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Kalaivani P, Prabhakaran R, Ramachandran E, Dallemer F, Paramaguru G, Renganathan R, Poornima P, Vijaya Padma V, Natarajan K. Influence of terminal substitution on structural, DNA, protein binding, anticancer and antibacterial activities of palladium(II) complexes containing 3-methoxy salicylaldehyde-4(N) substituted thiosemicarbazones. Dalton Trans 2012; 41:2486-99. [PMID: 22222360 DOI: 10.1039/c1dt11838b] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The variable chelating behavior of 3-methoxysalicylaldehyde-4(N)-substituted thiosemicarbazones was observed in equimolar reactions with [PdCl(2)(PPh(3))(2)]. The new complexes were characterized by various analytical, spectroscopic techniques (mass, (1)H-NMR, absorption, IR). All the new complexes were structurally characterized by single crystal X-ray diffraction. Crystallographic results showed that the ligands H(2)L(1) and H(2)L(4) are coordinated as binegative tridentate ONS donor ligands in the complexes 1 and 4 by forming six and five member rings. However, the ligands H(2)L(2) and H(2)L(3) bound to palladium in 2 and 3 as uninegative bidentate NS donors by forming a five member chelate ring. From this study, it was found that the substitution on terminal 4(N)-nitrogen may have an influence on the chelating ability of thiosemicarbazone. The presence of hydrogen bonding in 2 and 3 might be responsible for preventing the coordination of phenolic oxygen to the metal ion. The interaction of the complexes with calf-thymus DNA (CT-DNA) has been explored by absorption and emission titration methods. Based on the observations, an electrostatic binding mode of DNA has been proposed. The protein binding studies were monitored by quenching of tryptophan and tyrosine residues in the presence of complexes using Lysozyme as model protein. Antibacterial activity studies of the complexes have been screened against pathogenic bacteria such as Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. MIC50 values of the complexes showed that they exhibited significant activity against the pathogens and among them, 3 exhibited higher activity. Further, anticancer activity of the complexes on the lung cancer cell line A549 has also been studied.
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Kalaivani P, Prabhakaran R, Dallemer F, Poornima P, Vaishnavi E, Ramachandran E, Padma VV, Renganathan R, Natarajan K. DNA, protein binding, cytotoxicity, cellular uptake and antibacterial activities of new palladium(ii) complexes of thiosemicarbazone ligands: effects of substitution on biological activity. Metallomics 2012; 4:101-13. [DOI: 10.1039/c1mt00144b] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Prabhakaran R, Kalaivani P, Poornima P, Dallemer F, Paramaguru G, Vijaya Padma V, Renganathan R, Huang R, Natarajan K. One pot synthesis of structurally different mono and dimeric Ni(ii) thiosemicarbazone complexes and N-arylation on a coordinated ligand: a comparative biological study. Dalton Trans 2012; 41:9323-36. [DOI: 10.1039/c2dt12231f] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Priyarega S, Kalaivani P, Prabhakaran R, Hashimoto T, Endo A, Natarajan K. Nickel(II) complexes containing thiosemicarbazone and triphenylphosphine: Synthesis, spectroscopy, crystallography and catalytic activity. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.06.046] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Prabhakaran R, Sivasamy R, Angayarkanni J, Huang R, Kalaivani P, Karvembu R, Dallemer F, Natarajan K. Topoisomerase II inhibition activity of new square planar Ni(II) complexes containing N-substituted thiosemicarbazones: Synthesis, spectroscopy, X-ray crystallography and electrochemical characterization. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.03.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Sathish R, Sahu A, Natarajan K. Antiulcer and antioxidant activity of ethanolic extract of Passiflora foetida L. Indian J Pharmacol 2011; 43:336-9. [PMID: 21713043 PMCID: PMC3113390 DOI: 10.4103/0253-7613.81501] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 01/21/2011] [Accepted: 02/08/2011] [Indexed: 12/03/2022] Open
Abstract
Passiflora foetida L. (Passifloraceae), a widely growing perennial climber, has been used in traditional medicine for treating many ailments. The objective of the present study was to evaluate the effects of ethanolic extract of P. foetida (EEPF) whole plant on gastric ulcer. The antiulcer effects of EEPF at 100 and 200 mg/kg doses were evaluated on ethanol and aspirin-induced gastric ulcer models. The antioxidant parameters and histological changes in gastric tissue of ulcer rats were also determined in both the models. P. foetida treatment significantly (P < 0.01) reduced the ulcer index and significantly (P < 0.01) increased the gastric pH of both ethanol and aspirin-induced ulcer rats. P. foetida showed significant (P < 0.01) reduction in lipid peroxidation and increase in reduced glutathione levels. The observations confirm that EEPF whole plant has antiulcer and antioxidant activities.
