Doaa Abdelrahaman

Carbapenem-resistant Klebsiella pneumoniae is a major threat to global health, with increasing incidence in developing countries, including Egypt. This study determined carbapenem-resistance prevalence among clinical K. pneumoniae isolates from two Egyptian tertiary hospitals, characterized the major carbapenemase genes, and assessed the transferability of the resistance plasmids. VITEK^® 2 and MALDI-TOF MS identified 94 non-duplicate isolates. Susceptibility was determined by Kirby–Bauer diffusion and VITEK^® 2. MICs of imipenem, meropenem and colistin were confirmed by broth microdilution. Isolates were classified as multidrug-resistant (MDR), extensively drug-resistant (XDR), or pandrug-resistant (PDR) according to established definitions. Phenotypic (modified Hodge test [MHT], modified carbapenem inactivation method [mCIM], modified Carba NP test [mCNP]) and genotypic (PCR/BlastN) evaluation of carbapenemase production and plasmid transferability by conjugation were carried out in 18 isolates, selected to represent every carbapenemase genotype identified in the collection. All isolates were MDR, and 94.68% were carbapenem-resistant and fulfilled the criteria for XDR, remaining susceptible only to colistin and tigecycline. Carbapenemase production was confirmed phenotypically in 98.9% and genotypically in 97.9% of isolates. bla_OXA-48 (94.7%) and bla_NDM-1 (69.1%) predominated, with 67.0% co-carriage; bla_KPC occurred in 5.3%. Conjugation transferred carbapenemase-encoding plasmids to Escherichia coli J53 from 77.8% (14/18) of donors, conferring carbapenem non-susceptibility in all transconjugants. All isolates were colistin-susceptible by broth microdilution, the reference method. The high XDR prevalence, along with the conjugative transferability of bla_OXA-48/bla_NDM-1, is consistent with a mobile carbapenemase-encoding plasmid reservoir in Egyptian tertiary care, highlighting the significance of carbapenemase surveillance and stewardship. Plasmid characterization and clonal typing were not performed and are required to define that reservoir fully.

Background and Objectives: Alzheimer’s disease (AD) is the most common neurodegenerative disorder in the world. Due to failure of the traditional drugs to produce a complete cure for AD, the search for new safe and effective lines of therapy has attracted the attention of ongoing research. Canagliflozin is an anti-diabetic agent with proven efficacy in the treatment of neurological disorders in which mitochondrial dysfunction, oxidative stress, apoptosis, and autophagy play a pathophysiological role. Elucidation of the potential effects of different doses of canagliflozin on AD induced by aluminium chloride in rats and exploration of the molecular mechanisms that may contribute to these effects were the primary objectives of the current study. Materials and Methods: In a rat model of AD, the effect of three different doses of canagliflozin on the behavioural, biochemical, and histopathological alterations induced by aluminium chloride was assessed. Results: Canagliflozin administered to aluminium chloride-treated animals induced dose-dependent normalisation in the behavioural tests, augmentation of the antioxidant defence mechanisms, inhibition of TXNIP/NLRP3 inflammasome signalling, modulation of the SIRT1/HMGB1 axis, interference with the pro-inflammatory and the pro-apoptotic mechanisms, and restoration of the mitochondrial functions and autophagy in the hippocampal tissues to approximately baseline values. In addition, canagliflozin exhibited an interesting dose-dependent ability to repress aluminium chloride-induced histopathological changes in the brain. Conclusions: The effects of canagliflozin on oxidative stress, mitochondrial functions, inflammatory pathways, and autophagy signals may open new gates towards the mitigation of the pathologic features of AD.

Melamine (ML) is a common environmental contaminant, commonly used in food fraud, representing a serious health hazard and jeopardizing human and animal health. Recently, nootkatone (NK), a naturally occurring sesquiterpenoid, has garnered considerable attention due to its potential therapeutic advantages. We investigated the potential mechanisms underlying the protective effects of NK against ML-induced liver injury in rats. Five groups were utilized: control, ML, NK10, ML-NK5, and ML-NK10. ML induced substantial hepatotoxicity, including considerable alterations in biochemical parameters and histology. The oxidative distress triggered by ML increased the generation of malondialdehyde (MDA) and nitric oxide (NO) and decreased levels of reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) activities. In addition, decreased expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) and increased nuclear factor kappa beta (NF-κB) expression levels were observed in hepatocytes, which indicated the occurrence of inflammatory changes following ML exposure. These alterations were alleviated by NK supplementation in a dose-dependent manner. The data revealed that the favorable effects of NK were attributed, at least in part, to its antioxidant and anti-inflammatory properties. Moreover, our results were supported by molecular docking studies that revealed a good fit and interactions between NK and antioxidant enzymes. Thus, the current study demonstrated that NK is a potential new food additive for the prevention or treatment of ML-induced toxicity.

