Diagnostic radiographic examinations in Saudi Arabia based on thermoluminescent dosimetery

This study was performed as part of a comprehensive project to establish national diagnostic reference levels (NDRLs), for the first time, in Saudi Arabia. The study consisted of 240 patients who were referred for x-ray examinations at King Khalid University Hospital (KKUH) in Saudi Arabia. Patients’ information and exposure parameters for eight of the common x-ray examinations (12 standard projections) were evaluated. The patient mean dose values recorded at KKUH were compared with the corresponding values at other national institutions (Security Forces Hospital and King Abdul-Aziz City for Science and Technology). The patient exposure parameters of several radiographic projections [chest (posterior anterior), skull (anterior posterior/posterior anterior and lateral), cervical spine (anterior posterior and lateral) and lumbar spine (anterior posterior and lateral)] measured at KKUH were compared with their corresponding values at the International Hospitals (Iran, United Kingdom and Malaysia). We found that the patient mean dose values recorded at KKUH varied widely from those recorded at the other national institutions. In addition, the patient exposure parameters recorded at KKUH varied from those measured at the international hospitals. Variations in patient dose arising from a specific X-ray examination may emerge from complex causes, but in general, low peak kilovolt and high milli Amperes were associated with the higher doses. The results of this study will prove useful information for the formulation of NDRLs and also provide local diagnostic reference levels for several diagnostic x-ray examinations at KKUH, other national institutions and international hospitals.Key words: Harshaw 3500 reader, national hospitals, radiographic examinations, thermoluminescent dosimeters, x-rays

The effects of gold nanoparticles size and concentration on viscosity, flow activation energy, dielectric and optical properties

This study was carried out to investigate viscosity in relation with the temperature, flow activation energy and dielectric properties for 10, 20 and 50 nm gold nanoparticles size (GNPs) in addition to absorption and fluorescence spectra at different concentrations (0.2 × 10-3 to 1 × 10-2%) in an attempt to cover and understand the toxicity and potential role of their therapeutic and diagnostic use in medical applications. 10, 20 and 50 nm GNPs dissolved in aqueous solution were purchased (Product MKN-Au, Canada) and used in this study. Mechanical parameters were measured using Brookfield LVDV-III Programmable rheometer with temperature bath controlled by a computer. 0.5 ml of each GNP size in aqueous solution was poured in the sample chamber of the rheometer. The spindle was immersed and rotated in these gold nanofluids in the speed range from 50 to 250 rpm in steps of 20 min. Viscosity of GNPs was measured at temperature of 37°C and at a gradually increase of temperature to 42ºC. UV–Visible characterization of GNPs at different concentrations from 0.2 × 10-3 to 1 × 10-2 % was performed using UV-1601 PC, UV-Visible spectrophotometer. The absorbance measurements were made over the wavelength range of 250 to 700 nm using 1 cm path length quartz cuvettes. Fluorescence characterization of GNPs was performed over the wavelength range of 250 to 700 nm using FluoroMax-2 JOBIAN YVON-SPEX. The measured viscosities for all GNP sizes decreased with increasing the temperatures from 37 to 42°C. The GNPs with larger size (50 nm) exhibited higher viscosity values compared with 10 and 20 nm GNPs. The flow activation energies (kJ/mol) for 10, 20 and 50 nm GNPs were 332.55, 415.4 and 182.2 kJ/mol, respectively. The optical properties such as absorption maxima and the absorption intensity are particle size-dependent. The fluorescence emission band for GNPs with an excitation wavelength of 308 nm and photoluminescence (PL) band centre appeared at 408 nm. With the increase of GNPs concentration at a fixed GNP size of 20 nm, the intensity of emission band positioned increased, and the trend was consistent with the changes of the corresponding surface plasmon resonance (SPR) of GNPs. The presented dielectric data indicates that GNPs have strong dielectric dispersion corresponding to the alpha relaxation region in the frequency range of 20 Hz to 100 kHz which was identified as anomalous frequency dispersion. At a constant GNP size, the absorbance was found to be proportional to the concentration of gold. This is due to the increase in the number of GNPs as well as the increase in the SPR of GNPs. An intense absorption peak was observed at wavelength of 517 nm which is generally attributed to the surface plasmon excitation of the small spherical GNPs. The incident light at 308 nm will lead to excitation of the surface plasmon coherent electronic motion as well as the d electrons. This study suggests that the relaxation of these electronic motions followed by the recombination of the sp electrons with holes in the d band leads to the fluorescence emission. These results indicate that the intensity of fluorescence emission band of GNPs was dependent on the concentration of GNPs. A rapid decrease in the dielectric constant may be attributed to the tendency of dipoles in GNPs to orient themselves in the direction of the applied field in the low-frequency range. However, in the high-frequency range, the dipoles will hardly be able to orient themselves in the direction of the applied field and hence the value of the dielectric constant is nearly constant.Key words: Gold nanoparticles, viscosity, size, temperature, dielectric, absorption, fluorescence

