Antiulcerogenic and antioxidant activities of Plantago ovata ethanolic extract in rats

Abstract This study aimed to determine the antiulcerogenic and antioxidant activities of Psyllium (Plantago ovata Forssk) seed ethanolic extract in rats. We assessed the antioxidant potential using free radical scavenging on DPPH, -carotene bleaching activity, ferric reducing power, and hydroxyl radical scavenging activity. In the antiulcerogenic study, pre-treatment with Plantago ovata seeds ethanolic extract (POE) (400 mg/kg b.wt) significantly protected against ethanol-induced gastric ulcer in rats by decreasing the ulcer index value and preserving the integrity of the gastric mucosa. The oxidative stress status in the stomach tissues showed a significant increase in the antioxidant enzyme levels of superoxide dismutase, catalase, and glutathione peroxidase with a significant decrease in lipid peroxidation during pre-treatment with POE. In conclusion, the POE protects against gastric ulcer due to its antioxidant potential and presence of bioactive molecules.

Resumo O presente estudo teve como objetivo determinar as atividades antiulcerogênica e antioxidante das sementes de Psyllium (Plantago ovata Forssk) em ratos. O potencial antioxidante foi avaliado utilizando o método do sequestro do radical livre DPPH, autooxidação do -caroteno, poder redutor de ferro e atividade de sequestro do radical hidroxila. No estudo antiulcerogênico, o pré-tratamento com o extrato etanólico das sementes de Plantago ovata (POE) (400 mg/Kg b.wt) reduziu a úlcera gástrica induzida pelo etanol em ratos, diminuindo o valor do índice de úlcera e preservando a integridade da mucosa gástrica. O estudo do estresse oxidativo nos tecidos estomacais mostrou um aumento significativo dos níveis das enzimas antioxidantes superóxido dismutase, catalase e glutationa peroxidase, com uma diminuição significativa da peroxidação lipídica enquanto pré-tratamento com POE. Em conclusão, o POE protege contra úlcera gástrica devido aos seus potenciais antioxidantes e à presença de moléculas bioativas.

Establishment of local diagnostic reference levels for abdomen and chest radiographies in the region of Algarve, Portugal.

PURPOSE: To assess doses variabilities in the same abdomen and chest RX exams for adults, to check the need for dose harmonization. To calculate Diagnostic Reference Levels (DRL), mandatory in the European Union, for the Algarve district in Portugal. Our results can be a valuable reference for the Portuguese official determination of DRLs, still in progress. METHOD: We considered 4,936 abdomen and 41,320 chest radiographs of adults, covering 7 health centres and 35 radiographers in Algarve. Entrance skin dose (ESD) was calculated for each radiograph and the corresponding uncertainty estimated. Mean doses per centre and per technician, and their uncertainties, were calculated to access dose variabilities. DRLs, set at the 3rd quartile of the total ESD distribution, were determined for a standard patient and for intervals of body mass index (BMI) to study their correlation with patient anatomical variations. Standard quartile errors were estimated. RESULTS: Our results suggest significant dispersion in applied ESDs among different centres and radiographers. Estimates of DRLs also show small fluctuations across years and an important dependence on BMI intervals. For a standard patient, they are 8.7 ± 0.1 (abdomen) and 0.44 ± 0.01 (chest), while the European DRLs are, respectively, 5.1 and 0.2 (all in mGy). CONCLUSIONS: Results suggest that there is room for dose optimization and harmonization with European DRLs, urging a national dose survey and the establishment of official national DRLs. Official DRLs in intervals of BMI would be quite beneficial, to avoid unnecessary dose exposures.

Antiulcerogenic and antioxidant activities of Plantago ovata ethanolic extract in rats / Atividade antiulcerogênica e antioxidante do extrato etanólico de Plantago ovata em ratos

This study aimed to determine the antiulcerogenic and antioxidant activities of Psyllium (Plantago ovata Forssk) seed ethanolic extract in rats. We assessed the antioxidant potential using free radical scavenging on DPPH, ß-carotene bleaching activity, ferric reducing power, and hydroxyl radical scavenging activity. In the antiulcerogenic study, pre-treatment with Plantago ovata seeds ethanolic extract (POE) (400 mg/kg b.wt) significantly protected against ethanol-induced gastric ulcer in rats by decreasing the ulcer index value and preserving the integrity of the gastric mucosa. The oxidative stress status in the stomach tissues showed a significant increase in the antioxidant enzyme levels of superoxide dismutase, catalase, and glutathione peroxidase with a significant decrease in lipid peroxidation during pre-treatment with POE. In conclusion, the POE protects against gastric ulcer due to its antioxidant potential and presence of bioactive molecules.

