RESUMEN

This study investigates the photon interaction mechanism of various small molecule radiosensitizers, including Hydrogen Peroxide, Nimorazole, 5-Fluorouracil, NVX-108, and others, using the MCNP 6.3 Monte Carlo simulation code. The simulations focused on quantifying the linear attenuation coefficients, mean free path, and accumulation factors of these radiosensitizers, as well as their interactions in a simulated spherical water phantom irradiated with a 100 keV mono-energetic X-ray source. Our findings reveal significant variations in deposited energy, collision events, and mean free path among the radiosensitizers, indicating different efficacy levels in enhancing radiation therapy. Notably, NVX-108 demonstrated the highest energy deposition, suggesting its potential as a highly effective radiosensitizer. The study also examined the individual attenuation properties of these radiosensitizers against energetic photons, with NVX-108 showing the highest attenuation coefficient and a shorter mean free path, further supporting its superior potential in effective radiosensitization. It can be concluded that NVX-108 has higher interaction tendency with the energetic photons comparing other small-molecules under investigation.

RESUMEN

Shewanella putrefaciens is an opportunistic pathogen rarely responsible for human infection. However, it has been reported that it causes skin and soft tissue infections and bacteremia in immune-compromised patients, such as cellulitis, abscesses, bacteremia, and wound infection. It is an oxidase and catalase-positive non-fermenter gram-negative rod that produces hydrogen sulfide. We report the case of a 90-year-old woman, who presented an invasive infectious burn wound associated with Shewanella putrefaciens bacteremia. She was admitted into the burn center of the military hospital M.S Nekkache of Algiers, suffering from 40% TBSA with a history of diabetes. After one week of admission, the patient complained of a high fever. Microbiological culture of the catheter tip was positive and showed pale colonies on the MacConkey agar, non-lactose fermenting plate. Nutritive agar medium culture showed red pale tan colonies with a concentration >103 CFU. Identification and antibiotic susceptibility were obtained by the Phoenix system (Becton-Dickinson, USA) as Shewanella putrefaciens. This was confirmed by standards and semi-automated microbiological techniques. Gram stain showed Gram-negative bacilli with positive oxidase and catalase reactions. Production of hydrogen sulfide was confirmed by the semi-automated API 20NE method (biomerieux, France). The isolate was resistant to gentamicin, amikacin, ceftazidime, aztreonam, amoxicillin- clavulanic acid, cefepime, trimethoprim/sulfamethoxazole, and nitrofurantoin. In our case, S. putrefaciens was found in a mixed culture with Klebsiella pneumoniae. No earlier exposure of the patient to marine water had been noticed. Blood culture indicated colonies growth of Acinetobacter baumannii. No further isolation of this bacteria was noticed after treatment. The patient was given imipenem, vancomycin and colistin. Despite our best efforts, the patient could not be saved because of sepsis and renal function failure.

Shewanella putrefaciens est une bactérie opportuniste, rarement responsable d'infections humaines. Elle a toutefois été rapportée comme cause d'infections de la peau et des tissus mous (cellulites, abcès, surinfections de plaies) et de bactériémies chez des patients immunodéprimés. C'est un bacille à Gram négatif non fermentant, oxydase et catalase +, producteur de sulfure d'hydrogène. Nous présentons le cas d'une patiente diabétique de 90 ans ayant subi une bactériémie issue d'une surinfection de brûlure à Shewanella putrefaciens. Elle était hospitalisée dans l'hôpital militaire MS. Nekkache d'Alger à la suite d'une brûlure touchant 40% SCT. Une fièvre élevée a été constatée à J7. La culture de l'extrémité distale du cathéter montrait, sur gélose de McConkey, des colonies pâles non fermentantes. Sur milieu enrichi, on observait >103 CFU rouge pâle, identifiées à Shewanella putrefaciens par le système Phoenix (Beckton-Dickinson), identification confirmée par les techniques microbiologiques standard et semi- automatiques. La coloration de Gram était négative, les réactions catalasique et oxydasique étaient positives. La production de sulfure d'hydrogène était par API 20NE semi- automatique (BioMérieux). La bactérie résistait à gentamicine, amikacine, ceftazidime, aztréonam, amoxicilline- acide clavulanique, céfépime, triméthoprime- sulfaméthoxazole et nitrofurantoïne. Shewanella putrefaciens était associée à Klebsiella pneumoniæ et les hémocultures poussaient à Acinetobacter baumannii. Il n'y avait pas de notion d'exposition antérieure à l'eau de mer. La bactérie n'a pas été retrouvée après traitement par imipénème, vancomycine et colimycine. La patiente est toutefois décédée de sepsis et insuffisance rénale aiguë.

RESUMEN

We conducted a thirty-four-month retrospective study in the Burns Center from June 2015 to 30 April 2018. A total of 1585 burn wound swabs were taken from 258 admitted patients, of both sex and average age from 2 to 84 years old. Out of the 1585 burn wound swabs, 79.12% were positive for bacterial growth. Gram-negative bacteria were the most common bacteria isolated from burn wound swabs (68.95%), followed by cocci gram positive (28.62%), which were represented mainly by Staphylococcus spp. and Enterococcus spp. species, and then other species such as candida spp. (2.41%). Staphylococcus aureus was found to be the most common isolate (of the 70 Staphylococcus aureus, 52 were methicillino-resistant MRSA) followed by Pseudomonas aeruginosa (n=58; 25.71%), Klebsiella pneumoniae (n=43; 20.15%), Acinetobacter baumannii (n=18; 18.70%), Proteus spp. (n=17; 7.91%), Escherichia coli (n=14; 5,75%), Enterobacter spp. (n=8; 3.22%), Candida spp. (n=6, 2.41%), Stenotrophomonas maltophilia (n=2; 1.73%), and lastly Enterococcus spp. and Citrobacter freundii (n=1; 1.73%). P. aeruginosa was the most frequent Gram-negative bacteria isolated (33.91%). Most of the species isolated were multidrug-resistant (MDR). Knowledge of the bacteria responsible for infectious complications and their antibiotic susceptibilities is a prerequisite for treating burn patients.

