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1.
Data Brief ; 35: 106930, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33748366

RESUMEN

We describe here a multiproxy dataset (grain size, environmental magnetism, stable carbon isotope, total nitrogen, and total organic carbon) generated on a ~116 cm long trench profile from the high altitude alpine Badnikund lake in the Central Himalaya. The dataset also includes environmental magnetic and organic geochemistry data on catchment soils of the Bednikund lake. The presented data is related to the research article "Middle Holocene Indian summer monsoon variability and its impact on cultural changes in the Indian subcontinent" [1]. The chronology of the Bednikund lake trench (BBK) profile is well established with seven AMS 14C dates. The multiproxy data is provided in tabular format in an excel file along with ages in Mendeley Data Repository. The multiproxy data can be significantly utilized for regional correlation of Indian summer monsoon (ISM) variability during the middle Holocene as well as for correlation of global climatic events. The data can also be reutilized in paleoclimate modelling for precipitation change over the past ~6000 years.

2.
Compr Rev Food Sci Food Saf ; 18(4): 1003-1038, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33337007

RESUMEN

Fresh fruits and vegetables are a rich source of micronutrients. However, many foodborne illnesses have been linked to the consumption of fresh fruits and vegetables as they are reported to harbor contaminants such as microorganisms and pesticides. Recently reported foodborne outbreaks have been linked to a diverse group of fruits and vegetables due to the presence of various pathogens including Salmonella, Escherichia coli, and Listeria monocytogenes. Also, the increased use of pesticides has resulted in the deposition of chemical residues on the surface of fruits and vegetables, which has led to the adverse health conditions such as cancer, birth defects, and neurodevelopmental disorders. Fresh commodities are subjected to various treatments to prevent or minimize these outbreaks, and the main targets of such treatments have been the elimination of pathogens and degradation of toxic chemical residues. Here, we have discussed various decontamination methods including simple household washing, chemical treatments, and modern technologies with their mode of action for microbial and pesticide removal. The simple household processes are not very effective in the removal of pathogenic organisms and pesticides. The use of modern techniques like cold plasma, ozone, high hydrostatic pressure, and so on, showed better efficacy in the removal of microorganisms and pesticides. However, their industrial use is limited considering high installation and maintenance cost. In this review, we suggest combined methods based on their mode of decontamination and suitability for a selected fruit or vegetable for effective decontamination of microbes and pesticide together to reduce the treatment cost and enhance food safety.

3.
Food Chem ; 221: 576-581, 2017 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-27979243

RESUMEN

Synthesis of new zerumbone-bicarbonyl analogues by SeO2 oxidation is reported. Selective oxidation of methyl at C-13 to an aldehyde and a ketone with exo-cyclic double bond between C-13 and C-6 in zerumbone has been recognized. Both these compounds have an additional conjugated-carbonyl-functionality. They exhibited significantly higher antimutagenic activity than zerumbone against Salmonella tester strains. They are more active against Gram positive bacteria than Gram negative bacteria; however zerumbone showed highest activity against E. coli, whereas its derivatives were least effective against E. coli.


Asunto(s)
Antibacterianos/farmacología , Óxidos de Selenio/química , Sesquiterpenos/química
4.
Rev Sci Instrum ; 87(12): 124703, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28040939

RESUMEN

An Electric (E-) field sensor based on coplanar waveguide-fed microstrip antenna to measure E-field strength for dual-band operation at 914 MHz and 2.1 GHz is proposed, designed, and characterized. The parametric optimization of the design has been performed to obtain resonance at global system for mobile communication and universal mobile telecommunication system frequency band. Low return loss (-17 dB and -19 dB), appropriate gain (0.50 dB and 1.55 dB), and isotropic behaviour (directivity ∼ 1 dB), respectively, at 914 MHz and 2.1 GHz, are obtained for probing application. Antenna factor (AF) is used as an important parameter to characterize the performance of the E-field sensor. The AF measurement is explained in detail and results are reported. Finally, using the designed E-field sensor, the E-field strength measurements are carried out in a transverse electromagnetic cell. The key sources of uncertainties in the measurement are identified, evaluated, and incorporated into the final results. The measurement results are compared with theoretical values, which are found in good agreement. For comparative validation, the results are evaluated with reference to an already calibrated commercially available isotropic probe.