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Chawla A, Reddy S, Natarajan K, Thomas J, Sasidharan K. Posterior urethral valve associated with orthotopic ureterocele. Indian J Urol 2011; 24:569-70. [PMID: 19468522 PMCID: PMC2684411 DOI: 10.4103/0970-1591.44272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Symptomatic presentation of orthotopic ureterocele in infancy is very rare and its association with posterior urethral valves has not been reported till date. The first such case and a review of the literature on anomalies in association with posterior urethral valves is presented.
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Bose G, Waters B, Natarajan K, Stronach I, TIffany M, Nundlall N. 1574 poster A SECURE AND FLEXIBLE ENVIRONMENT FOR ANONYMISING RADIOTHERAPY DATA IN A CLINICAL DEPARTMENT. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)71696-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Hirons J, Stronach I, Natarajan K. 935 poster CONFIGURING THE MOSAIQ(r) ONCOLGY MANAGEMENT SYSTEM TO MEET LOCAL CLINICAL DEMAND. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)71057-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sathish R, Vyawahare B, Natarajan K. Antiulcerogenic activity of Lantana camara leaves on gastric and duodenal ulcers in experimental rats. JOURNAL OF ETHNOPHARMACOLOGY 2011; 134:195-197. [PMID: 21129476 DOI: 10.1016/j.jep.2010.11.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 10/27/2010] [Accepted: 11/22/2010] [Indexed: 05/30/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Lantana camara L. (Verbenaceae), a widely growing shrub has been used in the traditional medicine for treating many ailments. The objective of the present study was to evaluate the effects of methanolic extract of Lantana camara leaves on gastric and duodenal ulcers. MATERIALS AND METHODS The antiulcerogenic effect of methanolic extract of Lantana camara was evaluated in aspirin induced gastric ulcerogenesis in pyloric ligated rats, ethanol induced gastric ulcer, and cysteamine induced duodenal ulcer models. The extract was administered orally at two different doses of 250 mg/kg and 500 mg/kg. The lipid peroxidation, reduced glutathione levels of ethanol induced gastric ulcer model and inhibition zone in diameter against Helicobacter pylori also determined. RESULTS The L. camara extract significantly (P<0.01) reduced ulcer index, total acidity and significantly (P<0.01) increased the gastric pH of aspirin+pylorus-ligation induced ulcerogenesis and ethanol induced gastric ulcer models. The extract also significantly (P<0.01) reduced the ulcer index of cysteamine induced duodenal ulcer. The L. camara showed significant (P<0.01) reduction in lipid peroxidation and increase in reduced glutathione levels. The inhibition zone in diameter of extract against H. pylori was 20mm. CONCLUSION The methanolic extract of Lantana camara leaves shown healing of gastric ulcers and also prevents development of duodenal ulcers in rats.
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Prabhakaran R, Anantharaman S, Thilagavathi M, Kaveri MV, Kalaivani P, Karvembu R, Dharmaraj N, Bertagnolli H, Dallemer F, Natarajan K. Preparation, spectroscopy, EXAFS, electrochemistry and pharmacology of new ruthenium(II) carbonyl complexes containing ferrocenylthiosemicarbazone and triphenylphosphine/arsine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:844-853. [PMID: 21216187 DOI: 10.1016/j.saa.2010.12.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 12/10/2010] [Accepted: 12/14/2010] [Indexed: 05/30/2023]
Abstract
A new series of new hetero-bimetallic complexes containing iron and ruthenium of the general formula [RuCl(CO)(B)(EPh3)(L)] (where E=P or As; B=PPh3, AsPh3, py or pip; L=ferrocene derived monobasic bidentate thiosemicarbazone ligand) have been synthesized by the reaction between ferrocene-derived thiosemicarbazones and ruthenium(II) complexes of the type [RuHCl(CO)(B)(EPh3)2] (where E=P or As; B=PPh3, AsPh3, py or pip). The new complexes have been characterized by elemental analyses, IR, electronic, NMR (1H, 13C and 31P), EXAFS (extended X-ray absorption fine structure spectroscopy) and cyclic voltammetric techniques. Antibacterial activity of the new complexes has been screened against Escherichia coli, Vibrio cholerae, and Pseudomonas aeruginosa species.