O presente estudo teve como objetivo determinar as atividades antiulcerogênica e antioxidante das sementes de Psyllium (Plantago ovata Forssk) em ratos. O potencial antioxidante foi avaliado utilizando o método do sequestro do radical livre DPPH, autooxidação do ß-caroteno, poder redutor de ferro e atividade de sequestro do radical hidroxila. No estudo antiulcerogênico, o pré-tratamento com o extrato etanólico das sementes de Plantago ovata (POE) (400 mg/Kg b.wt) reduziu a úlcera gástrica induzida pelo etanol em ratos, diminuindo o valor do índice de úlcera e preservando a integridade da mucosa gástrica. O estudo do estresse oxidativo nos tecidos estomacais mostrou um aumento significativo dos níveis das enzimas antioxidantes superóxido dismutase, catalase e glutationa peroxidase, com uma diminuição significativa da peroxidação lipídica enquanto pré-tratamento com POE. Em conclusão, o POE protege contra úlcera gástrica devido aos seus potenciais antioxidantes e à presença de moléculas bioativas.

ON THE PLACEMENT OF APRON DOSEMETERS AND DOSE ASSESSMENT IN INTERVENTIONAL CARDIOLOGY PROCEDURES: PRELIMINARY RESULTS.

Personnel involved in interventional practices are likely to be exposed to higher radiation doses than other workers in the medical field. Personnel monitoring and radiation protection measures play a crucial role in keeping these doses below the limits. EURADOS (European Radiation Dosimetry Group) Working Group 12 performed a series of investigations showing how the complexity of the scattered field reaching the operators can influence the doses to the operators. The present work was aimed at determining the possible effects on the registered doses of the scattered field and the actual position of a dosemeter on apron. This study has been performed through Monte Carlo simulations and it was validated through measurements. It does not claim to identify the 'best' position for the dosemeter, but to assess the variability of its response, showing how a variability of the order of +/- 30% to 40 should be taken into account.

Antiulcerogenic and antioxidant activities of Plantago ovata ethanolic extract in rats.

This study aimed to determine the antiulcerogenic and antioxidant activities of Psyllium (Plantago ovata Forssk) seed ethanolic extract in rats. We assessed the antioxidant potential using free radical scavenging on DPPH, ß-carotene bleaching activity, ferric reducing power, and hydroxyl radical scavenging activity. In the antiulcerogenic study, pre-treatment with Plantago ovata seeds ethanolic extract (POE) (400 mg/kg b.wt) significantly protected against ethanol-induced gastric ulcer in rats by decreasing the ulcer index value and preserving the integrity of the gastric mucosa. The oxidative stress status in the stomach tissues showed a significant increase in the antioxidant enzyme levels of superoxide dismutase, catalase, and glutathione peroxidase with a significant decrease in lipid peroxidation during pre-treatment with POE. In conclusion, the POE protects against gastric ulcer due to its antioxidant potential and presence of bioactive molecules.

Determination of consensus k Q values for megavoltage photon beams for the update of IAEA TRS-398.

The IAEA is currently coordinating a multi-year project to update the TRS-398 Code of Practice for the dosimetry of external beam radiotherapy based on standards of absorbed dose to water. One major aspect of the project is the determination of new beam quality correction factors, k Q , for megavoltage photon beams consistent with developments in radiotherapy dosimetry and technology since the publication of TRS-398 in 2000. Specifically, all values must be based on, or consistent with, the key data of ICRU Report 90. Data sets obtained from Monte Carlo (MC) calculations by advanced users and measurements at primary standards laboratories have been compiled for 23 cylindrical ionization chamber types, consisting of 725 MC-calculated and 179 experimental data points. These have been used to derive consensus k Q values as a function of the beam quality index TPR20,10 with a combined standard uncertainty of 0.6%. Mean values of MC-derived chamber-specific [Formula: see text] factors for cylindrical and plane-parallel chamber types in 60Co beams have also been obtained with an estimated uncertainty of 0.4%.