5.
J Food Sci Technol ; 52(9): 5834-41, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26344998

RESUMEN

Natural additives for the control of microbial growth are in demand because consumers prefer them over synthetic ones. In the present investigation, the antibacterial activity of two natural preservatives, cinnamaldeyde and clove oil alone or in combinations was studied, and their potential as food preservative in model food systems and watermelon juice was evaluated. The cinnamaldehyde and clove essential oil showed minimum inhibitory concentration (MIC) at or below 5000 mg/l, and fractional inhibitory studies using both the oils showed synergistic effect. In artificially inoculated barley model food system and cabbage model food system, 2 MIC of oils was able to reduce the growth of the tested bacteria (more than 5 log) during 4 weeks storage at 37 °C, and similar reduction was also observed when combinations of oils were used at one eighth of MIC against Bacillus cereus and Yersinia enterocolitica, and one fourth of MIC against Staphylococcus aureus and Escherichia coli. Natural contaminants of watermelon juice were also reduced by the combination of one fourth of MIC of the oils, which was more effective than individual 2 MICs. These findings may be useful for food applications, but their effect on sensory quality of various foods need to be studied.

6.
Indian J Exp Biol ; 53(1): 36-43, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25675710

RESUMEN

This study evaluated the phytochemical and antimicrobial activities and also quantified bioactive nucleoside using high performance thin layer chromatography (HPTLC) of five extracts of Indian Himalayan Cordyceps sinensis prepared with different solvents employing accelerated solvent extraction (ASE) technique. The phytochemical potential of these extracts was quantified in terms of total phenolic and total flavonoid content while antioxidant activities were determined by 1,1-diphenyl-2-pycryl-hydrazyl (DPPH) and 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric-reducing antioxidant power (FRAP) assays. Total reducing power (TRP) was determined by converting iron (III) into iron (II) reduction assay. CS(50%Alc) (15.1 ± 0.67mg/g of dry extract) and CS(100%Alc) (19.3 ± 0.33 mg/g of dry extract) showed highest phenolic and flavonoid content, respectively while CS(Aq) extract showed maximum antioxidant activity and the highest concentration of the three nucleosides (adenine 12.8 ± 0.49 mg/g, adenosine 0.36 ± 0.28 mg/g and uracil 0.14 ± 0.36 mg/g of dry extract) determined by HPTLC. The evaluation of extracts for antimicrobial activity against gram-negative and gram-positive bacterial strains showed CS(25%Alc), CS(75%Alc) and CS(100%Alc) extract to be more effective against E. coli, P. aerugenosa and B. subtilis giving 9, 7 and 6.5 mm of zone of inhibition (ZOI) in 93.75, 93.75 and 45 µg concentration, respectively, whereas CS(Aq) extract showed minimal inhibition against these.


Asunto(s)
Antibacterianos/farmacología , Cordyceps/química , Extractos Vegetales/farmacología , Antioxidantes/farmacología , Cromatografía en Capa Delgada , Flavonoides/análisis , Pruebas de Sensibilidad Microbiana , Fenoles/análisis
7.
J Med Phys ; 39(4): 206-11, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25525307

RESUMEN

Medical electron linear accelerators with the capability of generating unflat photon (flattening filter-free, FFF) beams are also available commercially for clinical applications in radiotherapy. However, the beam characteristics evaluation criteria and parameters are not yet available for such photon beams. Atomic Energy Regulatory Board (AERB) of India constituted a Task Group comprising experts from regulatory agency, advisory body/research and technical institutions, and clinical radiotherapy centers in the country to evolve and recommend the acceptance criteria for the flattening filter-free (FFF) photon beams. The Task Group thoroughly reviewed the literature and inputs of the manufactures/suppliers of the FFF linac and recommended a set of dosimetry parameters for evaluating the characteristics of the unflat photon beam. The recommendations included the evaluation of quality index, degree of unflatness, difference in percentage surface dose between flat and unflat photon beams, percentage depth dose at 10 cm depth, off-axis-ratios and radiation beam penumbra. The recommended parameters were evaluated for FFF photon beams generated by three different models of the linac, and it was observed that recommended evaluation methods are simple and easy to be implemented with the existing dosimetry and quality assurance infrastructure of the linac facilities of the radiotherapy departments. Recommendations were also made for periodic quality control check of the unflat photon beams and constancy evaluation in the beam characteristics.

