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排序方式: 共有215条查询结果,搜索用时 15 毫秒
111.
Ravichandran P Baluchamy S Gopikrishnan R Biradar S Ramesh V Goornavar V Thomas R Wilson BL Jeffers R Hall JC Ramesh GT 《The Journal of biological chemistry》2011,286(34):29725-29733
With the widespread application of carbon nanotubes (CNTs) in diverse commercial processes, scientists are now concerned about the potential health risk of occupational exposures. In this study, CNT-induced pulmonary toxicity was investigated by exposing BALB/c mice to aerosolized single-wall (SW) CNT and multiwall (MW) CNT (5 μg/g of mice) for 7 consecutive days in a nose-only exposure system. Microscopic studies showed that inhaled CNTs were homogeneously distributed in the mouse lung. The total number of bronchoalveolar lavage polymorphonuclear leukocytes recovered from the mice exposed to SWCNT and MWCNT (1.2 × 10(6) ± 0.52 and 9.87 × 10(5) ± 1.45; respectively) was significantly greater than control mice (5.46 × 10(5) ± 0.78). Rapid development of pulmonary fibrosis in mice that inhaled CNT was also confirmed by significant increases in the collagen level. The lactate dehydrogenase levels were increased nearly 2- and 2.4-fold in mice that inhaled SWCNT and MWCNT, respectively, as compared with control mice. In addition, exposure of CNTs to mice showed a significant (p < 0.05) reduction of antioxidants (glutathione, superoxide dismutase, and catalase) and induction of oxidants (myloperoxidase, oxidative stress, and lipid peroxidation) compared with control. Apoptosis-related proteins such as caspase-3 and -8 activities were also significantly increased in mice that inhaled CNT than in control mice. Together, this study shows that inhaled CNTs induce inflammation, fibrosis, alteration of oxidant and antioxidant levels, and induction of apoptosis-related proteins in the lung tissues to trigger cell death. 相似文献
112.
Lockwood DN Suneetha L Sagili KD Chaduvula MV Mohammed I van Brakel W Smith WC Nicholls P Suneetha S 《PLoS neglected tropical diseases》2011,5(12):e1327
Background
Previous studies investigating the role of cytokines in the pathogenesis of leprosy have either been on only small numbers of patients or have not combined clinical and histological data. The INFIR Cohort study is a prospective study of 303 new multibacillary leprosy patients to identify risk factors for reaction and nerve damage. This study characterised the cellular infiltrate in skin and nerve biopsies using light microscopic and immunohistochemical techniques to identify any association of cytokine markers, nerve and cell markers with leprosy reactions.Methodology/Principal Findings
TNF-α, TGF-β and iNOS protein in skin and nerve biopsies were detected using monoclonal antibody detection immunohistochemistry techniques in 299 skin biopsies and 68 nerve biopsies taken from patients at recruitment. The tissues were stained with hematoxylin and eosin, modified Fite Faraco, CD68 macrophage cell marker and S100.Conclusions/Significance
Histological analysis of the biopsies showed that 43% had borderline tuberculoid (BT) leprosy, 27% borderline lepromatous leprosy, 9% lepromatous leprosy, 13% indeterminate leprosy types and 7% had no inflammation. Forty-six percent had histological evidence of a Type 1 Reaction (T1R) and 10% of Erythema Nodosum Leprosum. TNF-α was detected in 78% of skin biopsies (181/232), iNOS in 78% and TGF-β in 94%. All three molecules were detected at higher levels in patients with BT leprosy. TNF-α was localised within macrophages and epithelioid cells in the granuloma, in the epidermis and in dermal nerves in a few cases. TNF-α, iNOS and TGF-β were all significantly associated with T1R (p<0.001). Sixty-eight nerve biopsies were analysed. CD68, TNF-α and iNOS staining were detectable in 88%, 38% and 28% of the biopsies respectively. The three cytokines TNF-α, iNOS and TGF-β detected by immunohistochemistry showed a significant association with the presence of skin reaction. This study is the first to demonstrate an association of iNOS and TGF-β with T1R. 相似文献113.
Gupta V Gupta A Jafar T Gupta V Agrawal S Srivastava N Kumar S Singh AK Natu SM Agarwal CG Agarwal GG 《Cytokine》2012,57(1):32-36
Background
Tumour necrosis factor alpha is a multifunctional proinflammatory cytokine involved in the pathogenesis of metabolic syndrome, insulin resistance, and obesity. Aim of this study is to investigate in a North Indian female population the impact of the G-308A TNF-α variant on various components of the metabolic syndrome, Insulin Resistance, serum TNF-α and Leptin levels.Methods
The G-308A TNF-α polymorphism has been studied in 269 females with metabolic syndrome (NCEP ATP III criteria) (age 31.91 ± 6.05) and 272 healthy females without metabolic syndrome (age 30.96 ± 7.01). The G-308A variant was detected by PCR amplification and Nco-1 digestion.Results
Homozygous mutant genotype (AA) (p = <0.001: OR = 3.24: 95% CI = 2.15-4.89) and mutant allele (A) (p = <0.001: OR = 3.04: 95% CI = 2.08-4.43) of TNF-α was significantly less frequently observed in the control population as compared to study group. Furthermore, on dividing the subjects into two groups according to the absence (TNF-1 allele) or presence of the mutant A (TNF-2) allele, significant results were obtained in most of the metabolic risk factors.Conclusions
Our results suggest that the G-308A polymorphism of the TNF-α gene may be independently associated with hypertension, leptin level and hypercholesterolemia leading to metabolic syndrome independent of Insulin resistance and hyperglycemia. 相似文献114.
115.
