, Madhavan V, Kantor R, Sivamalar S, Gomathi S, Solomon SS, Kumarasamy N, Smith DM, Schooley RT, Solomon S, and Balakrishnan P
- Subjects
- Adolescent, Adult, Drug Resistance, Viral, Female, HIV Infections drug therapy, HIV-1 isolation & purification, Humans, India, Male, Middle Aged, Mutant Proteins genetics, Treatment Failure, Anti-HIV Agents administration & dosage, Antiretroviral Therapy, Highly Active methods, HIV Infections virology, HIV Reverse Transcriptase genetics, HIV-1 genetics, Mutagenesis, Insertional, Sequence Deletion
- Abstract
We report a high frequency of drug resistance mutations among patients with unusual insertions or deletions at the β(3)-β(4) hairpin-loop-coding region of HIV-1 subtype C reverse transcriptase, during failure of first-line antiretroviral therapy containing only reverse transcriptase inhibitors in Chennai, India.
- Published
- 2012
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210. Statin induced myotoxicity.
- Author
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Sathasivam S
- Subjects
- Cytochrome P-450 Enzyme System physiology, Genetic Predisposition to Disease, Humans, Hypolipidemic Agents therapeutic use, Muscular Diseases epidemiology, Muscular Diseases genetics, Muscular Diseases physiopathology, Myositis chemically induced, Myositis physiopathology, Rhabdomyolysis chemically induced, Risk Factors, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Hyperlipidemias drug therapy, Muscular Diseases chemically induced
- Abstract
Statins are an effective treatment for the prevention of cardiovascular diseases and used extensively worldwide. However, myotoxicity induced by statins is a common adverse event and a major barrier to maximising cardiovascular risk reduction. The clinical spectrum of statin induced myotoxicity includes asymptomatic rise in creatine kinase concentration, myalgia, myositis and rhabdomyolysis. In certain cases, the cessation of statin therapy does not result in the resolution of muscular symptoms or the normalization of creatine kinase, raising the possibility of necrotizing autoimmune myopathy. There is increasing understanding and recognition of the pathophysiology and risk factors of statin induced myotoxicity. Careful history and physical examination in conjunction with selected investigations such as creatine kinase measurement, electromyography and muscle biopsy in appropriate clinical scenario help diagnose the condition. The management of statin induced myotoxicity involves statin cessation, the use of alternative lipid lowering agents or treatment regimes, and in the case of necrotizing autoimmune myopathy, immunosuppression., (Copyright © 2012 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)
- Published
- 2012
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211. Viremia and HIV-1 drug resistance mutations among patients receiving second-line highly active antiretroviral therapy in Chennai, Southern India.
- Author
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Saravanan S, Vidya M, Balakrishnan P, Kantor R, Solomon SS, Katzenstein D, Kumarasamy N, Yeptomi T, Sivamalar S, Rifkin S, Mayer KH, and Solomon S
- Subjects
- Anti-HIV Agents pharmacology, Cross-Sectional Studies, Darunavir, Female, HIV Infections virology, HIV-1 drug effects, HIV-1 genetics, Humans, India, Male, Sulfonamides administration & dosage, Sulfonamides pharmacology, Viral Proteins genetics, Anti-HIV Agents administration & dosage, Antiretroviral Therapy, Highly Active methods, Drug Resistance, Viral, HIV Infections drug therapy, HIV-1 isolation & purification, Mutation, Missense, Viral Load
- Abstract
Background: A cross-sectional study among individuals receiving second-line antiretroviral treatment was conducted to report on the level of detectable viremia and the types of drug resistance mutations among those with detectable human immunodeficiency virus (HIV) type 1 plasma viral loads (PVLs)., Methods: PVLs were measured using Abbott m2000rt real-time polymerase chain reaction, and genotyping was performed with the ViroSeq genotyping system, version 2.0, and ViroSeq analysis software, version 2.8., Results: Of 107 patient plasma specimens consecutively analyzed, 30 (28%) had undetectable PVLs (<150 copies/mL), and 77 (72%) were viremic with a median PVL of 5450 copies/mL (interquartile range, 169-1 997 967). Sequencing was done for 107 samples with PVLs >2000 copies/mL: 33 patients (73%) had 1 of the protease (PR) inhibitor mutations; 41 (91%) had nucleoside reverse-transcriptase inhibitor (NRTI) mutations; 33 (73%) had non-NRTI (NNRTI) mutations; and 30 (66.7%) had both NRTI and NNRTI mutations. Triple-class resistance to NRTIs, NNRTIs, and PR inhibitors was observed in 24 (53%) patients. Based on the mutational profiles observed, all 45 sequences were susceptible to darunavir and tipranavir, whereas 47% showed resistance to lopinavir, 58% showed resistance to atazanavir, and >60% showed resistance to saquinavir, indinavir, nelfinavir, and fosamprenavir., Conclusions: The results of the study showed that the majority of patients receiving second-line antiretroviral therapy started to accumulate PR resistance mutations, and the mutation profiles suggest that darunavir might be the drug of choice for third-line regimens in India.
- Published
- 2012
- Full Text
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212. Reverse transcriptase substitution at codons 208 and 228 among treatment-experienced HIV-1 subtype-C-infected Indian patients is strongly associated with thymidine analogue mutations.
- Author
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Saravanan S, Madhavan V, Solomon SS, Kantor R, Katzenstein D, Sivamalar S, Kumarasamy N, Smith DM, Mayer KH, Solomon S, and Balakrishnan P
- Subjects
- DNA Mutational Analysis, DNA, Viral genetics, Drug Resistance, Viral genetics, HIV Infections drug therapy, HIV-1 drug effects, HIV-1 enzymology, Humans, India, Logistic Models, Reverse Transcriptase Inhibitors therapeutic use, Thymidine, Treatment Failure, Amino Acid Substitution, Codon genetics, HIV Infections genetics, HIV Reverse Transcriptase genetics, HIV-1 genetics
- Published
- 2012
- Full Text
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213. Optimizing secondary prevention: Statin prescribing across East and West London in accordance with NICE guidelines.
- Author
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Shakur R, Sathasivam S, Yu C, Cheung I, Selvakumaran A, Anandarajah C, Shakur A, Kaler M, and McElligott G
- Abstract
Objectives: Statins are a well-known primary and secondary prevention drug for cardiovascular disease and NICE guidelines have been issued to identify key indicators for their use. An audit looking into statin prescribing for medical inpatients was carried out in two geographically distinct London hospitals., Design: A prospective inpatient audit of medical prescription charts was performed. Blood results were reviewed for the inpatients during their admission to identify any contraindications for statin usage (rhabdomyolysis). The medical notes were also reviewed for patient refusal of statin therapy., Setting: The study was carried out at two distinct hospitals in London. Whipps Cross University Hospital (WCUH) and Chelsea & Westminster Hospital (CWH) are located in East London and West London, respectively. Acute medical, surgical, obstetrics and gynaecology, paediatric and palliative wards were excluded., Participants: A total of 309 inpatient medical notes and prescription chart data were collected from WCUH (n = 211) and CWH (n = 98)., Main Outcome Measures: High percentage of hospitalized patients are not prescribed statins despite clear clinical indications for their use. Regardless of geographical and socioeconomic factors between hospitals, statin prescribing remains suboptimal., Results: The patient demographics in both hospitals were very similar; the mean age at WCUH was 78 ± 15 1SD while at CWH the mean age was 74 ± 15 1SD. The results showed that approximately one-third of patients (30% at WCUH and 33% at CWH) had at least one indication for statin therapy according to NICE guidelines and yet they were not prescribed a statin. Ten percent of patients at WCUH and 13% of patients at CWH had ischaemic heart disease (IHD) and yet were not prescribed statins., Conclusion: Statin prescription is often overlooked in secondary care with patients being discharged without the appropriate assessment (NICE guidelines), which subsequently means repeat prescriptions are not provided by the GP. This study is the first to show that this problem is not due to resources or geography, but is inherent within the NHS system. Consequently, a revised prescription chart checking system has been suggested for pharmacists and junior doctors.