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Prabhakaran R, Kalaivani P, Jayakumar R, Zeller M, Hunter AD, Renukadevi SV, Ramachandran E, Natarajan K. Synthesis, structure and biological evaluation of bis salicylaldehyde-4(N)-ethylthiosemicarbazone ruthenium(iii) triphenylphosphine. Metallomics 2011; 3:42-8. [DOI: 10.1039/c0mt00062k] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Muthukumar M, Viswanathamurthi P, Prabhakaran R, Natarajan K. Ruthenium(III) chalconate complexes containing PPh3/AsPh3 and their use as catalysts. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.520707] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Balasubramanian V, Natarajan K, Hemambika B, Ramesh N, Sumathi CS, Kottaimuthu R, Rajesh Kannan V. High-density polyethylene (HDPE)-degrading potential bacteria from marine ecosystem of Gulf of Mannar, India. Lett Appl Microbiol 2010; 51:205-11. [PMID: 20586938 DOI: 10.1111/j.1472-765x.2010.02883.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Assessment of high-density polyethylene (HDPE)-degrading bacteria isolated from plastic waste dumpsites of Gulf of Mannar. METHODS AND RESULTS Rationally, 15 bacteria (GMB1-GMB15) were isolated by enrichment technique. GMB5 and GMB7 were selected for further studies based on their efficiency to degrade the HDPE and identified as Arthrobacter sp. and Pseudomonas sp., respectively. Assessed weight loss of HDPE after 30 days of incubation was nearly 12% for Arthrobacter sp. and 15% for Pseudomonas sp. The bacterial adhesion to hydrocarbon (BATH) assay showed that the cell surface hydrophobicity of Pseudomonas sp. was higher than Arthrobacter sp. Both fluorescein diacetate hydrolysis and protein content of the biofilm were used to test the viability and protein density of the biomass. Acute peak elevation was observed between 2 and 5 days of inoculation for both bacteria. Fourier transform infrared (FT-IR) spectrum showed that keto carbonyl bond index (KCBI), Ester carbonyl bond index (ECBI) and Vinyl bond index (VBI) were increased indicating changes in functional group(s) and/or side chain modification confirming the biodegradation. CONCLUSION The results pose us to suggest that both Pseudomonas sp. and Arthrobacter sp. were proven efficient to degrade HDPE, albeit the former was more efficacious, yet the ability of latter cannot be neglected. SIGNIFICANCE AND IMPACT OF THE STUDY Recent alarm on ecological threats to marine system is dumping plastic waste in the marine ecosystem and coastal arena by anthropogenic activity. In maintenance phase of the plastic-derived polyethylene waste, the microbial degradation plays a major role; the information accomplished in this work will be the initiating point for the degradation of polyethylene by indigenous bacterial population in the marine ecosystem and provides a novel eco-friendly solution in eco-management.
