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排序方式: 共有390条查询结果,搜索用时 78 毫秒
1.
Iman Jalilian Celine Heu Hong Cheng Hannah Freittag Melissa Desouza Justine R. Stehn Nicole S. Bryce Renee M. Whan Edna C. Hardeman Thomas Fath Galina Schevzov Peter W. Gunning 《PloS one》2015,10(5)
The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments. 相似文献
2.
Iman Y. Zaghloul Mahasen A. Radwan Zinat H. Aly 《Journal of trace elements in medicine and biology》2007,21(2):132-137
Cadmium has been associated with a number of adverse health effects but the impact of those effects on the pharmacokinetics of different drugs has not been investigated. Therefore, the pharmacokinetics of theophylline and ciprofloxacin were studied in cadmium-exposed and control rats (72 rats) following i.p. (6.5mg/kg) and p.o. (10mg/kg) administration, respectively. The third-generation offsprings of rats exposed to 100 microg/mL of cadmium chloride in drinking water were used in this study. Following 8 weeks of exposure, animals received the drugs as a single dose. Blood samples were withdrawn at different time-points and the plasma concentrations of both drugs were analyzed by HPLC. The pharmacokinetic parameters of theophylline and ciprofloxacin were altered significantly in the cadmium-exposed animals. For theophylline, a statistically significant increase (p<0.0001) in C(max) (69%) and AUC(0-)(infinity) (68%) of theophylline in the cadmium-exposed rats as compared to the control were observed. A corresponding significant (p<0.0001) reduction of 41% in clearance (CL/F) of theophylline was detected in the exposed group. Neither the half-life nor the mean residence time (MRT) showed any significant change due to the exposure to cadmium. For ciprofloxacin, no significant difference was seen in the C(max) of the exposed group as compared to the control animals. However, a delay in T(max) was observed in the exposed group (from 0.16(+/-0.003) to 0.37(+/-0.14)h). A small, but significant increase in t(1/2) (p<0.05) was detected (1.74(+/-0.25) vs. 1.45(+/-0.12)h). A significant reduction (p<0.05) of CL/F from 30.54(+/-1.9) to 24.01(+/-3.81)mL/min/kg was seen in the treated group. The current investigation showed that chronic exposure to cadmium could have a very significant impact on altering the pharmacokinetic parameters of various drugs. Therefore, in cadmium-polluted areas, dose adjustments and drug monitoring, especially for drugs with a narrow therapeutic window, should be carried out. 相似文献
3.
Iman J. Schultz Caiyong Chen Barry H. Paw Iqbal Hamza 《The Journal of biological chemistry》2010,285(35):26753-26759
Iron is an essential element for diverse biological functions. In mammals, the majority of iron is enclosed within a single prosthetic group: heme. In metazoans, heme is synthesized via a highly conserved and coordinated pathway within the mitochondria. However, iron is acquired from the environment and subsequently assimilated into various cellular pathways, including heme synthesis. Both iron and heme are toxic but essential cofactors. How is iron transported from the extracellular milieu to the mitochondria? How are heme and heme intermediates coordinated with iron transport? Although recent studies have answered some questions, several pieces of this intriguing puzzle remain unsolved. 相似文献
4.
Virgil Paunescu Florina M. Bojin Oana I. Gavriliuc Elena A. Taculescu Robert Ianos Valentin L. Ordodi Vlad F. Iman Calin A. Tatu 《Journal of cellular and molecular medicine》2014,18(6):962-965
There are few major morphologies of cell death that have been described so far: apoptosis (type I), cell death associated with autophagy (type II), necrosis (type III) and anchorage‐dependent mechanisms—anoikis. Here, we show for the first time a possibly novel mechanism inducing tumour cell death under in vitro conditions—enucleation. We pursued the influence of colloidal suspensions of Fe3O4 nanoparticles on tumour cell lines (SK‐BR‐3 and MCF‐7 breast cancer cell lines) grown according to standard cell culture protocols. Magnetite nanoparticles were prepared by combustion synthesis and double layer coated with oleic acid. Scanning and transmission electron microscopy revealed that tumour cells developed a network of intracytoplasmic stress fibres, which induce extrusion of nuclei, and enucleated cells die. Normal adult mesenchymal stem cells, used as control, did not exhibit the same behaviour. Intact nuclei were found in culture supernatant of tumour cells, and were visualized by immunofluorescence. Enucleation as a potential mechanism of tumour cell death might open new horizons in cancer biology research and development of therapeutic agents capable of exploiting this behaviour. 相似文献
5.
