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"Ahmed, Heba A."
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Evaluation of the antibacterial and antibiofilm effect of mycosynthesized silver and selenium nanoparticles and their synergistic effect with antibiotics on nosocomial bacteria
by
Mahmoud, Ekram Abdel-Rahman
,
Helmy, Mena Zarif
,
Ahmed, Heba A.
in
Analysis
,
Anti-Bacterial Agents - chemistry
,
Anti-Bacterial Agents - pharmacology
2025
Background
The healthcare sector faces a growing threat from the rise of highly resistant microorganisms, particularly Methicillin-resistant
Staphylococcus aureus
(MRSA) and multidrug-resistant
Pseudomonas aeruginosa
(MDR
P. aeruginosa
). Facing the challenge of antibiotic resistance, nanoparticles have surfaced as promising substitutes for antimicrobial therapy. Recent studies showcase the effectiveness of various fungi species in nanoparticle synthesis. Mycosynthesized silver nanoparticles (AgNPs) and selenium nanoparticles (SeNPs) using
Aspergillus carneus
MAK 259 has been investigated and demonstrate antibacterial, antibiofilm and synergistic activities against (MRSA) and (MDR
P. aeruginosa
).
Results
In the current research, silver nanoparticles (AgNPs) and selenium nanoparticles (SeNPs) were produced extracellularly using
A. carneus
MAK 259 culture supernatants. Colour change, an initial evaluation of the production of AgNPs and SeNPs. Then, UV absorption peaks at 410 nm and 260 nm confirmed the production of AgNPs and SeNPs, respectively. AgNPs and SeNPs were dispersed consistently between 5‒26 nm and 20–77 nm in size, respectively using TEM. FT-IR analysis was used for assessing proteins bound to the produced nanoparticles. The crystallinity and stability of AgNPs and SeNPs was confirmed using X-ray diffraction analysis and zeta potential measurements, respectively. Antibacterial, antibiofilm and synergistic effects of both (NPs) with antibiotics against MRSA and MDR
P. aeruginosa
were tested by Agar well diffusion, tissue culture plate and disc diffusion method respectively. Both (NPs) inhibited the growth of
P. aeruginosa
more than
S. aureus
. But, SeNPs was stronger. AgNPs had stronger antibiofilm effect especially on biofilms producing
S. aureus
. as regard synergestic effects, Both (NPs) had higher synergestic effects in combination with cell wall inhibiting antibiotics against
P. aeuroginosa
While, on
S. aureus
with antibiotics that inhibit protein synthesis and affect metabolic pathways.
Conclusions
Our study demonstrated that the mycosynthesized SeNPs had remarkable antibacterial effect while, mycosynthesized AgNPs exhibited a considerable antibiofilm effect. Both NPs exhibited higher synergistic effect with antibiotics with different modes of action. This approach could potentially enhance the efficacy of existing antibiotics, providing a new weapon against drug-resistant bacteria where the described silver and selenium nanoparticles play a pivotal role in revolutionizing healthcare practices, offering innovative solutions to combat antibiotic resistance, and contributing to the development of advanced medical technologies.
