Publications by authors named "Heba A Ahmed"

27 Publications

  • Page 1 of 1

Verapamil as an Adjunct Therapy to Reduce tPA Toxicity in Hyperglycemic Stroke: Implication of TXNIP/NLRP3 Inflammasome.

Mol Neurobiol 2021 Apr 13. Epub 2021 Apr 13.

Department of Anatomy and Neurobiology, College of Medicine, The University of Tennessee Health Science Center, 875 Monroe Avenue, Wittenborg Bldg, Room-231, Memphis, TN, 38163, USA.

Thrombolytic therapy has remained quite challenging in hyperglycemic patients for its association with poor prognosis and increased hemorrhagic conversions. We recently showed that tissue plasminogen activator (tPA)-induced cerebrovascular damage is associated with thioredoxin-interacting protein (TXNIP) upregulation, which has an established role in the detrimental effects of hyperglycemia. In the present work, we investigated whether verapamil, an established TXNIP inhibitor, may provide protection against hyperglycemic stroke and tPA-induced blood-brain barrier (BBB) disruption. Acute hyperglycemia was induced by intraperitoneal administration of 20% glucose, 15 min prior to transient middle cerebral artery occlusion (tMCAO). Verapamil (0.15 mg/kg) or saline was intravenously infused with tPA at hyperglycemic reperfusion, 1 h post tMCAO. After 24 h of ischemia/reperfusion (I/R), mice were assessed for neurobehavioral deficits followed by sacrifice and evaluation of brain infarct volume, edema, and microbleeding. Alterations in TXNIP, inflammatory mediators, and BBB markers were further analyzed using immunoblotting or immunostaining techniques. As adjunctive therapy, verapamil significantly reduced tPA-induced BBB leakage, matrix metalloproteinase 9 (MMP-9) upregulation, and tight junction protein deregulation, which resulted in lesser hemorrhagic conversions. Importantly, verapamil strongly reversed tPA-induced TXNIP/NLRP3 (NOD-like receptor pyrin domain-containing-3) inflammasome activation and reduced infarct volume. This concurred with a remarkable decrease in high-mobility group box protein 1 (HMGB-1) and nuclear factor kappa B (NF-κB) stimulation, leading to less priming of NLRP3 inflammasome. This preclinical study supports verapamil as a safe adjuvant that may complement thrombolytic therapy by inhibiting TXNIP's detrimental role in hyperglycemic stroke.
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http://dx.doi.org/10.1007/s12035-021-02384-zDOI Listing
April 2021

Manifestation of renin angiotensin system modulation in traumatic brain injury.

Metab Brain Dis 2021 Apr 9. Epub 2021 Apr 9.

Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Wittenborg Building, Room-231, Memphis, TN, 38163, USA.

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 (AT) and type 2 (AT) receptor signaling affects many pathophysiological processes, including TBI. ATR is highly expressed in neurons and astrocytes. The upregulation of ATR mediates the effects of angiotensin II (ANG II) including release of proinflammatory cytokines, cell death, oxidative stress, and vasoconstriction. The ATR, 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 ATR and activating ATR for treatment of TBI with variable outcomes. In this review, we summarize studies that describe the role of brain RAS signaling, through ATR and ATR in TBI, and its modulation with pharmacological approaches.
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http://dx.doi.org/10.1007/s11011-021-00728-1DOI Listing
April 2021

Verapamil Prevents Development of Cognitive Impairment in an Aged Mouse Model of Sporadic Alzheimer's Disease.

Mol Neurobiol 2021 Mar 11. Epub 2021 Mar 11.

Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, 38163, USA.

Currently, dementia is the only leading cause of death that is still on the rise, with total costs already exceeding those of cancer and heart disease and projected to increase even further in the coming years. Unfortunately, there are no satisfactory treatments and attempts to develop novel, more effective treatments have been extremely costly, albeit unsuccessful thus far. This has led us to investigate the use of established drugs, licensed for other therapeutic indications, for their potential application in cognitive disorders. This strategy, referred to as "drug repositioning," has been successful in many other areas including cancer and cardiovascular diseases. To our knowledge, this is the first study to investigate the effects of long-term treatment with verapamil, a calcium channel blocker commonly prescribed for various cardiovascular conditions and recently applied for prevention of cluster headaches, on the development of cognitive impairment in aged animals. Verapamil was studied at a low dose (1mg/kg/d) in a mouse model of sporadic Alzheimer's disease (sAD). Oral treatment with verapamil or vehicle was started, 24 h post-intracerebroventricular (ICV) streptozotocin/(STZ), in 12-month-old animals and continued for 3 months. Cognitive function was assessed using established tests for spatial learning, short-term/working memory, and long-term/reference memory. Our findings demonstrate that long-term low-dose verapamil effectively prevents development of ICV/STZ-induced cognitive impairment. It mitigates the astrogliosis and synaptic toxicity otherwise induced by ICV/STZ in the hippocampus of aged animals. These findings indicate that long-term, low-dose verapamil may delay progression of sAD in susceptible subjects of advanced age.
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http://dx.doi.org/10.1007/s12035-021-02350-9DOI Listing
March 2021

Pet birds as potential reservoirs of virulent and antibiotic resistant zoonotic bacteria.