Iman Al-Saleh Mai Abduljabbar Reem Al-Rouqi Rola Elkhatib Ammar Alshabbaheen Neptune Shinwari 《Biological trace element research》2013,153(1-3):145-154
The objective of this work was to assess exposure to mercury (Hg) and its induction of oxidative stress in 155 healthy lactating Saudi mothers and their infants. Samples of breast milk and blood were collected from the mothers, while urine was taken from both infants and mothers. Both urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were measured in mothers and infants as biomarkers of oxidative stress. The mean concentration of Hg in breast milk was 1.19 μg/L (range 0.012–6.44 μg/L) with only one mother having Hg >4 μg/L, the upper limit established by the US Agency for Toxic Substance and Disease Registry. However, 57.4 % had Hg ≥1 μg/L, the background level for Hg in human milk. The mean urinary Hg corrected for creatinine (Hg-C) in mothers and infants was 1.47 and 7.90 μg/g creatinine, respectively, with a significant correlation between the two (p?<?0.001). Urinary Hg levels over 5 μg/g creatinine (the background level in an unexposed population) were found in 3.3 % of mothers and 50.1 % of infants. None of the mothers had total blood Hg above the US Environmental Protection Agency’s maximum reference dose of 5.8 μg/L. No correlation was noted between urinary Hg in infants and Hg in breast milk (p?>?0.05). Hg in breast milk, though, was associated with Hg in blood (p?<?0.001), suggesting the efficient transfer of Hg from blood to milk. Hg in the breast milk of mothers and in the urine of infants affected the excretion of urinary MDA and 8-OHdG, respectively, in a dose-related manner. These findings reveal for the first time lactational exposure to Hg-induced oxidative stress in breast-fed infants, which may play a role in pathogenesis, particularly during neurodevelopment. This will also contribute to the debate over the benefits of breast milk versus the adverse effects of exposure to pollutants. Nevertheless, breastfeeding should not be discouraged, but efforts should be made to identify and eliminate the source of Hg exposure in the population. 相似文献
6.
Sassan Saber Reza Vazifehmand Iman Bagherizadeh Mahbubeh Kasiri 《Indian journal of human genetics》2013,19(3):366-368
Progressive familial intrahepatic cholestasis is an autosomal recessive liver disorder caused by (biallelic) mutations in the ATP8B1 of ABCB11 gene. A nine-year-old girl with cholestasis was referred for genetic counseling. She had a family history of cholestasis in two previous expired siblings. Genetic analysis of the ABCB11 gene led to the identification of a novel homozygous mutation in exon 25. The mutation 3593- A > G lead to a missense mutation at the amino acid level (His1198Arg). This mutation caused PFIC2 due to abnormal function in the bile salt export pump protein (BSEP). 相似文献
7.
The elm leaf beetle, Xanthogalerucella luteola (Coleoptera: Chrysomelidae) is the most serious pest of elm trees. This pest causes severe damage to elm trees during its growth stages and as a result, in the middle of summer, leaves become skeletised and start to fall down. In this work, biochemical characterisation of digestive α-amylase of this insect and its relationship with insect feeding was investigated. The insect gut was isolated and its α-amylase was extracted and starch (1%) was used as a substrate for the enzyme. Results showed that the enzyme’s optimum temperature and pH was 35?°C and 5.5, respectively. Some ions such as NaCl decreased the enzyme activity whilst MgCl2 and CaCl2 increased the enzyme activity. Gut content electrophoresis showed that only one α-amylase is active in this insect species. There was a correlation between the amount of leaf eaten by the insect and the amount of the enzyme activity. 相似文献
8.
Mahsa Rahimi Ali Sharifi‐Zarchi Javad Firouzi Mahnaz Azimi Nosratollah Zarghami Effat Alizadeh Marzieh Ebrahimi 《Journal of cellular and molecular medicine》2019,23(4):2442-2456
Several evidences support the idea that a small population of tumour cells representing self‐renewal potential are involved in initiation, maintenance, metastasis, and outcomes of cancer therapy. Elucidation of microRNAs/genes regulatory networks activated in cancer stem cells (CSCs) is necessary for the identification of new targets for cancer therapy. The aim of the present study was to predict the miRNAs pattern, which can target both metastasis and self‐renewal pathways using integration of literature and data mining. For this purpose, mammospheres derived from MCF‐7, MDA‐MB231, and MDA‐MB468 were used as breast CSCs model. They had higher migration, invasion, and colony formation potential, with increasing in stemness‐ and EMT‐related genes expression. Our results determined that miR‐204, ‐200c, ‐34a, and ‐10b contemporarily could target both self‐renewal and EMT pathways. This core regulatory of miRNAs could increase the survival rate of breast invasive carcinoma via up‐regulation of OCT4, SOX2, KLF4, c‐MYC, NOTCH1, SNAI1, ZEB1, and CDH2 and down‐regulation of CDH1. The majority of those target genes were involved in the regulation of pluripotency, MAPK, WNT, Hedgehog, p53, and transforming growth factor β pathways. Hence, this study provides novel insights for targeting core regulatory of miRNAs in breast CSCs to target both self‐renewal and metastasis potential and eradication of breast cancer. 相似文献
9.
In this study, for the first time, calcium oxide (CaO)/polylactic acid nanoscaffolds were synthesized by co‐precipitation assistant reverse micelles method. The physical and chemical (physicochemical) properties of the structures as dental resin composites were also studied. Nanocomposite materials as primary and basic dental compounds can be conveniently applied as dental filling materials with a high esthetic quality. In this research nanoscaffolds act as a bed for nanoparticles and improve the mechanical and chemical (mechanochemical) properties, CaO nanoparticles were loading in polylactic acid nanoscaffold as a bioactivity polymer for usage in the dental resin composites. Mechanical properties of the dental resin composite containing CaO/polylactic acid nanoscaffold were calculated: the flexural strength (137.2 MPa), modulus (12.9GPa) and compressive strength (344.2 MPa). Potential of the basic nanoparticle and the products were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), ultraviolet‐visible spectroscopy (UV‐visible) and atomic force microscopy (AFM) showed the size of the optimized nanostructures was about 85 to 120 nm. According to TGA results of polylactic acid nanofibers with thermal stability below 300°C these high thermal stability materials can be used as dental resin composites. 相似文献
10.