Partial attenuation of cytotoxicity and apoptosis by SOD1 in ischemic renal epithelial cells 总被引:1,自引:0,他引:1
Huan Ling Liang Jody Arsenault Jordan Mortensen Frank Park Christopher P. Johnson Vani Nilakantan 《Apoptosis : an international journal on programmed cell death》2009,14(10):1176-1189
Reactive oxygen species (ROS) contribute significantly to apoptosis in renal ischemia-reperfusion (IR) injury, however the
exact mechanisms are not well understood. We used novel lentiviral vectors to over-express superoxide dismutase 1 (SOD1) in
proximal tubular epithelial (LLC-PK1) cells and determined effects of SOD1 following ATP depletion-recovery, used as a model to simulate renal IR. SOD1 over-expression
partially protected against cytotoxicity (P < 0.001) and decreased superoxide (O2
•−) in ATP depleted cells. The ATP depletion-mediated increase in nuclear fragmentation, an index of apoptosis and activation
of caspase-3 was also partially blocked by SOD1 (P < 0.05). However, SOD1 over-expression was insufficient to completely attenuate caspase-3, indicating that ROS other than
cytoplasmic O2
•− are involved in ATP depletion mediated injury. To test the contribution of hydrogen peroxide, a subset of enhanced green
fluorescent protein (EGFP) and SOD1 (serum free and injured) cells were treated with polyethylene glycol-catalase (PEG-catalase).
As expected there was 50% reduction in cytotoxicity and caspase-3 in SOD1 cells compared to EGFP cells; catalase treatment
decreased both indices by an additional 28% following ATP depletion. To test the role of mitochondrial derived superoxide,
we also treated a subset of LLC-PK1 cells with the mitochondrial antioxidant, MitoTEMPO. Treatment with MitoTEMPO also decreased ATP depletion induced cytotoxicity
in LLC-PK1 cells in a dose dependant manner. These studies indicate that both SOD1 dependent and independent pathways are integral in
protection against ATP depletion-recovery mediated cytotoxicity and apoptosis, however more studies are needed to delineate
the signaling mechanisms involved. 相似文献
116.
A cytosine-specific DNA methyltransferase (EC 2.1.1.37) has been purified to near homogeneity from a mealybug (Planococcus lilacinus). The enzyme can methylate cytosine residues in CpG sequences as well as CpA sequences. The apparent molecular weight of
the enzyme was estimated as 135,000 daltons by FPLC. The enzyme exhibits a processive mode of action and a salt dependance
similar to mammalian methylases. Mealybug methylase exhibits a preference for denatured DNA substrates. 相似文献
117.
Edson Rodrigues Marcela Rosana da Silva Santos Edson Rodrigues Júnior Sree Vani Gannabathula Helena Passeri Lavrado 《Polar Biology》2009,32(5):691-702
The potential aerobic ATP-generating pathway and the argininolytic capacity of the Antarctic bivalve Laternula elliptica in its main tissues were measured by the specific activity of the enzymes malate dehydrogenase (MDH), citrate synthase (CS)
and arginase. The kidney showed the major potential for aerobic ATP-generating pathway and argininolytic capacity. High levels
of CS and MDH activities indicated that renal tissue can be involved in activities that require a lot of energy such as excretion
of metabolic end products, amino acids catabolism or even gluconeogenic activities related to inter-tissue metabolism. The
fact that kidneys are the main site for arginase activity is very unusual for mollusks and could be related to the living
habits of L. elliptica. Genetic expression of the L. elliptica renal arginase could be controlling the levels of l-arginine and forming urea in the excretory organ, which may not have its physiological functions directly affected by the
seasonal retraction of its siphons. Compared to the bivalve Dreissena polymorpha, renal arginase of L. elliptica is more resistant to inhibition by copper and cadmium. This could be related to naturally high levels of these metals in
the Antarctic marine environment and its bioaccumulation in the renal tissue of L. elliptica, as a probable advantage to its environmental adaptation. Different from other Antarctic animals that feed on Krill, the
arginase of L. elliptica is much more sensitive to fluoride inhibition. However, diet composition of L. elliptica would be expected to be variable site to site and its high sensitivity to fluoride inhibition may be a matter of concern
in areas near ornithogenic soils subjected to ice-melting processes. 相似文献
118.
119.
120.
Exposure of 25 °C-grown, seven-day-old rice seedlings to mild heat stress of 40 °C for 24 h in dark did not cause any change in protein or pigment content of the thylakoids, but produced major disorganization of chloroplast ultrastructure. This heat induced disorganization of thylakoid structure/organization caused significant (65 percnt;) loss in PSII activity, slight loss in PSI activity, and brought about a decrease in relative quantum efficiency of PSII. The herbicide 14C atrazine binding assay revealed a decreased number of binding sites of the herbicide and altered the herbicide dissociation constant, suggesting that the heat induced disorganization of the thylakoids affects the acceptor side of PSII. Cation induced Chla fluorescence analyses at room temperature and low temperature indicated thatin vivo heat exposure of rice seedlings altered the extent of energy transfer in favor of PSI. Immunoblotting analysis of several PSII polypeptides such as D1/D2 reaction dimer and Cyt b559 showed no major changes due to mild heat exposure except for the PSII core antenna polypeptide (CP43), which could reflect the reduction in PSII activity observed in light saturation studies. Similarly, haeme staining did not indicate any change in other cytochrome related polypeptides. Our results therefore clearly suggest thatin vivo exposure of rice seedlings to elevated (40 °C) temperature caused thylakoid structural disorganization, and this disorganization of some of the thylakoid complexes resulted in a loss in thylakoid photochemical function. 相似文献