Comp Immunol Microbiol Infect Dis 2021 Apr 15;75:101606. Epub 2020 Dec 15.

Department of Animal Medicine, Division of Infectious Diseases, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Sharkia Governorate, Egypt; Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, C1A 4P3, Canada.

Bacterial pathogens carried by pet birds are considered a risk for birds, workers, and pet owners. This study investigated the potential of pet birds as reservoirs for virulent multidrug-resistant (MDR) zoonotic bacteria and assessed the genetic relatedness and diversity of bacterial isolates from pet birds and human contacts. Cloacal and tracheal swabs from 125 pet birds and 70 hand swabs from human contacts were collected. The results revealed that the pet birds were reservoirs for Escherichia coli, Klebsiella pneumoniae (17.6 %, each), and Staphylococcus aureus (15.2 %). These isolates were also identified in their human contacts, at percentages of 14.3 %, 12.9 %, and 24.3 %, respectively. Virulence associated genes were identified from E. coli (stx2, stx2f, eaeA, and hlyA), K. pneumoniae (fimH, TraT, and magA), and S. aureus (PVL, hly, sea, sed genes) isolates. Multidrug-resistant E. coli, K. pneumoniae, and S. aureus were highly prevalent (81.3 %, 90.3 %, and 61.1 %, respectively). The genetic relationship between the E. coli and K. pneumoniae isolates from the pet birds and human contacts were determined by ERIC-PCR, while, RAPD-PCR was used for the S. aureus isolates. ERIC-PCR was found to have the highest discriminatory power. The clustering of the isolates from the pet birds and human contacts indicated potential transmission between the birds and workers. In conclusion, pet birds could act as potential reservoirs for zoonotic bacterial pathogens; thus, posing a risk to their human contacts.
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http://dx.doi.org/10.1016/j.cimid.2020.101606DOI Listing
April 2021

Diabetic rats are more susceptible to cognitive decline in a model of microemboli-mediated vascular contributions to cognitive impairment and dementia.

Brain Res 2020 12 28;1749:147132. Epub 2020 Sep 28.

Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States.

Vascular disease plays an important role in all kinds of cognitive impairment and dementia. Diabetes increases the risk of vascular disease and dementia. However, it is not clear how existing vascular disease in the brain accelerates the development of small vessel disease and promotes cognitive dysfunction in diabetes. We used microemboli (ME) injection model in the current study to test the hypothesis that cerebrovascular dysfunction in diabetes facilitates entrapment of ME leading to inflammation and cognitive decline. We investigated cognitive function, axonal/white matter (WM) changes, neurovascular coupling, and microglial activation in control and diabetic male and female Wistar rats subjected to sham or low/high dose ME injection. Diabetic male animals had cognitive deficits, WM demyelination and greater microglial activation than the control animals even at baseline. Functional hyperemia gradually declined in diabetic male animals after ME injection. Both low and high ME injection worsened WM damage and increased microglial activation in diabetic male and female animals. Low ME did not cause cognitive decline in controls, while promoting learning/memory deficits in diabetic female rats and no further decline in diabetic male animals. High ME led to cognitive decline in control male rats and exacerbated the deficits in diabetic cohort. These results suggest that the existing cerebrovascular dysfunction in diabetes may facilitate ME-mediated demyelination leading to cognitive decline. It is important to integrate comorbidities/sex as a biological variable into experimental models for the development of preventive or therapeutic targets.
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http://dx.doi.org/10.1016/j.brainres.2020.147132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606832PMC
December 2020

The NLRP3 inflammasome: a potential therapeutic target for traumatic brain injury.

Neural Regen Res 2021 Jan;16(1):49-57

Department of Anatomy and Neurobiology; Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA.

Although the precise mechanisms contributing to secondary brain injury following traumatic brain injury are complex and obscure, a number of studies have demonstrated that inflammatory responses are an obvious and early feature in the pathogenesis of traumatic brain injury. Inflammasomes are multiprotein complexes that prompt the stimulation of caspase-1 and subsequently induce the maturation and secretion of proinflammatory cytokines, such as interleukin-1β and interleukin-18. These cytokines play a pivotal role in facilitating innate immune responses and inflammation. Among various inflammasome complexes, the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is the best characterized, a crucial role for NLRP3 has been demonstrated in various brain diseases, including traumatic brain injury. Several recent studies have revealed the contribution of NLRP3 inflammasome in identifying cellular damage and stimulating inflammatory responses to aseptic tissue injury after traumatic brain injury. Even more important, blocking or inhibiting the activation of the NLRP3 inflammasome may have substantial potential to salvage tissue damage during traumatic brain injury. In this review, we summarize recently described mechanisms that are involved in the activation and regulation of the NLRP3 inflammasome. Moreover, we review the recent investigations on the contribution of the NLRP3 inflammasome in the pathophysiology of TBI, and current advances and challenges in potential NLRP3-targeted therapies. A significant contribution of NLRP3 inflammasome activation to traumatic brain injury implies that therapeutic approaches focused on targeting specific inflammasome components could significantly improve the traumatic brain injury outcomes.
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http://dx.doi.org/10.4103/1673-5374.286951DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7818859PMC
January 2021

