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排序方式: 共有1514条查询结果,搜索用时 15 毫秒
51.
Oddbjørn Haugen Marit Farstad Reidar Myklebust Venny Kvalheim Stig Hammersborg 《Scandinavian cardiovascular journal : SCJ》2013,47(5):331-338
Background. Recently we reported on cerebral metabolic changes suggesting ischemia in piglets during nitroprusside-induced low-pressure CPB. We here investigated whether a mean arterial pressure (MAP) of 40–45 mmHg could provoke similar changes by a NO-independent intervention. Methods. Piglets underwent 60 minutes normothermic followed by 90 minutes hypothermic CPB. The LP-group (n=8) had MAP of 40–45 mmHg by phentolamine while the HP-group (n=8) had MAP of 60–80 mmHg by norepinephrine. Cerebral glucose, lactate, pyruvate and glycerol were determined. In the last two animals of each group, cerebral tissue was examined by electron microscopy. Results. Cerebral lactate was higher in the LP-group than the HP-group during normothermic CPB. Compared with baseline, cerebral glucose of the LP-group decreased whereas lactate/pyruvate-ratio, lactate and glycerol-concentrations increased during normothermic CPB. In the HP-group these parameters remained unchanged. Electron microscopy showed 31.2% and 8.3% altered mitochondria in the cortical micrographs taken from the LP- and the HP-group, respectively (p<0.001). Conclusion. MAP below 45 mmHg during CPB was associated with cerebral biochemical and morphological changes consistent with anaerobic metabolism and subcellular injury. 相似文献
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53.
INTRODUCTION: This study investigated whether two levels of mean arterial pressure (MAP) during cardiopulmonary bypass did influence per-operative fluid shifts. METHODS: Sixteen pigs underwent 60 minutes of normothermic cardiopulmonary bypass (CPB) followed by 90 minutes of hypothermic CPB. Eight animals had a MAP of 60-80mmHg by norepinephrine (HP group). Another 8 animals had a MAP of 40-45 mmHg by phentolamine (LP group). Blood chemistry, plasma/interstitial colloid osmotic pressures, plasma volume, fluid balance, fluid extravasation rate and tissue water content were measured or calculated. RESULTS: The plasma volume was significantly lower in the HP group compared with the LP group after 60 minutes of CPB. Net fluid balance was 0.18 (0.05) ml x kg(-1) x min(-1) in the HP group and 0.21 ml x kg(-1) x min(-1) in the LP group (P > 0.05) while fluid extravasation rate was 1.18 (0.5) and 1.13 (0.4) ml x kg(-1) x min(-1) in the HP group and the LP group during CPB (P > 0.05). CONCLUSION: Net fluid balance and fluid extravasation rate were similar in the animals with elevated and with lowered MAP during CPB. 相似文献
54.
Danijela Marovic Hvard J. Haugen Visnja Negovetic Mandic Matej Par Kai Zheng Zrinka Tarle Aldo R. Boccaccini 《Materials》2021,14(10)
Experimental dental resin composites incorporating copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) were designed to impart antibacterial and remineralizing properties. The study evaluated the influence of Cu-MBGN on the mechanical properties and photopolymerization of resin composites. Cu-MBGN were synthesized using a microemulsion-assisted sol–gel method. Increasing amounts of Cu-MBGN (0, 1, 5, and 10 wt %) were added to the organic polymer matrix with inert glass micro- and nanofillers while maintaining a constant resin/filler ratio. Six tests were performed: X-ray diffraction, scanning electron microscopy, flexural strength (FS), flexural modulus (FM), Vickers microhardness (MH), and degree of conversion (DC). FS and MH of Cu-MBGN composites with silica fillers showed no deterioration with aging, with statistically similar results at 1 and 28 days. FM was not influenced by the addition of Cu-MBGN but was reduced for all tested materials after 28 days. The specimens with 1 and 5% Cu-MBGN had the highest FS, FM, MH, and DC values at 28 days, while controls with 45S5 bioactive glass had the lowest FM, FS, and MH. DC was high for all materials (83.7–93.0%). Cu-MBGN composites with silica have a potential for clinical implementation due to high DC and good mechanical properties with adequate resistance to aging. 相似文献
55.