8.
Indian J Pharm Sci ; 76(5): 458-61, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25425763

RESUMEN

The present study was aimed to evaluate the effect of natural specimen and laboratory cultured mycelia of Cordyceps sinensis on neuromuscular activity in mice. The powder of natural specimen and laboratory cultured Cordyceps sinensis was orally administered at the dose rate of 100, 300 and 500 mg/kg for 30 days. Natural specimen and in vitro propagated Cordyceps sinensis showed significant (P<0.05) enhancement in neuromuscular endurance and antidepressant activity at 300 and 500 mg/kg as compared to the control group. However, the fungus did not proved to be as effective as fluoxetine in exhibiting antidepressant action. Muscular endurance was determined on a Rota rod apparatus while antidepressant (mood elevating) activity was measured on a photoactometer in Swiss albino mice. The effects produced by both natural specimens and laboratory cultured Cordyceps sinensis were comparable and showed almost equal potency.

9.
J Food Sci Technol ; 51(11): 3061-71, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26396298

RESUMEN

Investigation was carried out to study kinetics of moisture loss, oil uptake and tristimulus colour during deep fat frying of Gethi (Dioscorea kamoonensis kunth) strips. Deep fat frying of Gethi strips of size 6 × 6 × 40 mm was carried out in a laboratory scale fryer at different temperatures ranging from 120 to 180 °C. The investigation showed that the moisture loss and oil uptake followed the first order kinetics equation (r > 0.95, p < 0.05). The kinetic coefficients for moisture loss and oil uptake increased significantly (p < 0.05) with temperature from 0.166 to 0.889 min(-1) and 0.139 to 0.430 min(-1) respectively. The temperature dependency of rate constants for moisture loss and oil uptake values was described using Arrhenius equation (r > 0.99, p < 0.01). The activation energies for moisture loss and oil uptake were found to be 41.53 KJ/mol and 27.12 KJ/mol respectively. The hunter colour parameters were significantly affected by frying temperature and frying time. The hunter lightness (L) value increased with respect to frying time initially, followed by decline and same trend was observed at higher temperatures of frying with elevated rate, whereas hunter redness (a) value increased significantly (p < 0.01) with time as well as temperature of frying and obeyed zero order rate equation. The temperature dependency kinetic coefficients of Hunter (a) value were described by Arrhenius equation and the energy of activation for change in hunter redness was found to be 42.41 KJ/mol (r > 0.99, p < 0.01). The other hunter colour parameters such as chroma, hue angle and total colour difference were markedly affected by frying temperature as well as frying time.

10.
Food Chem ; 141(2): 1097-103, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-23790891

RESUMEN

Zerumbone, the key constituent of Zingiber zerumbet Smith, is a very important bioactive phytochemical. Two new compounds viz. azazerumbone 1 and azazerumbone 2 were synthesised by ZnCl2-catalysed Beckmann rearrangement of the zerumbone oxime. The structure elucidation of these analogues of zerumbone was carried out by 1D ((1)H NMR and (13)C NMR) and 2D-NMR (COSY, HSQC and NOESY) spectral analysis. Studies on the antibacterial activity established that azazerumbone 2 had better activity than zerumbone. Among the tested bacteria, Bacillus cereus was the most sensitive and Yersinia enterocolitica was found to be the most resistant. These compounds exhibited strong protection against sodium azide induced mutagenicity of Salmonella typhimurium strains TA 98 and TA 1531. Azazerumbone 2 showed better antibacterial and antimutagenic activity than azazerumbone 1. The antibacterial and antimutagenic activities exhibited by zerumbone and its analogues demonstrate their potential for use as nutraceuticals and in food preservation.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Sesquiterpenos/química , Sesquiterpenos/farmacología , Zingiber officinale/química , Bacterias/efectos de los fármacos , Bacterias/genética , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Pruebas de Mutagenicidad , Mutágenos/toxicidad
11.
Food Chem ; 139(1-4): 332-8, 2013 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-23561114

