Ahmed K. Salama

Preparation of antibodies and development of an enzyme immunoassay for determination of atrazine in environmental samples

An indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed and optimized for atrazine determination in soil at different depths (0–10, 10–20, and 20–30 cm) before and after 48 h of application, corn shoot and cow milk samples collected from Dina farm, Egypt. This assay was based on a specific polyclonal antibodies (PAb) raised by immunizing New Zealand rabbits with an immunogen prepared by coupling 3-{4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine-2-yl} thiopropanoic acid to bovine serum albumin (BSA) via N-hydroxysuccinimide (NHS) active ester method. The sensitivity (estimated as IC50value) was 17.5 μg mL−1 with a detection limit of 0.1 ng mL−1. The maximum atrazine concentration was found in soil especially in the deepest layer (325 and 890 μg kg−1 before and after application, respectively). Atrazine concentration in corn shoot was 333.28, μg kg−1 dry plant, while there was no detectable amount in milk. All samples screened by ELISA were validated by gas chromatography mass spectrometer procedure (GC/MS). Good correlation was achieved between the two methods (r = 0.997 for soil and 0.9814 for plant). This study demonstrates the utility and convenience of the simple, practical and cost–effective ELISA method in the laboratory for analysis of environmental samples. The method is ideal for the rapid screening of large numbers of samples in laboratories where access to GC/MS facilities, is limited or lacking.

CRESCENT: a modular cost-efficient open-access testbed for cognitive radio networks routing protocols

Cognitive Radio Networks (CRNs) provide a solution to increase the utilization of the scarce radio frequency spectrum. Building testbeds for CRNs is one of the main challenges that can affect the wide deployability of such networks. Many testbeds were proposed for testing CRN routing protocols, but most of them are either pure simulations or require high deployment cost for buying and maintaining the needed hardware devices on a large scale. We propose CRESCENT: a modular framework for testing CRNs routing protocols with cost-efficient and large-scale deployability. CRESCENT is based on general purpose computers without the need for any special devices leveraging their built-in Wi-Fi interfaces as the default interface. The framework is built on top of Click modular router to ensure the ease of the development of new routing protocols while providing new modules that are essential for cognitive radio protocols.

Pharmacokinetic profile and anticholinesterase properties of phenamiphos in male rats

The pharmacokinetics and anticholinesterase properties of a single oral dose 6 mg/Kg of technical phenamiphos [ethyl 4-(methylthio)-m-tolyl isopropylphosphoramidate] were investigated in male rats. Animals were killed at each time intervals of 0.5, 1.0, 1.5, 3, 6, 12, 24, 48, and 72 hrs after dosing. The total recovered amount of phenamiphos from brain and plasma tissues reached high level at the first time interval and disappeared biexponentially from both tissues to low level at the end of the experiment. Brain tissue has a greater affinity to phenamiphos than plasma tissue. The half-life of the elimination of phenamiphos from brain and plasma were 100 and 212 hr corresponding to the rate constant values of 0.01 and 0.003 hr-1, respectively. Plasma AUC (area under the curve) value was 1239.81 micrograms hr/L, explaining there was no tendency for the compound to accumulate in the brain tissue (AUC = 774.38 micrograms hr/Kg) compared to the plasma. On the other hand, determination of cholinesterase activity showed that, phenamiphos inhibited the enzymes in both brain and plasma, where the depression of ChE activity was usually more marked in plasma than in brain.

Oxidative Stress and Pharmacokinetics of Pendimethalin in Female Rats

The propensity of a dinitroaniline pre-emergence herbicide, pendimethalin, to induce oxidative stress, changes in biochemical parameters, pharmacokinetics, tissue distribution and excretion in serum, kidney, liver and brain of female rats following four oral doses of 109.4 mg/kg b.wt every other day were studied. When rats exposed to pendimethalin, significant increases in tissue malondialdehyde, lactic dehydrogenase and alkaline phosphatase levels (p<0.05) were noticed compared to controls. The activities of catalase in all the tested tissues except brain were significantly increased (p<0.05) after pendimethalin treatment. Pharmacokinetic studies illustrated that when rats were treated with a single dose of 109.4 mg/kg b.wt of pendimethalin, the percentages of pendimethalin excretion in the urine and faeces were 8.72 and 14.31 after 24 which increased to 23.81 and 71.21 after 168 h of administration. The Peak concentrations of pendimethalin were reached at 12 h in serum (3229.14 ng/mL), liver (10162.32 ng/g) and kidneys (1969.17 ng/g), whereas the peak concentration (245.92 ng/g) reached at 24 h after dosing. In all the tested tissues the compound declined in all tissues as time passed after 72 h in serum or after 120 h in liver, kidneys and brain following administration. The disappearance of pendimethalin was found to be biexponentially from the tested tissues with half-life) t½ (of 14.0, 15.0, 2.5, and 29.0 h for the serum, liver, brain and kidneys, respectively. It can be concluded that when female rats are exposed to pendimethalin, it is readily absorbed and subsequently distributed throughout the whole body influencing on the biomarkers oxidative stress and enzyme activities.