Accuracy of PCR, mycobacterial culture and interferon-γ assays for detection of Mycobacterium bovis in blood and milk samples from Egyptian dairy cows using Bayesian modelling.

Prev Vet Med 2020 Aug 7;181:105054. Epub 2020 Jun 7.

Department of Bacteriology, Immunology and Mycology, Faculty of Veterinary Medicine, Benha University, Egypt.

The number of bovine tuberculosis (bTB) infected dairy herds in Egypt is growing and this calls for accurate and reliable diagnostic methods at cow level for cost-effective bTB eradication as culling of the whole herd is not economically sustainable. The present study aimed to estimate the sensitivity (Se) and specificity (Sp) of PCR, mycobacterial culture and interferon-γ (IFN-γ) assays for Mycobacterium bovis (M. bovis) detection in blood and milk samples from dairy cows in Egyptian dairy herds within a Bayesian framework. As a secondary objective, the distribution of true within-herd prevalence of M. bovis infection was estimated. Blood and milk samples were collected from 245 Holstein dairy cows in 11 Egyptian dairy herds and subjected to PCR, mycobacterial culture and IFN-γ testing. With respect to the detection of M. bovis in blood, IFN-γ recorded higher Se [0.97 (95% Posterior Credible Interval (PCI): 0.87-1.00)] than PCR [0.68 (95% PCI: 0.53-0.95)] and culture [0.22 (95% PCI: 0.13-0.37)]. However, Sp estimates of PCR [0.98 (95% PCI: 0.95-1.00)], culture [0.99 (95% PCI: 0.98-1.00)] and IFN-γ [0.97 (95% PCI: 0.88-1.00)] were comparable. As for milk samples, Se estimate of PCR [0.29 (95% PCI: 0.01-0.60)] was higher than that of culture [0.08 (95% PCI: 0.001-0.23)]. However, the Sp estimates of both tests were statistically similar. The estimated true within-herd prevalences of M. bovis varied across the tested bovine subpopulations and ranged between 0.06 and 0.66. In conclusion, IFN-γ registered a similar overall performance to PCR but was superior to mycobacterial culture. With its good accuracy and wide applicability, IFN-γ lends itself to use in the Egyptian bTB eradication program.
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http://dx.doi.org/10.1016/j.prevetmed.2020.105054DOI Listing
August 2020

The Brain AT2R-a Potential Target for Therapy in Alzheimer's Disease and Vascular Cognitive Impairment: a Comprehensive Review of Clinical and Experimental Therapeutics.

Mol Neurobiol 2020 Aug 12;57(8):3458-3484. Epub 2020 Jun 12.

Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee Health Science Center, 855 Monroe Avenue, Wittenborg Bldg, Room-231, Memphis, TN, 38163, USA.

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.
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http://dx.doi.org/10.1007/s12035-020-01964-9DOI Listing
August 2020

Tissue Plasminogen Activator Promotes TXNIP-NLRP3 Inflammasome Activation after Hyperglycemic Stroke in Mice.

Mol Neurobiol 2020 Jun 14;57(6):2495-2508. Epub 2020 Mar 14.

Department of Anatomy and Neurobiology, College of Medicine, The University of Tennessee Health Science Center, 875 Monroe Avenue, Wittenborg Bldg, Room-231, Memphis, TN, 38163, USA.

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.
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http://dx.doi.org/10.1007/s12035-020-01893-7DOI Listing
June 2020

Interleukin-27 and interleukin-35 in de novo acute myeloid leukemia: expression and significance as biological markers.

J Blood Med 2019 1;10:341-349. Epub 2019 Oct 1.

Department of Medical Oncology, South Egypt Cancer Institute, Assiut University, Assiut, Egypt.

Background And Objectives: IL27 and IL35 are regulatory T cells (T-regs) related cytokines; they were accused in eukemogenesis of acute myeloid leukemia (AML). This study aimed to assess the expression of these cytokines in de novo AML and investigate their role as biomarkers.

Subjects And Methods: Seventy newly diagnosed patients with primary AML and 30 matched healthy volunteers were recruited. AML diagnosis was confirmed with flowcytometric and immunophenotypic analyses, while ELISA was used to assess serum levels of IL27 and IL35 in patients and controls. Receiver operating characteristic curve analysis was used to estimate IL27 and IL35 optimum cutoff values for predicting AML.