RESUMEN

Tetrahydrocurcumin (THC), the hydrogenated and stable form of curcumin, exhibits physiological and pharmacological activities similar to curcumin. A protocol has been developed for the synthesis of novel conjugates of THC with alanine (2a), isoleucine (2b), proline (2c), valine (2d), phenylalanine (2e), glycine (2f) and leucine (2g) in high yields (43-82%). All the derivatives of THC exhibited more potent anti-microbial activity than THC against Bacillus cereus, Staphylococcus aureus, Escherichia coli and Yersinia enterocolitica. The MIC values of the derivatives were 24-37% of those for THC in case of both gram-positive and gram-negative bacteria. Derivatives 2g and 2d exhibited maximum anti-mutagenicity against Salmonella typhimurium TA 98 and TA 1538, respectively at a low concentration of 313 µg/plate, with comparable activity for THC evident only at 3750 µg/plate. These results clearly demonstrated that the conjugation of THC at the phenolic position with amino acids led to significant improvement of its in vitro biological attributes.


Asunto(s)
Aminoácidos/química , Antibacterianos/farmacología , Antimutagênicos/farmacología , Curcumina/análogos & derivados , Antibacterianos/síntesis química , Antimutagênicos/síntesis química , Bacterias/efectos de los fármacos , Curcumina/química , Curcumina/farmacología , Pruebas de Sensibilidad Microbiana
12.
Food Chem ; 136(2): 650-8, 2013 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-23122110

RESUMEN

Tetrahydrocurcumin (THC, 1) and zingerone (2) are biologically active molecules originating from the important spices turmeric and ginger, respectively. Novel quinoline derivatives of THC and zingerone have been synthesised by an efficient protocol involving their reaction with substituted 2-aminobenzophenones and 2-aminoacetophenone. Radical-scavenging activities (RSA) of THC, zingerone and their quinoline derivatives were evaluated. The amino-substituted quinoline derivative of THC, 1e, showed antioxidant activity superior to those of 1 and 1a. Derivatives 1b, 1c, 1d and 1f exhibited relatively lower RSA at equimolar concentrations (∼50-55 µmol). A similar trend was also seen in zingerone (2) and its derivatives (2a-2e), with 2e displaying the best RSA. Derivatives of THC (1a-1f) showed stronger antimicrobial activity than THC (1) against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Yersinia enterocolitica. Also, derivatives of zingerone (2b-2e) exhibited lower minimum inhibitory concentrations (MIC) values than zingerone (2) and its derivative, 2a for both Gram-positive and Gram-negative bacteria. The molecules may have potential pharmacological applications.


Asunto(s)
Antibacterianos/síntesis química , Antioxidantes/síntesis química , Curcumina/análogos & derivados , Guayacol/análogos & derivados , Quinolinas/síntesis química , Antibacterianos/química , Antibacterianos/farmacología , Antioxidantes/química , Antioxidantes/farmacología , Bacterias/efectos de los fármacos , Curcumina/síntesis química , Curcumina/química , Curcumina/farmacología , Guayacol/síntesis química , Guayacol/química , Guayacol/farmacología , Quinolinas/química , Quinolinas/farmacología
13.
Mol Biol Rep ; 40(3): 2573-80, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23242653

RESUMEN

We have isolated and in silico characterized a cold-induced LlaDREB1b encoding a putative DRE-binding transcription factor from Lepidium latifolium. Its cDNA (JN214345) sequence (998 bp) consisted of a 642 bp ORF, 168 and 188 bp of 5' and 3' UTR regions, respectively, encoding a protein of 213 aa with deduced molecular mass 23.85 kDa and pI of 4.63. In silico and phylogenetic analysis further suggested that the protein showed features of a typical member of the AP2/EREBP family of DNA-binding proteins. Southern blot analysis indicated that multiple copies of the gene could be present in the genome. Its transcripts were abundant in leaves, petiole and stem, but scarce in roots and could strongly be induced by cold treatment (4 °C), weakly by drought and salt stress, and did not respond to ABA treatment. Thus, LlaDREB1b is a potential candidate for abiotic stress-tolerance engineering in crop plants upon its further functional validation.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Lepidium/genética , Lepidium/metabolismo , Proteínas de Plantas/genética , Estrés Fisiológico , Factores de Transcripción/genética , Secuencia de Aminoácidos , ADN Complementario/química , ADN Complementario/genética , Lepidium/clasificación , Datos de Secuencia Molecular , Especificidad de Órganos/genética , Fenotipo , Filogenia , Alineación de Secuencia , Especificidad de la Especie
14.
J Ethnopharmacol ; 136(1): 260-6, 2011 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-21549819