- Published
- 2011
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214. Treatment for sialorrhea (excessive saliva) in people with motor neuron disease/amyotrophic lateral sclerosis.
- Author
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Young CA, Ellis C, Johnson J, Sathasivam S, and Pih N
- Subjects
- Botulinum Toxins, Type A, Humans, Motor Neuron Disease complications, Parotid Gland, Randomized Controlled Trials as Topic, Salivation drug effects, Sialorrhea etiology, Submandibular Gland, Amyotrophic Lateral Sclerosis complications, Botulinum Toxins administration & dosage, Neuromuscular Agents administration & dosage, Sialorrhea drug therapy
- Abstract
Background: Motor neuron disease (MND), also known as amyotrophic lateral sclerosis, is a progressive, neurodegenerative condition which may cause dysphagia, as well as limb weakness, dysarthria, emotional lability and respiratory failure. Since normal salivary production is 0.5 to 1.5 litres daily, loss of salivary clearance due to dysphagia leads to salivary pooling and sialorrhea, often resulting in distress and inconvenience to patients., Objectives: To systematically review evidence on treatment of sialorrhea in MND, including medications, radiotherapy and surgery., Search Strategy: We searched the Cochrane Neuromuscular Disease Group Specialized Register (1 October 2010), the Cochrane Central Register of Controlled Trials )(CENTRAL) (The Cochrane Library issue 3, 2010), MEDLINE (January 1966 to September 2010), EMBASE (January 1980 to September 2010), AMED (1985 to September 2010) and CINAHL Plus (January 1937 September 2010). All bibliographies of the identified randomized trials were reviewed and authors contacted as needed. Known experts in the field were contacted to identify further published and unpublished papers., Selection Criteria: We included randomized and quasi-randomised controlled studies on any intervention for sialorrhea and related symptoms, in people with MND., Data Collection and Analysis: Review authors summarised data independently in a customised data collection form and confirmed data presented in Cochrane Review Manager software., Main Results: Only one randomized controlled trial was identified. This was a well designed study of botulinum toxin B injected into parotid and submandibular glands of 20 patients, which showed positive results for four weeks (Jackson 2009). There was low risk of bias in the study and no significant adverse events reported., Authors' Conclusions: There is some evidence for use of botulinum toxin injections to salivary glands for the treatment of sialorrhea in MND. Further research is required on this important symptom. Data are needed on the problem of sialorrhea in MND and its measurement, both by patient self report measures and objective tests. These will allow the development of better randomized controlled trials.
- Published
- 2011
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215. Motor neurone disease: clinical features, diagnosis, diagnostic pitfalls and prognostic markers.
- Author
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Sathasivam S
- Subjects
- Biomarkers, Diagnosis, Differential, Diagnostic Errors, Electromyography, Health Status Indicators, Humans, Magnetic Resonance Imaging, Motor Neuron Disease epidemiology, Motor Neuron Disease physiopathology, Neural Conduction, Prognosis, Risk Factors, Motor Neuron Disease diagnosis
- Abstract
Motor neurone disease (MND) is a rapidly progressive adult-onset neurodegenerative disorder. In recent years, there has been an increased understanding regarding the epidemiology and clinical features of the different variants of MND. In addition, new diagnostic criteria have been proposed to increase the sensitivity of the diagnosis. This review highlights these new concepts and discusses the differential diagnoses of MND, highlighting the common pitfalls and misdiagnoses. It also discusses the prognostic markers for MND and a possible change in the natural history of the disease course.
