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排序方式: 共有105条查询结果,搜索用时 31 毫秒
81.
Geetha Arumugam Monika Padmanaban Dhanya Krishnan Saranya Panneerselvam Surendran Rajagopal 《Biological trace element research》2011,142(3):424-434
Chronic pancreatitis is a serious condition associated with severe abdominal pain, and a significant percentage of patients
progresses to irreversible calcification in pancreas. The present study evaluates the degree to which the levels of trace
elements, copper, iron, selenium, zinc and haemoglobin-Fe3+, in blood, serum and pancreas have any role to play in the calcification process associated with fibrosis in pancreas. Twenty-seven
calcific (CCP) and 23 non-calcific chronic pancreatitis (CP) patients and equal number of age- and sex-matched normal volunteers
(50) were enrolled in the study. Surgically removed pancreatic tissue and blood samples were analysed for copper, iron, selenium,
zinc, protein, collagen and lipid peroxidation products in terms of malondialdehyde, protein carbonyls, glutathione, methemoglobin,
methemoglobin reductase and ceruloplasmin activity levels. We could find that the pancreatic tissue levels of copper, iron,
protein and collagen contents were significantly elevated in CCP patients when compared to CP patients. Serum levels of copper,
free ionic copper and iron were also elevated in CCP patients. The serum and the pancreatic tissue level of zinc and selenium
showed a significant decrease in CCP patients. The level of methemoglobin was elevated more significantly with the concomitant
decline in the activity of methemoglobin reductase. There was a positive correlation between the pancreatic level of copper
and iron with the collagen and protein levels. The results of the present study revealed that the levels of copper and iron,
the pro-oxidants and zinc and selenium may influence calcification process in CCP patients. Hypoxia-related tissue injury
due to the formation of oxidised haemoglobin may also contribute to the pathogenesis of calcification in pancreas. 相似文献
82.
Ataxia Telangiectasia (A-T) is an inherited immunodeficiency disorder wherein mutation of the ATM kinase is responsible for the A-T pathogenesis. Although the precise role of ATM in A-T pathogenesis is still unclear, its function in responding to DNA damage has been well established. Here we demonstrate that in addition to its role in DNA repair, ATM also regulates proteasome-mediated protein turnover through suppression of the ISG15 pathway. This conclusion is based on three major pieces of evidence: First, we demonstrate that proteasome-mediated protein degradation is impaired in A-T cells. Second, we show that the reduced protein turnover is causally linked to the elevated expression of the ubiquitin-like protein ISG15 in A-T cells. Third, we show that expression of the ISG15 is elevated in A-T cells derived from various A-T patients, as well as in brain tissues derived from the ATM knockout mice and A-T patients, suggesting that ATM negatively regulates the ISG15 pathway. Our current findings suggest for the first time that proteasome-mediated protein degradation is impaired in A-T cells due to elevated expression of the ISG15 conjugation pathway, which could contribute to progressive neurodegeneration in A-T patients. 相似文献
83.
Narayanan Surendran Sydney O. Ugwu Eric J. Sterling James Blanchard 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1995,670(2)
The overall objective of this research was to develop a sensitive, specific, and stability-indicating HPLC assay for the determination of the [Nle4-DPhe7]α-melanocyte-stimulating hormone analog known as Melanotan-1 (MT-1) in biological matrices, i.e., cell culture transport media and human plasma. Separation was accomplished isocratically within 8.0 min using a C8 reversed-phase column. The mobile phase consisted of 0.1 M phosphate buffer-acetonitrile (80:20, v/v) with 18 μl/l triethylamine at pH 2.50. The flow-rate was 1 ml/min with detection at 214 nm. Standard curves (n = 5) were linear over the concentration range 100–1000 ng/ml. The precision, accuracy, intra- and inter-day variations were good with C.V.s typically within 8.7% for concentrations greater than 100 ng/ml. This method was applied to a study of the transport of MT-1 in the Caco-2 cell monolayer model. 相似文献
84.
Surendran S 《Cell biology international》2001,25(5):485-488
Treatment of human amniotic epithelial (HAE) cells with anti-Fas monoclonal antibody (CH 11) at 100 ng/ml or 1 microg/ml for 12 or 24 h increased necrotic cell death. Apoptotic cell death induced by this antibody was significantly increased, although far fewer cells underwent apoptosis, as determined by the TUNEL method. This study suggests that Fas antigen is an important mediator in HAE cell death. 相似文献
85.
