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排序方式: 共有173条查询结果,搜索用时 62 毫秒
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Markus Kamler Jan Goedeke Nikolaus Pizanis Vitaliy Milekhin Fritz-Ulrich Schade Heinz Jakob 《European journal of cardio-thoracic surgery》2005,28(2):259-265
OBJECTIVE: Induced hypothermia has been shown to be protective during cardiac surgery, but also in traumatic, ischemic, burn, and neurological injury. In previous in vivo animal experiments, we documented increased leukocyte/endothelial (L/E) cell interaction following normothermic extracorporeal blood circulation (ECC). This study was carried out to investigate whether reduced core temperature during ECC affects the damage to the microcirculation as evidenced by leukocyte adherence and edema formation. METHODS: Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in Syrian golden hamsters. ECC was introduced via a micro-rollerpump (1 ml/min) and a 60 cm silicon tube (1mm inner diameter) shunted between the carotid artery and the jugular vein after application of 300IE Heparin/kg per body weight. Experiments were performed in chronically instrumented, awake animals (age 10-14 weeks, weight 65-75 g). Animals of the experimental group were cooled to 18 degrees C body temperature while ECC, followed by a rewarming period (n=7), controls experienced ECC under normothermia (37 degrees C, n=7). RESULTS: 30 min ECC at 18 degrees C resulted in a decrease of rolling and adherent leucocytes (stickers) in postcapillary venules after 1, 4 and 8h compared with the control group (119+/-46 vs. 274+/-113 n/mm2, P<0.05, mean+/-SD; n=7 in each group). Functional capillary density was significantly reduced during hypothermia (80+/-16 vs. 148+/-16 cm/cm2, P<0.05), but restored after rewarming. In contrast, edema formation was markedly increased during hypothermia. CONCLUSIONS: Hypothermia during ECC significantly reduced L/E cell interaction in the early post-ECC period. Hypothermia markedly reduced microvascular perfusion, but was completely restored upon rewarming. Despite a reduced number of adherent leukocytes, no protection of endothelial barrier function was seen as a consequence of induced hypothermia. 相似文献
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Cinzia Dello Russo Anne I Boullerne Vitaliy Gavrilyuk Douglas L Feinstein 《Journal of neuroinflammation》2004,1(1):1-15
Background
Under pathological conditions, microglia produce proinflammatory mediators which contribute to neurologic damage, and whose levels can be modulated by endogenous factors including neurotransmitters such as norepinephrine (NE). We investigated the ability of NE to suppress microglial activation, in particular its effects on induction and activity of the inducible form of nitric oxide synthase (NOS2) and the possible role that IL-1β plays in that response.Methods
Rat cortical microglia were stimulated with bacterial lipopolysaccharide (LPS) to induce NOS2 expression (assessed by nitrite and nitrate accumulation, NO production, and NOS2 mRNA levels) and IL-1β release (assessed by ELISA). Effects of NE were examined by co-incubating cells with different concentrations of NE, adrenergic receptor agonists and antagonists, cAMP analogs, and protein kinase (PK) A and adenylate cyclase (AC) inhibitors. Effects on the NFκB:IκB pathway were examined by using selective a NFκB inhibitor and measuring IκBα protein levels by western blots. A role for IL-1β in NOS2 induction was tested by examining effects of caspase-1 inhibitors and using caspase-1 deficient cells.Results
LPS caused a time-dependent increase in NOS2 mRNA levels and NO production; which was blocked by a selective NFκB inhibitor. NE dose-dependently reduced NOS2 expression and NO generation, via activation of β2-adrenergic receptors (β2-ARs), and reduced loss of inhibitory IkBα protein. NE effects were replicated by dibutyryl-cyclic AMP. However, co-incubation with either PKA or AC inhibitors did not reverse suppressive effects of NE, but instead reduced nitrite production. A role for IL-1β was suggested since NE potently blocked microglial IL-1β production. However, incubation with a caspase-1 inhibitor, which reduced IL-1β levels, had no effect on NO production; incubation with IL-receptor antagonist had biphasic effects on nitrite production; and NE inhibited nitrite production in caspase-1 deficient microglia.Conclusions
NE reduces microglial NOS2 expression and IL-1β production, however IL-1β does not play a critical role in NOS2 induction nor in mediating NE suppressive effects. Changes in magnitude or kinetics of cAMP may modulate NOS2 induction as well as suppression by NE. These results suggest that dysregulation of the central cathecolaminergic system may contribute to detrimental inflammatory responses and brain damage in neurological disease or trauma. 相似文献4.