Aflatoxin B₁ (AF) is an unavoidable environmental pollutant that contaminates food, feed, and grains, which seriously threatens human and animal health. Arabic gum (AG) has recently evoked much attention owing to its promising therapeutic potential. Thus, the current study was conducted to look into the possible mechanisms beyond the ameliorative activity of AG against AF-inflicted hepatic injury. Male Wistar rats were assigned into four groups: Control, AG (7.5 g/kg b.w/day, orally), AF (200 µg/kg b.w), and AG plus AF group. AF induced marked liver damage expounded by considerable changes in biochemical profile and histological architecture. The oxidative stress stimulated by AF boosted the production of plasma malondialdehyde (MDA) level along with decreases in the total antioxidant capacity (TAC) level and glutathione peroxidase (GPx) activity. Additionally, AF exposure was associated with down-regulation of the nuclear factor erythroid2–related factor2 (Nrf2) and superoxide dismutase1 (SOD1) protein expression in liver tissue. Apoptotic cascade has also been evoked following AF-exposure, as depicted in overexpression of cytochrome c (Cyto c), cleaved Caspase3 (Cl. Casp3), along with enhanced up-regulation of inflammatory mediators such as tumor necrosis factor-α (TNF-α), interleukin (IL)-6, inducible nitric oxide synthase (iNOS), and nuclear factor kappa-B transcription factor/p65 (NF-κB/p65) mRNA expression levels. Interestingly, the antioxidant and anti-inflammatory contents of AG may reverse the induced oxidative damage, inflammation, and apoptosis in AF-exposed animals.

New quinazoline derivatives were designed based on the structural modification of the reported inhibitors to enhance their selectivity toward Aurora A. The synthesized compounds were tested over Aurora A, and a cytotoxicity assay was performed over NCI cell lines to select the best candidate for further evaluation. Compound 6e (2-(3-bromophenyl)-8-fluoroquinazoline-4-carboxylic acid) was the most potent compound among the tested derivatives. A Kinase panel assay was conducted for compound 6e over 14 kinases to evaluate its selectivity profile. Further cell cycle and apoptosis analysis were evaluated for compound 6e over the MCF-7 cell line at its IC₅₀ of 168.78 µM. It arrested the cell cycle at the G1 phase and induced apoptosis. Molecular docking was performed to explore the possible binding mode of compound 6e into the active site. It showed significant binding into the main pocket in addition to potential binding interactions with the key amino acid residues. Accordingly, compound 6e can be considered a potential lead for further structural and molecular optimization of the quinazoline-based carboxylic acid scaffold for Aurora A kinase selective inhibition with apoptosis properties.

Although the combination of antibiotics is generally well-tolerated, they may have nephrotoxic effects. This study investigated whether tigecycline (TG) and gentamicin (GM) co-administration could accelerate renal damage. Male Wistar rats were randomly divided into six experimental groups: the control, TG7 (tigecycline, 7 mg/kg), TG14 (tigecycline, 14 mg/kg), GM (gentamicin, 80 mg/kg), TG7+GM, and TG14+GM groups. The combination of TG and GM evoked renal damage seen by the disruption of kidney function tests. The perturbation of renal tissue was mainly confounded to the TG and GM-induced oxidative damage, which was exhibited by marked increases in renal MDA (malondialdehyde) along with a drastic reduction in GSH (reduced-glutathione) content and CAT (catalase) activity compared to their individual treatments. More obvious apoptotic events and inflammation were also revealed by elevating the annexin-V and interleukin-6 (IL-6) levels, aside from the upregulation of renal PCNA (proliferating cell nuclear antigen) expression in the TG and GM concurrent treatment. The principal component analysis indicated that creatinine, urea, annexin-V, IL-6, and MDA all played a role in discriminating the TG and GM combined toxicity. Oxidative stress, inflammatory response, and apoptosis were the key mechanisms involved in this potentiated toxicity.