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Resultados 6161-6170 de 6,546
Cardiac toxicity of heavy metals (cadmium and mercury) and pharmacological intervention by vitamin C in rabbits Texto completo
2020
Tareen, Shaukat | Awan, Zubia | Mumtaz, Shumaila | Shakir, Hafiz Abdullah | Ahmad, Farooq | Ulhaq, Mazhar | T̤āhir, Ḥāfiz̤ Muḥammad | Awan, Muhammad Siddique | Sharif, Saima | Irfan, Muhammad | Khan, Muhammad Adeeb
Mercury and cadmium are highly dangerous metals that can lead to disastrous effects in animals and humans. The aim of the current research was to elucidate the poisonous effects of mercuric chloride and cadmium chloride individually and in combination on biochemical profiles of plasma and their accumulation in heart. The therapeutic effect of vitamin C against these metals in rabbits was also studied. Mercuric chloride (1.2 μg/g), cadmium chloride (1.5 μg/g), and vitamin C (150 μg/g of body weight) were orally given to treatment groups of the rabbits (1—control; 2—vitamin; 3—CdCl₂; 4—HgCl₂; 5—vitamin + CdCl₂; 6—vitamin + HgCl₂; 7—CdCl₂ + HgCl₂, and 8—vitamin + CdCl₂ + HgCl₂. After the biometric determination of all intoxicated rabbits, biochemical parameters, viz low-density lipoproteins (LDL), high-density lipoproteins (HDL), cholesterol, creatine kinase, and troponin T (TnT) were analyzed using available kits. Levels of cholesterol (0.7 ± 0.1 mmol/l), creatine kinase (2985.2 ± 11 IU/L), LDL (20.35 ± 1.31 mg/dl), and troponin T (1.22 ± 0.03 μg/l) were significantly (P < 0.05) increased. HDL (84.78 ± 4.30 mg/dl) was significantly (P < 0.05) decreased, while supplementation of vitamin C decreased the adverse effects of CdCl₂ and HgCl₂ on biochemical parameters in all metal-exposed groups. A similar trend was also seen in rabbits treated with CdCl₂ + vitamin and vitamin + CdCl₂ + HgCl₂. Accumulation of Cd and Hg was higher in heart tissues. This study, therefore, provides awareness on the cardiac toxicity of mercury and cadmium chlorides in the rabbits and the possible protective role of vitamin C against the perturbations induced by metals.
Mostrar más [+] Menos [-]Screening of human health risk to infants associated with the polychlorinated biphenyl (PCB) levels in human milk from Punjab Province, Pakistan Texto completo
2020
Naqvi, Anber | Qadir, Abdul | Mahmood, Adeel | Baqar, Mujtaba | Aslam, Iqra | Jamil, Nadia | Mumtaz, Mehvish | Saeed, Salman | Zhang, Gan
This study assessed the polychlorinated biphenyl (PCB) levels in human milk and its associated health risk to infants from rural and urban settings of five districts of Punjab Province, Pakistan. The ∑₃₄PCB concentrations ranged from 30.9 to 68.3 ng g⁻¹ on lipid weight (l.w.) basis. The ∑₈DL-PCB concentrations were ranged from 0.29 to 1.35 ng g⁻¹ l.w., (mean 6.2 ± 8.7 ng g⁻¹ l.w.), with toxicity equivalent to polychlorinated dibenzodioxins (PCDDs) ranging from 8.58 × 10⁻⁶ to 0.05 ng TEQ g⁻¹ l.w. The spatial trend of PCB levels in human milk revealed higher bioaccumulative levels for urban mothers as compared with rural counterparts. The estimated daily intake (EDI) values of DL-PCBs to infants through trans-mammary transfer were considerably higher than tolerable daily intake limits established by WHO (i.e., 1–4 pg TEQ kg⁻¹ bw) and other globally recognized organizations. Similarly, the hazard quotient values for TEQ ∑₈DL-PCBs (range 1.21 to 79.87) were far above the benchmark value of 1 at all the sampling sites, indicating the high levels of adverse health risks to infants in the region through breast milk consumption. The ∑₃₄PCB levels were found to be negatively correlated with mother’ age (r = −0.31; p = 0.02), parity (r = − 0.85; p = 0.001), and infant’ birth weight (r = − 0.73; p = 0.01). The present study suggests undertaking comprehensive public health risk assessment studies and firm regulatory measures to safeguard human health risks.