Journal Article
Tissue Plasminogen Activator Promotes TXNIP-NLRP3 Inflammasome Activation after Hyperglycemic Stroke in Mice
2020
Hyperglycemia has been shown to counterbalance the beneficial effects of tissue plasminogen activator (tPA) and increase the risk of intracerebral hemorrhage in ischemic stroke. Thioredoxin interacting protein (TXNIP) mediates hyperglycemia-induced oxidative damage and inflammation in the brain and reduces cerebral glucose uptake/utilization. We have recently reported that TXNIP-induced NLRP3 (NOD-like receptor pyrin domain-containing-3) inflammasome activation contributes to neuronal damage after ischemic stroke. Here, we tested the hypothesis that tPA induces TXNIP-NLRP3 inflammasome activation after ischemic stroke, in hyperglycemic mice. Acute hyperglycemia was induced in mice by intraperitoneal (IP) administration of a 20% glucose solution. This was followed by transient middle cerebral artery occlusion (t-MCAO), with or without intravenous (IV) tPA administered at reperfusion. The IV-tPA exacerbated hyperglycemia-induced neurological deficits, ipsilateral edema and hemorrhagic transformation, and accentuated peroxisome proliferator activated receptor-γ (PPAR-γ) upregulation and TXNIP/NLRP3 inflammasome activation after ischemic stroke. Higher expression of TXNIP in hyperglycemic t-MCAO animals augmented glucose transporter 1 (GLUT-1) downregulation and increased vascular endothelial growth factor-A (VEGF-A) expression/matrix metallopeptidase 9 (MMP-9) signaling, all of which result in blood brain barrier (BBB) disruption and increased permeability to endogenous immunoglobulin G (IgG). It was also associated with a discernible buildup of nitrotyrosine and accumulation of dysfunctional tight junction proteins: zonula occludens-1 (ZO-1), occludin and claudin-5. Moreover, tPA administration triggered activation of high mobility group box protein 1 (HMGB-1), nuclear factor kappa B (NF-κB), and tumor necrosis factor-α (TNF-α) expression in the ischemic penumbra of hyperglycemic animals. All of these observations suggest a powerful role for TXNIP-NLRP3 inflammasome activation in the tPA-induced toxicity seen with hyperglycemic stroke.
Journal Article
Manifestation of renin angiotensin system modulation in traumatic brain injury
by
Tauheed, Ishrat
,
Golnoush, Mirzahosseini
,
Ahmed, Heba A
in
Angiotensin AT1 receptors
,
Angiotensin II
,
Astrocytes
2021
Traumatic brain injury (TBI) alters brain function and is a crucial public health concern worldwide. TBI triggers the release of inflammatory mediators (cytokines) that aggravate cerebral damage, thereby affecting clinical prognosis. The renin angiotensin system (RAS) plays a critical role in TBI pathophysiology. RAS is widely expressed in many organs including the brain. Modulation of the RAS in the brain via angiotensin type 1 (AT1) and type 2 (AT2) receptor signaling affects many pathophysiological processes, including TBI. AT1R is highly expressed in neurons and astrocytes. The upregulation of AT1R mediates the effects of angiotensin II (ANG II) including release of proinflammatory cytokines, cell death, oxidative stress, and vasoconstriction. The AT2R, mainly expressed in the fetal brain during development, is also related to cognitive function. Activation of this receptor pathway decreases neuroinflammation and oxidative stress and improves overall cell survival. Numerous studies have illustrated the therapeutic potential of inhibiting AT1R and activating AT2R for treatment of TBI with variable outcomes. In this review, we summarize studies that describe the role of brain RAS signaling, through AT1R and AT2R in TBI, and its modulation with pharmacological approaches.
Journal Article
Coagulation parameters abnormalities and their relation to clinical outcomes in hospitalized and severe COVID-19 patients: prospective study
by
Elbadry, Mahmoud I.
,
Esmaeel, Hend M.
,
Ahmed, Heba A.
in
692/308
,
692/53/2422
,
Blood Coagulation
2022
There has been growing attention toward the predictive value of the coagulation parameters abnormalities in COVID-19. The aim of the study was to investigate the role of coagulation parameters namely Prothrombin concentration (PC), activated Partial thromboplastin Time (aPTT), D-Dimer (DD), Anti Thrombin III (ATIII) and fibrinogen (Fg) together with hematological, and biochemical parameters in predicting the severity of COVID-19 patients and estimating their relation to clinical outcomes in hospitalized and severe COVID-19 Patients. In a prospective study, a total of 267 newly diagnosed COVID-19 patients were enrolled. They were divided into two groups; hospitalized group which included 144 patients and non-hospitalized group that included 123 patients. According to severity, the patients were divided into severe group which included 71 patients and non-severe group that included 196 patients who were admitted to ward or not hospitalized. Clinical evaluation, measurement of coagulation parameters, biochemical indices, outcome and survival data were recorded. Hospitalized and severe patients were older and commonly presented with dyspnea (P ≤ 0.001). Differences in coagulation parameters were highly significant in hospitalized and severe groups in almost all parameters, same for inflammatory markers. D-dimer, AT-III and LDH showed excellent independently prediction of severity risk. With a cut-off of > 2.0 ng/L, the sensitivity and specificity of D dimer in predicting severity were 76% and 93%, respectively. Patients with coagulation abnormalities showed worse survival than those without (p = 0.002). Early assessment and dynamic monitoring of coagulation parameters may be a benchmark in the prediction of COVID-19 severity and death.