Results: Serum levels of both cytokines were significantly higher in AML patients than controls (<0.001), with no effect of gender or French-American-British subtypes. Significant correlations of IL27 and IL35 with poor prognostic factors and with each other were detected in patients only. IL27 optimum cutoff for predicting AML was >43, AUC (0.926) with a sensitivity 74% and specificity 96.6% (<0.001), while for IL35>27.8, AUC (0.972) with 88% and 98% sensitivity and specificity, respectively (<0.001).

Conclusion: Conclusively, this study proved that IL27and IL35 could identify AML patients from healthy subjects, and their overexpression denotes poor prognosis. Based on the simplicity and wide availability of their detection technique we recommend the inclusion of IL27 and IL35 in the diagnostic/prognostic workup of AML; however, further longitudinal research is needed to prove their exact prognostic value.
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http://dx.doi.org/10.2147/JBM.S221301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6783395PMC
October 2019

Angiotensin receptor (AT2R) agonist C21 prevents cognitive decline after permanent stroke in aged animals-A randomized double- blind pre-clinical study.

Behav Brain Res 2019 02 5;359:560-569. Epub 2018 Oct 5.

Program in Clinical and Experimental Therapeutics, Charlie Norwood VA Medical Center and University of Georgia College of Pharmacy, Augusta, GA, United States; Departments of Neurology, Augusta University, Augusta, GA, United States. Electronic address:

Post stroke cognitive impairment (PSCI) is an understudied, long-term complication of stroke, impacting nearly 30-40% of all stroke survivors. No cure is available once the cognitive deterioration manifests. To our knowledge, this is the first study to investigate the long-term effects of C21 treatment on the development of PSCI in aged animals. Treatments with C21 or vehicle were administered orally, 24 h post-stroke, and continued for 30 days. Outcome measures for sensorimotor and cognitive function were performed using a sequence of tests, all blindly conducted and assessed at baseline as well as at different time points post-stroke. Our findings demonstrate that the angiotensin receptor (AT2R) agonist C21 effectively prevents the development of PSCI in aged animals.
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http://dx.doi.org/10.1016/j.bbr.2018.10.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6371811PMC
February 2019

Efflux Pump Inhibitors, Alpha-Tocopherol and Aspirin: Role in Campylobacter jejuni and Campylobacter coli Fluoroquinolone Resistance.

Microb Drug Resist 2019 Mar 2;25(2):203-211. Epub 2018 Oct 2.

4 Veterinary Hospital, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt .

This study aimed to investigate how efflux pump activity contributes to high fluoroquinolone (FQ) resistance in Campylobacter jejuni and Campylobacter coli isolates and to evaluate the modulatory effects of α-tocopherol and aspirin on FQ phenotypic resistance profiles. Minimum inhibitory concentration (MIC) values were obtained for different FQ agents following exposure to different efflux pump inhibitors (EPIs), including PaβN (50 μg/mL), which targets the cmeABC efflux system, and chlorpromazine (45 μg/mL) and verapamil (120 μg/mL), which target the MFS efflux system. The modulatory effects of aspirin (100 and 200 μg/mL) and α-tocopherol (4 and 10 μg/mL) on FQ resistance profiles were examined. PaβN had no effect on the MIC values of all FQ agents, while MFS efflux system inhibitors reduced the resistance level of different FQ agents and achieved an effect nearly comparable with that of α-tocopherol (10 μg/mL). Aspirin exerted a dose-dependent excitatory effect on phenotypic resistance profiles, and this may raise concerns about its usage in both veterinary and clinical settings. While an efflux system other than cmeABC may play a role in FQ resistance in Campylobacter species, lipophilic substances may represent a new approach for controlling efflux pump activities.
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http://dx.doi.org/10.1089/mdr.2018.0086DOI Listing
March 2019

Molecular identification of avian influenza virus subtypes H5N1 and H9N2 in birds from farms and live bird markets and in respiratory patients.

PeerJ 2018 5;6:e5473. Epub 2018 Sep 5.

Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.

Background: Avian influenza viruses (AIVs) have been endemic in Egypt since 2006, and the co-circulation of high-pathogenic avian influenza H5N1 and low-pathogenic avian influenza H9N2 subtypes in poultry has been reported; therefore, Egypt is considered a hotspot for the generation of new subtypes and genotypes. We aimed to characterize AIVs circulating on commercial farms and in live bird markets (LBMs) during the winters of 2015 and 2016 in the study area and to identify H5N1 and H9N2 viruses in respiratory patients.

Methods: In total, 159 samples were collected from ducks, pigeons and quails on farms ( = 59) and in LBMs ( = 100) and screened by real-time RT-PCR for H5N1 and H9N2 subtypes. Clinical and postmortem examination was carried out on birds from the farms. Positive H5N1 samples were sequenced and analysed for mutations. Tracheal swabs were also collected from 89 respiratory patients admitted to respiratory hospitals in the same study area.

Results: Overall, H5N1 was identified in 13.6% of birds from farms, while it was detected in 17% of birds in LBMs. Subtype H9N2 was only identified from pigeons on farms (6.5%) and LBMs (11.4%). Sequencing of the haemagglutination gene (HA) in nine representative H5N1 isolates revealed a multi-basic amino acid motif at the cleavage site (321-PQGEKRRKKR/GLF-333), which is characteristic of highly pathogenic AIV, in five of our isolates, while the other four isolates showed an amino acid substitution (Q322K) at this cleavage site to make it (321-P K GEKRRKKR/GLF-333). All the isolates belonged to clade 2.2.1.2, and a comparison of HA sequences at the amino acid level showed 98.8-100% homology among the nine isolates, while they showed 94.1-96.1% identity with reference strains and the commonly used vaccine strain in Egypt. Out of 89 respiratory patients, 3.4% were positive for H5N1 and no patients were positive for H9N2.

Discussion: Our results indicated the circulation of the endemic H5N1 and H9N2 viruses among poultry in 2015 and 2016. Birds on farms and in LBMs are reservoirs playing a role in the dissemination of the virus and producing a public health risk. The application of proper hygienic measures in farms and LBMs to control the exposure of birds and humans to the source of infection along with continuous monitoring of the circulating viruses will provide information on understanding the evolution of the viruses for vaccine studies.
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http://dx.doi.org/10.7717/peerj.5473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129142PMC
September 2018

RAS modulation prevents progressive cognitive impairment after experimental stroke: a randomized, blinded preclinical trial.

J Neuroinflammation 2018 Aug 13;15(1):229. Epub 2018 Aug 13.

Program in Clinical and Experimental Therapeutics, Charlie Norwood VA Medical Center and University of Georgia College of Pharmacy, HM Bldg., 1120 15th St, Augusta, GA, 30912, USA.

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.
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http://dx.doi.org/10.1186/s12974-018-1262-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6090822PMC
August 2018

Molecular characterization, antibiotic resistance pattern and biofilm formation of Vibrio parahaemolyticus and V. cholerae isolated from crustaceans and humans.

Int J Food Microbiol 2018 Jun 21;274:31-37. Epub 2018 Mar 21.

Department of Fish Diseases and Health, Faculty of Fish Resources, Suez University, Egypt.

Human infection with pathogenic vibrios is associated with contaminated seafood consumption. In the present study, we examined 225 crustaceans collected from retail markets in Egypt. Stool samples from gastroenteritis patients were also examined. Bacteriological and molecular examinations revealed 34 (15.1%) V. parahaemolyticus and 2 (0.9%) V. cholerae from crustaceans, while V. parahaemolyticus isolates were identified in 3 (3%) of the human samples. The virulence-associated genes tdh and/or trh were detected in 5.9% and 100% of the crustacean and human samples, respectively, whereas the two V. cholerae isolates were positive for the ctx and hlyA genes. Antibiotic sensitivity revealed high resistance of the isolates to the used antibiotics and an average MAR index of 0.77. Biofilm formation at different temperatures indicated significantly higher biofilm formation at 37 °C and 25 °C compared with 4 °C. Frequent monitoring of seafood for Vibrio species and their antibiotic, molecular and biofilm characteristics is essential to improve seafood safety.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2018.03.013DOI Listing
June 2018

Fluoroquinolone resistance and gyrA mutations in Campylobacter jejuni and Campylobacter coli isolated from chicken in Egypt.

J Glob Antimicrob Resist 2018 06 1;13:22-23. Epub 2018 Mar 1.

Veterinary Hospital, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Egypt. Electronic address:

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http://dx.doi.org/10.1016/j.jgar.2018.02.019DOI Listing
June 2018

Molecular Characterization of Cronobacter sakazakii in Egypt, Survival and Thermoresistance at Different Temperatures: A Potential Public Health Risk.

Vector Borne Zoonotic Dis 2018 02 12;18(2):101-107. Epub 2017 Dec 12.

Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University , Zagazig, Egypt .

Cronobacter sakazakii has been implicated in causing serious infections in neonates due to consumption of contaminated infant powdered milk. The zoonotic potential of the organism was not clear due to scarce evidence about the role of food animals in the transmission of infection. C. sakazakii was identified in infant powdered milk (n = 100), infant stool (n = 100), and dairy animal feces (n = 100) with the percentages of 1%, 2%, and 4%, respectively. The outer membrane protein A (ompA) gene was characterized in all isolates of different origin, while gene encoding for zinc-metaloprotease (zpx) was only identified in isolates from animal feces. Genotyping of C. sakazakii isolates using enterobacterial repetitive intergenic consensus polymerase chain reaction revealed heterogenicity. The survival and thermotolerance of one potentially virulent C. sakazakii isolate of animal origin were examined at different temperatures. The isolate could survive with a stationary number at refrigeration temperature and the number increased significantly at room temperature after 24 h. The isolate showed thermoresistance when subjected to temperature range from 54°C to 64°C with D values ranged from 13.79 and 4.64 min and z value of 14.42. To the best of our knowledge, this is the first report of C. sakazakii isolation from buffalo feces in Egypt.
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http://dx.doi.org/10.1089/vbz.2017.2169DOI Listing
February 2018

Role of angiotensin system modulation on progression of cognitive impairment and brain MRI changes in aged hypertensive animals - A randomized double- blind pre-clinical study.

Behav Brain Res 2018 07 8;346:29-40. Epub 2017 Dec 8.

Program in Clinical and Experimental Therapeutics, Charlie Norwood VA Medical Center and University of Georgia College of Pharmacy, Augusta, GA, United States; Department of Neurology, Augusta University, Augusta, GA, United States. Electronic address:

Growing evidence suggests that renin angiotensin system (RAS) modulators support cognitive function in various animal models. However, little is known about their long-term effects on the brain structure in aged hypertensive animals with chronic cerebral hypoperfusion as well as which specific domains of cognition are most affected. Therefore, in the current study we examined the effects of Candesartan and Compound 21 (C21) (RAS modulators) on aspects of cognition known to diminish with advanced age and accelerate with hypertension and vascular disease. Outcome measures for sensorimotor and cognitive function were performed using a sequence of tests, all blindly conducted and assessed at baseline and after 4 and 8 weeks of chronic hypoxic hypoperfusion and treatment. Magnetic resonance imaging (MRI) was performed at the end of the 8 week study period followed by animal sacrifice and tissue collection. Both Candesartan and C21 effectively preserved cognitive function and prevented progression of vascular cognitive impairment (VCI) but only candesartan prevented loss of brain volume in aged hypertensive animals. Collectively, our findings demonstrate that delayed administration of RAS modulators effectively preserve cognitive function and prevent the development / progression of VCI in aged hypertensive animals with chronic cerebral hypoperfusion.
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http://dx.doi.org/10.1016/j.bbr.2017.12.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5866136PMC
July 2018

Seroprevalence of Brucella spp. in Cattle, Molecular Characterization in Milk, and the Analysis of Associated Risk Factors with Seroprevalence in Humans, Egypt.

Vector Borne Zoonotic Dis 2016 12 18;16(12):758-764. Epub 2016 Oct 18.

1 Animal Health Research Institute , Mansoura Provincial Lab., Mansoura, Egypt .

The objective of the present study was to estimate the seroprevalence of Brucella spp. in humans and cattle at Sharkia Governorate, Egypt. In addition, identification of Brucella spp. in milk samples by PCR and culture with the evaluation of the risk factors associated with Brucella spp. seroprevalence in humans were carried out. Overall, the seroprevalence of Brucella antibodies in the examined cattle was 23.8%, while in human participants it was 21%. The examination of 205 milk samples using PCR revealed that 6.3% were positive for B. abortus biovar 1 and the results were confirmed by culture methods. Multivariate logistic regression revealed that consumption of unpasteurized dairy products, occupational contact with animals, and knowledge about the disease are risk factors associated with infection in humans. This study documented the endemic status of brucellosis in Egypt. Hygienic measures and increased awareness about the disease are recommended to minimize the spread of infection from animals to humans.
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http://dx.doi.org/10.1089/vbz.2016.1985DOI Listing
December 2016

Characterization of Virulence-Associated Genes, Antimicrobial Resistance Genes, and Class 1 Integrons in Salmonella enterica serovar Typhimurium Isolates from Chicken Meat and Humans in Egypt.

Foodborne Pathog Dis 2016 06 15;13(6):281-8. Epub 2016 Mar 15.

3 Department of Food Hygiene, Animal Health Research Institute , Mansoura, Egypt .

Foodborne pathogens are leading causes of illness especially in developing countries. The current study aimed to characterize virulence-associated genes and antimicrobial resistance in 30 Salmonella Typhimurium isolates of chicken and human origin at Mansoura, Egypt. The results showed that invA, avrA, mgtC, stn, and bcfC genes were identified in all the examined isolates, while 96.7% and 6.7% were positive for sopB and pef genes, respectively. The highest resistance frequencies of the isolates were to chloramphenicol and trimethoprim-sulfamethoxazole (73.3%, each), followed by streptomycin (56.7%), tetracycline and ampicillin (53.3%, each), and gentamicin (30%). However, only 2.7% of the isolates were resistant to cefotaxime and ceftriaxone each. Different resistance-associated genes, including blaTEM, aadB, aadC, aadA1, aadA2, floR, tetA(A), tetA(B), and sul1, were identified in Salmonella Typhimurium isolates with the respective frequencies of 53.3%, 6.7%, 23.3%, 46.7%, 63.3%, 73.3%, 60%, 20%, and 96.7%. None of the isolates was positive for blaSHV, blaOXA, and blaCMY genes. The results showed that the intI1 gene was detected in 24 (80%) of the examined Salmonella Typhimurium isolates. Class 1 integrons were found in 19 (79.2%) isolates that were intI1 positive. Seven integron profiles (namely: P-I to P-VII) were identified with P-V (gene cassette dfrA15, aadA2), the most prevalent profile. To the best of our knowledge, this is the first study to characterize the unusual gene cassette array dfrA12-OrfF-aadA27 from Salmonella Typhimurium isolates in Egypt.
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http://dx.doi.org/10.1089/fpd.2015.2097DOI Listing
June 2016