Pesticides-induced oxidative damage: Possible in vitro protection by antioxidants

To determine if quinine has a metabolic effect during treatment of severe or complicated malaria, we studied its effects on plasma glucose and plasma insulin levels in 150 pregnant women with malaria referred to Madani maternity teaching hospital, Gezira state and 50 healthy pregnant controls. Levels were determined at baseline (day 0) before the start of quinine treatment, after 2 days of treatment (2 hours after the 4th dose) and after 7 days of treatment (day 8). There was a statistically significant increase in plasma insulin concentrations during the quinine infusion and fall in plasma glucose concentration (P < 0.001). Quinine administered at the recommended dose and rate can disrupt plasma glucose homeostasis although it is still the drug of choice for severe and complicated malaria in Sudan.S health status (SHS) is characterized by ambiguous health complaints, general weakness, and lack of vitality, and it has become a new public health challenge in China and worldwide. SHS is believed to be a subclinical, reversible stage of chronic disease. As studies of intervention and prognosis for SHS are expected to become increasingly important, a reliable and valid instrument for its assessment is essential. A questionnaire for measuring SHS in urban Chinese was developed based on focus group discussions and a literature review. Questionnaire validity and reliability were evaluated in a small pilot study and then in a cross-sectional study of 3000 individuals. The analyses included tests for reliability and internal consistency, exploratory and confirmatory factor analysis, and tests for discriminative ability and convergent validity. The final questionnaire incorporated 25 items on SHS (SHSQ-25), and encompassed 5 subscales: fatigue, cardiovascular system, digestive tract, immune system, and mental status. The SHSQ-25 has proved to be a reliable and valid instrument for measuring sub-health status in urban Chinese. The progress of a combined genomics and glycomics study for exploring the mechanism of SHS and an example of screening novel biomarkers for metabolic syndrome by profiling human plasma N-glycans will be presented.T interactions of membrane receptors during cell adhesion play pivotal roles in tissue morphogenesis during development. Our lab focuses on developing multi-scale models to decompose the mechanical and chemical complexity in cell adhesion. Recent experimental evidences show that clustering is a generic process for cell adhesive receptors. However, the physical basis of such receptor clustering is not understood. We introduced the effect of molecular flexibility to evaluate the dynamics of receptors. By delivering new theory to quantify the changes of binding free energy in different cellular environments, we revealed that restriction of molecular flexibility upon binding of membrane receptors from apposing cell surfaces (trans) causes large entropy loss, which dramatically increases their lateral interactions (cis). This provides a new molecular mechanism to initialize receptor clustering on the cell-cell interface. By using the subcellular simulations, we further found that clustering is a cooperative process requiring both trans and cis interactions. The detailed binding constants during these processes are calculated and compared with experimental data from our collaborator’s lab.P malnutrition is common in patients requiring liver transplantation (LT). However, their nutritional parameters characteristics remain unclear.We examined various nutritional parameters upon admission in 226 consecutive adult patients who underwent LTbetween February 2008 and August 2012;correlations with Child-Pugh (CP) classification, original disease, skeletal muscle mass (SMM) and zinc (Zn) levels.CP-A patients had higher Zn, prealbumin (PA) and branched-chain amino acids (BCAAs)-to-tyrosine (TYR) ratio (BTR) than those with CP-B or CP-C. When patients were grouped whether or not they received BCAAs before admission, TYR levels were higher among those with CP-C than with CP-A/B (P=0.025) who did not receive BCAAs, but did not differ in those administered with BCAAs. BTR was lower in patients with CP-C than with CP-A/B in both groups (P=0.001 and P=0.010, respectively), whereas BCAAs did not differ between patients with CP-A/B and CP-C in either group.SMM correlated positively with TYR (r=0.435, P<0.001) and BCAAs (r=0.193, P=0.029) but negatively with BTR (r=0.272, P=0.002). Zn correlated positively with PA (r=0.457,P<0.001) and BTR (r=0.261,P<0.001) but negatively with ammonia (r=-0.172,P=0.014) and TYR (r=-0.197,P=0.005).Acute liver failure patients had the highest ammonia, Zn, TYR, lowest BTRwith relatively low BCAAs and high PA while alcoholic cirrhosis patients had the highest BCAAs and TYR mean levels. Hepatocellular carcinoma patients had higher BCAAs than cholestatic diseases patients who had the lowest BCAAs and Zn mean levels. Pre-transplant disease, SMM and Zn play important roles in amino acid metabolism and nutrition.Evaluation of said parameters is recommended to tailor peri-LT nutritional regimens.Methods: Hep2 was cultured with medium containing ethidium bromide (EB) to get ρ0 cells, and then PCR, confocal microscope, transmission electron microscopy and growth defect experiment were used to identify the cell model. Afterwards, the radiosensitivity of ρ0 and Hep2 cells were examined by colony formation assay. After radiation, cell proliferation was detected by CCK8 kit, cell cycle and apoptosis were analyzed by flow cytometry, ATP was detected by kit and reactive oxygen species (ROS) content was evaluated by Dichloro-Fluorescein diacetate salt (DCFH-DA) staining method.Wastewater contaminated soil poses serious environmental and health problems in Saudi Arabia and requires technological solutions for mitigating potential environmental risks. In spite the efforts of the Agriculture Ministry and agencies of water resources to overcome those problems, they still exist. In this concern, the effects of an arbuscular mycorrhizal (AM) fungus (Glomus deserticola Trappe and John) on growth, relative chlorophyll content and some mineral nutrients and heavy metal contents of broad bean (Vicia faba) plants grown in sterilized soil irrigated with different concentrations of wastewater were studied. Application of wastewater significantly reduced growth, chlorophyll content, nutrient contents, and levels of mycorrhizal colonization of bean plants comparing to control untreated plants, mainly at high concentrations. However, the rate of reduction was more pronounced in nonmycorrhizal treated plants. Mycorrhizal broad bean plants had significantly higher biomass, plant heights, leaf area, nutrients content (N, P, K), and relative chlorophyll content compared to those of non-mycorrhizal plants irrigated with or without sewage water. Under sewage water application, the AM colonization had greatly reduced the heavy metal contents (Zn, Co, Mn, Cu) in shoot and root tissues of the broad bean plants as compared to their equivalent non-mycorrhizal plants. This study indicates that growing broad bean plants with AM inoculum can minimize the heavy metals toxicity and increase growth and P uptake. In this regard, the AM fungi have a protective role to the host plants, and thus play important roles in soil contaminant immobilization processes. Therefore, the AM fungi are important in phytoremediation of heavy metals in wastewater contaminated soil.