Calculated beam quality correction factors for ionization chambers in MV photon beams.

The beam quality correction factor, [Formula: see text], which corrects for the difference in the ionization chamber response between the reference and clinical beam quality, is an integral part of radiation therapy dosimetry. The uncertainty of [Formula: see text] is one of the most significant sources of uncertainty in the dose determination. To improve the accuracy of available [Formula: see text] data, four partners calculated [Formula: see text] factors for 10 ionization chamber models in linear accelerator beams with accelerator voltages ranging from 6 MV to 25 MV, including flattening-filter-free (FFF) beams. The software used in the calculations were EGSnrc and PENELOPE, and the ICRU report 90 cross section data for water and graphite were included in the simulations. Volume averaging correction factors were calculated to correct for the dose averaging in the chamber cavities. A comparison calculation between partners showed a good agreement, as did comparison with literature. The [Formula: see text] values from TRS-398 were higher than our values for each chamber where data was available. The [Formula: see text] values for the FFF beams did not follow the same [Formula: see text], [Formula: see text] relation as beams with flattening filter (values for 10 MV FFF beams were below fits made to other data on average by 0.3%), although our FFF sources were only for Varian linacs.

Activity estimation and biokinetic analysis of 99mTc-DMSA in renal infant patients using a gamma camera.

Biokinetic data from the administration of radiopharmaceuticals is essential in nuclear medicine dosimetry. It has particular significance in children, as their metabolism is very different from adults. Biokinetic models for paediatric patients could therefore need to be adapted to better reflect their absorption, retention and excretion functions, when compared to adults. Obtaining quality in vivo infant or paediatric biokinetic data is then essential to improve the available reference models, which in turn can lead to the optimization of paediatric procedures and protocols in clinical practice. This study analyses the biokinetic behaviour of 99mTc-dimercaptosuccinic acid (DMSA), in 8 infants aged 4 months to 2 years old, through an imaging study using a gamma camera, and compares the obtained values with those obtained with the reference ICRP biokinetic model. The in vivo data was treated using an adapted methodology from the MIRD 16 pamphlet. Activity curves for the liver, the kidney and the whole body, were built, and new effective absorption, retention and excretion half-lives were estimated, and compared with the reference biokinetic parameters of ICRP 128. The obtained residence time in the kidneys of 2.56 h, has a deviation of 30.8% to the ICRP 128 value of 3.70 h. The obtained maximum uptake in the kidneys was of 0.22/A0, which compares to the value of 0.31/A0 for ICRP. The obtained biokinetic parameters were used to estimate the absorbed dose. The obtained dose values are smaller than the reference ICRP 128 ones by 32.1% in the kidneys, and 18.4% in the liver.

Assessment of the Absorbed Dose in the Kidney of Nuclear Nephrology Paediatric Patients using ICRP Biokinetic Data and Monte Carlo Simulations with Mass-Scaled Paediatric Voxel Phantoms.

The aim of this work is to use Monte Carlo simulations and VOXEL phantoms to estimate the absorbed dose in paediatric patients (aged from 2 weeks to 16 y), with normal renal function, to whom technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) was administered, for diagnostic renal scintigraphy purposes; and compare them with values obtained using the International Commission on Radiological Protection (ICRP) methodology. In the ICRP methodology, the cumulated absorbed dose in the kidneys is estimated by multiplying the administered activity with the corresponding given dose coefficients. The other methods were based on Monte Carlo simulations performed on two paediatric voxel phantoms (CHILD and BABY), and another three phantoms, which were modified to suit the mass of the patients' kidneys, and other anatomical factors. Different S-values were estimated using this methodology, which together with solving the ICRP biokinetic model to determine the cumulated activities, allowed for the estimation of absorbed doses different from those obtained with the ICRP method, together with new dose coefficients. The obtained values were then compared. The deviations suggest that the S-values are strongly dependent on the patient's total body weight, which could be in contrast with the ICRP data, which is provided by age, regardless of other anatomical parameters.

A Review of Radiation Protection Requirements and Dose Estimation for Staff and Patients in CT Fluoroscopy.

