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排序方式: 共有746条查询结果,搜索用时 15 毫秒
41.
Widespread use of cerium oxide (CeO2) nanoparticles (NPs) is found in almost all areas of research due to their distinctive properties. CeO2 NPs synthesized via green chemistry have been characterized for antioxidant, phytochemical, and biological potential. Physical characterization through scanning electron microscopy, XRD, and TGA showed that the NPs are circular in shape, 20‐25 nm in size, and stable in a wide range of temperature. NPs display significant antioxidant (32.7% free radical scavenging activity) and antileishmanial (IC50 48 µg mL?1) properties. In vitro toxicity tested against lymphocytes verified that NPs are biocompatible (99.38% viability of lymphocytes at 2.5 μg mL?1). In vivo toxicity experiments showed no harmful effects on rat serum chemistry and histology of various organs and did not even change the concentration of antioxidative enzymes, total protein contents, lipid peroxidation, and nitrosative stress. These observations are in line with the statement that plant‐based synthesis of CeO2 NPs lessens or nullifies in vitro and in vivo toxicity and hence CeO2 NPs are regarded as a safe and biocompatible material to be used in drug delivery.  相似文献   
42.
Diffuse optical imaging (DOI) techniques provide a wide‐field or macro assessment of the functional tumor state and have shown substantial promise for monitoring treatment efficacy in cancer. Conversely, intravital microscopy provides a high‐resolution view of the tumor state and has played a key role in characterizing treatment response in the preclinical setting. There has been little prior work in investigating how the macro and micro spatial scales can be combined to develop a more comprehensive and translational view of treatment response. To address this, a new multiscale preclinical imaging technique called diffuse and nonlinear imaging (DNI) was developed. DNI combines multiphoton microscopy with spatial frequency domain imaging (SFDI) to provide multiscale data sets of tumor microvascular architecture coregistered within wide‐field hemodynamic maps. A novel method was developed to match the imaging depths of both modalities by utilizing informed SFDI spatial frequency selection. An in vivo DNI study of murine mammary tumors revealed multiscale relationships between tumor oxygen saturation and microvessel diameter, and tumor oxygen saturation and microvessel length (|Pearson's ρ| ≥ 0.5, P < 0.05). Going forward, DNI will be uniquely enabling for the investigation of multiscale relationships in tumors during treatment.   相似文献   
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Functional & Integrative Genomics - This humble effort highlights the intricate details of metagenomics in a simple, poetic, and rhythmic way. The paper enforces the significance of the...  相似文献   
45.
Plant Cell, Tissue and Organ Culture (PCTOC) - Four serotypes of the dengue virus that can cause severe disease in humans greatly increases the complexity of vaccine development. In this study, we...  相似文献   
46.
Ahmad W  Ali MN  Farah MA  Ateeq B 《Chromosoma》2002,110(8):570-574
An in vivo study of the effects of pentachlorophenol was carried out with a pre-acclimatized fish species, Heteropneustes fossilis, using four sub-lethal concentrations, 0.1, 0.2, 0.3 and 0.4 ppm, and three sampling times, 48, 72 and 96 h. Cytogenetic preparations were stained by the haematoxylin-eosin technique. The incidence of micronuclei was scored by a manual and an automated method. Small-sized micronuclei appeared in the cytoplasm in addition to the main nucleus. The frequency of micronucleated erythrocytes peaked at 4 days (96 h) exposure. The percentage of single micronuclei increased with longer exposures. The Mann-Whitney U test showed all micronuclei frequencies were significantly different from control (P<0.05). No statistical difference was observed between scores obtained by the manual and automated methods. A linear relationship between the percentage of micronucleated erythrocytes and dose was confirmed at all levels. Computer image analysis of morphological variations of erythrocytes indicated a 1:5 ratio of micronuclei and main nucleus accompanied by a reduction in cell volume by 600 dot units. Pentachlorophenol-mediated genotoxicity was confirmed in this fish for the first time. Possible consequences of genotoxicity and cytotoxicity are discussed.  相似文献   
47.
Recent studies have revealed potent pharmacological activities of manganese-containing cationic porphyrins. An analytical method employing high-performance liquid chromatography with spectrophotometric and electrochemical detection (HPLC-UV/EC) suitable for in vivo applications is described for a series of manganese(III) cationic porphyrins with good separation and resolution. In particular, this method resolved the four atropisomers of manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP5+ or AEOL-10113), verified by mass spectrometry. Electrochemical and spectrophotometric methods of detection were compared using manganese(III) meso-tetrakis(1,3-diethylimidazolium-2-yl)porphyrin (MnTDE-2-ImP5+ or AEOL-10150), the lead catalytic antioxidant of this series. Both methods of detection were quantitative, but electrochemical detection, although less specific for in vivo applications, appears to be considerably more sensitive than spectrophotometric detection.  相似文献   
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49.
Maintaining blood-brain barrier integrity and minimizing neuronal injury are critical components of any therapeutic intervention following ischemic stroke. However, a low level of vitamin D hormone is a risk factor for many vascular diseases including stroke. The neuroprotective effects of 1,25(OH)2D3 (vitamin D) after ischemic stroke have been studied, but it is not known whether it prevents ischemic injury to brain endothelial cells, a key component of the neurovascular unit. We analyzed the effect of 1,25(OH)2D3 on brain endothelial cell barrier integrity and tight junction proteins after hypoxia/reoxygenation in a mouse brain endothelial cell culture model that closely mimics many of the features of the blood-brain barrier in vitro. Following hypoxic injury in bEnd.3 cells, 1,25(OH)2D3 treatment prevented the decrease in barrier function as measured by transendothelial electrical resistance and permeability of FITC-dextran (40 kDa), the decrease in the expression of the tight junction proteins zonula occludin-1, claudin-5, and occludin, the activation of NF—kB, and the increase in matrix metalloproteinase-9 expression. These responses were blocked when the interaction of 1,25(OH) )2D3 with the vitamin D receptor (VDR) was inhibited by pyridoxal 5’-phosphate treatment. Our findings show a direct, VDR-mediated, protective effect of 1,25(OH) )2D3 against ischemic injury-induced blood-brain barrier dysfunction in cerebral endothelial cells.  相似文献   
50.