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Natarajan K, Thielen K, Hermanns HD, Roth P. Thermal Decomposition of Cyanogen Measured in C2N2/O2 and C2N2/H2 Reaction Systems by Atomic Resonance Absorption. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19860900607] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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66
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Gowri S, Muthukumar M, Krishnaraj S, Viswanathamurthi P, Prabhakaran R, Natarajan K. Ruthenium(II) unsymmetrical N2O2 tetradentate Schiff-base complexes: synthesis, characterization, and catalytic studies. J COORD CHEM 2010. [DOI: 10.1080/00958970903499651] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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67
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Davies NP, Wilson M, Natarajan K, Sun Y, MacPherson L, Brundler MA, Arvanitis TN, Grundy RG, Peet AC. Non-invasive detection of glycine as a biomarker of malignancy in childhood brain tumours using in-vivo 1H MRS at 1.5 tesla confirmed by ex-vivo high-resolution magic-angle spinning NMR. NMR IN BIOMEDICINE 2010; 23:80-87. [PMID: 19795380 DOI: 10.1002/nbm.1432] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Management of brain tumours in children would benefit from improved non-invasive diagnosis, characterisation and prognostic biomarkers. Metabolite profiles derived from in-vivo MRS have been shown to provide such information. Studies indicate that using optimum a priori information on metabolite contents in the construction of linear combination (LC) models of MR spectra leads to improved metabolite profile estimation. Glycine (Gly) is usually neglected in such models due to strong overlap with myo-inositol (mI) and a low concentration in normal brain. However, biological studies indicate that Gly is abundant in high-grade brain tumours. This study aimed to investigate the quantitation of Gly in paediatric brain tumours using MRS analysed by LCModel, and its potential as a non-invasive biomarker of malignancy. Single-voxel MRS was performed using PRESS (TR 1500 ms, TE 30 ms/135 ms) on a 1.5 T scanner. Forty-seven cases (18 high grade (HG), 17 low grade (LG), 12 ungraded) were retrospectively selected if both short-TE and long-TE MRS (n = 33) or short-TE MRS and high-resolution magic-angle spinning (HRMAS) of matched surgical samples (n = 15) were available. The inclusion of Gly in LCModel analyses led to significantly reduced fit residues for both short-TE and long-TE MRS (p < 0.05). The Gly concentrations estimated from short-TE MRS were significantly correlated with the long-TE values (R = 0.91, p < 0.001). The Gly concentration estimated by LCModel was significantly higher in HG versus LG tumours for both short-TE (p < 1e-6) and long-TE (p = 0.003) MRS. This was consistent with the HRMAS results, which showed a significantly higher normalised Gly concentration in HG tumours (p < 0.05) and a significant correlation with the normalised Gly concentration measured from short-TE in-vivo MRS (p < 0.05). This study suggests that glycine can be reliably detected in paediatric brain tumours using in-vivo MRS on standard clinical scanners and that it is a promising biomarker of tumour aggressiveness.
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Muthukumar M, Sivakumar S, Viswanathamurthi P, Karvembu R, Prabhakaran R, Natarajan K. Studies on ruthenium(III) chalcone thiosemicarbazone complexes as catalysts for carbon–carbon coupling. J COORD CHEM 2009. [DOI: 10.1080/00958970903373922] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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69
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Karvembu R, Prabhakaran R, Muthu Tamizh M, Natarajan K. Ruthenium and enzyme-catalyzed dynamic kinetic resolution of alcohols. CR CHIM 2009. [DOI: 10.1016/j.crci.2008.09.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Muthusamy G, Viswanathamurthi P, Muthukumar M, Natarajan K. Thiosemicarbazone Complexes of Ruthenium(II) and Rhodium(I) Containing Triphenylphosphine. PHOSPHORUS SULFUR 2009. [DOI: 10.1080/10426500802429781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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71
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Kaliyaperumal K, Natarajan K. Scientometric Analysis of Literature Output on Retina. DESIDOC JOURNAL OF LIBRARY & INFORMATION TECHNOLOGY 2009. [DOI: 10.14429/djlit.29.259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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72
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Mahadevappa B, Suresh SC, Natarajan K, Thomas J. Cystogram with dumbbell shaped urinary bladder in a sliding inguinal hernia. J Radiol Case Rep 2009; 3:7-9. [PMID: 22470640 DOI: 10.3941/jrcr.v3i2.91] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Sliding inguinal hernias present with various symptoms and these are usually direct inguinal hernias containing various abdominal viscera. Case reports and series have been published with various organs and rare organs being part of the hernia. Urinary bladder is a known content of sliding hernias. This case report emphasizes this aspect in a picturesque manner and the importance of radiological investigations for pre-surgical evaluation.