Occurrence, Virulence Factors, Antimicrobial Resistance, and Genotyping of Staphylococcus aureus Strains Isolated from Chicken Products and Humans.

Vector Borne Zoonotic Dis 2016 Mar 25;16(3):157-64. Epub 2016 Jan 25.

3 Department of Microbiology, Animal Health Research Institute , Mansoura Branch, Mansoura, Egypt .

Staphylococcus aureus in food is a consequence of inadequate hygienic handling and processing, posing a potential risk to public health. The current study aimed to characterize virulence factors, as well as antimicrobial resistance of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) isolated from retail chicken products and hand swabs from vendors in Egypt. In addition, genetic relatedness of the isolates from chicken and humans was evaluated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using protein A as a target. A total of 110 samples were collected from chicken products (n = 80) and vendors (n = 30). Overall, 30 (37.5%) chicken products samples were positive for S. aureus, whereas hand swabs from meat handlers revealed that 18 (60%) were positive. Ten MRSA strains were characterized by the presence of the mecA gene, comprising seven isolates from chicken and three from humans. Virulence-associated factors were evaluated by PCR, revealing that 31.3% of S. aureus isolates harbored the Panton-Valentine leukocidin (PVL) gene, whereas 10.4% were positive for the sea and sed genes each, and only two isolates were positive for γ-hemolysin-associated gene. Genotyping using spa PCR-RFLP showed identical restriction banding patterns of MRSA isolates of human and chicken meat origin, indicating the genetic relatedness of the isolates. To the best of our knowledge, this is the first study to characterize PVL-positive MRSA from chicken products and to utilize spa-RFLP for evaluating the genetic relatedness between MRSA of human and chicken origin in Egypt.
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http://dx.doi.org/10.1089/vbz.2015.1891DOI Listing
March 2016

ERIC-PCR Genotyping of Some Campylobacter jejuni Isolates of Chicken and Human Origin in Egypt.

Vector Borne Zoonotic Dis 2015 Dec 18;15(12):713-7. Epub 2015 Nov 18.

4 Veterinary Hospital, Faculty of Veterinary Medicine, Zagazig University , Zagazig, Egypt .

The public health importance of the genus Campylobacter is attributed to several species causing diarrhea in consumers. Poultry and their meat are considered the most important sources of human campylobacteriosis. In this study, 287 samples from chicken (131 cloacal swabs, 39 chicken skin, 78 chicken meat, and 39 cecal parts) obtained from retail outlets as well as 246 stool swabs from gastroenteritis patients were examined. A representative number of the biochemically identified Campylobacter jejuni isolates were identified by real-time PCR, confirming the identification of the isolates as C. jejuni. Genotyping of the examined isolates (n = 31) by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) revealed a high discriminatory index of ERIC-PCR (D = 0.948), dividing C. jejuni isolates of chicken and human origins into 18 profiles and four clusters. The 18 profiles obtained indicated the heterogeneity of C. jejuni. Dendrogram analysis showed that four clusters were generated; all human isolates fell into clusters I and III. These observations further support the existence of a genetic relationship between human and poultry isolates examined in the present study. In conclusion, the results obtained support the speculation that poultry and poultry meat have an important role as sources of infection in the acquisition of Campylobacter infection in humans.
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http://dx.doi.org/10.1089/vbz.2015.1836DOI Listing
December 2015

Vascular protection with dipeptidyl peptidase-IV inhibitors in diabetes: experimental and clinical therapeutics.

Pharmacotherapy 2015 Mar 10;35(3):277-97. Epub 2015 Mar 10.

Program in Clinical and Experimental Therapeutics, Department of Clinical and Administrative Pharmacy and Division of Experience Programs, College of Pharmacy, University of Georgia, Augusta, Georgia; Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia, Georgia Regents University, Augusta, Georgia.