Background

Similar to other developing countries, Pakistan is going through a rapid nutrition transition where shift from underweight to overweight and obesity is occurring. In this paper, we report on the relationship of household socioeconomic position (SEP), community SEP and urbanicity with under- and over-weight categories of BMI among Pakistani women.

Methods

We analyzed data on 4,767 women ages 15-49 years enrolled in a nationally representative Pakistan Demographic Health Survey (PDHS) conducted in 2012-13 that employed a multistage, stratified cluster sampling design. We assessed the association of urbanicity, household and community SEP derived from household assets and utilities, with categories of body mass index (BMI) using multinomial regression analysis where normal weight (BMI 18.6-22.5) was the reference category.

Results

Thirteen percent of women were underweight (BMI <18.5), 15% pre-overweight (BMI: 22.6-24.9), 25% overweight (BMI: 25.0–29.9) and 14% were obese (BMI≥30). Pre-overweight, overweight and obesity among women increased across household wealth quintiles (HWQs) in a graded fashion whereas there was no significant difference in underweight by household wealth. Women in urban areas were more likely to be obese. There was a pronounced increase in adjusted odds ratios (aORs) for overweight/obesity across HWQs within urban areas compared to rural areas. There was a steeper gradient in aORs for obesity from 1st to 5th HWQs in high income communities compared to the middle- and low income communities. In community-level analyses, communities in urban areas were more likely to have higher levels of obesity while in rural areas, especially in Sindh, more communities were more likely to have a higher level of underweight.

Conclusion

A shift to higher overweight and obesity than underweight in Pakistan is associated with high household and community wealth as well as living in urban areas. Clustering of obesity and underweight in distinct communities afford opportunity for tailored intervention programs.  相似文献   
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