| 1. |
- Chang-Chun, Chen, et al.
(author)
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Nucleoside transport inhibition mediates lidoflazine-induced cardioprotection during intermittent aortic crossclamping
- 1992
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In: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier. - 0022-5223 .- 1097-685X. ; 104:6, s. 1602-1609
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Journal article (peer-reviewed)abstract
- The effects of pretreatment with the nucleoside transport inhibitor lidoflazine on repeated ischemia-reperfusion injury induced by normothermic intermittent aortic crossclamping were studied in canine hearts. Eighteen mongrel dogs were allocated to three groups: placebo (n = 6), lidoflazine (1 mg/kg) (n = 6), and lidoflazine (1 mg/kg) plus the adenosine receptor blocker aminophylline (7 mg/kg) (n = 6). Pretreatment was performed intravenously during 15 minutes before extracorporeal circulation. All hearts were subjected to four intervals of 15 minutes of global ischemia each followed by 10 minutes of reperfusion. After weaning from extracorporeal circulation, functional recovery was followed for 1 hour. In the lidoflazine group, myocardial adenosine content (0.25 +/- 0.06 mumol/gm dry weight) was 3.5 times higher than that in the control group (0.07 +/- 0.03 mumol/gm dry weight; p < 0.05) at the end of the last aortic crossclamping. The release of adenosine from the myocardium during each reperfusion period was significantly higher than that in the control group (p < 0.05). Myocardial extraction of lactate was normalized at every reperfusion interval in the lidoflazine group but not in the control group (p < 0.05). In the lidoflazine group functional recovery was significantly better than that in the control group. Positive rate of rise of pressure, negative rate of rise of pressure, and cardiac output recovered to, respectively, 150% +/- 19%, 82% +/- 8%, and 131% +/- 15% in the lidoflazine group versus, respectively, 37% +/- 9%, 23% +/- 7%, and 29% +/- 8% in the control group (p < 0.001) at 1 hour after extracorporeal circulation. When the adenosine receptor blocker aminophylline was administered in association with lidoflazine, protection dropped significantly: positive and negative rate of rise of pressure and cardiac output were, respectively, 58% +/- 8%, 46% +/- 9%, and 67% +/- 16% at 1 hour after extracorporeal circulation (p < 0.05 versus lidoflazine alone). These results suggest that the cardioprotective effects of lidoflazine are at least in part mediated by adenosine receptor stimulation via nucleoside transport inhibition-induced accumulation of endogenous adenosine in the myocardium.
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| 2. |
- Chang, J Y, et al.
(author)
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Kinetic studies on uptake of serotonin and noradrenaline into pial arteries of rats
- 1990
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In: Journal of Cerebral Blood Flow and Metabolism. - 1559-7016. ; 10:1, s. 22-31
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Journal article (peer-reviewed)abstract
- A population of cerebrovascular nerve fibers have recently been found to store serotonin (5-hydroxytryptamine; 5-HT). There is reason to assume that these 5-HT-containing fibers have a sympathetic rather than an intracerebral origin. This was further elucidated in the present study in which the uptake mechanisms of 5-HT and noradrenaline (NA) were characterized and compared in rat pial arteries by measuring the accumulation of [3H]5-HT and [14C]NA under various experimental conditions in vitro. Sympathectomized vessels served as blanks. The uptake into the perivascular sympathetic nerves was dependent on time as well as concentration and was saturable. The Km values were similar, 0.17 microM for 5-HT and 0.15 microM for NA, but the Vmax value was 10 times higher for NA (2.38 and 25 pmol/mg/15 min, respectively). The two amines competed with each other in the sympathetic uptake, as studied by inhibition of the accumulation of one labeled amine by the other nonlabeled amine. Corticosterone, acting on the extraneuronal process, significantly inhibited the 5-HT uptake but had no substantial effect on NA. Reserpine, blocking the intraaxonal vesicular stores, markedly attenuated the accumulation of NA, but not of 5-HT. The selective uptake blocker paroxetine reduced the 5-HT uptake with much higher potency than the NA uptake, whereas desipramine predominantly inhibited NA uptake. The pial 5-HT uptake was not significantly affected by lesion of the raphe complex, whereas it was reduced to half following superior cervical ganglionectomy. The results suggest that the 5-HT present in nerves associated with pial vessels at the base of the brain is taken up through an efficient axonal mechanism, functionally related but not identical to the uptake process for NA.
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| 3. |
- Dunuwila, Dilum D., et al.
(author)
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Sol-gel derived titanium carboxylate thin films for optical detection of analytes
- 1994
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 66:17, s. 2739-2744
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Journal article (peer-reviewed)abstract
- The feasibility of using a sol-gel derived titanium carboxylate thin film, which can be supported on glass, for the fabrication of optical test strips was investigated using a model probe/ analyte combination. The porous films, being optically transparent and baring the capability to host probe molecules, provided an excellent system to investigate the possibility of making optical test strips. A colorimetric reagent, an iron(III) porpohyrin, was chosen as the probe molecule to detect free cyanide ion concentrations in aqueous solutions. Entrapment of the porphyrin in the film was accomplished by direct dissolution of the porphyrin in the sol-gel solutions. Chemically induced structural modifications of the polymer were carried out to stabilize the encapsulated metalloporphyrin within the sol-gel derived matrix. The syntheses of this model analyte detection system and its response are presented. An optical parameter reflective of the chemical changes that occur in the system was selected as the measurement tool; its response asymptotically increased over the cyanide ion concentration range of 40-25 000 ppm.
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| 4. |
- Hang, Chang C., et al.
(author)
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Automatic Tuning and Adaptation for PID Controllers—A Survey
- 1992
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In: Adaptive Systems in Control and Signal Processing 1992.