The dipeptidyl peptidase-IV (DPP-IV) inhibitors, also known as gliptins, are widely used in clinical practice either as monotherapy or in combination with other agents for the management of type 2 diabetes mellitus (T2DM). The gliptins are effective, safe, well tolerated, and conveniently administered once/day. Moreover, these agents have a low risk for drug interactions and do not require initial dosage titrations to lessen adverse effects. They are not only clinically desirable, having the most favorable side-effect profile of all available antihyperglycemic medications, but they can also be used in any stage of renal or hepatic impairment. The antihyperglycemic effects of gliptins are attributed to inhibition of the DPP-IV enzyme, thereby prolonging the half-life (t1/2 ) of incretin hormones (substrates) to promote glucose-stimulated insulin secretion. Beyond their glucose-lowering effects, gliptins may also reduce the risk of cardiovascular disease by improving endothelial function, lowering blood pressure, reducing inflammation, and delaying the progression of atherosclerosis. Although the vascular protective effects of gliptins depend on incretins, the contributions of other biologically important endogenous vasoactive substrates of DPP-IV are worthy of consideration from a therapeutic standpoint. Future and ongoing studies should help determine whether these vascular protective effects contribute to improved cardiovascular outcomes in patients with T2DM. The experimental and clinical evidence supporting the vascular protective effects of gliptins is reviewed.
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http://dx.doi.org/10.1002/phar.1547DOI Listing
March 2015

Development of real time PCR to study experimental mixed infections of T. congolense Savannah and T. b. brucei in Glossina morsitans morsitans.

PLoS One 2015 4;10(3):e0117147. Epub 2015 Mar 4.

Division of Pathway Medicine, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.

Tsetse flies are able to acquire mixed infections naturally or experimentally either simultaneously or sequentially. Traditionally, natural infection rates in tsetse flies are estimated by microscopic examination of different parts of the fly after dissection, together with the isolation of the parasite in vivo. However, until the advent of molecular techniques it was difficult to speciate trypanosomes infections and to quantify trypanosome numbers within tsetse flies. Although more expensive, qPCR allows the quantification of DNA and is less time consuming due to real time visualization and validation of the results. The current study evaluated the application of qPCR to quantify the infection load of tsetse flies with T. b. brucei and T. congolense savannah and to study the possibility of competition between the two species. The results revealed that the two qPCR reactions are of acceptable efficiency (99.1% and 95.6%, respectively), sensitivity and specificity and can be used for quantification of infection load with trypanosomes in experimentally infected Glossina morsitans morsitans. The mixed infection of laboratory Glossina species and quantification of the infection suggests the possibility that a form of competition exists between the isolates of T. b. brucei and T. congolense savannah that we used when they co-exist in the fly midgut.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0117147PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4349444PMC
November 2015

A comparative evaluation of PCR- based methods for species- specific determination of African animal trypanosomes in Ugandan cattle.

Parasit Vectors 2013 Nov 1;6(1):316. Epub 2013 Nov 1.

Division of Pathway Medicine and Centre for Infectious Diseases, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.

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.
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http://dx.doi.org/10.1186/1756-3305-6-316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4029050PMC
November 2013

Seafood a potential source of some zoonotic bacteria in Zagazig, Egypt, with the molecular detection of Listeria monocytogenes virulence genes.

Vet Ital 2013 Jul-Sep;49(3):299-308

Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, 44511 Zagazig, Egypt.

This article describes the results of a study conducted on 71 fresh seafood samples (fish and shellfish) marketed in Zagazig city, Sharkia province, Egypt, as well as on 50 human stool samples collected at the Zagazig University Hospital. The samples were examined for the presence of Listeria monocytogenes and Escherichia coli. The investigation of L. monocytogenes virulence genes was performed using Polymerase Chain Reaction (PCR), while the microbiological quality of the seafood samples was evaluated using the coliform count and aerobic plate count (APC) as indicators. Out of the examined 71 seafood samples, 20 (28.2%) were identified as L. monocytogenes, 15 (75%) of which were confirmed as virulent strains. Also, out of 50 human stool samples, only 1 (2%) was identified as virulent L. monocytogenes. E. coli serotypes were isolated from only 11.3% of seafood and 30% of human stool samples. In shellfish, the APC and most probable number of coliforms (MPC) were higher than those obtained from other fish samples. Multiplex PCR targeting internalin genes allowed simultaneous identification of L. monocytogenes and differentiation of virulent strains, thus enabling more timely detection of cases and sources of food borne listeriosis. The article concludes by stressing that the isolation of potentially virulent L. monocytogenes and E. coli from both seafood samples and humans emphasises the potential public health hazard caused by eating raw or undercooked shellfish.
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http://dx.doi.org/10.12834/VetIt.1305.05DOI Listing
August 2014

The best practice for preparation of samples from FTA®cards for diagnosis of blood borne infections using African trypanosomes as a model system.

Parasit Vectors 2011 May 7;4:68. Epub 2011 May 7.

Centre for Infectious Diseases, Division of Pathway Medicine, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK.

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.
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http://dx.doi.org/10.1186/1756-3305-4-68DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108913PMC
May 2011