Journal Article
Extended-spectrum β-lactamase-producing E. coli from retail meat and workers: genetic diversity, virulotyping, pathotyping and the antimicrobial effect of silver nanoparticles
by
El Feky, Tamer M.
,
Elamin, Amina M.
,
Elsohaby, Ibrahim
in
Animals
,
Antibiotic resistance
,
Antibiotics
2023
Background
The spread of extended-spectrum
β
-lactamases (ESBL) producing
E. coli
from food animals and the environment to humans has become a significant public health concern. The objectives of this study were to determine the occurrence, pathotypes, virulotypes, genotypes, and antimicrobial resistance patterns of ESBL-producing
E. coli
in retail meat samples and workers in retail meat shops in Egypt and to evaluate the bactericidal efficacy of silver nanoparticles (AgNPs-H
2
O
2
) against multidrug resistant (MDR) ESBL-producing
E. coli
.
Results
A total of 250 retail meat samples and 100 human worker samples (hand swabs and stool) were examined for the presence of ESBL- producing
E. coli
. Duck meat and workers’ hand swabs were the highest proportion of ESBL- producing
E. coli
isolates (81.1%), followed by camel meat (61.5%). Pathotyping revealed that the isolates belonged to groups A and B1. Virulotyping showed that the most prevalent virulence gene was Shiga toxin 2 (
stx2
) associated gene (36.9%), while none of the isolates harbored
stx1
gene. Genotyping of the identified isolates from human and meat sources by REP-PCR showed 100% similarity within the same cluster between human and meat isolates. All isolates were classified as MDR with an average multiple antibiotic resistance (MAR) index of 0.7. AgNPs-H
2
O
2
at concentrations of 0.625, 1.25, 2.5 and 5 μg/mL showed complete bacterial growth inhibition.
Conclusions
Virulent MDR ESBL-producing
E. coli
were identified in retail meat products in Egypt, posing significant public health threats. Regular monitoring of ESBL-producing
E. coli
frequency and antimicrobial resistance profile in retail meat products is crucial to enhance their safety. AgNPs-H
2
O
2
is a promising alternative for treating MDR ESBL-producing
E. coli
infections and reducing antimicrobial resistance risks.
Journal Article
RAS modulation prevents progressive cognitive impairment after experimental stroke: a randomized, blinded preclinical trial
by
Fouda, Abdelrahman Y.
,
Pillai, Bindu
,
Ahmed, Heba A.
in
Aging
,
Alzheimer's disease
,
Amyloid beta-Peptides - pharmacology
2018
Background
With the aging population, the prevalence and incidence of cerebrovascular disease will continue to rise, as well as the number of individuals with vascular cognitive impairment/dementia (VCID). No specific FDA-approved treatments for VCID exist. Although clinical evidence supports that angiotensin receptor blockers (ARBs) prevent cognitive decline in older adults, whether ARBs have a similar effect on VCID after stroke is unknown. Moreover, these agents reduce BP, which is undesirable in the acute stroke period, so we believe that giving C21 in this acute phase or delaying ARB administration would enable us to achieve the neurovascular benefits without the risk of unintended and potentially dangerous, acute BP lowering.