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Cordyceps sinensis is a traditional Chinese medicine used for promotion of health, longevity and athletic power. However, the molecular mechanism for anti-fatigue activity and physical fitness has not yet been reported. AIM OF THE STUDY: The present study was conducted to evaluate the exercise endurance promoting activities of fungal traditional Chinese medicine (FTCM) Cordyceps sinensis cultured whole mycelium (CS) and the underlying mechanisms. MATERIALS AND METHODS: CS was orally supplemented (200mg/kg body weight/day) to rats for 15days with or without swimming exercise along with exercise and placebo groups. RESULTS: Both CS supplementation and supplementation concurrent with exercise improved exercise endurance by 1.79- (P<0.05) and 2.9-fold (P<0.01) respectively as compared to placebo rats. CS supplementation concurrent with exercise also increased the swimming endurance by 1.32-fold (P<0.05) over the exercise group. To study the molecular mechanism of the observed effect, we measured the expression levels of endurance responsive skeletal muscle metabolic regulators AMPK, PGC-1α and PPAR-δ as well as endurance promoting and antioxidant genes like MCT1, MCT4, GLUT4, VEGF, NRF-2, SOD1 and TRX in red gastrocnemius muscle. Our results indicate that CS supplementation significantly upregulates the skeletal muscle metabolic regulators, angiogenesis, better glucose and lactate uptake both in exercised and non-exercised rats. We have also observed increased expression of oxidative stress responsive transcription factor NRF-2 and its downstream targets SOD1 and TRX by CS supplementation. CONCLUSION: CS supplementation with or without exercise improves exercise endurance capacity by activating the skeletal muscle metabolic regulators and a coordinated antioxidant response. Consequently, CS can be used as a potent natural exercise mimetic.


Asunto(s)
Productos Biológicos/farmacología , Cordyceps , Regulación de la Expresión Génica , Músculo Esquelético/metabolismo , Condicionamiento Físico Animal/fisiología , Resistencia Física/fisiología , Natación/fisiología , Animales , Suplementos Dietéticos , Glucosa/metabolismo , Ácido Láctico/metabolismo , Masculino , Micelio , Factor 2 Relacionado con NF-E2/metabolismo , Resistencia Física/genética , Ratas , Ratas Sprague-Dawley , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa-1 , Tiorredoxinas/metabolismo , Regulación hacia Arriba
15.
Crit Rev Food Sci Nutr ; 50(8): 728-60, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20830634

RESUMEN

Carotenoids are one of the most widespread groups of pigments in nature and more than 600 of these have been identified. Beside provitamin A activity, carotenoids are important as antioxidants and protective agents against various diseases. They are isoprenoids with a long polyene chain containing 3 to 15 conjugated double bonds, which determines their absorption spectrum. Cyclization at one or both ends occurs in hydrocarbon carotene, while xanthophylls are formed by the introduction of oxygen. In addition, modifications involving chain elongation, isomerization, or degradation are also found. The composition of carotenoids in food may vary depending upon production practices, post-harvest handling, processing, and storage. In higher plants they are synthesized in the plastid. Both mevalonate dependent and independent pathway for the formation of isopentenyl diphosphate are known. Isopentenyl diphosphate undergoes a series of addition and condensation reactions to form phytoene, which gets converted to lycopene. Cyclization of lycopene either leads to the formation of ß-carotene and its derivative xanthophylls, ß-cryptoxanthin, zeaxanthin, antheraxanthin, and violaxanthin or α-carotene and lutein. Even though most of the carotenoid biosynthetic genes have been cloned and identified, some aspects of carotenoid formation and manipulation in higher plants especially remain poorly understood. In order to enhance the carotenoid content of crop plants to a level that will be required for the prevention of diseases, there is a need for research in both the basic and the applied aspects.