Health risk assessment of heavy metals content in cocoa and chocolate products sold in Saudi Arabia

Abstract The study was carried out to assess the level of 10 heavy metals in 27 representative samples of cocoa and chocolate products sold in Saudi Arabia markets using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The mean levels of heavy metals were in the range of 0.033–0.123; 0.001–0.080; 0.010–0.046; 0.013–0.070; 0.61–9.74; 0.27–3.17; 0.02–0.67; 1.11–14.22; 0.18–0.66; and 11.38–72.12 µg/g for Pb, Cd, As, Hg, Cu, Ni, Co, Mn, Cr, and Al, respectively. These values were used to determine the estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TCR) associated with dietary exposure to these potentially toxic elements. The EDI values did account for 0.027–0.077; 0.002–0.032; 0.014–0.023; 0.013–0.069; 0.85–5.92; 0.27–1.85; 0.018–0.069; 1.37–8.68; 0.164–0.290; and 10.80–40.75 µg/kg/d for Pb, Cd, As, Hg, Cu, Ni, Co, Mn, Cr, and Al, respectively. They were below the tolerable intake limits in all foodstuffs analyzed, except in cocoa product where Al exceeded the permissible limit. The THQ and HI values were also lower than the safe standard 1 for all foodstuffs analyzed, except for cocoa products where the HI value was 1.909. This high value of HI indicates that consumption of more amounts of cocoa products frequently may result in adverse non-carcinogenic health effect in consumers in future. The THQ of cobalt in cocoa products was 0.806 which enhanced the GTHQ to be 1.196 and thus cobalt contributing 34.08% to the HI explaining that the risk was mainly contributed by cobalt. The TCR values did not exceed the limit, except for Ni in cocoa products which exceed the limit for acceptable risk of developing cancer indicating some concern.

Lactational Exposure to Pesticides: A Review

The aim of this study is to review the reports of pesticides have been detected in human breast milk in worldwide. Contamination levels of pesticides such as organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), carbamates and pyrethroids in human breast milk were found to be varied in different countries. The chemical properties of chemicals such as lack of ionization, small molecular weight, low volume of distribution, low maternal serum protein binding, and high lipid solubility, facilitate compound excretion into human milk. Since exposure to pesticides during the early postnatal stages may disturb the normal development of the newborn, such studies may shed light on the wide variety of pesticides that have been detected in human breast milk.

Remediation of lead and cadmium-contaminated soils

ABSTRACT The research was designated to study the ability of plants to bio-accumulate, translocate and remove the heavy metals, lead and cadmium from contaminated soil. The herbal plant ryegrass, Lolium multiflorum was investigated as a bio-accumulator plant for these metals. The translocation of these heavy metals in the herbal plant was compared considering root to shoot transport and redistribution of metals in the root and shoot system. The trace metal contents from root and shoot parts were determined using atomic absorption spectrometer. The results showed that the percent of lead and cadmium transferred to ryegrass plant were averaged as 51.39, and 74.57%, respectively, while those remained in the soil were averaged as 48.61 and 25.43% following 60 days of treatment. The soil-plant transfer index in root and shoot system of ryegrass was found to be 0.32 and 0.20 for lead, and 0.50 and 0.25 for cadmium. These findings indicated that the herbal plant ryegrass, Lolium multiflorum is a good accumulator for cadmium than lead. The soil-plant transfer factor (the conc. of heavy metal in plant to the conc. in soil) indicated that the mechanism of soil remedy using the investigated plant is phytoextraction where the amounts of heavy metals transferred by plant roots into the above ground portions were higher than that remained in the soil. The method offers green technology solution for the contamination problem since it is effective technology with minimal impact on the environment and can be easily used for soil remedy.

Uptake, excretion, and metabolism of phorate in the land snail, Helix aspersa (Muller)

Abstract Uptake, excretion, and metabolism of phorate (O,O‐diethyl S‐ethylthiomethyl phosphorodithioate) following application to lettuce leaves were investigated in the land snail , Helix aspersa. Snails were fed on a leaf disc of lettuce immersed in a solution of 100 ppm of phorate. Snails were dissected at time intervals between 1 and 7 days after dosing. Phorate was readily absorbed within 24 hrs following ingestion. The amount of phorate reached a peak value of 880 ug at 4days, and then dropped as time passed to the end of experiment (7days) indicating there was no accumulation of the compound in the snail tissues. Phorate was metabolized to phorate sulfoxide and phorate sulfone. Phorate and/or its metabolites were rapidly excreted soon after ingestion. The major compound identified in the excreta was the unchanged phorate.

Biochemical response of the brown garden snails, Helix aspersa to chlorfluazuron and flufenoxuron

Abstract The two insect growth inhibitors, chlorfluazuron (IKI7899) and flufenoxuron (Cascade) were evaluated for their toxic and biochemical action against the terrestrial snails Helix aspersa (Muller). Chlorfluazuron was found to be more toxic to the snails than flufenoxuron. The experimental snails were fed on lettuce discs treated with low concentration (1%) of each compound for a duration time of 1,2,3 and 5 days. There were no significant differences between treated and untreated snails in total proteins, total lipids and glycogen content except in the case of chlorfluazuron treated snails, the glycogen content was increased. Both compounds reduced the activity of alkaline phosphatase (AIP). Chlorfluazuron decreased the activity of acid phosphatase(AcP) and phenoloxidase (PO) enzymes, while flufenoxuron has an opposite effect. Chlorfluazuron exhibited an increase in the activities of transaminases(GOT and GPT) whereas both enzymes were not affected by the flufenoxuron treatment. These results indica...