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11.
BACKGROUND: The effects of hypothermic injury to the liver were investigated on an isolated perfusion circuit by comparing porcine livers with varying degrees of preservation injury. METHODS: A group of unstored livers (n = 5) were compared to livers stored in University of Wisconsin (UW) solution for 18 h (n = 5), and a group of livers stored in Hartmann's solution for 18 h (n = 5). RESULTS: We observed that the degree of platelet sequestration was directly related to the severity of the preservation injury. After 2 h of isolated liver perfusion, the perfusate platelet count fell from 148 +/- 14 x 10(9)/L to 84 +/- 13 x 10(9)/L for control livers. In comparison for livers stored in UW solution, the platelet count fell from 173 +/- 43 x 10(9)/L to 61 +/- 14 x 10(9)/L representing a 64.8% fall, while for those stored in Hartmann's solution, an even more profound fall from 152 +/- 36 x 10(9)/L to 19 +/- 9 x 10(9)/L (87.5% fall) was observed. The difference between the UW-stored and Hartmann's-stored livers was significant (P < 0.05). However, using this model, the degree of leukocyte sequestration did not differentiate the groups. Both histological and ultrastructural examination of liver biopsies taken immediately following revascularization demonstrated that for mild degrees of preservation injury following hypothermic storage, changes occur to the sinusoidal lining cells well before changes to the parenchymal elements. CONCLUSIONS: These findings substantiate the hypothesis that the primary injury associated with hypothermia involves the sinusoidal lining cells (non-parenchymal elements), that it is predominantly a reperfusion phenomenon and that efforts at improving preservation should therefore be targeted primarily at these cells and not the hepatocytes. 相似文献
12.
L Bell A Solieri P West K Burgess T Dowdeswell 《Canadian Metallurgical Quarterly》1997,26(6):1080-1085
In this article the authors discuss the development, use and auditing of nursing care protocols, which have been implemented and form a guide for nurses caring for patients with fractured neck of femur in Southend Health Care NHS Trust. The development of these protocols occurred after an initial medical audit, which was followed by a far larger multidisciplinary audit, and both of these revealed there was need for changes in the clinical management of such patients; subsequently a large multidisciplinary working group worked together to develop care protocols/pathways to enable closure of the audit loop. The reasons for focusing on fractured neck of femur as a high priority condition are also discussed. All professional groups caring for these patients were involved in the multidisciplinary working group, which was formed to close the audit loop and to improve clinical practices by increasing the systemization and coordination of care. The development of the nursing protocols represented an extremely important part of this process, and the care of about 700 patients was examined during this work. The audit and associated subsequent work have resulted in direct improvements to both patient care and health outcomes, and the authors conclude that there is great value in developing multidisciplinary protocols, particularly those involving nurses, because they spend more time with patients whilst they are in hospital than any other professional group. The benefits of these nursing protocols have been multifold, in particular they have facilitated a clearer flow of patients through the hospital, increased awareness of responsibilities and reduced duplication of effort, and ensured patients receive the best possible care over the 24-hour period. 相似文献
13.
14.
WR Bell 《Canadian Metallurgical Quarterly》1996,22(6):459-478
During activation of the fibrinolytic system plasminogen is converted to plasmin by tissue plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA). t-PA is predominantly released from endothelial cells, u-PA primarily by renal parenchymal cells. The activation of plasminogen is regulated by plasminogen activator inhibitor-1 (PAI-1), plasmin is controlled by alpha 2-plasmin inhibitor. The fibrinolytic system is not only involved in the intravascular dissolution of fibrin (thrombi), it also plays a vital role in normal physiologic reproduction, wound repair, angiogenesis, and tissue remodeling. Fibrinolysis is also a vital component in the pathogenesis of neoplastic disease. It is essential in releasing cells from their primary site of origin, providing nutrition for neoplastic cell growth and promoting cell mobility and motility. In neoplastic cells the degradation of the extracellular matrix proteins is facilitated by excessive expression of u-PA, t-PA, and u-PAR. In many forms of carcinoma increased expression of u-PAR and u-PA is associated with significantly shorter survival. Greater expression of u-PA in breast cancer cells, for example, is associated with shorter survival and increased relapse rate. Progressively aggressive neoplastic cells evidence high expression of u-PA and u-PAR activities, variable expression of t-PA, and enhanced PAI-1 and PAI-2 activities. In acute nonlymphocytic leukemias, poor outcome correlates with high t-PA levels. In acute progranulocytic leukemia there is a high incidence of DIC. Neoplastic prostatic tissue also expresses high u-PA activity and the more aggressive the cell line, the greater the number of u-PAR and the higher the u-PA activity. In gynecologic malignancies, a greater expression of u-PA in combination with cathepsin D is associated with widespread disease and poor prognosis. High u-PA values were also seen in patients with brain, gastric, and hepatic malignancies. It is evident that the plasminogen-plasmin system is a vital component in the biology of neoplastic disease and that it is, in theses conditions, in no way beneficial to the host. 相似文献
15.
