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21.
James A. Case Bai Ling Hsu Timothy M. Bateman S. James Cullom 《Journal of nuclear cardiology》2007,14(3):324-333
Background High-quality attenuation maps are critical for attenuation correction of myocardial perfusion single photon emission computed
tomography studies. The filtered backprojection (FBP) approach can introduce errors, especially with low-count transmission
data. We present a new method for attenuation map reconstruction and examine its performance in phantom and patient data.
Methods and Results The Bayesian iterative transmission gradient algorithm incorporates a spatially varying gamma prior function that preferentially
weights estimated attenuation coefficients toward the soft-tissue value while allowing data-driven solutions for lung and
bone regions. The performance with attenuation-corrected technetium 99m sestamibi clinical images was evaluated in phantom
studies and in 50 low-likelihood patients grouped by body mass index (BMI). The algorithm converged in 15 iterations in the
phantom studies. For the clinical studies, soft-tissue estimates had significantly greater uniformity of mediastinal coefficients
(mean SD, 0.005 cm−1 vs 0.011 cm−1; P<.0001). The accuracy and uniformity of the Bayesian iterative transmission gradient algorithm were independent of BMI, whereas
both declined at higher BMI values with FBP. Attenuation-corrected perfusion images showed improvement in myocardial wall
variability (4.8% to 4.1%, P=.02) for all BMI groups with the new method compared with FBP.
Conclusion This new method for attenuation map reconstruction provides rapidly converging and accurate attenuation maps over a wide spectrum
of patient BMI values and significantly improves attenuation-corrected perfusion images. 相似文献
22.
石杉碱甲类似物的研究II.N-甲基吡啶酮石杉碱甲类似物的合成 总被引:4,自引:1,他引:3
石杉碱甲(1)是从中草药石杉属植物千层塔(Lycopodium serratum Thunb.)中分得的一种高效可逆的乙酰胆碱酯酶抑制剂,临床试验证实它对早老性痴呆症有显著疗效。本文报道N-甲基吡啶酮石杉碱甲类似物2和3的合成。2-甲氧基-5-甲氧羰基-11-亚甲基-5,9-甲撑环辛-7-烯并吡啶(9)在乙腈中用三甲基氯硅烷和碘化钠选择性脱保护以定量的产率得吡啶酮10,再用甲醇钠和碘甲烷甲基化得N-甲基吡啶酮11,11经碱性水解,Curtius重排和氨基的脱保护得N-甲基吡啶酮石杉碱甲类似物2。通过类似的途径从中间体2-甲氧基-5-甲氧羰基-7-甲基-11-酮-5,9-甲撑环辛-7-烯并吡啶(14)合成了类似物3。类似物2和3的乙酰胆碱酯酶抑制活性均低于天然石杉碱甲。 相似文献
23.
蝎毒多肽对大鼠纤溶系统的作用 总被引:1,自引:0,他引:1
从蝎毒中获取具有多种药理活性的肽类混合物(简称SVP),用下肢血管灌流和整体给药的动物模型,观察对血管灌流液内纤溶酶原激活物(PA)活性、血浆优球蛋白纤溶活性(EFA)、纤溶酶(PL)活性的影响。结果:1~20μg/ml灌流3min和0.8,1.6mg·kg-1ipSVP1h血浆中PA活性与对照组相比明显升高(P<0.05或P<0.01),这可能与血管内皮细胞释放PA活性增加有关。 相似文献
24.
The prevalence of LRRK2 Gly2385Arg variant in Chinese Han population with Parkinson's disease. 总被引:2,自引:0,他引:2
Cao Li Zhang Ting Xiao Qin Wang Ying Bai Li Lu Guo Qiang Ma Jian Fang Zhang Jing Ding Jian Qing Chen Sheng Di 《Movement disorders》2007,22(16):2439-2443
We conducted a case-control study to determine the prevalence of the LRRK2 Gly2385Arg variant in patients with Parkinson's disease in Han population in mainland China. Heterozygous LRRK2 Gly2385Arg variant was identified in 14 of 235 patients with Parkinson's disease (5.69%), but not in 214 unrelated healthy controls. Multivariate analysis indicated the frequency of Gly2385Arg variant in the female patients with early age at onset is higher than their male counterparts. The founder haplotype analysis showed the variant carriers shared the same founder. Clinically, the LRRK2 Gly2385Arg carriers presented with classical Parkinson's disease symptoms. Our study indicates that the LRRK2 Gly2385Arg variant is a potential ethnic-specific genetic risk factor of Parkinson's disease within Chinese Han ethnicity. 相似文献
25.