Antony P. McNamee Surendran Sabapathy Indu Singh Jarod Horobin Janelle Guerrero Michael J. Simmonds 《PloS one》2016,11(1)
Introduction
Given the severity of the current imbalance between blood donor supply and recipient demand, discarded blood drawn from the routine venesections of haemochromatosis (HFE-HH) patients may serve as a valuable alternative source for blood banks and transfusion. We investigated whether functional or biochemical differences existed between HFE-HH and control blood samples, with particular focus upon the haemorheological properties, to investigate the viability of venesected blood being subsequently harvested for blood products.Methods
Blood samples were collected from HFE-HH patients undergoing venesection treatment (n = 19) and healthy volunteers (n = 8). Moreover, a second experiment investigated the effects of a dose-response of iron (0, 40, 80, 320 mM FeCl3) on haemorheology in healthy blood samples (n = 7). Dependent variables included basic haematology, iron status, haematocrit, red blood cell (RBC) aggregation (native and standardised haematocrit) and “aggregability” (RBC tendency to aggregate in a standard aggregating medium; 0.4 L/L haematocrit in a Dx70), and RBC deformability.Results
Indices of RBC deformability were significantly decreased for HFE-HH when compared with healthy controls: RBC deformability was significantly decreased at 1–7 Pa (p < 0.05), and the shear stress required for half maximal deformability was significantly increased (p < 0.05) for HFE-HH. RBC aggregation in plasma was significantly increased (p < 0.001) for HFE-HH, although when RBC were suspended in plasma-free Dx70 no differences were detected. No differences in RBC deformability or RBC aggregation/aggregability were detected when healthy RBC were incubated with varying dose of FeCl3.Conclusion
HFE-HH impairs the haemorheological properties of blood; however, RBC aggregability was similar between HFE-HH and controls when cells were suspended in a plasma-free medium, indicating that plasma factor(s) may explain the altered haemorheology in HFE-HH patients. Acute exposure to elevated iron levels does not appear (in isolation) to account for these differences. Further consideration is required prior to utilising routine venesection blood for harvesting RBC concentrates due to the potential risk of microvascular disorders arising from impaired haemorheology. 相似文献86.
87.
Narayanan Surendran Charles J. Stankovic Barbra H. Stewart 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,691(2):851
The objective of this research was to develop a rapid, sensitive and reliable method for the separation of phosphonodipeptide prodrugs and parent compounds to facilitate the evaluation of cell permeation using in vitro cell culture models. Separation was accomplished isocratically within 10.0 min using a C18 (150×4.6 mm I.D., 3 μm) reversed-phase column. The mobile phase consisted of 5 mM tetrahexyl ammonium (ion-pair reagent) in 0.02 M phosphate buffer pH 6.5-acetonitrile (48.5:51.5, v/v). The flow-rate was 1.1 ml/min with detection at 221 nm. The standard curves were linear (r2>0.999) over the concentration range 1–100 μM. The method was reliable and reproducible, with the limit of quantitation being 1 μM (25 ng on column). 相似文献
88.
Rakesh Kumar P. K. Surendran Nirmala Thampuran 《World journal of microbiology & biotechnology》2008,24(5):627-631
A rapid and sensitive 8-h PCR assay has been developed for detection of Salmonella serovars in seafood. A total of 110 fresh and raw seafood samples were analysed for the presence of Salmonella using different enrichment periods prior to PCR assay. Seafood samples included in this study were fish, shrimps, mussels,
crabs, edible oysters, and clams, collected from local fish markets in Cochin (India). The assay was performed with a Salmonella-specific 284 bp invA gene amplicon. Specificity and sensitivity of the assay were ascertained with seafoods spiked with viable Salmonella cells to a level of 106 to 2 CFU per 25 g. Detection efficiency of the assay increased with increasing enrichment period for seafood, and 33.6% of
seafood samples were found positive for Salmonella by 8-h PCR assay. Detection limit for the 8-h PCR assay showed visible 284 bp amplicon from seafood homogenates spiked with 2 CFU per 25 g.
Seafood samples spiked with different Salmonella serovars, namely Salmonella typhi, Salmonella typhimurium, Salmonella enteritidis, Salmonella mbandka, Salmonella bareilly, and Salmonella weltevreden, were detected, confirming this technique would be ideal for detection of the Salmonella serovars prevalent in seafood. This study also covered inhibition by the seafood matrix and the detection limit for dead
Salmonella cells during the PCR assay. There was no visible inhibition of this Salmonella PCR assay by seafood matrices. The detection limit for dead Salmonella cells by 8-h PCR assay was 2 × 103 CFU per 25 g seafood. The data indicated that dead cells of Salmonella in naturally contaminated seafood samples do not interfere with the assay resulting in false positives. 相似文献
89.
Narasimhulu KV Gopal NO Rao JL Vijayalakshmi N Natarajan S Surendran R Mohan V 《Biophysical chemistry》2005,114(2-3):137-147
The pancreatic stones (Pancreatic calculi) collected from patients suffering from chronic calcific pancreatitis were studied in a view to explore the constituents involved in the calcification. The calcified stones were characterized by XRD, EPR and IR spectroscopic techniques. The detailed studies indicate that these stones consist of calcium carbonate as a major component, besides phosphates and other protein content. The presence of aragonite phases in the biomineralized stones is also discussed. The EPR spectra gave an evidence of the presence of traces of manganese in different oxidation states, which is used as one of the EPR probes in the present work. The samples were sintered at different temperatures to remove all the organic matter, and their EPR spectra have been studied to obtain detailed information regarding the changes in the symmetry of these stone samples. The X-irradiated sample was also characterized by EPR and the resonance signals are attributed to freely rotating CO(2)(-) radicals. The infrared spectrum reveals the presence of many organic bands corresponding to the protein amides. 相似文献
90.
Wong GW Foster PS Yasuda S Qi JC Mahalingam S Mellor EA Katsoulotos G Li L Boyce JA Krilis SA Stevens RL 《The Journal of biological chemistry》2002,277(44):41906-41915