372 research outputs found

    Toxoplasma gondii: Prolonged in-vitro maintenance of virulent tachyzoites in fluid media at low temperatures

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    Background: Prolonged maintenance of infective Toxoplasma gondii tachyzoites (T.g.T.) is an important subject for research purposes. This study aimed to evaluate four serum free fluid media for prolonged in vitro maintenance of T.g.T.Methods: The four fluid media Phosphate buffered saline (PBS) pH 7.2 and Roswell Park Memorial Institute (RPMI-1640) with or without 3% fetal bovine serum (FBS) were evaluated for maintenance of virulent T.g.T. The four media were tested after incubation at three different temperature degrees in the darkness.Results: Prolonged maintenance period for infective T.g.T. was recorded especially in the absence of FBS supplement. RPMI without FBS was able to maintain infective T.g.T. for 16 days post incubation (dpi) at refrigerator temperature. This period decreased to 10 dpi and 6 dpi after incubation in the same media at 18–22 oC and 37 oC, respectively. Cultivation of T.g.T. in RPMI supplemented with 3% FBS and in PBS proved to maintain infective T.g.T. for 14 dpi at refrigerator temperature, and for 9 and 5 dpi when the two media were incubated at 18–22 oC and 37 oC, respectively. Shorter periods for keeping the T.g.T. infectivity were recorded using PBS supplemented with 3% FBS under all tested temperature conditions.Conclusion: This method allows economic long-lasting maintenance of tachyzoites for 16th dpi in RBMI that can be reactivated by reinoculation in mice.Keywords:  Toxoplasma gondii, Tachyzoites, Fluid media, Temperatur

    Analysis of RC Continuous Beams Strengthened with FRP Plates: A Finite Element Model

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    Strengthening of reinforced concrete (RC) beams with externally bonded fibre reinforced polymer (FRP) plates/sheets technique has become widespread in the last two decades. Although a great deal of research has been conducted on simply supported RC beams, a few studies have been carried out on continuous beams strengthened with FRP composites.  This paper presents a simple uniaxial nonlinear finite-element model (UNFEM) that is able to accurately estimate the load-carrying capacity and the behaviour of RC continuous beams flexurally strengthened with externally bonded FRP plates on both of the upper and lower fibres. A 21-degree of freedom element is proposed with layer-discretization of the cross-sections for finite element (FE) modelling. Realistic nonlinear constitutive relations are employed to describe the stress-strain behaviour of each component of the strengthened beam. The FE model is based on nonlinear fracture mechanics. The interfacial shear and normal stresses in the adhesive layer are presented using an analytical uncoupled cohesive zone model with a mixed-mode fracture criterion. The results of the proposed FE model are verified by comparison with various selected experimental measurements available in the literature. The numerical results of the plated beams (beams strengthened with FRP plates) agreed very well with the experimental results. The use of FRP increased the ultimate load capacity up to 100 % compared with the non-strengthened beams as occurred in series (S). The major objective of the current model is to help engineers’ model FRP-strengthened RC continuous beams in a simple manner

    Bioactivity of Samsum ant (Pachycondyla sennaarensis) venom against lipopolysaccharides through antioxidant and upregulation of Akt1 signaling in rats

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    BACKGROUND: This study aimed at investigating the oxidative stress ameliorating effect, lipids profile restoration, and the anti-inflammatory effect of Samsum Ant Venom (SAV) in induced endotoxemic male rats, injected with bacterial lipopolysaccharides (LPS). RESULTS: Results revealed that LPS significantly increased the oxidative stress indications in LPS-injected rats. A significant increase of both malondialdehyde (MDA), and advanced oxidative protein products (AOPP), as well as a significant suppression of glutathione were all detected. Treatment with 100 μg/kg dose of SAV significantly restored the oxidative stress normal indications and increased the total glutathione levels. Treatment of the LPS-rats with 100 μg/kg dose of SAV showed a clear anti-inflammatory function; as the histological architecture of the hepatic tissue was partially recovered, along with a valuable decrease in the leukocytes infiltrated the hepatic tissues. Treatment of some rat groups with 600 μg/kg dose of SAV after LPS injection induced a severe endotoxemia that resulted in very high mortality rates. SAV versus the effects of LPS on AKT1, Fas, TNF-α and IFN-γ mRNA expression. SAV was found to significantly lower Fas gene expression comparing to the LPS group and restore the level of IFN-γ mRNA expression to that of the control group. CONCLUSION: In conclusion, SAV, at the dose of 100 μg/kg body weight, maintained and restored the oxidative stability, the anti-inflammatory, and the hypolipidemic bioactivity in rats after induced disruption of these parameters by LPS injection. This improvement by SAV was mediated by upregulation of AKT1