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Q fever is a zoonotic infection caused by Coxiella burnetii. The most common clinical manifestation of acute Q fever infection is as an atypical community-acquired pneumonia. The pulmonary findings are accompanied by extrapulmonary findings, most typically an increase in serum transaminases and splenomegaly. Because C. burnetii is difficult to culture, the diagnosis of Q fever is usually made serologically. The diagnosis of acute Q fever atypical community-acquired pneumonia is made by demonstrating a fourfold or greater increase in titer between acute and convalescent specimens or by demonstrating elevated immunoglobulin (IgM) (phase II) titers. Chronic Q fever is manifested as granulomatous hepatitis or more commonly as culture-negative endocarditis (CNE). Chronic Q fever (CNE) is a difficult diagnosis because of difficulty in culturing the organism from the blood and the vegetations with Q fever CNE are small or absent. The diagnosis of chronic Q fever CNE is based on serology. Such patients commonly have highly elevated IgM and IgG titers (phase I/II) titers. Chronic Q fever CNE may involve native or prosthetic heart valves. Q fever prosthetic valve endocarditis is rare compared with native valve Q fever endocarditis. Q fever prosthetic valve endocarditis usually requires valve replacement for cure. We present a case of chronic Q fever bioprosthetic aortic valve endocarditis that was successfully treated with doxycycline monotherapy that did not require aortic valve replacement. 相似文献
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Michael George Zaki Ghali Vitaliy Marchenko 《Respiratory physiology & neurobiology》2013,187(2):176-182
The mammalian nervous system exhibits fast synchronous oscillations, which are especially prominent in respiratory-related nerve discharges. In the phrenic nerve, they include high- (HFO), medium- (MFO), and low-frequency (LFO) oscillations. Because motoneurons firing at HFO-related frequencies had never been recorded, an epiphenomenological mechanism for their existence had been posited. We have recently recorded phrenic motoneurons firing at HFO-related frequencies in unanesthetized decerebrate rats and showed that they exhibit dynamic coherence with the phrenic nerve, validating synchronous motoneuronal discharge as a mechanism underlying the generation of HFO. In so doing, we have helped validate the conclusions of previous studies by us and other investigators who have used changes in fast respiratory oscillations to make inferences about central respiratory pattern generation. Here, we seek to review changes occurring in fast synchronous oscillations during non-eupneic respiratory behaviors, with special emphasis on gasping, and the inferences that can be drawn from these dynamics regarding respiratory pattern formation. 相似文献
8.
Vitaliy V. Sanin Yury Yu. Kaplansky Maksym I. Aheiev Evgeny A. Levashov Mikhail I. Petrzhik Marina Ya. Bychkova Andrey V. Samokhin Andrey A. Fadeev Vladimir N. Sanin 《Materials》2021,14(12)
The NiAl–Cr–Co–X alloys were produced by centrifugal self-propagating high-temperature synthesis (SHS) casting. The effects of dopants X = La, Mo, Zr, Ta, and Re on combustion, as well as the phase composition, structure, and properties of the resulting cast alloys, have been studied. The greatest improvement in overall properties was achieved when the alloys were co-doped with 15% Mo and 1.5% Re. By forming a ductile matrix, molybdenum enhanced strength characteristics up to the values σucs = 1604 ± 80 MPa, σys = 1520 ± 80 MPa, and εpd = 0.79%, while annealing at T = 1250 ℃ and t = 180 min improved strength characteristics to the following level: σucs = 1800 ± 80 MPa, σys = 1670 ± 80 MPa, and εpd = 1.58%. Rhenium modified the structure of the alloy and further improved its properties. The mechanical properties of the NiAl, ZrNi5, Ni0.92Ta0.08, (Al,Ta)Ni3, and Al(Re,Ni)3 phases were determined by nanoindentation. The three-level hierarchical structure of the NiAl–Cr–Co+15%Mo alloy was identified. The optimal plasma treatment regime was identified, and narrow-fraction powders (fraction 8–27 µm) characterized by 95% degree of spheroidization and the content of nanosized fraction <5% were obtained. 相似文献
9.
Mohamadreza Nassajian Moghadam Vitaliy Kolesov Arne Vogel Harm-Anton Klok Dominique P. Pioletti 《Biomaterials》2014
Temperature has been extensively explored as a trigger to control the delivery of a payload from environment-sensitive polymers. The need for an external heat source only allows limited spatiotemporal control over the delivery process. We propose a new approach by using the dissipative properties of a hydrogel matrix as an internal heat source when the material is mechanically loaded. The system is comprised of a highly dissipative hydrogel matrix and thermo-sensitive nanoparticles that shrink upon an increase in temperature. Exposing the hydrogel to a cyclic mechanical loading for a period of 5 min leads to an increase of temperature of the nanoparticles. The concomitant decrease in the volume of the nanoparticles increases the permeability of the hydrogel network facilitating the release of its payload. As a proof-of-concept, we showed that the payload of the hydrogel is released after 5–8 min following the initiation of the mechanical loading. This delivery method would be particularly suited for the release of growth factor as it has been shown that cell receptor to growth factor is activated 5–20 min following a mechanical loading. 相似文献
10.
Elena V. Preobrazhenskaya Aglaya G. Iyevleva Amina M. Suleymanova Vladislav I. Tiurin Natalia V. Mitiushkina Ilya V. Bizin Alexandr O. Ivanstov Olga A. Gorustovich Kseniya V. Shelekhova Denis Y. Kachanov Svetlana R. Varfolomeeva Vitaliy Y. Roschin Anna N. Kazakova Dmitriy V. Litvinov Tatiana V. Shamanskaya Nikita A. Savelov Evgeny N. Suspitsin Evgeny N. Imyanitov 《Pediatric blood & cancer》2020,67(5)