- Published
- 2010
216. Managing patients with amyotrophic lateral sclerosis.
- Author
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Sathasivam S
- Subjects
- Humans, Amyotrophic Lateral Sclerosis mortality, Amyotrophic Lateral Sclerosis therapy, Patient Care Team, Quality of Life
- Abstract
Amyotrophic lateral sclerosis (ALS) is the most common rapidly progressive adult-onset neurodegenerative disorder. There have been great advances in the management of patients with ALS over the past decade. It starts with the giving of the diagnosis and continues to the terminal phase of the disease. This review will examine the impact of medical and non-medical interventions on improving survival and quality of life in these patients, emphasizing the importance of a multidisciplinary approach.
- Published
- 2009
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217. VEGF and ALS.
- Author
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Sathasivam S
- Subjects
- Animals, Humans, Amyotrophic Lateral Sclerosis metabolism, Vascular Endothelial Growth Factor A metabolism
- Abstract
In amyotrophic lateral sclerosis (ALS), an adult-onset progressive degeneration of motor neurons occurring as sporadic and familial disease, there is emerging evidence for and against the role of vascular endothelial growth factor (VEGF), an endothelial cell mitogen crucial for angiogenesis, in its etiopathogenesis. Our understanding of the role of VEGF in ALS has come from studies of both experimental models and human cases. In this article, I have examined in detail the in vitro and in vivo evidence for and against VEGF in ALS, concluding that more compelling evidence is required before we can conclusively link VEGF to ALS in humans.
- Published
- 2008
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218. An acute evolving flaccid quadriparesis in an elderly woman.
- Author
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Lim R, Sathasivam S, and Larner AJ
- Subjects
- Aged, Diagnosis, Differential, Female, Humans, Quadriplegia therapy, Quadriplegia diagnosis
- Published
- 2008
- Full Text
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219. Steroids and immunosuppressant drugs in myasthenia gravis.
- Author
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Sathasivam S
- Subjects
- Drug Therapy, Combination, Glucocorticoids therapeutic use, Humans, Immunosuppressive Agents therapeutic use, Glucocorticoids pharmacology, Immunosuppressive Agents pharmacology, Myasthenia Gravis drug therapy
- Abstract
In chronic autoimmune conditions such as myasthenia gravis (MG), immunosuppression--usually long-term--is often necessary. The mechanisms of action of immunosuppressant drugs in MG fall into three main categories: inhibition of the cell cycle (azathioprine, cyclophosphamide, methotrexate and mycophenolate mofetil), immunosuppression of T cells (steroids, ciclosporin and tacrolimus), and B-cell depletion (rituximab). Data on immunosuppressant drugs in MG derive mainly from clinical experience, observational studies and expert opinion. The main drawbacks of the randomized evidence are the small size of most drug trials, variations in study design, and a lack of head-to-head studies. It is therefore difficult to determine the relative efficacy of each immunosuppressant. Oral prednisolone, usually started at a low dose on an alternate-day regimen, and gradually increased, is the recommended first-choice short-term immunosuppressant. Long-term immunosuppression regimens vary between different countries and physicians. Azathioprine is often the first-choice drug for long-term immunosuppression, and it is usually started together with steroids to allow tapering of steroids to the lowest dose possible. Methotrexate, mycophenolate mofetil or tacrolimus should be considered in patients who are intolerant of or unresponsive to azathioprine. Ciclosporin and cyclophosphamide should only be considered as a last resort, as these drugs can cause serious adverse events. Data on rituximab use in MG are sparse, but the initial results are promising.
- Published
- 2008
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220. Immunosuppressive agents for myasthenia gravis.