Asunto(s)
Carotenoides/química , Carotenoides/genética , Ingeniería Genética , Antioxidantes , Disponibilidad Biológica , Carotenoides/biosíntesis , Productos Agrícolas/química , Productos Agrícolas/genética , Dieta , Manipulación de Alimentos , Conservación de Alimentos , Regulación de la Expresión Génica , Promoción de la Salud , Humanos , Estructura Molecular , Plantas Comestibles/química , Plantas Comestibles/genética , Plantas Modificadas Genéticamente
16.
Int J Biomed Sci ; 5(1): 37-43, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23675112

RESUMEN

An isocratic liquid chromatographic method with UV detection at 220 nm is described for simultaneous determination of ceftriaxone sodium and sulbactam sodium in Sulbactomax. Chromatographic separation of two drugs was achieved on a Hypersil ODS C-18 column using a mobile phase consisting of a binary mixture of acetonitrile and tetrabutyl ammonium hydroxide adjusted to pH7.0 with orthophosphoric acid in ratio 70:30. The developed Liquid Chromatographic method offers symmetric peak shape, good resolution and reasonable retention time for both drugs. Linearity, accuracy and precision were found to be acceptable over the concentration range of 125-750 ppm for ceftriaxone sodium and 62.5-375 ppm for sulbactam sodium. The LC method can be used for the quality control of formulated products containing ceftriaxone and sulbactam.

17.
Br J Radiol ; 81(971): 865-71, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18941046

RESUMEN

The aim of this study was to evaluate the impact of intensity-modulated radiation therapy (IMRT) on the incidence and severity of chronic dysphagia in patients with head and neck cancer. 62 evaluable patients with head and neck cancer who were treated with IMRT with or without concurrent chemotherapy were analysed. The majority of the patients (77.4%) had advanced locoregional disease. 45 patients underwent definitive IMRT and 17 received post-operative IMRT. Concurrent chemotherapy was given to 29 of the 45 patients treated with definitive IMRT. The average prescribed dose to clinical target volume (CTV)1 was 66-70 Gy (definitive IMRT) and 56-62 Gy (post-operative IMRT); 60 Gy to CTV2; 54 Gy to CTV3; and 50-52 Gy to the supraclavicular area. At a median follow-up of 19 months, 2-year actuarial locoregional control and survival was 77% and 74%, respectively. At 6 months after IMRT, chronic dysphagia was Grade 0 in 77.1% of patients, Grade 1 in 10.5% and Grade 2 in 12.3%. Acute mucositis showed no correlation with long-term dysphagia. The percutaneous endoscopic gastrostomy or nasogastric tube was removed in all of the patients within 8 weeks of completion of treatment. Xerostomia was Grade 0 in 61.4% of patients, Grade 1 in 31.5% and Grade 2 in 7% of patients. In conclusion, IMRT conferred a major favourable impact on chronic dysphagia in patients with locally advanced head and neck cancers, with satisfactory locoregional control.


Asunto(s)
Trastornos de Deglución/etiología , Neoplasias de Cabeza y Cuello/radioterapia , Radioterapia de Intensidad Modulada/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Relación Dosis-Respuesta en la Radiación , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Dosificación Radioterapéutica , Radioterapia de Intensidad Modulada/métodos , Xerostomía/etiología
18.
Clin Oncol (R Coll Radiol) ; 18(6): 497-504, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16909975

RESUMEN

AIMS: Dryness of the mouth is one of the most distressing chronic toxicities of radiation therapy in head and neck cancers. In this study, parotid function was assessed in patients with locally advanced head and neck cancers undergoing intensity-modulated radiotherapy (IMRT) with or without chemotherapy. Parotid function was assessed with the help of a questionnaire and parotid scintigraphy, especially with regards to unilateral sparing of the parotid gland. MATERIALS AND METHODS: In total, 19 patients were treated with compensator-based IMRT between February 2003 and March 2004. The dose to the clinical target volume ranged between 66 and 70 Gy in 30-35 fractions to 95% of the isodose volume. Ipsilateral high-risk neck nodes received an average dose of 60 Gy and the contralateral low-risk neck received a dose of 54-56 Gy. Eight of 19 patients also received concomitant chemotherapy. RESULTS: Subjective toxicity to the parotid glands was assessed with the help of a questionnaire at 0, 3 and 6 months and objective toxicity was assessed with parotid scintigraphy at 0 and 3 months. The mean dose to the ipsilateral parotid gland ranged from 19.5 to 52.8 Gy (mean 33.14 Gy) and the mean dose to the contralateral gland was 11.1-46.6 Gy (mean 26.85 Gy). At a median follow-up of 13 months, 9/19 patients had no symptoms of dryness of the mouth (grade I), 8/19 had mild dryness of the mouth (grade II) and only 2/19 had grade III xerostomia, although the parotid gland could only be spared on one side in most of the patients. CONCLUSIONS: Minimising the radiation dose to one of the parotid glands with the help of IMRT in patients with advanced head and neck cancers can prevent xerostomia in most patients and parotid scintigraphy is a useful method of documenting xerostomia.