The combination of fluoroscopically guided interventional procedures with computed tomography (CTF) has become widespread around the world. The benefits of CTF include the ability to obtain a real-time visualization of the entire body, increased target accuracy and improved visualization of biopsy needles. Modern CTF units work with variable frame rates for image selection, and therefore the dose distributions for patients and staff can considerably vary, creating growing concern in terms of the occupational exposure of interventionists and the drawback of a higher exposure of the patient. A literature review of the latest CTF publications is summarized in this article. A wide range of CTF studies reveal different treatment methods used in clinical practice, and therefore the differences in the exposures between them; as well as in the radiation protection tools and dose monitoring. Further optimization of radiation protection methods, harmonization of exposure patterns as well as training and education of CTF staff on the basis of the information in the survey, are strongly recommended.

A dosimetric study of prostate brachytherapy using Monte Carlo simulations with a voxel phantom, measurements and a comparison with a treatment planning procedure.

In prostate brachytherapy treatments, there is an initial swelling of the prostate of the patient due to an oedema related to the insertion of the seeds. The variation of the prostate volume can lead to variations in the final prescribed dose in treatment planning procedures. As such, it is important to understand their influence for dose optimisation purposes. This work reports on a dosimetric study of the swelling of the prostate in prostate brachytherapy using Monte Carlo simulations. Dosimetric measurements performed on a physical anthropomorphic tissue-equivalent prostate phantom and thermoluminescent dosimeters (TLDs) were used to validate the MC model. Finally the MC model was also used to simulate prostate swelling in a real treatment planning procedure. The obtained results indicate that the parameters mentioned above represent a source of uncertainty in dose assessment in prostate brachytherapy, and can be detrimental to a correct dose evaluation in treatment plannings, and that these parameters can be accurately determined by means of MC simulations with a voxel phantom.

Assessment of the occupational exposure in real time during interventional cardiology procedures.

Interventional cardiology (IC) procedures can be complex, requiring the operators to work near the patient, during long exposure times. Owing to scattered radiation in the patient and the fluoroscopic equipment, the medical staff are exposed to a non-uniform radiation field and can receive high radiation doses. In this study, it is proposed to analyse staff doses obtained in real time, during IC procedures. A system for occupational dosimetry in real time was used. In order to identify some parameters that may affect the staff doses, Monte Carlo (MC) calculations, using MCNPX v.2.7.0 code and voxel phantoms, were performed. The data obtained from measurements, together with MC simulations, allowed the identification of actions and behaviours of the medical staff that could be considered a risk under routine working conditions. The implementation of this monitoring system for exposure of personnel may have a positive effect on optimisation of radiological protection in fluoroscopically guided cardiac procedures.

Assessment of patient dose reduction by bismuth shielding in CT using measurements, GEANT4 and MCNPX simulations.

This work reports on the use of two different Monte Carlo codes (GEANT4 and MCNPX) for assessing the dose reduction using bismuth shields in computer tomography (CT) procedures in order to protect radiosensitive organs such as eye lens, thyroid and breast. Measurements were performed using head and body PMMA phantoms and an ionisation chamber placed in five different positions of the phantom. Simulations were performed to estimate Computed Tomography Dose Index values using GEANT4 and MCNPX. The relative differences between measurements and simulations were <10 %. The dose reduction arising from the use of bismuth shielding ranges from 2 to 45 %, depending on the position of the bismuth shield. The percentage of dose reduction was more significant for the area covered by the bismuth shielding (36 % for eye lens, 39 % for thyroid and 45 % for breast shields).

Estimation of the collective ionizing dose in the Portuguese population for the years 2011 and 2012, due to nuclear medicine exams.

OBJECTIVES: In 2009-2010 a Portuguese consortium was created to implement the methodologies proposed by the Dose Datamed II (DDM2) project, aiming to collect data from diagnostic X-ray and nuclear medicine (NM) procedures, in order to determine the most frequently prescribed exams and the associated ionizing radiation doses for the Portuguese population. The current study is the continuation of this work, although it focuses only on NM exams for the years 2011 and 2012. MATERIAL AND METHODS: The annual frequency of each of the 28 selected NM exams and the average administered activity per procedure was obtained by means of a nationwide survey sent to the 35 NM centres in Portugal. RESULTS: The results show a reduction of the number of cardiac exams performed in the last two years compared with 2010, leading to a reduction of the annual average effective dose of Portuguese population due to NM exams from 0.08 mSv ± 0.017 mSv/caput to 0.059 ± 0.011 mSv/caput in 2011 and 0.054 ± 0.011 mSv/caput in 2012. Portuguese total annual average collective effective dose due to medical procedures was estimated to be 625.6 ± 110.9 manSv in 2011 and 565.1 ± 117.3 manSv in 2012, a reduction in comparison with 2010 (840.3 ± 183.8 manSv). CONCLUSIONS: The most frequent exams and the ones that contributed the most for total population dose were the cardiac and bone exams, although a decrease observed in 2011 and in 2012 was verified. The authors intend to perform this study periodically to identify trends in the annual Portuguese average effective dose and to help to raise awareness about the potential dose optimization.

Future development of biologically relevant dosimetry.

Proton and ion beams are radiotherapy modalities of increasing importance and interest. Because of the different biological dose response of these radiations as compared with high-energy photon beams, the current approach of treatment prescription is based on the product of the absorbed dose to water and a biological weighting factor, but this is found to be insufficient for providing a generic method to quantify the biological outcome of radiation. It is therefore suggested to define new dosimetric quantities that allow a transparent separation of the physical processes from the biological ones. Given the complexity of the initiation and occurrence of biological processes on various time and length scales, and given that neither microdosimetry nor nanodosimetry on their own can fully describe the biological effects as a function of the distribution of energy deposition or ionization, a multiscale approach is needed to lay the foundation for the aforementioned new physical quantities relating track structure to relative biological effectiveness in proton and ion beam therapy. This article reviews the state-of-the-art microdosimetry, nanodosimetry, track structure simulations, quantification of reactive species, reference radiobiological data, cross-section data and multiscale models of biological response in the context of realizing the new quantities. It also introduces the European metrology project, Biologically Weighted Quantities in Radiotherapy, which aims to investigate the feasibility of establishing a multiscale model as the basis of the new quantities. A tentative generic expression of how the weighting of physical quantities at different length scales could be carried out is presented.

Medical staff extremity dosimetry in CT fluoroscopy: an anthropomorphic hand voxel phantom study.

This work aims to contribute to the study of the radiation dose distribution delivered to the hands of medical staff members during a general computed tomographic (CT) fluoroscopic guided procedure. In this study, both Monte Carlo simulations and measurements were performed. For free-in-air and computed tomography dose index (CTDI) body phantom measurements, a standard pencil ionization chamber (IC) 100 mm long was used. The CT scanner model was implemented using MCNPX (Monte Carlo N-Particle eXtended) and was successfully validated by comparing the simulated results with measurements. Subsequently, CT images of a hand, together with an anthropomorphic phantom, were voxelized and used with the MCNPX code for dose calculations. The hand dose distribution study was performed both by using thermo-luminescent detector measurements and Monte Carlo simulations. The validated simulation tool provides a new perspective for detailed investigations of CT-irradiation scenarios. Simulations show that there is a strong dose gradient, namely the even zones of the hand that are in precise vicinity to the x-ray beam only receive about 4% of the maximum dose delivered to adjacent areas which are directly exposed to the primary x-ray beam. Finally, the scatter contribution of the patient was also studied through MC simulations. The results show that for directly exposed parts of the hand surface, the dose is reduced by the body of the patient (due to the shielding), whereas the dose is increased by scattered radiation from the patient for parts of the skin that receive scattered radiation only.

Efficiency correction factors of an ACCUSCAN whole-body counter due to the biodistribution of 134Cs, 137Cs and 60Co.