- Author
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Hart IK, Sathasivam S, and Sharshar T
- Subjects
- Adrenal Cortex Hormones therapeutic use, Azathioprine therapeutic use, Cyclophosphamide therapeutic use, Cyclosporine therapeutic use, Drug Therapy, Combination, Humans, Mycophenolic Acid analogs & derivatives, Mycophenolic Acid therapeutic use, Prednisolone therapeutic use, Randomized Controlled Trials as Topic, Tacrolimus therapeutic use, Immunosuppressive Agents therapeutic use, Myasthenia Gravis drug therapy
- Abstract
Background: The benefits of different immunosuppressants for myasthenia gravis (MG) are unclear., Objectives: Assessment of immunosuppressant drug efficacy in MG., Search Strategy: We searched the Cochrane Neuromuscular Disease Group Trials Register, MEDLINE (from January 1966 to July 2007), EMBASE (from January 1980 to July 2007), review and trial bibliographies and contacted trial authors., Selection Criteria: Types of studies: Randomised and quasi-randomised controlled trials., Types of Participants: Any age, any type or severity of MG regardless of concomitant treatment. Types of interventions: Any immunosuppressive agent. Types of outcome measures: Primary: (1) Improvement or not at six months. Secondary: (1) Improvement or not at one year (2) Need for other treatment, for example corticosteroid dose, at six months (3) Number of exacerbations during the first year (4) Acetylcholine receptor antibody titre after at least six months (5) Occurrence of one or more adverse events at any time after the introduction of treatment., Data Collection and Analysis: One author extracted and two checked the data., Main Results: Seven trials are included but few reported the outcomes selected for this review. A meta-analysis of ciclosporin versus placebo from two trials (59 participants) - one as monotherapy (20 participants) and the other with corticosteroids (39 participants) - showed that it resulted in improvement of participants in the ciclosporin group compared with those in the placebo group, with a relative rate of improvement of 2.44 (95% confidence interval (CI) 1.13 to 5.27). In addition the weighted mean difference in QMG score between the ciclosporin and placebo groups was -0.34 (95% CI -0.52 to -0.17). Azathioprine (plus prednisolone for first month) had no significant benefit over prednisolone alone (41 participants). The effects of azathioprine plus prednisolone versus prednisolone plus placebo were similar (34 participants). Cyclophosphamide was reported to be statistically more efficacious than placebo at 12 months in corticosteroid-dependent participants (23 participants), but no raw data were available. Trials of mycophenolate mofetil and tacrolimus did not provide relevant endpoint data for this review. All trials had low numbers of participants. Adverse event reporting was variable. Trial protocol heterogeneity prevented comparison of the different immunosuppressants., Authors' Conclusions: In generalised MG, limited evidence from small RCTs suggests that ciclosporin, as monotherapy or with corticosteroids, or cyclophosphamide with corticosteroids, significantly improve MG.Limited evidence from RCTs shows no significant benefit from azathioprine (as monotherapy or with steroids), mycophenolate mofetil (as monotherapy or with either corticosteroids or ciclosporin) or tacrolimus (with corticosteroids or plasma exchange). Bigger, better-designed, longer trials are needed.
- Published
- 2007
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221. Susac syndrome in a patient with hepatitis C.
- Author
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Chawla A, Sathasivam S, Nayar R, and Doran M
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- Adult, Basal Ganglia pathology, Central Nervous System Diseases diagnosis, Corpus Callosum pathology, Diagnosis, Differential, Female, Follow-Up Studies, Hearing Loss, Sensorineural diagnosis, Humans, Magnetic Resonance Imaging, Retinal Artery Occlusion diagnosis, Syndrome, Central Nervous System Diseases complications, Hearing Loss, Sensorineural etiology, Hepatitis C, Chronic complications, Retinal Artery Occlusion etiology
- Abstract
A 38-year-old woman seropositive for hepatitis C developed headache, sensorineural hearing loss, encephalopathy, and retinal arteriolar occlusions. Brain MRI showed signal abnormalities in the basal ganglia and corpus callosum. These features are consistent with Susac syndrome, a multifocal central nervous system disorder of uncertain etiology. This is the first reported case of Susac syndrome in a patient with hepatitis C.