The protective role of quercetin and arginine on gold nanoparticles induced hepatotoxicity in rats

Mohamed Anwar K Abdelhalim,1 Sherif A Abdelmottaleb Moussa,2,3 Huda Abdo Yahya Qaid1 1Department of Physics and Astronomy, College of Sciences, King Saud University, Riyadh, Saudi Arabia; 2Committee of Radiation and Environmental Pollution Protection (CREPP), Department of Physics, College of Science, Al-Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia; 3Biophysics Group, Biochemistry Department, Genetic Engineering and Biotechnology Division, National Research Centre, Giza, Egypt Background: The aim of the study was to confirm the hepatotoxicity induced by small-sized gold nanoparticles (GNPs) and evaluate the role of quercetin (Qur) and arginine (Arg) against hepatotoxicity caused by GNPs.Methods: Twenty-five healthy male Wistar-Kyoto rats were used. GNPs were administered intraperitoneally to these rats at the dose of 50 µL for seven consecutive days. The role of Qur and Arg antioxidants against toxicity induced by GNPs was detected through the measurement of serum liver function and oxidative stress biomarkers in the liver tissues.Results: Coadministration of Qur and Arg along with GNPs significantly induced dramatic alterations in the biochemical parameters. Levels of malondialdehyde, gamma-glutamyl transferase, alanine aminotransferase, alkaline phosphatase, and total protein increased significantly in the GNPs injected group than in the control group, while reduced glutathione was greatly reduced in the GNPs group than in the control group. It also significantly decreased liver enzymes and the oxidative stress, therefore improving the liver damage and hepatotoxicity induced by GNPs.Conclusion: This study demonstrated that Qur and Arg antioxidants effectively improved the hepatic oxidative damage induced by GNPs. It also substantiates the application of Qur and Arg as protecting stand-in against GNPs’ hepatotoxicity. Keywords: antioxidants, oxidative stress, gold nanoparticles, hepatotoxicity, quercetin, arginine, rat

Potential effects of different natural antioxidants on inflammatory damage and oxidative-mediated hepatotoxicity induced by gold nanoparticles

Mohamed Anwar K Abdelhalim,1 Sherif A Abdelmottaleb Moussa,2,3 Huda AY Qaid,1 Mohammed Suliman Al-Ayed1 1Department of Physics and Astronomy, College of Science, King Saud University, Riyadh, Saudi Arabia; 2Committee of Radiation and Environmental Pollution Protection, Department of Physics, College of Science, Al-Imam Mohammad Ibn Saud Islamic University, Riyadh, Saudi Arabia; 3Biophysics Group, Biochemistry Department, Genetic Engineering and Biotechnology Division, National Research Centre, Giza, Egypt Objective: The objective of this study was to verify and confirm the oxidative-mediated hepatotoxicity, inflammatory liver damage, and oxidative stress induced by intraperitoneal administration of gold nanoparticles (GNPs) in vivo; characterize the effect of different natural antioxidants on these hazardous changes; and finally choose the most powerful antioxidant among these different natural antioxidants.Methods: Ten-nanometer GNPs were dissolved in aqueous solution of 0.01% concentration. A dose of 50 µL of 10 nm GNPs was administered intraperitoneally for 7 days to the rats, whereas the antioxidants were orally administered for the same time period. The antioxidants used in the study were vitamin E (Vit E), α-lipoic acid (ALA), quercetin (Qur), arginine (Arg), and melanin. Forty Wistar-Kyoto male rats were used. Rats were arbitrarily divided into seven groups after acclimatization for 1 week. For serum separation, blood samples were obtained from each animal. Serum liver function markers and tissue oxidative stress and lipid proxidation biomarkers were assessed.Results: The increase in the levels of gamma-glutamyl transferase, alkaline phosphatase, total protein, alanine aminotransferase, and total bilirubin in the serum of rats and the increase of malondialdehyde in the hepatic tissue and decrease in reduced glutathione when compared with the control in this study confirmed the ability of GNPs to cause hazardous effects.Conclusion: Treatment of rats with Vit E, ALA, Qur, Arg, and melanin along with GNPs significantly inhibited the inflammatory liver damage, lipid peroxidation, and the oxidative stress induced by GNPs in vivo, but with different responses due to their evaluated normalization values, and it has been confirmed that melanin is the most powerful antioxidant among these different natural antioxidants, ie, it has the most effective potential role against the hepatic inflammatory damage, oxidative stress, and lipid peroxidation. Keywords: antioxidants, oxidative stress, gold nanoparticles, hepatotoxicity, vitamin E, α-lipoic acid, quercetin, arginine, melanin, rat

Effect of melanin on gold nanoparticle-induced hepatotoxicity and lipid peroxidation in rats