Nous avons revu rétrospectivement les 1 585 prélèvements cutanés réalisés sur les 258 patients (des 2 sexes, âgés de 2 à 84 ans) hospitalisés dans notre CTB entre juin 2015 et avril 2018 inclus, dont 79,12% étaient positifs. Les bactéries à Gram négatif prédominaient (68,95%), les Gram positif représentaient 28,62% et Candida 2,41%. Staphylococcus aureus était la bactérie la plus fréquente (70 pousses dont 52 SARM), suivie de Pseudomonas æruginosa (58 soit 25,71%), Klebsiella pneumoniæ (n=43; 20,15%), Acinetobacter baumannii (n=18; 18,70%), Proteus spp. (n=17; 7,91%), Escherichia coli (n=14; 5,75%), Enterobacter spp. (n=8; 3,22%), Candida spp. (n=6, 2,41%), Stenotrophomonas maltophilia (n=2; 1,73%), enfin Enterococcus spp et Citrobacter freundii (n=1; 1,73%). P. æruginosa était la bactérie à Gram négatif la plus fréquemment retrouvée (33,91%). La plupart des germes étaient des BMR. La connaissance des bactéries responsables d'infections et de leurs antibiogrammes est nécessaire au traitement des brûlés.

RESUMEN

BACKGROUND: Magnetic resonance imaging (MRI) contrast agents have an important role to differentiate healthy and diseased tissues. Access and design new contrast agents for the optimal use of MRI are necessary. This study aims to evaluate iron oxide-4A nanocomposite ability to act as a magnetic resonance imaging contrast agent. MATERIAL AND METHODS: Iron oxide-4A nanocomposite (F4A) was synthesized. MTT assay was used to consider the nanocomposite safety for cell culture. The T1 and T2 relaxation times were measured using a 1.5 Tesla clinical MRI scanner. Then the corresponding relaxivities were determined. RESULTS: The average particle diameter of the nanocomposite was 50 to 100 nm based on scanning electron microscope (SEM) image. A linear relationship between relaxation rates and the Fe concentration of the nanocomposite was obtained. The T1 and T2 relaxivities of the nanocomposite were calculated 5.413 and 1092.1 mM-1.s-1, respectively which led to the T2/T1 relaxivity ratio of 201.75. CONCLUSION: The high T2/T1 relaxivity ratio of the iron oxide-4A nanocomposite confirms it's potential to act as a T2 contrast agent.

RESUMEN

BACKGROUND: While the benefits of cone-beam computed tomography (CBCT) are well known in maxillofacial imaging, the use of this modality is not risk-free. OBJECTIVE: The aim of this study was to evaluate the exposure doses received by patients during maxillofacial imaging with CBCT. METHODS: Entrance surface dose (ESD) was measured by using thermoluminescent dosimeters (TLDs) attached to the eyes lids, parotid glands and thyroid of 64 patients in two imaging centers (A and B). Phantom dosimetry was performed by a cylindrical poly-methyl methacrylate (PMMA) head-size phantom and an ionization chamber for different exposure parameters. NewTom VGi and Planmeca Promax 3D CBCT scanners were used at centers A and B, respectively. RESULTS: The mean ESD of the eyes, parotid glands and thyroid were 2.57, 2.33 and 0.28 mGy in center A, 0.35, 2.11 and 0.37 mGy in center B, respectively. ESD of the eyes revealed a significant difference in two centers; in center B, it was 86.4% lower than center A. In the phantom dosimetry, the measured doses of NewTom VGi were 2.63 and 2.08 mGy, respectively by changing field of view (FOV) size from 8×8 cm2 (height × diameter) to 6×6 cm2. For Planmeca Promax 3D, it ranged from 0.98 to 3.24 mGy depending on exposure parameters. CONCLUSION: There is a wide range of radiation doses dependent on the units, patients and selected scan parameters. Inappropriate selection of exposure settings, especially FOV size, can seriously increase patient dose.

RESUMEN

The purpose of this study was to investigate the adsorption of uranium (VI) ions on the polypyrrole adsorbent. Polypyrrole was synthesized by a chemical method using polyethylene glycol, sodium dodecylbenzenesulfonate, and cetyltrimethylammonium bromide as the surfactant and iron (III) chloride as an oxidant in the aqueous solution. The effect of various surfactants on the synthesized polymers and their performance as the uranium adsorbent were investigated. Adsorbent properties were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. The effect of different parameters such as pH, contact time, initial metal ion concentrations, adsorbent dose, and the temperature was investigated in the batch system for uranium adsorption process. It has been illustrated that the adsorption equilibrium time is 7min. The results showed that the Freundlich model had the best agreement and the maximum adsorption capacity of polypyrrole for uranium (VI) was determined 87.72mg/g from Langmuir isotherm. In addition, the mentioned adsorption process was fast and the kinetic data were fitted to the Pseudo first and second order models. The adsorption kinetic data followed the pseudo-second-order kinetic model. Moreover, the thermodynamic parameters ΔG0, ΔH0 and ΔS0 showed that the uranium adsorption process by polypyrrole was endothermic and spontaneous.