Methods
The aim of our study was to determine the impact of candesartan (ARB) or compound-21 (an angiotensin type 2 receptor––AT2R––agonist) on long-term cognitive function post-stroke, in spontaneously hypertensive rats (SHRs). We hypothesized that AT2R stimulation, either directly with C21, or indirectly by blocking the angiotensin type 1 receptor (AT1R) with candesartan, initiated after stroke, would reduce cognitive impairment. Animals were subjected to a 60-min transient middle cerebral artery occlusion and randomly assigned to either saline/C21 monotherapy, for the full study duration (30 days), or given sequential therapy starting with saline/C21 (7 days) followed by candesartan for the remainder of the study (21 days). Outcome measures included sensorimotor/cognitive-function, amyloid-β determination, and histopathologic analyses.
Results
Treatment with RAS modulators effectively preserved cognitive function, reduced cytotoxicity, and prevented chronic-reactive microgliosis in SHRs, post-stroke. These protective effects were apparent even when treatment was delayed up to 7 days post-stroke and were independent of blood pressure and β-amyloid accumulation.
Conclusion
Collectively, our findings demonstrate that RAS modulators effectively prevent cognitive impairment after stroke, even when treatment is delayed.
Journal Article
Endothelial Thioredoxin-Interacting Protein Depletion Reduces Hemorrhagic Transformation in Hyperglycemic Mice after Embolic Stroke and Thrombolytic Therapy
2021
We hypothesize that endothelial-specific thioredoxin-interacting protein knock-out (EC-TXNIP KO) mice will be more resistant to the neurovascular damage (hemorrhagic-transformation-HT) associated with hyperglycemia (HG) in embolic stroke. Adult-male EC-TXNIP KO and wild-type (WT) littermate mice were injected with-streptozotocin (40 mg/kg, i.p.) for five consecutive days to induce diabetes. Four-weeks after confirming HG, mice were subjected to embolic middle cerebral artery occlusion (eMCAO) followed by tissue plasminogen activator (tPA)-reperfusion (10 mg/kg at 3 h post-eMCAO). After the neurological assessment, animals were sacrificed at 24 h for neurovascular stroke outcomes. There were no differences in cerebrovascular anatomy between the strains. Infarct size, edema, and HT as indicated by hemoglobin (Hb)-the content was significantly higher in HG-WT mice, with or without tPA-reperfusion, compared to normoglycemic WT mice. Hyperglycemic EC-TXNIP KO mice treated with tPA tended to show lower Hb-content, edema, infarct area, and less hemorrhagic score compared to WT hyperglycemic mice. EC-TXNIP KO mice showed decreased expression of inflammatory mediators, apoptosis-associated proteins, and nitrotyrosine levels. Further, vascular endothelial growth factor-A and matrix-metalloproteinases (MMP-9/MMP-3), which degrade junction proteins and increase blood-brain-barrier permeability, were decreased in EC-TXNIP KO mice. Together, these findings suggest that vascular-TXNIP could be a novel therapeutic target for neurovascular damage after stroke.
Journal Article
comparative evaluation of PCR- based methods for species- specific determination of African animal trypanosomes in Ugandan cattle
by
Welburn, Susan C
,
Picozzi, Kim
,
Ahmed, Heba A
in
Animals
,
Biomedical and Life Sciences
,
Biomedicine
2013
BACKGROUND: In recent years, PCR has been become widely applied for the detection of trypanosomes overcoming many of the constraints of parasitological and serological techniques, being highly sensitive and specific for trypanosome detection. Individual species-specific multi-copy trypanosome DNA sequences can be targeted to identify parasites. Highly conserved ribosomal RNA (rRNA) genes are also useful for comparisons between closely related species. The internal transcribed spacer regions (ITS) in particular are relatively small, show variability among related species and are flanked by highly conserved segments to which PCR primers can be designed. Individual variations in inter-species length makes the ITS region a useful marker for identification of multiple trypanosome species within a sample. METHODS: Six hundred blood samples from cattle collected in Uganda on FTA cards were screened using individual species-specific primers for Trypanosoma congolense, Trypanosoma brucei and Trypanosoma vivax and compared to a modified (using eluate extracted using chelex) ITS-PCR reaction. RESULTS: The comparative analysis showed that the species-specific primer sets showed poor agreement with the ITS primer set. Using species-specific PCR for Trypanozoon, a prevalence of 10.5% was observed as compared to 0.2% using ITS PCR (Kappa = 0.03). For Trypanosoma congolense, the species-specific PCR reaction indicated a prevalence of 0% compared to 2.2% using ITS PCR (Kappa = 0). For T. vivax, species-specific PCR detected prevalence of 5.7% compared to 2.8% for ITS PCR (Kappa = 0.29). CONCLUSIONS: When selecting PCR based tools to apply to epidemiological surveys for generation of prevalence data for animal trypanosomiasis, it is recommended that species-specific primers are used, being the most sensitive diagnostic tool for screening samples to identify members of Trypanozoon (T. b. brucei s.l). While ITS primers are useful for studying the prevalence of trypanosomes causing nagana (in this study the species-specific primers did not detect the presence of T. congolense) there were discrepancies between both the species-specific primers and ITS for the detection of T. vivax.