北京石景山地区孕妇女婴幼儿血铅动态研究 总被引:8,自引:2,他引:6
在严格的质量保证措施下,北京石景山地区270名孕妇及其婴儿进行了血铅的追瞎调查。结果显示:孕3月血铅水平为45.0μg/L,分娩前血铅水平为64.8μg/L,孕期血铅呈升高趋势,其中后3月升高明显,分娩前血铅约为孕3月血铅的1.5倍;脐带血铅水平为51.9μg/L,其中有10.4%的胎儿脐血铅高于100μg/L; 相似文献
26.
27.
This apparatus is designed in accordance with the doctrine and principles of traditional Chinese medicine and based on the theory of meridian and specific massage procedure in conjunction with the "Information Theory" and electron utilizing technique. It utilizes a programmed induction "Special Wave" to stimulate a series of acupuncture points, combined with administration of western drugs from a regime of "General Attack" treatment on the gallbladder stones, to enhance their evacuation. By stimulating the specific acupuncture points with this apparatus through the action of "Special Wave" strong contraction of the gallbladder can be elicitated. Experiments on dogs showed that under such stimulation the intra-gallbladder pressure can be increased 26 times, producing a jet of bile flow which facilitates the expulsion and evacuation of stones in the gallbladder. Method of use: first place a conductive rubber pad on the acupuncture point to be stimulated, then use a hand-held electrode to massage-stimulate the meridian. It is carried out forward and backward along the direction of meridian. The whole procedure is carried out under direct visualization with the help of ultrasonic B-scan. When dilatation of the common bile duct is observed, the hand-help electrode is used to perform push-compress massage on the meridian, and acupuncture points making the stones enter the common bile duct B-scan give proper orientation for the manipulation. This method has been tested clinically on 410 patients with good results. The evacuation rate of the gallbladder stones was 92.7% with complete evacuation achieved in 17.3%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
28.
29.
Functional tyrosine kinase inhibitor profiling: a generally applicable method points to a novel role of platelet-derived growth factor receptor-beta in tuberous sclerosis 总被引:1,自引:0,他引:1 下载免费PDF全文
Arbiser JL Govindarajan B Bai X Onda H Kazlauskas A Lim SD Amin MB Claesson-Welsh L 《The American journal of pathology》2002,161(3):781-786
A ubiquitous herpesvirus that establishes life-long infection, the Epstein-Barr virus (EBV) has yielded little insight into how a single agent in general accord with its host can produce diverse pathologies ranging from oral hairy leukoplakia to nasopharyngeal carcinoma, from infectious mononucleosis to Hodgkin's disease (HD) and Burkitt's lymphoma. Its pathogenesis is further confounded by the less than total association of virus with histologically similar tumors. In other viral systems, defective (interfering) viral genomes are known to modulate outcome of infection, with either ameliorating or intensifying effects on disease processes initiated by prototype strains. To ascertain whether defective EBV genomes are present in HD, we examined paraffin-embedded tissue from 56 HD cases whose EBV status was first determined by cytohybridization for nonpolyadenylated EBV RNAs (EBERs). Using both standard polymerase chain reaction (PCR) and PCR in situ hybridization, we successfully amplified sequences that span abnormally juxtaposed BamHI W and Z fragments characteristic of defective heterogeneous (het) EBV DNA from 10 of 32 (31%) EBER-positive tumors. Of 24 EBER-negative HD, 8 yielded PCR products indicating presence of het EBV DNA. Two of these contained defective EBV in the apparent absence of the prototype virus. Of the 42 tumors analyzed for defective EBV by both PCR techniques, there was concordance of results in 38 (90%). Detection of defective EBV genomes with the potential to disrupt viral gene regulation suggests one mechanism for pathogenic diversity that may also account for loss of prototypic EBV from individual tumor cells. 相似文献
30.
Cytogenetic and molecular cytogenetic studies of a case of interstitial deletion of proximal 15q 总被引:3,自引:0,他引:3
Vijay Tonk Herman E. Wyandt Peter Osella James Skare Bai Lin Wu Bassem Haddad Aubrey Milunsky 《Clinical genetics》1995,48(3):151-155
A 4-month-old child with multiple anomalies was determined to have an interstitial deletion of chromosome 15, i.e., del(15) (q12q14). The deletion appears not to be a typical deletion of 15q12 such as seen in Angelman and Prader-Willi syndromes, but appears to be more distal, involving either loss of all of 15q12 and part of 15q14, or part of 15q12 and most of 15q14. In either case, 15q13 is missing. Fluorescent in situ hybridization with probes for 15 centromere (D15Z), pericentromeric satellite sequences (D15Z1), and chromosome 15 painting probes shows the deleted chromosome to involve only 15 and no other acrocentric chromosome. Hybridization with probes for the AS and PWS loci (D15S11 and GABAB3, Oncor) show both sites to be intact in the deleted 15. The case is compared with two other reports with overlapping interstitial deletions of proximal 15q, neither of which shows typical features of Angelman or Prader-Willi syndromes. 相似文献