JB Henshaw CA Olsen AR Farnbach KH Nielson JD Bell 《Canadian Metallurgical Quarterly》1998,37(30):10709-10721
Bilayers composed of phosphatidylcholine initially resist catalysis by phospholipase A2. However, after a latency period, they become susceptible when sufficient reaction products (lysolecithin and fatty acid) accumulate in the membrane. Temperature near the main bilayer phase transition and calcium concentration modulate the effectiveness of the reaction products. The purpose of this study was to examine the individual contributions of lysolecithin and palmitic acid to the susceptibility of dipalmitoylphosphatidylcholine vesicles and to rationalize the effects of temperature and calcium. Various fluorescent probes (Prodan, Laurdan, pyrene-labeled fatty acid, and dansyl-labeled phospholipid) were used to assess changes in the ability of the reaction products to perturb the bilayer and to affect the interactions with the enzyme. Un-ionized palmitic acid decreased bilayer polarity and perturbed the membrane surface exposing some of the Prodan to bulk water. Lysolecithin increased bilayer polarity and the rate of dipolar relaxation in response to the excited states of Laurdan and Prodan. A combination of the individual contributions of each product was observed when palmitic acid and lysolecithin were present together at low calcium, and the effects of lysolecithin dominated at high calcium. Palmitic acid, but not lysolecithin, promoted the binding of phospholipase A2 to the bilayer surface in the absence of calcium. Lysolecithin reduced the ability of fatty acid to enhance binding apparently by altering the structure of fatty acid domains in the membrane. Furthermore, increased temperature and ionization of the fatty acid tended to cause segregation of bound phospholipase A2 into domains poor in phospholipid content which presumably impeded bilayer hydrolysis. In contrast, un-ionized palmitic acid and lysolecithin promoted hydrolysis by augmenting a step distal to the adsorption of enzyme to the bilayer. This kinetic response to lysolecithin was calcium-dependent. A model accounting for these varied influences of the reaction products is presented. 相似文献
16.
IR Whittle M Glasby A Lammie H Bell U Ungerstedt 《Canadian Metallurgical Quarterly》1998,9(12):2821-2825
The neuropathological and immunocytochemical changes in the sheep forebrain following 7 days of microdialysis, using a catheter approved for human use, are described. There was no behavioural dysfunction and light microscopy revealed mild astrogliosis and patchy macrophage infiltration immediately adjacent to the catheter track. The surrounding neuropil was normal. There was one small subcortical haemorrhage (10 x 1.5 mm). These findings are similar to those following microdialysis in rodents and suggest that the risk of significant damage to the human brain is low, that neuropathological changes in the brain around the catheter should not interfere with local brain metabolism, and that the catheter should be affixed in such a way as to minimize movement-induced damage to the brain. 相似文献
17.
18.
Kester Bruce E. Gilliland J. L. Fritts Stewart S. Bell Zeb G. Smith Hubert Berby Richard H. 《Industry Applications, IEEE Transactions on》1972,(1):8-18
MAN is but a part of the universe; his capabilities make him a significant link, in the cycle of life. To ensure this life, man must live in harmony with his environment. Recently, a disharmony has been discovered which could have grave effects upon the existence of man. It appears that man in his great thrust forward is destroying his own environment. The gravity of this threat to man's own existence carries some intrinsic problems of its own: man must allow his reason rather than his emotion to take command. 相似文献
19.
In this paper we describe an apparatus for reproducibly measuring thermal shock resistance of thick polymer layers bonded to metals. The thermal shock behavior is discussed in terms of epoxy samples bonded to an aluminum substrate. It was found that both high resin toughness and low resin thermal expansion coefficient improved thermal shock resistance of thick coatings, but only a sample containing 60wt. % glass beads did not develop a failure crack. Effects of sample thickness, temperature gradient, and resin composition on thermal shock behavior are discussed. 相似文献
20.
M. J. Danzig J. L. O'Donnell E. W. Bell J. C. Cowan H. M. Teeter 《Journal of the American Oil Chemists' Society》1957,34(3):136-138
Summary Soybean fatty acids were conjugated with alkali, and the contained, conjugated dienoic acids were isomerized with iodine to
thetrans,trans configuration. Adducts were prepared from thesetrans,trans-conjugated acids by condensation with maleic anhydride and acrylic acid. The adducts were isolated, purified, and converted
to esters by using a variety of alcohols, including methyl, ethyl,n-propyl,n-butyl, and allyl alcohols. Esters made from saturated alcohols were converted into the corresponding epoxy derivatives.
All of the esters (except allyl) and all of the epoxy esters were compatible with an equal weight of polyvinyl chloride and
appeared to be primary plasticizers for this plastic. The epoxy esters were effective in inhibiting heat deterioration of
polyvinyl chloride.
Presented at fall meeting. American Oil Chemists' Society, September 23–26, 1956, Chicago, Ill. 相似文献