- Published
- 2007
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222. Apoptosis in amyotrophic lateral sclerosis--what is the evidence?
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Sathasivam S and Shaw PJ
- Subjects
- Animals, Humans, Mice, Mice, Transgenic, Motor Neurons pathology, Proto-Oncogene Proteins c-bcl-2 metabolism, Receptors, Tumor Necrosis Factor metabolism, Tumor Suppressor Protein p53 metabolism, Amyotrophic Lateral Sclerosis pathology, Apoptosis physiology
- Abstract
There is increasing evidence that a programmed mechanism of cell death resembling apoptosis is responsible for motor-neuron degeneration in amyotrophic lateral sclerosis. Our understanding of the cell-death pathway has come from studies of both experimental models and human tissue. Here we examine in detail the in vitro and in vivo evidence for and against apoptosis in amyotrophic lateral sclerosis, looking at morphological changes, caspase activation, alterations in Bcl-2 oncoproteins, involvement of death receptors, expression of apoptosis-related molecules, and the role of the p53 pathway. Finally, we present evidence of potential therapeutic agents that could modulate the apoptotic pathway in amyotrophic lateral sclerosis and slow disease progression.
- Published
- 2005
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223. Acute pancreatitis following liver resection: report of three fatal cases and a review of the literature.
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Sathasivam S, Ritchie A, Brooks AJ, and Morris DL
- Subjects
- Acute Disease, Aged, Fatal Outcome, Female, Humans, Male, Hepatectomy adverse effects, Pancreatitis etiology
- Abstract
Pancreatitis is a well recognised but rare complication following liver resection. The precise aetiology is not well understood and the clinical diagnosis may frequently be obscured by the postoperative state. Postoperative pancreatitis has a high mortality rate and should always be considered in patients who unexpectantly deteriorate postoperatively. We present three fatal cases of pancreatitis following liver resection. The literature is reviewed to elucidate common factors in patients who develop postoperative pancreatitis.
- Published
- 2004
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224. The effect of contact area on wear in relation to fixed bearing and mobile bearing knee replacements.
- Author
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Sathasivam S, Walker PS, Campbell PA, and Rayner K
- Subjects
- Biocompatible Materials, Humans, In Vitro Techniques, Materials Testing, Microscopy, Electron, Scanning, Particle Size, Polyethylene, Prosthesis Design, Prosthesis Failure, Knee Prosthesis
- Abstract
It is generally assumed that the wear rates in knee replacements are reduced as the contact area is increased. Hence, fixed bearing or mobile bearing designs with large contact areas throughout the full range of flexion wear less than partially conforming fixed-bearing designs. This hypothesis was investigated in an experimental model, where flat-ended ultra high molecular weight polyethylene pins of varying diameters were reciprocated and rotated on polished metal plates under a constant load with serum lubrication. The pin diameters ranged from 8-23 mm, giving nominal contact pressures from 23.9-2.8 MPa, covering the range associated with a wide spectrum of total knees including mobile-bearings. For pin diameters of 8-12 mm, the mean wear rates were in the range of 5.0-16.0 E-10 g/cycle. For diameters of 17 and 23 mm, the mean wear rates were approximately 1.0 E-10 g/cycle. The latter wear rates were significantly less than the former. Scanning electron microscopy indicated milder wear processes with the larger diameters, while the smaller diameters exhibited transverse ripples and cracks and detachment of thin layers from the surface. The percentages of granules (mostly submicron), fibrils and flakes, and the sizes of these particle types were similar among all pin diameters, except that, for the 23 mm pin diameter, the percentage of fibrils increased and of flakes decreased. This work supports the hypothesis that larger contact areas, up to the maximum area tested in our study, produce lower wear rates, and suggests that there is no disadvantage regarding particle type or size associated with the larger areas of contact., (Copyright 2001 John Wiley & Sons, Inc.)
