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排序方式: 共有435条查询结果,搜索用时 15 毫秒
71.
72.
Francesca Galeffi Simone Degan Gavin Britz Dennis A Turner 《Journal of cerebral blood flow and metabolism》2016,36(4):696-701
We investigated microvascular reactivity to synaptic train stimulation after induction of subarachnoid hemorrhage in adult rats, analyzing tissue oxygen levels [pO2] in intact hippocampus. In control rats, hippocampal pO2 averaged 11.4 mm Hg whereas hemodynamic responses averaged 13.1 mm Hg (to a 25 s train). After subarachnoid hemorrhage (at 2 days), we recorded a dramatic elevation in baseline pO2 in the hippocampus (to 68.4 mm Hg) accompanied by inverted pO2 responses to synaptic train stimulation (−9.46 mm Hg). These significant changes in baseline hippocampal pO2 and inverted pO2 responses after subarachnoid hemorrhage indicate severe alterations of neurovascular coupling and neuronal viability. 相似文献
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74.
Transrectal endosonography is one of the most sensitive techniques to evaluate prostatic disease and is far more accurate than conventional sonography. A retrospective review of sonographic characteristics of the prostate was made in an attempt to define the ability of the technique to distinguish benign from malignant disease. Analysis included evaluation of the capsule (smoothness, regularity, and/or invasion), abnormal foci (echogenicity, margination, brightness, thickness, and symmetry), and presence of acoustic shadowing and/or enhancement from the abnormal foci. Evaluation of 443 pathologically proved cases (the majority being large lesions) showed that differentiation between benign and large and/or invasive malignant disease may be suggested by results of transrectal endosonography. However, there is still great overlap of the sonographic appearances. 相似文献
75.
Pond GD; Seeley GW; Ovitt TW; Chernin MM; Yoshino MT; Roehrig H; McIntyre KE 《Radiology》1989,170(2):367-370
This prospective study compared images obtained with a photostimulable imaging plate with matched images obtained with a conventional screen-film combination in 26 patients undergoing intraoperative arteriography. Diagnostic accuracy of the two techniques was assessed objectively, and image quality was assessed subjectively. In 16 patients (62%), the radiation exposure was reduced by 50% for the imaging plate technique by decreasing the mAs level generally used for the screen-film combination. Because of the dynamic range of the imaging plate system, no repeat examinations were necessary, while 12% of the screen-film studies had to be repeated because of over- or under-penetration. Imaging plate studies required 6% more time for processing than screen-film studies. Receiver-operating-characteristic analysis indicated no difference in diagnostic accuracy between the two imaging techniques. Subjective evaluation also revealed no difference in observer preference for imaging plate or screen-film studies. The imaging plate technique is an excellent alternative to screen-film studies in the operating room. 相似文献
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79.
Genetic association of an alpha2-macroglobulin (Val1000lle) polymorphism and Alzheimer's disease 总被引:6,自引:1,他引:5
Liao A; Nitsch RM; Greenberg SM; Finckh U; Blacker D; Albert M; Rebeck GW; Gomez-Isla T; Clatworthy A; Binetti G; Hock C; Mueller-Thomsen T; Mann U; Zuchowski K; Beisiegel U; Staehelin H; Growdon JH; Tanzi RE; Hyman BT 《Human molecular genetics》1998,7(12):1953-1956
alpha2-Macroglobulin (A2M) is a proteinase inhibitor found in association
with senile plaques (SP) in Alzheimer's disease (AD). A2M has been
implicated biochemically in binding and degradation of the amyloid beta
(Abeta) protein which accumulates in SP. We studied the relationship
between Alzheimer's disease and a common A2M polymorphism, Val1000
(GTC)/Ile1000 (ATC), which occurs near the thiolester active site of the
molecule. In an initial exploratory data set (90 controls and 171
Alzheimer's disease) we noted an increased frequency of the G/G genotype
from 0.07 to 0.12. We therefore tested the hypothesis that the G/G genotype
is over-represented in Alzheimer's disease in an additional independent
data set: a group of 359 controls and 566 Alzheimer's disease patients. In
the hypothesis testing cohort, the G/G genotype increased from 0.07 in
controls to 0.12 in Alzheimer's disease (P < 0.05, Fisher's exact test).
The odds ratio for Alzheimer's disease associated with the G/G genotype was
1.77 (1.16-2.70, P < 0.01) and in combination with APOE4 was 9.68 (95%
CI 3.91-24.0, P < 0.001). The presence of the G allele was associated
with an increase in Abeta burden in a small series. The A2M receptor,
A2M-r/LRP, is a multifunctional receptor whose ligands include
apolipoprotein E and the amyloid precursor protein. These four proteins
have each been genetically linked to Alzheimer's disease, suggesting that
they may participate in a common disease pathway.
相似文献
80.
Autonomic response to auditory stimulation 总被引:2,自引:0,他引:2
SH Anderssen RB Nicolaisen GW Gabrielsen 《Acta paediatrica (Oslo, Norway : 1992)》1993,82(12):913-918
Autonomic and behavioral response to fear stimulation (sudden noise 80 dB) was studied in 12 sleeping infants at ages 8–50 weeks. The aim of the present study was to identify a possible passive defense response in infants. The response, which is widespread in birds and mammals, is characterized by apnea and bradycardia with circulatory changes as seen during the forced diving response. Upon stimulation, two respiratory responses were elicited: apnea preceded by irregular respiration or simple irregular respiration. Apnea was elicited in 58% of stimulations at ages 8–16 weeks compared to 14% at 28–50 weeks. The mean duration of apnea decreased from 7.8 s(± 1.8 s) at 8–13 weeks to 4.7s (± 1.1s) at 17–20 weeks. The preceding irregular respiration increased from 5.3 s (± 4.4 s) to 10.6 s (± 5.4 s) at the same ages. The heart rate response was biphasic and were interpreted as the orienting response. The mean deceleration in relation to apnea was 16% at 8–16 weeks and was reduced to 8% at 28–50 weeks. Infants of smoking mothers were more prone to respond with apnea than infants of nonsmoking mothers (73% versus 38%). REM sleep and long postprandial sleep time increased the probability of apnea response (62% versus 38% and 66% versus 35%). The responses seen may be interpreted as expressions of the passive defense response. 相似文献