摘要:

AbstractThe association of erythrocyte spectrin with desmin filaments was investigated using two in vitro assays. The ability of spectrin to promote the interaction of desmin filaments with membranes was investigated by electron microscopy of desmin filament‐erythrocyte inside‐out vesicle preparations. Desmin filaments bound to erythrocyte inside‐out vesicles in a spectrin‐dependent manner, demonstrating that spectrin is capable of mediating the association of desmin filaments with plasma membranes. A quantitative sedimentation assay was used to demonstrate the direct association of spectrin with desmin filaments in vitro. When increasing concentrations of spectrin were incubated with desmin filaments, spectrin cosedimented with desmin filaments in a concentration‐dependent manner. At near saturation the spectrin:desmin molar ratio in the sedimented complex was 1:230. Our results suggest that, in addition to its well characterized associations with actin, spectrin functions to mediate the association of intermediate filaments with plasma membranes. It might be that nonerythrocyte spectrins share erythrocyte spectrin's ability to bind to intermediate filaments and function in nonerythroid cells to promote the interaction of intermediate filaments with actin filaments and/or the plasma

ISSN:0730-2312    

DOI:10.1002/jcb.240300202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThis review summarizes progress in nonenzymatic glycosylation research of potential relevance to atherosclerosis using a hypothetical model based on current concepts of atherogenesis. Recently, new information has been presented showing that the initial Amadori product undergoes a series of further reactions and rearrangements to form adducts, called advanced glycosylation end products (AGE). These products are irreversible and accumulate indefinitely on long‐lived molecules. These AGE covalently trap soluble plasma proteins, act as signals for macrophage recognition and uptake, and induce mutations in double‐stranded plasmid DNA. Covalent trapping of low‐density lipoprotein (LDL) by AGE on collagen or elastin could promote lipid accumulation in the arterial wall, whereas AGE trapping of von Willebrand factor would increse platelet adhesion and aggregation leading to intimal smooth muscle cell proliferation. Recognition and uptake of AGE‐proteins by scavenging macrophages could further contribute to the process of atherogenesis by stimulating release of macrophage secretory products such as macrophage‐derived growth factor. Accumulation of AGE on smooth muscle cell DNA might also enhance arterial smooth muscle cell proliferation by increasing the rate of mutations affecting growth controls. This model should provide the basis for future ex

ISSN:0730-2312    

DOI:10.1002/jcb.240300203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractWe present evidence that specific receptors are utilized by neutrophils to control their interaction with endothelial cells at sites of acute inflammation and that these receptors are related if not identical to lymphocyte “homing receptors” for lymphoid tissue high endothelium. We speculate that such receptors play a fundamental but not exclusive role in controlling the extravasation and tissue localization of all bone marrow‐derived nucleated cells. In addition, we emphasize the active role of endothelial cells in the process of lymphocyte migration and leukocyte extravasation. By the expression of as yet unidentified organ‐specific determinants for lymphocyte recognition, endothelial cells control the exit of particular lymphocyte subsets into mucosal versus nonmucosal sites, thus helping to determine the unique features of mucosal versus nonmucosal immune responses. Furthermore, we argue that endothelial cells are exquisitely responsive to local immune reactivity and present evidence that specific lymphokines, including γ‐interferon, play an important role in inducing postcapillary venules to express differentiated features required for the support of lymphocyte traffic into lymphoid organs and into sites of chronic inflammation. Leukocytes, endothelial cells, and probably other tissue cell classes appear to interact at multiple levels by a variety of mechanisms to regulate the local extravasation of immune effe

ISSN:0730-2312    

DOI:10.1002/jcb.240300204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0730-2312    

DOI:10.1002/jcb.240300205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractHighly sensitive immunoassays have been used to quantitate aflatoxins (AF) and N‐nitrosamines (NNO) in human body fluids and tissues, respectively. This approach was taken in order to quantitate environmental exposure to these agents at an individual level to facilitate the investigation of their role in the etiology of human cancer. In order to analyse AF in human urine, an immunopurification step has been developed by using AF‐specific antibody bound to AH‐Sepharose 4B gel in a small (4‐ml gel volume) affinity column prior to enzyme‐linked immunosorbent assay (ELISA). The ELISA can be used to quantitate aflatoxin B1(AFB1) over the range 0.01 ng/ml to 10 ng/ml and the assay system has been validated by using human urine samples spiked with AFB1over this concentration range. In addition, 29 urine samples from the Philippines have been analysed and found to contain a range of levels from zero to 4.25 ng/ml AFB1equivalent with a mean of 0.875 ng/ml. This compared with a mean of 0.066 ng/ml AFB1equivalent in samples from France.Radioimmunoassay of O6‐methyldeoxyguanosine (O6‐medG) has been performed on human oesophageal and cardiac stomach mucosal DNA from tissue samples obtained during surgery in Linxian County, People's Republic of China, an area of high risk for both oesophageal and stomach cancer. Using the methodology described and having 1 mg of hydrolyzed DNA allows the detection of approximately 25 fmol O6medG per mg DNA. Of the 37 tissue samples analyzed from Linxian County, 17 samples had levels of O6‐medG ranging from 15 to 50 fmol/mg DNA, ten showed higher levels up to 160 fmol/mg DNA, and the remaining ten samples were below the limit of detection. For comparison, 12 tissue samples were obtained from hospitals in Europe and all showed levels below 45 fmol O6‐medG/mg DNA with seven below the limit of detection. All tissue samples from Linxian county showed normal levels of O6‐alkylguanine DNA alkyltransferase when compared to levels in other parts of the world.The approaches described appear promising for assessing the role of AFB1in the etiology of human liver cancer and of nitrosamines as possible causative agents in oesophagea

ISSN:0730-2312    

DOI:10.1002/jcb.240300206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0730-2312    

DOI:10.1002/jcb.240300201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY