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Elkhatib, Walid F.

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0000-0001-5815-3200
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56593725900
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Walid F. Elkhatib
Last Name
Elkhatib
First Name
Walid F.
Main Affiliation
Galala University
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Professor Head of Microbiology Departmen

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  • Publication
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    The antibacterial effect and the incidence of post-operative pain after the application of nano-based intracanal medications during endodontic retreatment: a randomized controlled clinical trial
    (Springer, 2021-10-25) Fahim, Mahmoud M.; Saber, Shehab Eldin Mohamed; Nagy, Mohamed Mokhtar; Schafer, Edgar; Elkhatib, Walid F.
    Objective This clinical trial aimed to evaluate the effect of nano-silver and nano-calcium hydroxide intracanal medicaments (ICM) during retreatment regarding their antibacterial effect and their effect on post-operative pain and flare-ups. Materials and methods Sixty-nine patients scheduled for endodontic retreatment were included in this randomized clinical trial and randomly allocated to 3 equal groups (n = 23) according to the type of ICM used. The first microbial sampling (S1) representing the original microbiota was obtained after the removal of the old canal filling. After chemo-mechanical debridement, another sample (S2) was obtained representing the microbial state before ICM application. Patients were randomly allocated to receive either nano-silver (nano-Ag), nano-calcium hydroxide (nano-CH), or calcium hydroxide (CH) as ICM. Patients rated their pain pre-operatively and then after 6, 12, 24, 48, and 72 h. During the second visit (7 days later), the last microbial sample (S3) was obtained after removal of the ICM. Reduction of total bacterial and total E. faecalis counts and the biofilm-forming capability of the existing microbiota were determined. Results Results showed reduction in total bacterial count, total E. faecalis count and the biofilm-forming,capability of the existing microbiota after chemo-mechanical debridement (S1-S2) and after the application of ICM (S3-S2). However, the reduction after cleaning and shaping was significantly more pronounced (p < 0.001) compared to the effect of ICM application, with no difference between the 3 ICM (p > 0.05). Post-operative pain was significantly reduced at the 48- and 72-h intervals after the application of nano-Ag and nano-CH only (p < 0.001), with no significant difference between these two ICM (p > 0.05). The incidence of flare-ups in all groups was similar (p > 0.05). Conclusions The antibacterial effect of the nano-Ag and nano-CH was equivalent to that of CH, but they contributed to better pain control.
  • Publication
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    Improvement of caffeic acid biotransformation into para‐hydroxybenzoic acid by CI‐24 via gamma irradiation and model‐based optimization.
    (John Wiley & Sons, 2021-04-19) Singab, Raghda Abdelnasser; Elleboudy, Nooran Sherif; Yassein, Mahmoud Abdulmegead; Hassouna, Nadia Adelhaleem; Elkhatib, Walid F.
    Para-hydroxybenzoic acid (PHBA) has great potential in biological applications due to its putative antiviral activity against SARS-CoV-2 and its antimicrobial activity in the face of the radically increasing number of multidrug-resistant pathogens. This is in addition to its antimutagenic, anti-inflammatory, antioxidant, hypoglycemic, antiestrogenic, and antiplatelet aggregating activities. In this study, an approximate sixfold increase in the production of PHBA was achieved via biotransformation of caffeic acid by Candida albicans. The improvement was performed in two steps: first, through mutation by gamma irradiation (5 KGy dose), resulting in the recovery of a mutant (CI-24), which produced approximately triple the amount of PHBA produced by the wild-type isolate. Then, biotransformation by this mutant was further optimized via response surface methodology model-based optimization. The maximum PHBA production (7.47 mg/mL) was obtained in a fermentation medium composed of 1% w/v yeast extract as a nitrogen source, with an initial pH of 6.6, incubated at 28 °C at an agitation rate of 250 rpm. To further enhance the performance and economics of the process, cells of the CI-24 mutant were immobilized in calcium alginate beads and could retain an equivalent biotransformation capacity after three successive biotransformation cycles.
  • Publication
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    Biogenic and biocompatible silver nanoparticles for an apoptotic anti-ovarian activity and as polydopamine-functionalized antibiotic carrier for an augmented antibiofilm activity.
    (Elsevier, 2021-10-01) Aboelmaati, Mohamed G.; Abdel Gaber, Sara A.; Soliman, Wafaa E.; Abdelhameed, Amr M.; Sahyon, Heba A.; El-Kemary, Maged; Elkhatib, Walid F.