Asunto(s)
Neoplasias de Cabeza y Cuello/radioterapia , Glándula Parótida/efectos de la radiación , Radioterapia de Intensidad Modulada/efectos adversos , Xerostomía/prevención & control , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Terapia Combinada , Progresión de la Enfermedad , Relación Dosis-Respuesta en la Radiación , Estudios de Factibilidad , Estudios de Seguimiento , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/cirugía , Humanos , Imagen por Resonancia Magnética/métodos , Recurrencia Local de Neoplasia , Estadificación de Neoplasias , Glándula Parótida/diagnóstico por imagen , Glándula Parótida/fisiopatología , Cintigrafía , Dosificación Radioterapéutica , Radioterapia de Intensidad Modulada/métodos , Sensibilidad y Especificidad , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X/métodos , Resultado del Tratamiento , Xerostomía/etiología
19.
Radiat Oncol ; 1: 31, 2006 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-16939650

RESUMEN

BACKGROUND AND PURPOSE: Intensity modulated radiotherapy (IMRT) is a powerful tool, which might go a long way in reducing radiation doses to critical structures and thereby reduce long term morbidities.The purpose of this paper is to evaluate the impact of IMRT in reducing the dose to the critical normal tissues while maintaining the desired dose to the volume of interest for thoracic malignancies. MATERIALS AND METHODS: During the period January 2002 to March 2004, 12 patients of various sites of malignancies in the thoracic region were treated using physical intensity modulator based IMRT. Plans of these patients treated with IMRT were analyzed using dose volume histograms. RESULTS: An average dose reduction of the mean values by 73% to the heart, 69% to the right lung and 74% to the left lung, with respect to the GTV could be achieved with IMRT.The 2 year disease free survival was 59% and 2 year overall survival was 59%. The average number of IMRT fields used was 6. CONCLUSION: IMRT with inverse planning enabled us to achieve desired dose distribution, due to its ability to provide sharp dose gradients at the junction of tumor and the adjacent critical organs.


Asunto(s)
Pulmón/efectos de la radiación , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Neoplasias Torácicas/radioterapia , Adulto , Anciano , Supervivencia sin Enfermedad , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dosis de Radiación , Resultado del Tratamiento
20.
J Med Phys ; 31(2): 67-71, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21206667

RESUMEN

Multiple fields in IMRT and optimization allow conformal dose to the target and reduced dose to the surroundings and the regions of interest. Thus we can escalate the dose to the target to achieve better tumor control with low morbidity. Orientation of multiple beams can be achieved by i) different gantry angles, ii) rotating patient's couch isocentrically. In doing so, one or more beam may pass through different materials like the treatment couch, immobilization cast fixation plate, head and neck rest or any other supportive device. Our observations for 6MV photon beam on PRIMUS-KXE2 with MED-TEC carbon fiber tabletop and 10 × 10 cm(2) field size reveals that the maximum dose attenuation by the couch was of the order of 2.96% from gantry angle 120-160°. Attenuation due to cast fixation base plate of PMMA alone was of the order of 5.8-10.55% at gantry angle between 0 and 90°. Attenuation due to carbon fiber base plate alone was 3.8-7.98%. Attenuation coefficient of carbon fiber and PMMA was evaluated and was of the order of 0.082 cm(-1) and 0.064 cm(-1) respectively. Most of the TPS are configured for direct beam incidence attenuation correction factors only. Whereas when the beam is obliquely incident on the couch, base plate, headrest and any other immobilization device get attenuated more than the direct beam incidence. The correction factors for oblique incidence beam attenuation are not configured in most of the commercially available treatment planning systems. Therefore, such high variations in dose delivery could lead to under-dosage to the target volume for treatments requiring multiple fields in IMRT and 3D-CRT and need to be corrected for monitor unit calculations.

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