The efficiency calibration of whole-body counters (WBCs) for monitoring of internal contaminations is usually performed with anthropomorphic physical phantoms assuming homogeneous activity distribution. Besides the inherent limitations of these phantoms in resembling the human anatomy, they do not represent a realistic activity distribution, since in real situations each incorporated radionuclide has its particular biodistribution after entering the systemic circulation. Moreover, the activity content in the different organs and tissues comprising the biokinetics is time dependent. This work aims at assessing the whole-body counting efficiency deviations arising from considering a detailed voxel phantom instead of a standard physical phantom (BOMAB) and at evaluating the effect of the anatomical differences between both phantoms. It also aims at studying the efficiency considering the biodistribution of a set of radionuclides of interest incorporated in the scope of environmental and occupational exposures (inhalation and ingestion) and at computing the time-dependent efficiency correction factors to account for the biodistribution variation over time. For the purpose, Monte Carlo (MC) simulations were performed to simulate the whole-body counting efficiencies and biokinetic models were used to estimate the radionuclides' biokinetic behaviour in the human body after intake. The comparison between the efficiencies obtained with BOMAB and the voxel phantom showed deviations between 1.8 and 11.7 %, proving the adequacy of the BOMAB for WBC calibration. The obtained correction factors show that the effect of the biodistribution in the whole-body counting efficiency is more pronounced in cases of acute activity uptake and long-term retention in certain organs than in cases of homogeneous distribution in body tissues, for which the biokinetics influence can be neglected. This work further proves the powerful combination of MC simulation methods using voxel phantoms and biokinetic models for internal dosimetry studies.

Performance assessment and uncertainty evaluation of a portable NaI-based detection system used for thyroid monitoring.

This work aims at assessing the performance of a portable detection system, equipped with an NaI(Tl) scintillation detector for in vivo thyroid monitoring, which was properly calibrated using an anthropomorphic neck phantom. The anthropomorphic physical phantoms commonly used for the efficiency calibration of in vivo counters often present certain limitations regarding the geometry and the activity distribution. Therefore, the feasibility of these detection systems for in vivo monitoring should be assessed whenever possible. To accomplish this assessment, patients to whom (99m)Tc and (123)I marked radiopharmaceuticals have been administered in the framework of nuclear medicine diagnostic procedures were monitored. As the biokinetic models of the administered radiopharmaceuticals are known, the time-dependent activity functions in the critical organs after administration are easily quantified. The measured activities in the thyroid using the NaI(Tl) scintillation detector were compared with the estimated activities using the biokinetic models, in order to reach conclusion about the applicability of the portable scintillation counter for in vivo thyroid monitoring. The state-of-the-art Monte Carlo computer program PENELOPE and two voxel phantoms (male and female) were used to evaluate the overall uncertainties influencing the thyroid monitoring. A computational parametric study was performed to quantify the influence of several parameters in the activity quantification (neck-detector distance, thyroid shape, thyroid size and overlying tissue thickness), which allowed one to gain insight and to better understand the discrepancies between the calculated and measured activities.

Study of nuclear medicine practices in Portugal from an internal dosimetry perspective.

Nuclear medicine practices involve the handling of a wide range of pharmaceuticals labelled with different radionuclides, for diagnostic and therapeutic purposes. This work intends to evaluate the potential risks of internal contamination of nuclear medicine staff in several Portuguese nuclear medicine services and to conclude about the requirement of a routine internal monitoring. A methodology proposed by the International Atomic Energy Agency (IAEA), providing a set of criteria to determine the need, or not, for an internal monitoring programme, was applied. The evaluation of the risk of internal contaminations in a given set of working conditions is based on the type and amount of radionuclides being handled, as well as the safety conditions with which they are manipulated. The application of the IAEA criteria showed that 73.1% of all the workers included in this study should be integrated in a routine monitoring programme for internal contaminations; more specifically, 100% of workers performing radioimmunoassay techniques should be monitored. This study suggests that a routine monitoring programme for internal exposures should be implemented in Portugal for most nuclear medicine workers.

Performance and ruminal protozoa in lambs with chromium supplementation.

The effects of chromium picolinate (CrPic) oral supplementation on the performance and ruminal protozoa population in sheep was investigated. Twenty-four male lambs were treated with four different levels of CrPic: placebo, 0.250, 0.375 and 0.500mg of chromium/animal/day during 84 days. The base ration was Panicum maximum cv Massai hay and concentrate. Feed intake was measured three times a week. Lambs were weighed every 2 weeks. Ruminal content was sampled five times during the trial to quantify ruminal protozoa. No difference (p>0.05) between treatments was recorded for any parameter measured: initial and final mean body weight, dry matter intake, daily gain and total body weight gain. There was a negative linear relationship between Cr supplementation and protozoa count (p=0.0013) with no additional decrease when CrPic supplemental levels were higher than 0.375mg/day. Therefore, Cr supplementation must be carried out carefully and more studies need to address stressed animals or possible toxic effects of Cr in the animal itself or to the ruminal protozoa population.