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排序方式: 共有416条查询结果,搜索用时 15 毫秒
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Magnetic resonance angiography (MRA) of the circle of Willis: a prospective comparison with conventional angiography in 54 subjects 总被引:4,自引:0,他引:4
We prospectively correlated the findings of magnetic resonance angiography (MRA) with those of transfemoral four-vessel angiography in 54 patients to investigate the direction of flow within the circle of Willis. Our primary goal was to assess the direction of flow using the size of the vessel and signal intensity, without saturation techniques. Analysis of the circle of Willis, especially the communicating arteries, was performed double-blind by two groups of two radiologists. Three types of arteries were identified: high flow or cross-cerebral circulation, patent and nonvisualised arteries. Cerebral angiography was the standard for comparison between the two methods. MRA did not reveal any arteries invisible on angiography, thus providing a specificity of 100%. The sensitivity of MRA was 89.2% for the anterior and 81.3% for the posterior communicating arteries, and 100% for the anterior, middle and posterior cerebral arteries. MRA was shown to be a useful technique for the assessment of patency of the circle of Willis. 相似文献
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Cell-free extracts of nitrate-grown Penicillium politans NRC-510 could catalyze the hydrolytic deamination of adenosine to inosine maximally at pH 6.0 and 45 degrees C. However the same extracts could not catalyze the N-glycosidic bond cleavage of adenosine at pH 4.0, 6.0 and 8.0. Incubation of the extracts at 55 degrees C for 30 minutes caused about 31% loss in activity whereas incubation of the extracts at 60 degrees C for 15 minutes caused a complete loss of enzyme activity. Results indicated the absence of the involvement of sulfhydryl groups in the catalytic site of adenosine deaminase. The enzyme is inhibited by ethylene diamine tetraacetate indicating that adenosine deaminase is a metalloenzyme. MnCl2 and MgCl2 had a remarkable activating effect, whereas HgCl2, CaCl2 and ZnSO4 showed an inhibitory effect on enzyme activity. Dialyzing the extracts for 24 hours significantly increase deaminase activity by about 33%. The apparent K(m) value was calculated for adenosine and found to be 3.63 x 10(-3) M, which indicates high affinity of adenosine deaminase for its substrate adenosine. 相似文献
5.
Mohamed Abd El-Aziz M. Farag Latifa Ahmad Alkandary Maryam Ibrahim Alshatti Maged Ali H. Shoukeer 《The Egyptian Journal of Radiology and Nuclear Medicine》2018,49(3):873-877
Reported cases encountered difficulty in differentiating between inflammatory carcinoma and breast edema caused by congestive heart failure especially if the breast edema is unilateral. Our presented case is an elderly woman with unilateral breast edema due to congestive heart failure that was initially suspected to have breast cancer based on clinical findings. However imaging studies showed breast edema pattern with no definite underlying mass. This edema was resolved with standard treatment of heart failure. Congestive heart failure may be a possible cause of unilateral breast edema especially in a patient with background of congestive heart failure. 相似文献
6.
Laize Peron Tófolo Tatiane Aparecida da Silva Ribeiro Ananda Malta Rosiane Aparecida Miranda Rodrigo Mello Gomes Júlio Cezar de Oliveira Latifa Abdennebi-Najar Douglas Lopes de Almeida Amanda Bianchi Trombini Claudinéia Conationi da Silva Franco Audrei Pavanello Gabriel Sergio Fabricio Wilson Rinaldi Luiz Felipe Barella Paulo Cezar de Freitas Mathias Kesia Palma-Rigo 《European journal of nutrition》2015,54(8):1353-1362
7.
Hind Bouguerra Elyes Boutouria Mokhtar Zorraga Amal Cherif Rihab Yazidi Naima Abdeddaiem Latifa Maazaoui Awatef ElMoussi Salma Abid Slim Amine Leila Bouabid Souha Bougatef Mohamed Kouni Chahed Afif Ben Salah Jihene Bettaieb Nissaf Bouafif Ben Alaya 《Influenza and other respiratory viruses》2020,14(5):507-514
8.
Nesrine Barbana Adel Ben Youssef Mohamed Ali Rezgui Latifa Bousselmi Mohammad Al-Addous 《Materials》2020,13(22)
Titanium dioxide thin films immobilized over treated stainless steel were prepared using the pulsed electrophoretic deposition technique. The effects of process parameters (deposition time, applied voltage, initial concentration, and duty cycle) on photocatalytic efficiency and adhesion properties were investigated. To optimize the multiple properties of the thin film, a response surface methodology was combined with a desirability optimization methodology. Additionally, a quadratic model was established based on response surface analysis. The precision of the models was defined based on the analysis of variance (ANOVA), R2, and the normal plot of residuals. Then, a desirability function was used to optimize the multiple responses of the TiO2 thin film. The optimum values of applied voltage, catalyst concentration, duty cycle, and deposition time were 4 V, 16.34 g/L, 90% DC, and 150 s, respectively. Under these conditions, the decolorization efficiency of tested dye solution reached 82.75%. The values of critical charges LC1, LC2, and LC3 were 5.9 N, 12.5 N, and 16.7 N, respectively. 相似文献
9.
Philippe Grandjean Latifa Abdennebi‐Najar Robert Barouki Carl F. Cranor Ruth A. Etzel David Gee Jerrold J. Heindel Karin S. Hougaard Patricia Hunt Tim S. Nawrot Gail S. Prins Beate Ritz Morando Soffritti Jordi Sunyer Pal Weihe 《Basic & clinical pharmacology & toxicology》2019,125(Z3):70-80
Much progress has happened in understanding developmental vulnerability to preventable environmental hazards. Along with the improved insight, the perspective has widened, and developmental toxicity now involves latent effects that can result in delayed adverse effects in adults or at old age and additional effects that can be transgenerationally transferred to future generations. Although epidemiology and toxicology to an increasing degree are exploring the adverse effects from developmental exposures in human beings, the improved documentation has resulted in little progress in protection, and few environmental chemicals are currently regulated to protect against developmental toxicity, whether it be neurotoxicity, endocrine disruption or other adverse outcome. The desire to obtain a high degree of certainty and verification of the evidence used for decision‐making must be weighed against the costs and necessary duration of research, as well as the long‐term costs to human health because of delayed protection of vulnerable early‐life stages of human development and, possibly, future generations. Although two‐generation toxicology tests may be useful for initial test purposes, other rapidly emerging tools need to be seriously considered from computational chemistry and metabolomics to CLARITY‐BPA‐type designs, big data and population record linkage approaches that will allow efficient generation of new insight; epigenetic mechanisms may necessitate a set of additional regulatory tests to reveal such effects. As reflected by the Prenatal Programming and Toxicity (PPTOX) VI conference, the current scientific understanding and the timescales involved require an intensified approach to protect against preventable adverse health effects that can harm the next generation and generations to come. While further research is needed, the main emphasis should be on research translation and timely public health intervention to avoid serious, irreversible and perhaps transgenerational harm. 相似文献
10.
Y. Bensafta H. Maghrebi A. Daghfous S. Ayadi A. Makni R. Ksantini W. Rebai F. Fteriche F. Chebbi M. Jouini M. Kacem Z. Ben Safta 《Journal Africain d'Hépato-Gastroentérologie》2014,8(3):164-167