    The Motion of a Point Vortex in Multiply Connected Polygonal Domains

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    We study the motion of a single point vortex in simply and multiply connected polygonal domains. In case of multiply connected domains, the polygonal obstacles can be viewed as the cross-sections of 3D polygonal cylinders. First, we utilize conformal mappings to transfer the polygonal domains onto circular domains. Then, we employ the Schottky-Klein prime function to compute the Hamiltonian governing the point vortex motion in circular domains. We compare between the topological structures of the contour lines of the Hamiltonian in symmetric and asymmetric domains. Special attention is paid to the interaction of point vortex trajectories with the polygonal obstacles. In this context, we discuss the effect of symmetry breaking, and obstacle location and shape on the behavior of vortex motion

    Comparison of cognitive function, socioeconomic level, and the health-related quality of life between epileptic patients with attention deficit hyperactivity disorder and without

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    Background Epilepsy is one of the most common neurological conditions. Attention deficit hyperactivity disorder (ADHD) in children with epilepsy proves to be very common. Both epilepsy and ADHD impair quality of life. We aimed to evaluate cognitive function, socioeconomic level, and quality of life (QOL) among children with ADHD and epilepsy. A total of 100 children were divided into 5 groups (20 children/group) as (I) epilepsy, (II) ADHD with epilepsy, (III) ADHD with EEG changes, (IV) ADHD without EEG changes, and (V) control. Children aged between 6 and 11 years were recruited for this study. Early Childhood Epilepsy Severity Scale (E-Chess), Conners’ Parent Rating Scale (CPRS), Wechsler Intelligence Scale for Children-3rd edition (WISC-III), socioeconomic scale for assessment of social burden and socioeconomic classes, and PedsQL (quality of life measure) assessed. Results Children with ADHD and epilepsy had the lowest PedsQL total scores and lower scores than other groups especially in performance IQ score. The highest percentage of low socioeconomic class (25%) was observed in the group of ADHD with epilepsy and the group of epilepsy. Conclusion ADHD with epilepsy is associated with low performance IQ, poor socioeconomic level, and quality of life. Pediatric Quality of Life Inventory scores show significant correlation with total IQ score in the group of ADHD with epilepsy

    Melittin Exerts Beneficial Effects on Paraquat-Induced Lung Injuries in Mice by Modifying Oxidative Stress and Apoptosis

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    Melittin (MEL) is a 26-amino acid peptide with numerous biological activities. Paraquat (PQ) is one of the most widely used herbicides, although it is extremely toxic to humans. To date, PQ poisoning has no effective treatment, and therefore the current study aimed to assess for the first time the possible effects of MEL on PQ-induced lung injuries in mice. Mice received a single intraperitoneal (IP) injection of PQ (30 mg/kg), followed by IP treatment with MEL (0.1 and 0.5 mg/kg) twice per week for four consecutive weeks. Histological alterations, oxidative stress, and apoptosis in the lungs were studied. Hematoxylin and eosin (H&E) staining indicated that MEL markedly reduced lung injuries induced by PQ. Furthermore, treatment with MEL increased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity, and decreased malonaldehyde (MDA) and nitric oxide (NO) levels in lung tissue homogenates. Moreover, immunohistochemical staining showed that B-cell lymphoma-2 (Bcl-2) and survivin expressions were upregulated after MEL treatment, while Ki-67 expression was downregulated. The high dose of MEL was more effective than the low dose in all experiments. In summary, MEL efficiently reduced PQ-induced lung injuries in mice. Specific pharmacological examinations are required to determine the effectiveness of MEL in cases of human PQ poisoning

    Salivary composition and dental caries among children controlled asthmatics

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    AbstractBackground and objectiveAsthma patients can be effectively treated and controlled with currently available medications, inhaled ß2-agonists and corticosteroids have harmful effects on dentition. Therefore we aimed to investigate the influence of exposure to inhaled ß2-agonists and corticosteroids on the composition of saliva as a risk factor to increase the incidence of dental caries among children aged 8–14years old. The study group is compared with a control group of healthy children of the same age group.Patient and methodsIn a triple-blind analytical case–control study, children were selected according to inclusion criteria, divided into asthmatic group1 (n=60), who were controlled by ß2-agonists and corticosteroids for at least six months. Control group (group II) was first-degree relatives (n=60) matched for age. DMFS and DMFT index scores were recorded in both groups. Saliva samples were collected from each child for testing electrolytes, pH, and cariogenic bacteria.ResultsThe results showed higher prevalence of caries among asthmatics (group I) than controls (group II). As well as a positive correlation between, duration of asthma and the caries indices, Streptococcus mutans, Lactobacilli colonies bacteria count in asthmatic were higher than in controls. Salivary electrolytes were significantly elevated in asthmatics with caries.ConclusionPrevalence of dental caries was higher in asthmatics than controls. High caries incidence in asthmatics related to salivary acidic pH, increase S. mutans, Lactobacilli count and medication. There is a need to create awareness among dental practitioners and pulmonologists regarding the increased caries risk in asthmatics
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