Mostrar más [+] Menos [-]Protective potency of Astragalus polysaccharides against tilmicosin- induced cardiac injury via targeting oxidative stress and cell apoptosis-encoding pathways in rat Texto completo
2020
Awad, Ashraf | Khalil, Samah R. | Hendam, Basma M. | Abd El-Aziz, Reda M. | Metwally, Mohamed M. M. | Imam, Tamer S.
Tilmicosin (Til) was purposed to be used in the treatment of a wide range of respiratory diseases in livestock. However, undesirable adverse effects, cardiac toxicity, in particular, may be associated with Til therapy. In the present study, the response of adult rats administered Til subcutaneously at different doses (10, 25, 50, 75, and 100 mg/kg b.w.; single injection) was evaluated. Astragalus polysaccharide (AP) at two doses (100 and 200 mg/kg b.w.; intraperitoneally) was investigated for its potential to counteract the cardiac influences, involving the oxidative stress-induced damage and apoptotic cell death, elicited by the Til treatment at a dose of 75 mg/kg b.w. in rats. Til induced mortalities and altered the levels of the biomarkers for the cardiac damage, particularly in the rats treated with the doses of 75 and 100 mg/kg b.w.; similarly, morphological alterations in cardiac tissue were seen at all studied doses. AP was found to cause a significant (P ˂ 0.05) decline in the levels of impaired cardiac injury markers (troponin, creatine phosphokinase, and creatine phosphokinase-MB), improvement in the antioxidant endpoints (total antioxidant capacity), and attenuation in the oxidative stress indices (total reactive oxygen species, 8-hydroxy-2-deoxyguanosine, lipid peroxides [malondialdehyde], and protein carbonyl), associated with a significant (P ˂ 0.05) modulation in the mRNA expression levels of the encoding genes (Bcl-2, Bax, caspase-3, P53, Apaf-1, and AIF), related to the intrinsic pathway of apoptotic cell death in the cardiac tissue. AP administration partially restored the morphological changes in the rat’s heart. The highest protective efficacy of AP was recorded at a dose level of 200 mg/kg b.w. Taken together, these results indicated that AP is a promising cardioprotective compound capable of attenuating Til-induced cardiac impact by protecting the rat cardiac tissue from Til-induced apoptosis when administered concurrently with and after the Til injection.
Mostrar más [+] Menos [-]Input and output of cadmium (Cd) for paddy soil in central south China: fluxes, mass balance, and model predictions Texto completo
2020
Xie, Yun-He | Zhu, Jian | Liu, Sai-Hua | Pan, Shu-Fang | Ji, Xiong-Hui
It is important to provide a more comprehensive understanding of cadmium (Cd) input and output in different contamination zones. In this study, we choose 15 sampling areas in three types of contamination zones (industrial and mining, suburb, and rural) to systematically study the inventory of soil Cd input and output in Changzhutan (CZT) urban agglomerations, Hunan Province, China. The results showed that the value of total Cd input in industrial and mining (34.58 g/ha/year) was respectively about 2 and 3 times of that in suburb and in rural. Meanwhile, the total output flux in industrial and mining also presented highest value (38.67 g/ha/year) among the zones. As for the contributions, atmospheric deposition was responsible for 85–89% of the total input fluxes, which was significantly higher than those of irrigation water and fertilizer. Crop harvesting, especially straw removal, was the dominant output pathway, contributing 66–78%. Moreover, Cd annual balance illustrated that the net input fluxes under straw removal scenario were negative in all zones, and it was opposite under straw returning scenario. Further, the changes of soil Cd concentrations under straw returning and straw removal scenario were compared by a dynamic mathematical model. The modeling results presented that the soil Cd content continued to increase under straw returning in 100 years, while it was declining under straw removal scenario. This prediction indicated straw removal was an important remediation for Cd-polluted paddy soil, especially in Hunan. Nevertheless, more treatment measures need to conduct to reach the safety limits in paddy soil.
Mostrar más [+] Menos [-]The relationship between cement production, mortality rate, air quality, and economic growth for China, India, Brazil, Turkey, and the USA: MScBVAR and MScBGC analysis Texto completo
2020
Bildirici, Melike E.
The related literature reveal that the papers on environmental pollution do not sufficiently analyse the cement production which is an important determinant of air pollution and health problems by using econometric methods. To fill this gap, this paper aims to examine the relationship between cement production, air pollution, mortality rate, and economic growth by employing MS Bayesian Vector Autoregressive (MScBVAR) and Markov Switching Bayesian Granger causality (MScBGC) approaches from 1960 to 2017 for China, Brazil, India, Turkey and the USA. MSIA(2)-BVAR(1) model for China, MSIAH(2)-BVAR(3) models for India, MSIAH(3)-BVAR(2) for Brazil, and MSIAH(3)-BVAR(1) for Turkey, and MSIAH(2)-BVAR(2) for the USA were selected. The MScBGC results revealed that the cement production is granger cause of mortality rate, air pollution, and economic growth in all regimes for China, India, Brazil, Turkey, and the USA.
