283 research outputs found

    Toxicity and field persistence of thiamethoxam and dinotefuran against cabbage aphid, Brevicoryne brassica L. (Homoptera: Aphididae) under laboratory and field conditions

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    Cabbage aphid, Brevicoryne brassica L. is one of the most destructive and economically important insect pests of canola (Brassica napus L.) worldwide including Egypt. Few information is available on the effect of neonicotinoid insecticides (thiamethoxam and dinotefuran) against cabbage aphid on canola fields in Egypt, particularly in Assiut Governorate. Thus, this study was carried out to evaluate the toxicity and field persistence of thiamethoxam and dinotefuran against cabbage aphid under laboratory and field conditions. Under laboratory condition, thiamethoxam was showed high toxic effect against adult field strain of cabbage aphid with LC50 values, 84.10, 6.60 and 3.21 mg/L after 24, 48 and 72 hrs post treatment, respectively.  In addition, dinotefuran also exhibited toxic effect against this pest but less than thiamethoxam where the LC50 values were 300.50, 43.85 and 6.74 mgL-1, respectively after the periods of exposure. Based on the relative potency values, thiamethoxam was more effective than dinotefuran with 3.6, 6.6 and 2.1 fold after the periods of exposure. Under field condition, both thiamethoxam and dinotefuran exhibited efficiency against cabbage aphid population on canola plants after one, three, seven, fifteen and twenty-one days of treatments but thiamethoxam was more efficient than dinotefuran. Cabbage aphid reduction percent were 62.07, 89.80, 96.02, 96.59 and 94.55% for thiamethoxam and 8.58, 65.63, 86.77, 93.92 and 71.18% for dinotefuran after periods of exposure. The obtained data from this study indicated that thiamethoxam have a high toxicity effect against cabbage aphid under laboratory and field conditions. Based on our results, we suggest using thiamethoxam for cabbage aphid control in canola fields in Assiut Governorate, however more trails are needed about which in other Egyptian Governorates

    Properties of cellulosic fabrics treated by water-repellent emulsions

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    Water-repellent cotton, jute and linen fabrics have been prepared by treating them with emulsions made of beeswax/stearic acid (BW/SA) mixture. Different BW/SA ratios are tested to find out the best formulation recipe and different additives are incorporated in order to enhance emulsion stability and water repellency rating, such as alkali and metal salts. Triethanolamine (TEA) alkali has been selected for promoting the water repellency results. Cellulosic fabrics are pre-/post-treated with metal salts (aluminium chloride and zirconyl chloride) to enhance their physical attachment to the surfaces. Optimum emulsion ingredients for best results are found to be BW: SA (1:1), in presence of TEA (0.5 mole equivalent of SA) and zirconyl chloride concentration (1 g/L). Treated fabrics have been imparted with a water repellency characteristic, showing a value of 90, 80 and 80 for cotton, linen, and jute fabric respectively. Mechanical properties for treated fabrics are also demonstrated. FTIR spectra of treated fabric show no evidence of any chemical reactions between the substrate and the emulsion. Emulsions show stable rheological behavior upon storing for 3 months

    Quinazolin-4-one/3-cyanopyridin-2-one Hybrids as Dual Inhibitors of EGFR and BRAFV600E^{V600E}: Design, Synthesis, and Antiproliferative Activity

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    A novel series of hybrid compounds comprising quinazolin-4-one and 3-cyanopyridin-2-one structures has been developed, with dual inhibitory actions on both EGFR and BRAFV600E. These hybrid compounds were tested in vitro against four different cancer cell lines. Compounds 8, 9, 18, and 19 inhibited cell proliferation significantly in the four cancer cells, with GI50 values ranging from 1.20 to 1.80 µM when compared to Doxorubicin (GI50 = 1.10 µM). Within this group of hybrids, compounds 18 and 19 exhibited substantial inhibition of EGFR and BRAFV600E. Molecular docking investigations provided confirmation that compounds 18 and 19 possess the capability to inhibit EGFR and BRAFV600E. Moreover, computational ADMET prediction indicated that most of the newly synthesized hybrids have low toxicity and minimal side effects

    Design, Synthesis, and Biological Evaluation of Novel 3-Cyanopyridone/Pyrazoline Hybrids as Potential Apoptotic Antiproliferative Agents Targeting EGFR/BRAFV600E^{V600E} Inhibitory Pathways

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    A series of novel 3-cyanopyridone/pyrazoline hybrids (21–30) exhibiting dual inhibition against EGFR and BRAFV600E has been developed. The synthesized target compounds were tested in vitro against four cancer cell lines. Compounds 28 and 30 demonstrated remarkable antiproliferative activity, boasting GI50 values of 27 nM and 25 nM, respectively. These hybrids exhibited dual inhibitory effects on both EGFR and BRAFV600E pathways. Compounds 28 and 30, akin to Erlotinib, displayed promising anticancer potential. Compound 30 emerged as the most potent inhibitor against cancer cell proliferation and BRAFV600E. Notably, both compounds 28 and 30 induced apoptosis by elevating levels of caspase-3 and -8 and Bax, while downregulating the antiapoptotic Bcl2 protein. Molecular docking studies confirmed the potential of compounds 28 and 30 to act as dual EGFR/BRAFV600E inhibitors. Furthermore, in silico ADMET prediction indicated that most synthesized 3-cyanopyridone/pyrazoline hybrids exhibit low toxicity and minimal adverse effects

    Impact of severity, duration, and etiology of hyperthyroidism on bone turnover markers and bone mineral density in men