Journal Article
The Brain AT2R—a Potential Target for Therapy in Alzheimer’s Disease and Vascular Cognitive Impairment: a Comprehensive Review of Clinical and Experimental Therapeutics
2020
Dementia is a potentially avertable tragedy, currently considered among the top 10 greatest global health challenges of the twenty-first century. Dementia not only robs individuals of their dignity and independence, it also has a ripple effect that starts with the inflicted individual’s family and projects to the society as a whole. The constantly growing number of cases, along with the lack of effective treatments and socioeconomic impact, poses a serious threat to the sustainability of our health care system. Hence, there is a worldwide effort to identify new targets for the treatment of Alzheimer’s disease (AD), the leading cause of dementia. Due to its multifactorial etiology and the recent clinical failure of several novel amyloid-β (Aβ) targeting therapies, a comprehensive “multitarget” approach may be most appropriate for managing this condition. Interestingly, renin angiotensin system (RAS) modulators were shown to positively impact all the factors involved in the pathophysiology of dementia including vascular dysfunction, Aβ accumulation, and associated cholinergic deficiency, in addition to tau hyperphosphorylation and insulin derangements. Furthermore, for many of these drugs, the preclinical evidence is also supported by epidemiological data and/or preliminary clinical trials. The purpose of this review is to provide a comprehensive update on the major causes of dementia including the risk factors, current diagnostic criteria, pathophysiology, and contemporary treatment strategies. Moreover, we highlight the angiotensin II receptor type 2 (AT2R) as an effective drug target and present ample evidence supporting its potential role and clinical applications in cognitive impairment to encourage further investigation in the clinical setting.
Journal Article
best practice for preparation of samples from FTA®cards for diagnosis of blood borne infections using African trypanosomes as a model system
by
Hide, Geoff
,
Welburn, Susan C
,
Picozzi, Kim
in
Biomedical and Life Sciences
,
Biomedicine
,
blood
2011
BACKGROUND: Diagnosis of blood borne infectious diseases relies primarily on the detection of the causative agent in the blood sample. Molecular techniques offer sensitive and specific tools for this although considerable difficulties exist when using these approaches in the field environment. In large scale epidemiological studies, FTA®cards are becoming increasingly popular for the rapid collection and archiving of a large number of samples. However, there are some difficulties in the downstream processing of these cards which is essential for the accurate diagnosis of infection. Here we describe recommendations for the best practice approach for sample processing from FTA®cards for the molecular diagnosis of trypanosomiasis using PCR. RESULTS: A comparison of five techniques was made. Detection from directly applied whole blood was less sensitive (35.6%) than whole blood which was subsequently eluted from the cards using Chelex®100 (56.4%). Better apparent sensitivity was achieved when blood was lysed prior to application on the FTA cards (73.3%) although this was not significant. This did not improve with subsequent elution using Chelex®100 (73.3%) and was not significantly different from direct DNA extraction from blood in the field (68.3%). CONCLUSIONS: Based on these results, the degree of effort required for each of these techniques and the difficulty of DNA extraction under field conditions, we recommend that blood is transferred onto FTA cards whole followed by elution in Chelex®100 as the best approach.
Journal Article