Impaired immune responsiveness in Plasmodium berghei immune mice 总被引:1,自引:0,他引:1
T. P. M. SCHETTERS J. H. J. VAN RUN–VAN BREDA TH. VAN DE WIEL C. C. HERMSEN J. CURFS W. M. C. ELING 《Parasite immunology》1989,11(5):519-528
Mice immunized against Plasmodium berghei parasites by drug-controlled infection exhibited decreased immunoresponsiveness against rabbit red blood cells (RRBC). Increasing RRBC antigen dose increased responsiveness, but agglutinating anti-RRBC antibodies of the IgG class remained undetectable. Clearance of colloidal carbon from the bloodstream of malaria-immunized mice was not different from controls. Removal of all the persistent parasites from immune mice did not restore responsiveness until 140 days after treatment, suggesting that the parasite per se did not influence responsiveness directly. Because of this, and because of the fact that priming of mice with RRBC before P. berghei immunization was not more effective than priming after immunization, it was concluded that antigen uptake and subsequent presentation were not impaired in P. berghei immune mice, in contrast to infected mice. Anti-RRBC antibodies were detected in serum of P. berghei immune mice, but regulation of responsiveness to RRBC by transfer of such immune mouse serum was not found. Immunoglobulin levels, especially of the IgG2 and IgG3 subclass were elevated in sera of P. berghei immune mice, which indicated an LPS-like polyclonal activation. The results also suggest that during drug-controlled infection, which leads to immunity against infection, a state of B-cell tolerance is induced. 相似文献
56.
M. Gómez-Florit R. Xing J.M. Ramis S. Taxt-Lamolle H.J. Haugen S.P. Lyngstadaas M. Monjo 《Journal of dentistry》2014
Objectives
The aim of this study was to evaluate the influence of different titanium zirconium (TiZr) alloy surfaces on primary human gingival fibroblasts (HGF) for improved soft tissue integration of dental implants.Methods
TiZr polished, machined and machined + HCl/H2SO4 acid-etched surfaces were modified by cathodic polarization and/or HNO3/HF acid etching. Contact angle of surfaces was measured. The influence of modified TiZr surfaces on HGF was evaluated through the analysis of cell number, morphology, recovery after a wound (wound healing assay) and the expression of several genes, including matrix metalloproteinase-1 (MMP1) and metallopeptidase inhibitor-1 (TIMP1).Results
Modification of TiZr surfaces decreased its hydrophilicity. Hydride implementation on TiZr surfaces via cathodic polarization increased TIMP1 expression and decreased MMP1/TIMP1 mRNA ratio. Cathodic polarization of machined surfaces promoted cell attachment. Cells on machined and machined + cathodic polarization surfaces grew aligned to the microgrooves whereas on all polished surfaces they grew randomly. Acid etching of polished and machined surfaces did not improve HGF function.Conclusions
Hydride implementation on TiZr machined surfaces may be used as new dental implant material for improved soft tissue integration.Clinical significance
Enhancing dental implant surfaces’ bioactivity by hydride implementation may promote soft tissue attachment and sealing around the implant and reduce peri-implantitis related to ECM-destruction compared with conventional machined surfaces. 相似文献57.
58.
Live S. Nordhagen Ina Kreyberg Karen Eline S. Bains Kai-Håkon Carlsen Kari Glavin Håvard O. Skjerven Milada C. Småstuen Katarina Hilde Björn Nordlund Riyas Vettukattil Gunilla Hedlin Berit Granum Christine M. Jonassen Hrefna K. Gudmundsdóttir Guttorm Haugen Eva Maria Rehbinder Cilla Söderhäll Anne Cathrine Staff Karin C. Lødrup Carlsen PreventADALL study group 《Acta paediatrica (Oslo, Norway : 1992)》2020,109(12):2594-2603
59.