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    <p>Abstract</p> <p>Background</p> <p>Hyperthyroidism is accompanied by osteoporosis with higher incidence of fracture rates. The present work aimed to study bone status in hyperthyroidism and to elucidate the impact of severity, duration, and etiology of hyperthyroidism on biochemical markers of bone turnover and bone mineral density (BMD).</p> <p>Methods</p> <p>Fifty-two male patients with hyperthyroidism, 31 with Graves' disease (GD) and 21 with toxic multinodular goiter (TNG), with an age ranging from 23 to 65 years were included, together with 25 healthy euthyroid men with matched age as a control group. In addition to full clinical examination, patients and controls were subjected to measurement of BMD using dual-energy X-ray absorptiometery scanning of the lower half of the left radius. Also, some biochemical markers of bone turnover were done for all patients and controls.</p> <p>Results</p> <p>Biochemical markers of bone turnover: included serum bone specific alkaline phosphatase, osteocalcin, carboxy terminal telopeptide of type l collagen also, urinary deoxypyridinoline cross-links (DXP), urinary DXP/urinary creatinine ratio and urinary calcium/urinary creatinine ratio were significantly higher in patients with GD and TNG compared to controls (P < 0.01). However, there was non-significant difference in these parameters between GD and TNG patients (P > 0.05). BMD was significantly lower in GD and TNG compared to controls, but the Z-score of BMD at the lower half of the left radius in patients with GD (-1.7 ± 0.5 SD) was not significantly different from those with TNG (-1.6 ± 0.6 SD) (>0.05). There was significant positive correlation between free T3 and free T4 with biochemical markers of bone turnover, but negative correlation between TSH and those biochemical markers of bone turnover. The duration of the thyrotoxic state positively correlated with the assessed bone turnover markers, but it is negatively correlated with the Z-score of BMD in the studied hyperthyroid patients (r = -0.68, P < 0.0001).</p> <p>Conclusion</p> <p>Men with hyperthyroidism have significant bone loss with higher biochemical markers of bone turnover. The severity and the duration of the thyrotoxic state are directly related to the derangement of biochemical markers of bone turnover and bone loss.</p

    Mitochondrial oxidative stress and nitrate tolerance – comparison of nitroglycerin and pentaerithrityl tetranitrate in Mn-SOD(+/- )mice

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    BACKGROUND: Chronic therapy with nitroglycerin (GTN) results in a rapid development of nitrate tolerance which is associated with an increased production of reactive oxygen species (ROS). According to recent studies, mitochondrial ROS formation and oxidative inactivation of the organic nitrate bioactivating enzyme mitochondrial aldehyde dehydrogenase (ALDH-2) play an important role for the development of nitrate and cross-tolerance. METHODS: Tolerance was induced by infusion of wild type (WT) and heterozygous manganese superoxide dismutase mice (Mn-SOD(+/-)) with ethanolic solution of GTN (12.5 μg/min/kg for 4 d). For comparison, the tolerance-free pentaerithrityl tetranitrate (PETN, 17.5 μg/min/kg for 4 d) was infused in DMSO. Vascular reactivity was measured by isometric tension studies of isolated aortic rings. ROS formation and aldehyde dehydrogenase (ALDH-2) activity was measured in isolated heart mitochondria. RESULTS: Chronic GTN infusion lead to impaired vascular responses to GTN and acetylcholine (ACh), increased the ROS formation in mitochondria and decreased ALDH-2 activity in Mn-SOD(+/- )mice. In contrast, PETN infusion did not increase mitochondrial ROS formation, did not decrease ALDH-2 activity and accordingly did not lead to tolerance and cross-tolerance in Mn-SOD(+/- )mice. PETN but not GTN increased heme oxygenase-1 mRNA in EA.hy 926 cells and bilirubin efficiently scavenged GTN-derived ROS. CONCLUSION: Chronic GTN infusion stimulates mitochondrial ROS production which is an important mechanism leading to tolerance and cross-tolerance. The tetranitrate PETN is devoid of mitochondrial oxidative stress induction and according to the present animal study as well as numerous previous clinical studies can be used without limitations due to tolerance and cross-tolerance

    Roles of Superoxide, Peroxynitrite, and Protein Kinase C in the Development of Tolerance to Nitroglycerin

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    ABSTRACT A current hypothesis states that tolerance to nitroglycerin (GTN) involves increased formation of superoxide (O 2 . ). Studies showing that inhibitors of protein kinase C (PKC) prevent tolerance to GTN suggest the involvement of PKC activation, which can also increase O 2 . . We examined the roles of O 2 . , peroxynitrite (ONOO Ϫ ), and PKC activation in GTN tolerance. Pre-exposure of rat aortic rings to GTN (5 ϫ 10 Ϫ4 M) for 2 h caused tolerance to the vasodilating effect of GTN, as evidenced by a substantial rightward shift of GTN concentration-relaxation curves. This shift was reduced by treatment of the rings with the antioxidants uric acid, vitamin C, or tempol or the PKC inhibitor chelerythrine. We also found that O 2 . generation via xanthine/ xanthine oxidase in the bath induced tolerance to GTN. However, responses to nitroprusside were not affected. In vivo tolerance produced in rats by 3-day i.v. infusion of GTN was also almost completely prevented by coinfusion of tempol. In bovine aortic endothelial cells (EC), addition of GTN produced a marked increase in tyrosine nitrosylation, indicating increased ONOO Ϫ formation. This action was blocked by prior treatment with uric acid, superoxide dismutase, N G -nitro-L-arginine methyl ester, or chelerythrine. We also demonstrated that GTN translocates the ␣-and ⑀PKC isoforms in EC. However, PKC was not affected by GTN treatment. In conclusion, tolerance to GTN involves enhanced production of O 2 . and ONOO Ϫ and activation of NO synthase. Furthermore, sustained activation of ␣-and ⑀PKC isozymes in EC by GTN may play a role in development of tolerance
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