    Silver nanoparticles (AgNPs) could be employed in the combat against COVID-19, yet are associated with toxicities. In this study, biogenic and biocompatible AgNPs using the agro-waste, non-edible Hibiscus sabdariffa stem were synthesized. Under optimized reaction conditions, synthesized green AgNPs were crystalline, face cubic centered, spherical with a diameter of around 17 nm and a surface charge of -20 mV. Their murine lethal dose 50 (LD50) was 4 folds higher than the chemical AgNPs. Furthermore, they were more murine hepato- and nephro-tolerated than chemical counterparts due to activation of Nrf-2 and HO-1 pathway. They exerted an apoptotic anti-ovarian cancer activity with IC50 value 6 times more than the normal cell line. Being functionalized with polydopamine and conjugated to either moxifloxacin or gatifloxacin, the conjugates exerted an augmented antibiofilm activity against Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii biofilms that was significantly higher than antibiotic alone or functionalized AgNPs suggesting a synergistic activity. In conclusion, this study introduced a facile one-pot synthesis of biogenic and biocompatible AgNPs with preferential anti-cancer activity and could be utilized as antibiotic delivery system for a successful eradication of Gram-negative biofilms.
  • Publication
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    Protective Role of Copper Oxide-Streptomycin Nano-drug Against Potato Brown Rot Disease Caused by Ralstonia solanacearum
    (Springer Nature, 2021-04-15) Attia, Mohamed S.; Balabel, Naglaa M.; Ababutain, Ibtisam M.; Osman, Mahmoud S.; Nofel, Mohamed M.; Abd Elkodous, Mohamed; El-Batal, Ahmed I.; Elkhatib, Walid F.; El-Sayyad, Gharieb Saied
    Potato plants can be infected by different bacterial diseases, among them, the potato brown rot disease, caused by Ralstonia solanacearum. The novelty of the present research is to assess the potential impact of the synthesized copper oxide NPs (CuO NPs)-streptomycin nano-drug synthesized by gamma irradiation for inducing the systemic resistance against potato brown rot disease. CuO NPs-streptomycin was completely-characterized by UV–Vis., XRD, FTIR, HRTEM, SEM, and EDX elemental analysis. In the greenhouse experiment, the efficiency of CuO NPs was tested after three times of application. Disease index percent, phytochemicals, and metabolic indicators of resistance (as a response to induction of systemic resistance) were investigated. Our results indicated that treatment with CuO NPs during planting was more effective for increasing the protection percent by 55.8% and reducing the disease severity by 37.5% in the infected potato plants. CuO NPs-streptomycin increased not only the photosynthetic pigments but also the osmolytes contents. The highest reduction in malondialdehyde (44.89%) and hydrogen peroxide (32.9%) contents was achieved in the case of potato plants treated one week after planting. Therefore, it suggested applying CuO NPs-streptomycin in controlling plant disease since they are cost-effective and eco-friendly.
  • Publication
    Metadata only
    Phenotypic characterization of NKT-like cells and evaluation of specifically related cytokines for the prediction of unexplained recurrent miscarriage
    (ELSEVIER, 2021-11-15) Khalaf, Wafaa S.; Mahmoud, Mohammad R.A.; Hashem, Hany R.; Soliman, Wafaa E.; Elkhatib, Walid F.
    Problem Immune system dysregulation is a major cause of unexplained recurrent miscarriage (URM). Women with URM need screening for their pregnancy microenvironment and immune regulators, to prevent spontaneous abortion. Method of study In this study, we evaluated NKT-like cell subsets in the peripheral venous blood of women with URM using flow cytometry. The expression levels of specifically related Th1 cytokines (IFN-γ and IL-2), Th2 cytokine (IL-4), and Th17 cytokines (IL-17), were measured using enzyme-linked immunosorbent assay. Results The percentage of CD16+CD56+NKT-like (Double Positive NKT-like; DPNKT-like) cell subset and the levels of IL-2 and IFN-γ were significantly elevated in the blood of non-pregnant and pregnant patients with URM compared with the healthy control groups, and these parameters were significantly increased after pregnancy in the same patients with URM. Based on the prevalence of the candidate immunological factors in patients with URM, the prognostic significance of the NKT-like cell subsets, IFN-γ, and IL-2 profiles were evaluated as potential predictors of URM. A cut-off point of 2.55% for the DPNKT-like cell subset in the blood and cut-off values of 39.5 and 20.5 pg/ml for the levels of IFN-γ and IL-2, respectively could be used for the prediction of the risk of spontaneous abortion. To the best of our knowledge, this is the first study that described the prognostic significance of the aforementioned immunological parameters before and after pregnancy, and highlighted the correlation of NKT-like cells and the candidate Th1 cytokines with pregnancy loss in women with URM. Conclusions DPNKT-like cells, IFN-γ, and IL-2 patient profiles could be used as markers to predict the risk of miscarriage in patients with URM.