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排序方式: 共有870条查询结果,搜索用时 687 毫秒
81.
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Peifang Tian Ivan C. Teng Larry D. May Ronald Kurz Kun Lu Miriam Scadeng Elizabeth M. C. Hillman Alex J. De Crespigny Helen E. D’Arceuil Joseph B. Mandeville John J. A. Marota Bruce R. Rosen Thomas T. Liu David A. Boas Richard B. Buxton Anders M. Dale Anna Devor 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(34):15246-15251
Changes in neuronal activity are accompanied by the release of vasoactive mediators that cause microscopic dilation and constriction of the cerebral microvasculature and are manifested in macroscopic blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signals. We used two-photon microscopy to measure the diameters of single arterioles and capillaries at different depths within the rat primary somatosensory cortex. These measurements were compared with cortical depth-resolved fMRI signal changes. Our microscopic results demonstrate a spatial gradient of dilation onset and peak times consistent with “upstream” propagation of vasodilation toward the cortical surface along the diving arterioles and “downstream” propagation into local capillary beds. The observed BOLD response exhibited the fastest onset in deep layers, and the “initial dip” was most pronounced in layer I. The present results indicate that both the onset of the BOLD response and the initial dip depend on cortical depth and can be explained, at least in part, by the spatial gradient of delays in microvascular dilation, the fastest response being in the deep layers and the most delayed response in the capillary bed of layer I. 相似文献
83.
A.I. Fiorelli G.H.B. Coelho J.L. Oliveira Jr C.N.G. Nascimento L.B. Vilas Boas C.F.C. Napolitano F. Bacal E.A. Bochi N.A.G. Stolf 《Transplantation proceedings》2009,41(3):962-964
Objective
Arrhythmogenic right ventricular dysplasia (ARVD) is a myocardial disease of familiar, origin where the myocardium is replaced by fibrofatty tissue predominantly in the right ventricle. Herein we have presented the clinical courses of 4 patients with ARVD who underwent orthotopic heart transplantation.Patients and Methods
Among 358 adult patients undergoing heart transplantation, 4 (1.1%) displayed ARVD. The main indication for transplantation was the progression to heart failure associated with arrhythmias. All 4 patients displayed rapid, severe courses leading to heart failure with left ventricular involvement and uncontrolled arrhythmias.Results
In all cases the transplantation was performed using a bicaval technique with prophylactic tricuspid valve annuloplasty. One patient developed hyperacute rejection and infection, leading to death on the 7th day after surgery. The other 3 cases showed a good evolution with clinical remission of the symptoms. Pathological study of the explanted hearts confirmed the presence of the disease.Conclusions
ARVD is a serious cardiomyopathy that can develop malignant arrhythmias, severe ventricular dysfunction with right ventricular predominance, and sudden cardiac death. Orthotopic heart transplantation must always be considered in advanced cases of ARVD with malignant arrhythmias or refractory congestive heart failure with or without uncontrolled arrhythmias, because it is the only way to remit the symptoms and the disease. 相似文献84.
85.
Surgical bacterial infections and antimicrobial susceptibility patterns at Lilongwe Central Hospital
RM Banda AS Muula GR Gwaza DC Namarika KC Ng'oma FE Chintolo H Yamakazi AP Muyco 《Malawi medical journal : the journal of Medical Association of Malawi》2001,13(3):27-29
A cross sectional study was done between October 1999 and February 2000 to determine antimicrobial susceptibility patterns of consecutive bacterial isolates of 102 clinical samples among surgical in-patients at Lilongwe Central Hospital (LCH), Malawi. Antimicrobial susceptibility was determined using comparative disc diffusion techniques. 83 (81.4%) samples were culture positive for bacterial growth while 19 (18.6%) grew nothing. Of the 93 culture positive specimens, Staphylococcus aureus was the predominant organism 43(51.8%) followed by Proteus species 8(9.6%) and E. coli 7(8.4%). Overall, 98.6% of all isolates tested against ciprofloxacin were susceptible, and against gentamicin and flucloxacin were 84.8% and 66.7% respectively. 59.3% of isolates tested against chloramphenicol were resistant. We recommend a review on the use of chloramphenicol as first-line antimicrobial therapy among surgical in-patients at Lilongwe Central Hospital. We also recommend restricted use of antimicrobials so as to minimise development of drug resistance. Periodic susceptibility studies are necessary to guide judicious use of antibiotics. 相似文献
86.
87.
88.
Dr. phil. F. Boas 《Pflügers Archiv : European journal of physiology》1882,27(1):214-222
Ohne Zusammenfassung 相似文献
89.
90.
Cenk Ayata Andrew K Dunn Yasemin Gursoy-OZdemir Zhihong Huang David A Boas Michael A Moskowitz 《Journal of cerebral blood flow and metabolism》2004,24(7):744-755
Laser speckle flowmetry (LSF) is useful to assess noninvasively two-dimensional cerebral blood flow (CBF) with high temporal and spatial resolution. The authors show that LSF can image the spatiotemporal dynamics of CBF changes in mice through an intact skull. When measured by LSF, peak CBF increases during whisker stimulation closely correlated with simultaneous laser-Doppler flowmetry (LDF) measurements, and were greater within the branches of the middle cerebral artery supplying barrel cortex than within barrel cortex capillary bed itself. When LSF was used to study the response to inhaled CO2 (5%), the flow increase was similar to the response reported using LDF. For the upper and lower limits of autoregulation, mean arterial pressure values were 110 and 40 mm Hg, respectively. They also show a linear relationship between absolute resting CBF, as determined by [C]iodoamphetamine technique, and 1/tau(c) values obtained using LSF, and used 1/tau(c) values to compare resting CBF between different animals. Finally, the authors studied CBF changes after distal middle cerebral artery ligation, and developed a model to investigate the spatial distribution and hemodynamics of moderate to severely ischemic cortex. In summary, LSF has distinct advantages over LDF for CBF monitoring because of high spatial resolution. 相似文献