Mohamed Anwar K Abdelhalim,1 Sherif A Abdelmottaleb Moussa,2,3 Huda AY Qaid,1 Mohammed Suliman Al-Ayed1 1Department of Physics and Astronomy, College of Science, King Saud University, Riyadh, Saudi Arabia; 2Committee of Radiation and Environmental Pollution Protection (CREPP), Department of Physics, College of Science, Al-Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia; 3Biophysics Group, Biochemistry Department, Genetic Engineering and Biotechnology Division, National Research Center, Giza, Egypt Introduction: Melanin pigments are produced by melanocytes and are believed to act as antioxidants based on the belief that melanin can suppress electronically stirred states and scavenge the free radicals. Materials and methods: The study was aimed to verify and prove the toxicity induced by administration of gold nanoparticles (GNPs) and to characterize the role of melanin as an antioxidant against inflammatory liver damage, oxidative stress, and lipid peroxidation induced intraperitoneally by GNPs in vivo. Results: The findings from this study confirmed that administration of GNPs intraperitoneally caused liver damage in addition to producing oxidative stress and fatty acid peroxidation. The treatment of rats with melanin along with GNPs induced dramatic changes in all the measured biochemical parameters. Our data demonstrated that melanin completely inhibited inflammatory liver damage, oxidative stress, and lipid peroxidation, which was confirmed by the histological investigation of different liver sections stained by H&E. Conclusion: These results suggest the beneficial use of melanin together with GNPs for alleviating its toxicity. Other studies should be implemented taking into consideration the role of melanin in comparison with other natural antioxidants. Keywords: liver, gold nanoparticles, hepatotoxicity, oxidative stress, lipid peroxidation, histological investigatio

Effects of quercetin and arginine on the nephrotoxicity and lipid peroxidation induced by gold nanoparticles in vivo

Mohamed Anwar K Abdelhalim, Huda AY Qaid, Yanallah Al-Mohy, Mohammed Suliman Al-Ayed Department of Physics and Astronomy, College of Science, King Saud University, Riyadh, Saudi Arabia Introduction: This study aimed to evaluate the nephrotoxicity caused by gold nanoparticles (GNPs) and investigate the potential roles of quercetin (Qur) and arginine (Arg) in mitigating the inflammatory kidney damage and dysfunction and inhibiting the toxicity induced by GNPs in rats.Methods: Kidney function was assessed using various serum biomarkers, including blood urea nitrogen (BUN), uric acid (URIC), and creatinine (CR), while toxicity was evaluated by measuring the biomarkers glutathione (GSH) and malondialdehyde (MDA) in kidney tissues. Results: Administration of GNPs to the rats severely affected the serum kidney biomarkers, as confirmed by the notable increases in BUN, URIC, and CR. Substantial changes in the levels of the biomarkers MDA and GSH in the kidney tissues were also observed, with a reduced level of GSH and elevated MDA activity. The administration of Qur or Arg exerted a protective effect against GNP-induced inflammatory kidney damage and toxicity, but with different responses according to their evaluated normalized values.Conclusion: This study demonstrates the beneficial effects of supplementation with Qur or Arg during the treatment with GNPs, potentially providing a powerful tool for cancer therapy. Keywords: gold nanoparticles, nephrotoxicity, lipid peroxidation, inflammatory damage, natural antioxidant

Transfer and Transcriptomic Profiling in Liver and Brain of European Eels ( Anguilla anguilla ) After Diet‐borne Exposure to Gold Nanoparticles

A nanometric revolution is underway, promising technical innovations in a wide range of applications and leading to a potential boost in environmental discharges. The propensity of nanoparticles (NPs) to be transferred throughout trophic chains and to generate toxicity was mainly assessed in primary consumers, whereas a lack of knowledge for higher trophic levels persists. The present study focused on a predatory fish, the European eel (Anguilla anguilla) exposed to gold NPs (AuNPs; 10 nm, polyethylene glycol–coated) for 21 d at 3 concentration levels in food: 0 (NP0), 1 (NP1), and 10 (NP10) mg Au kg−1. Transfer was assessed by Au quantification in eel tissues, and transcriptomic responses in the liver and brain were revealed by a high‐throughput RNA‐sequencing approach. Eels fed at NP10 presented an erratic feeding behavior, whereas Au quantification only indicated transfer to intestine and kidney of NP1‐exposed eels. Sequencing of RNA was performed in NP0 and NP1 eels. A total of 258 genes and 156 genes were significantly differentially transcribed in response to AuNP trophic exposure in the liver and brain, respectively. Enrichment analysis highlighted modifications in the immune system–related processes in the liver. In addition, results pointed out a shared response of both organs regarding 13 genes, most of them being involved in immune functions. This finding may shed light on the mode of action and toxicity of AuNPs in fish.Approches à différentes échelles pour caractériser les interactions cellulaires, le transfert trophique et les impacts toxiques de nanoparticules métalliques chez les organismes aquatiquesCOntinental To coastal Ecosystems: evolution, adaptability and governanc