- Published
- 2001
- Full Text
- View/download PDF
225. Brown-Vialetto-Van Laere syndrome: case report and literature review.
- Author
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Sathasivam S, O'Sullivan S, Nicolson A, Tilley PJ, and Shaw PJ
- Subjects
- Adult, Humans, Male, Bulbar Palsy, Progressive diagnosis, Hearing Loss, Sensorineural diagnosis
- Abstract
We describe a case of the Brown-Vialetto-Van Laere syndrome, which is a rare disorder characterized by progressive pontobulbar palsy associated with sensorineural deafness. More than 30 cases have been reported since the first case was described in 1894. We review the literature of this condition, comparing our case with those reported in the literature and emphasizing important features to improve our understanding of this syndrome.
- Published
- 2000
- Full Text
- View/download PDF
226. Methodology for long-term wear testing of total knee replacements.
- Author
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Walker PS, Blunn GW, Perry JP, Bell CJ, Sathasivam S, Andriacchi TP, Paul JP, Haider H, and Campbell PA
- Subjects
- Biomechanical Phenomena, Humans, Knee Prosthesis, Materials Testing methods
- Abstract
This article begins to address the validation requirements of wear testing on total knee replacements in a knee simulator. The knee simulator has four stations. The axial force is variable but reaches a maximum of 2.3 kN. Physiologic anteroposterior shear force and rotational torques are supplied to the knee. The forces and displacements are timed to coincide with those of a typical gait cycle. Kinematics of the simulator are dependent on the type of knee being tested. Tests of designs with well known clinical histories were done to 10 million cycles. The relative amounts and types of wear shown by the designs were similar to that found in their clinical histories. Wear tracks on more conforming designs were larger, and the penetration into the plastic appeared to be less. This did not necessarily mean that wear, as measured by loss of material, was reduced on conforming designs. Delamination of the plastic was achieved only after aging the tibial components. Wear particles isolated from the lubricating fluid were similar in size and shape to those isolated from in vivo specimens. However, the relative amounts of wear particle shapes were different depending on the design. At the start of the tests, all of the flexibly mounted tibial components showed more motion than after 5 million cycles, indicating that the surface of the plastic became more conforming. This study showed that knee wear similar to wear observed in vivo can be reproduced in the laboratory. The parameters and methods elucidated in this introductory study should form the basis for use in preclinical wear tests of total knee replacements.
- Published
- 2000
- Full Text
- View/download PDF
227. A simplified radiographic method for measuring bone-component motion in total knees.
- Author
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Walker PS and Sathasivam S
- Subjects
- Biomechanical Phenomena, Femur diagnostic imaging, Humans, Motion, Radiographic Image Interpretation, Computer-Assisted, Rotation, Software, Tibia diagnostic imaging, Knee Joint diagnostic imaging, Knee Prosthesis
- Abstract
Measurement of the relative motion between an implant and the surrounding bone over different time periods is valuable for assessing and comparing the component stability and predicting the potential future outcome. The RSA method, where small beads are implanted in the bone adjacent to the component, can measure implant-bone position to an accuracy of about 0.1 mm. However, the method involves special radiographic views and analytical software, not readily available. For purposes of component assessment on a more routine basis and for multi-centre trials, a method was developed where standard A-P and M-L radiographs were used. Computer software was written which estimated the out-of-plane rotations of the component relative to the plane of the film, and then carried out corrections to enhance the accuracy of calculation of the bead heights relative to the component. The theoretical errors were shown to be less than 0.04 mm for the expected range of out-of-plane rotations. When radiographs of components in simulated bones were taken at a range of rotations, the 95% confidence limits for axial displacement were found to be less than +0.3 mm, and for rotation in the plane to be 0.6 degrees. This indicated that the method was useful for studying knee components where the sinkage could reach a range of 0.5-2 mm in a 2 year period.
- Published
- 1992
- Full Text
- View/download PDF
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