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Natarajan K. Surgical instruments and endoscopes of Susruta, the sage surgeon of ancient India. Indian J Surg 2008; 70:219-23. [PMID: 23133066 DOI: 10.1007/s12262-008-0063-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2008] [Accepted: 07/24/2008] [Indexed: 10/21/2022] Open
Abstract
Susruta, the great sage surgeon, philosopher and teacher of ancient India, practiced around 600 bc. He is renowned all over the world for his contribution to surgery in general and plastic surgery in particular especially rhinoplasty. But his contribution to endoscopes is not well known to the medical world. His contribution to surgical instruments including endoscopes is reviewed here. Literature survery was the basis of this study. Susruta samhita [1], the treatise compiled by Susruta, various commentaries on it by different authors [2, 3] and other related literature are used as primary sources. Susruta belonged to a period between 600 and 800 bc. His conception of surgical instruments, the description of their quality, methods of manufacture and their usage are very unique, as there were no earlier comprehensive descriptions of similar surgical instruments by any surgeon, not only in India but also the whole world. Susruta was perhaps the first surgeon in the world to describe different types of surgical instruments including endoscopes. This is far beyond the imagination of any other surgeon at that period of time and obviously he was far ahead of his time in this field.
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Muthukumar M, Viswanathamurthi P, Natarajan K. Synthesis and spectral characterization of 2'-hydroxy chalconate complexes of ruthenium(II) and their catalytic and biological applications. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 70:1222-1226. [PMID: 18068426 DOI: 10.1016/j.saa.2007.10.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 10/25/2007] [Accepted: 10/31/2007] [Indexed: 05/25/2023]
Abstract
The reactions of [RuHCl(CO)(B)(EPh3)2] (B=EPh3 or pyridine; E=P or As) and 2'-hydroxychalcones in 1:2 ratio led to the formation of [Ru(CO)(B)(L)2] (B=PPh3, AsPh3 or Py; L=2'-hydroxychalcones). The new complexes have been characterized by analytical and spectral (IR, electronic and 1H NMR) data. They have been assigned an octahedral structure. The new complexes were found to catalyze the oxidation of alcohols to aldehydes using N-methylmorpholine-N-oxide as co-oxidant. All the new complexes were found to be active against bacteria such as E. coli, Salmonella typhi and fungi Aspergillus niger. The activity was compared with standard Streptomycin or Bavistin.
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Davies NP, Wilson M, Harris LM, Natarajan K, Lateef S, Macpherson L, Sgouros S, Grundy RG, Arvanitis TN, Peet AC. Identification and characterisation of childhood cerebellar tumours by in vivo proton MRS. NMR IN BIOMEDICINE 2008; 21:908-918. [PMID: 18613254 DOI: 10.1002/nbm.1283] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
(1)H MRS has great potential for the clinical investigation of childhood brain tumours, but the low incidence in, and difficulties of performing trials on, children have hampered progress in this area. Most studies have used a long-TE, thus limiting the metabolite information obtained, and multivariate analysis has been largely unexplored. Thirty-five children with untreated cerebellar tumours (18 medulloblastomas, 12 pilocytic astrocytomas and five ependymomas) were investigated using a single-voxel short-TE PRESS sequence on a 1.5 T scanner. Spectra were analysed using LCModel to yield metabolite profiles, and key metabolite assignments were verified by comparison with high-resolution magic-angle-spinning NMR of representative tumour biopsy samples. In addition to univariate metabolite comparisons, the use of multivariate classifiers was investigated. Principal component analysis was used for dimension reduction, and linear discriminant analysis was used for variable selection and classification. A bootstrap cross-validation method suitable for estimating the true performance of classifiers in small datasets was used. The discriminant function coefficients were stable and showed that medulloblastomas were characterised by high taurine, phosphocholine and glutamate and low glutamine, astrocytomas were distinguished by low creatine and high N-acetylaspartate, and ependymomas were differentiated by high myo-inositol and glycerophosphocholine. The same metabolite features were seen in NMR spectra of ex vivo samples. Successful classification was achieved for glial-cell (astrocytoma + ependymoma) versus non-glial-cell (medulloblastoma) tumours, with a bootstrap 0.632 + error, e(B.632+), of 5.3%. For astrocytoma vs medulloblastoma and astrocytoma vs medulloblastoma vs ependymoma classification, the e(B.632+) was 6.9% and 7.1%, respectively. The study showed that (1)H MRS detects key differences in the metabolite profiles for the main types of childhood cerebellar tumours and that discriminant analysis of metabolite profiles is a promising tool for classification. The findings warrant confirmation by larger multi-centre studies.
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