Mostrar más [+] Menos [-]Plant isoflavones can prevent adverse effects of benzene on porcine ovarian activity: an in vitro study Texto completo
2020
Sirotkin, Alexander | Záhoranska, Zuzana | Tarko, Adam | Popovska-Percinic, Florina | Alwasel, Saleh | Harrath, Abdel Halim
We evaluated the influence of the oil-related environmental contaminant benzene (0, 10, 100, or 1000 ng/mL) alone and in combination with apigenin, daidzein, or rutin (10 μg/mL each) on viability; proliferation (accumulation of proliferating cell nuclear antigen); apoptosis (accumulation of Bax); and release of progesterone (P), testosterone (T), and estradiol (E) in cultured porcine ovarian granulosa cells. Cell viability; proliferation; apoptosis; and release of P, T, and E have been analyzed by the trypan blue test, quantitative immunocytochemistry, and ELISA, respectively. Benzene did not affect apoptosis, but reduced ovarian cell viability and P and E release, and promoted proliferation and T output. Apigenin did not affect cell viability, but stimulated proliferation and T and E release, and inhibited apoptosis and P secretion. It prevented and reversed the action of benzene on proliferation and P and T release, and induced the inhibitory action of benzene on apoptosis. Daidzein promoted cell viability, proliferation, P release, but not apoptosis and T or E release. Daidzein induced the stimulatory effect of benzene on T, without modifying other effects. Rutin administered alone reduced cell viability and apoptosis, and promoted cell proliferation. Furthermore, rutin prevented and reversed the effect of benzene on proliferation and P and E release. These observations suggest the direct action of benzene and plant polyphenols on basic ovarian cell functions, and the ability of apigenin and rutin, but not of daidzein, to prevent benzene effects on the ovary.
Mostrar más [+] Menos [-]Cynara scolymus leaves extract alleviates nandrolone decanoate-induced alterations in testicular function and sperm quality in albino rats Texto completo
2020
Mohammed, Eman Taha | Radi, Abeer M. | Aleya, Lotfi | Abdel-Daim, Mohamed M.
Nandrolone decanoate (ND) is a commonly used anabolic-androgenic steroid. These drugs are illegally self-administered by athletes to enhance their sports performance. However, their abuse could influence the testicular function and fertility. The main objective of this study was to evaluate the possible protective effects of Cynara scolymus leaf extract (CLE) on ND-induced testicular dysfunction in rats. Five groups of adult male rats (10 rats each) were used. Group I rats received only saline and served as controls. Group II rats were injected with a vehicle once weekly, while group III rats received intramuscular injections of ND (20 mg/kg/week for 60 days). Group IV rats orally received 1 g/kg/day of CLE and group V rats received ND and CLE at the aforementioned doses. The results revealed that ND has a negative impact on the testicular function as evidenced by the significant increases (p ≤ 0.05) in testicular malondialdehyde concentration and serum non-prostatic acid phosphatase activity, as well as the significant decreases in serum testosterone levels, testicular weight, glutathione concentration, catalase enzyme activity, and total antioxidant capacity. These results were accompanied by considerable alterations of sperm characters and histopathological studies of the testicular tissue. However, co-treatment with CLE extract significantly alleviated (p ≤ 0.05) almost all ND-induced pathological alterations. In conclusion, co-treatment of ND-intoxicated rats with CLE ameliorated the toxic effects of ND on the testicular structure and function, probably due to its antioxidant activity.
Mostrar más [+] Menos [-]The role of governments in mitigating SO2 pollution in China: a perspective of fiscal expenditure Texto completo
2020
Jiang, Lei | Zhou, Haifeng | He, Shixiong
China has suffered from extensive and serious SO₂ pollution. The central and provincial governments have reinforced environmental awareness by increasing fiscal expenditure for environmental protection for years. This paper extended an environmental Kuznets curve (EKC) framework to evaluate the direct and indirect spillover effects of environmental awareness of provincial governments on SO₂ emissions, applying spatial econometric models. The empirical findings are as follows. (1) There exists an inverted U-shaped curve. Of 30 Chinese provinces, only 9 provinces, namely, 8 eastern provinces and Inner Mongolia, have passed the turning point at about 53,000 Yuan while the rest 21 provinces have not yet. (2) Expenditure for environmental protection is negatively correlated with SO₂ pollution. In other words, environmental awareness of governments contributes to substantially reducing SO₂ emissions. Besides, significant and negative spillover effects of environmental awareness are found, implying that provinces follow suit if neighboring provinces enhance environmental awareness by increasing spending on environmental protection, thereby reducing SO₂ emissions. (3) The SO₂ reduction policy implemented by the central government is found to have a negative impact on SO₂ emissions, implying that the policy effectively works. To conclude, the central and provincial governments play pivotal roles in addressing the problem of SO₂ pollution in China. Hence, more expenditure for environmental protection cannot be overstated for China’s environmental quality improvements and sustainable development.