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Conference paper (peer-reviewed)abstract
- Adaptive techniques such as gain scheduling, automatic tuning and continuous adaptation have been used in industrial single-loop controllers for about ten years. This paper gives a survey of the different adaptive techniques, the underlying process models and control designs. The paper ends with an overview of industrial adaptive single-loop controllers.
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| 10. |
- Sahlin, C, et al.
(author)
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Changes in contractile response and effect of a calcium antagonist, nimodipine, in isolated intracranial arteries of baboon following experimental subarachnoid hemorrhage
- 1990
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In: Brain Research Bulletin. - 0361-9230. ; 24:3, s. 355-361
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Journal article (peer-reviewed)abstract
- Isolated pial arteries from a previously well-characterized model of experimental subarachnoid hemorrhage (SAH) in baboon were tested for their contractile response to 5-hydroxytryptamine (5-HT), norepinephrine (NE), and prostaglandin F2 alpha (PGF2 alpha) and the effect of the calcium antagonist, nimodipine. Autologous blood was injected cisternally at three times with one-day intervals to a total amount of 11.5-29.5 ml (mean: 18.5 ml), and the animals were killed 7 days after the first injection. Untreated animals served as controls. The degree of maximum contraction (EAm) with 5-HT and NE in the control situation was for the three arteries tested in the order middle cerebral greater than anterior cerebral greater than basilar artery. Experimental SAH markedly increased EAm, by 190-370 percent above control values (depending on type of vessel) for 5-HT and 170-185 percent for NE. In addition, the sensitivity to 5-HT was significantly increased, as evidenced by a left-shift of the concentration-response curve. Previous exposure of the artery to 10(-6) M nimodipine reduced the contractile response of both amines to approximately half, the inhibition being slightly less pronounced post-SAH. When vessels were contracted beforehand with the amines or with PGF2 alpha, followed by administration of increasing amount of nimodipine (10(-9) M to 10(-6) M), a concentration-dependent relaxation was obtained by up to 60 percent of the original level. This relaxing effect was significantly less following SAH in the experiments with NE and PGF2 alpha compared to 5-HT; the contraction in the presence of 5-HT did not differ before and after experimental SAH. The experiments show that SAH markedly enhances the intrinsic activity for both 5-HT and NE. Nimodipine inhibits the contractile response less efficiently following experimental SAH. The difference in the responsiveness to 5-HT on the one hand, and to NE and PGF2 alpha on the other, could be due to differences in the blood-induced alterations of those calcium channels that are influenced by the calcium antagonist, nimodipine.
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| 11. |
- Sellström, Eva, et al.
(author)
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Injuries in Swedish Day-Care Centers
- 1994
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In: Pediatrics. - 0031-4005. ; 84:6, s. 1033-1036
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Journal article (peer-reviewed)abstract
- In the developed countries, an increasing number of children are enrolled in day-care centers. When parents leave their child in a day-care center they expect high standards of health and safety. Accidental injuries are a major threat in this age group. In a comparable institution that serves children, the school, the risk of injury is higher than in the home environment.1-2 Thus, safety in day-care centers cannot be taken for granted. A few studies of injuries in day-care centers have been reported, from the Nordic countries2,3-5 and from the US.6-10 Most of these studies, however, have been small and most lack information on time of exposure. Information about the risk of injury in Swedish day-care centers might be of interest as enrollment has been high for a long time. In Sweden, within the frame of a national injury program,11 a number of local hospital- and health center-based injury report systems have been set up. All have a basic common coding. These systems enable compilation of injuries in day-care centers on a national basis. The aim of our study was to analyze child injuries in day-care centers as reported in 10 local injury registry systems in Sweden regarding incidence, type, and mechanism of injury. METHOD Data were compiled from 10 local injury registry systems, covering 1- to 2-year periods. The earliest registers were from the years 1983 to 1984 and the latest from 1991. These systems were set up in all medical institutions at a predefined level, covering all individuals in a total or a part of a county.
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| 12. |
- von Mecklenburg, Claes, et al.
(author)
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Ultrastructural cerebrovascular changes in a model of subarachnoid hemorrhage in baboon based on triple cisternal blood injection
- 1990
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In: Surgical Neurology. - 0090-3019. ; 33:3, s. 195-201
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Journal article (peer-reviewed)abstract
- In a subarachnoid hemorrhage model in the baboon, achieved through three cisternal blood injections with 1-day intervals, the cerebral arteries were dissected out 7 days after the first blood injection for electron microscopy All the animals showed ultrastructural changes in the cerebral arteries: two with severe, one with moderate, and three with mild alterations in the vessel walls. The most constant findings were seen in the muscle cells of the media layer. Fragmentation of the nuclei was frequently observed together with cytoplasmic vacuoles. Scattered groups or single degenerated muscle cells were also noted. In the intima the changes included rounding of the nuclei along with the appearance of cytoplasmic vacuoles. Desquamation or flattening of the endothelium and loss of tight junctions were encountered in some vessel areas. Degenerating mitochondria were a common finding.
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| 15. |
- Åström, Karl Johan, et al.
(author)
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Automatic Tuning and Adaptation for PID Controllers : A Survey
- 1993
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In: Control Engineering Practice. - 0967-0661. ; 1:4, s. 699-714
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Journal article (peer-reviewed)abstract
- Adaptive techniques such as gain scheduling, automatic tuning and continuous adaptation have been used in industrial single-loop controllers for about ten years. This paper gives a survey of the different adaptive techniques, the underlying process models and control designs. An overview of industrial products is also presented, which includes a fairly detailed investigation of four different adaptive single-loop controllers.
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