Mostrar más [+] Menos [-]Persistence and dissipation kinetics of tebuconazole in apple, tomato, chilli and onion crops of Himachal Pradesh, India Texto completo
2020
Dubey, Jatiender Kumar | Patyal, Surender Kumar | Katna, Sapna | Shandil, Deepika | Devi, Nisha | Singh, Gaganpreet | Singh, Gagandeep
Tebuconazole is a broad-spectrum fungicide extensively used worldwide for the control of many diseases such as powdery mildew and scab in apple, early blight of tomato, anthracnose of chilli, white rot and purple blotch of onion etc. Maximum residue level of this compound has not been worked out on these crops in India; the persistence and dissipation kinetics of tebuconazole on apple, tomato, chilli and onion were studied following three foliar applications of the formulation Folicur 430 SC at a standard dose (X) 322, 268.75, 215 and 215 g a.i./ha and at double dose (2X) 645, 537.5, 430 and 430 g a.i./ha, respectively, to work out the safe waiting periods and half-life period of tebuconazole. Extraction was done using QuEChERS method and cleanup by using dispersive solid-phase method. Tebuconazole residues were estimated on gas chromatograph-mass spectrometry (GC-MS). The recovery of tebuconazole in fortified matrix was above 90% with a limit of quantification (LOQ) at 0.05 mg kg⁻¹. The initial deposits of tebuconazole on apple at two locations under study ranged from 1.986–2.011 mg kg⁻¹at X dose to 3.698–3.843 mg kg⁻¹ at 2X dose. The initial deposits in tomato, chilli and onion were 1.129, 1.760 and 1.169 mg kg⁻¹ at X dose and 2.213, 2.784 and 2.340 mg kg⁻¹, respectively at the 2X dose. Dissipation of the fungicide followed first-order of kinetics and the half life of degradation ranged from 1.30–2.25 days at X dose to 1.40–2.62 days at 2X days on different crops under study. Residues declined below the determination limit (LOQ) of 15 and 20 days after spraying, respectively, at X and 2X dose in apple; 7 and 10 days in tomato; 10 and 15 days in chilli and onion. Waiting periods of 5, 2, 7 and 12 days, respectively, are suggested for apple, tomato, chilli and onion at 2X dose.
Mostrar más [+] Menos [-]Do the performance and efficiency of China’s carbon emission trading market change over time? Texto completo
2020
Zhang, Shiyi | Jiang, Kai | Wang, Lan | Bongers, Geoff | Hu, Guoping | Li, Jia
Whether or not China can succeed at the forefront of international development in the coming decades will largely hinge on its ability to adapt to low-carbon economic development and its efforts to promote the Unified National Emission Trading System (UNETS). To understand the evolution of China’s carbon market, this paper firstly divides the development of China’s regional carbon markets into three phases: pilot construction (phase 1, before 31 May 2015), preparation for the UNETS (phase 2, 1 June 2015–19 December 2017), and formal construction of the UNETS (phase 3, 20 December 2017–present). Then this research reviews the trading performance and employs four robust variance ratio (VR) tests to capture structural changes and examine the efficiency of China’s eight regional carbon markets in different periods. Results show that compared to phase 1, smaller price volatility, larger daily trading volume, and higher market liquidity are more frequent at the later stages of majority markets. Despite these improvements, results from the VR tests indicate that the statistic in majority of China’s regional carbon markets is insignificant in any given period and, therefore, they are not weak-form efficient. The additional detrended cross-correlation analysis demonstrates that market liquidity affects market efficiency in the Hubei market only, which implies that Hubei, where the market liquidity reaches almost 100% in phase 3, is highly likely to be weak-form efficient shortly. Finally, several recommendations are provided to improve the efficiency and maturity of China’s carbon markets, including strengthening legislation, improving the market design, and constructing information platforms.
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