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排序方式: 共有580条查询结果,搜索用时 15 毫秒
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Adverse reaction to intravenous gadoteridol 总被引:1,自引:0,他引:1
4.
Intestinal schistosomiasis japonica: CT-pathologic correlation 总被引:1,自引:0,他引:1
Lee RC; Chiang JH; Chou YH; Rubesin SE; Wu HP; Jeng WC; Hsu CC; Tiu CM; Chang T 《Radiology》1994,193(2):539
5.
Routine 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) myocardial tomography using a normal large field of view gamma-camera 总被引:1,自引:0,他引:1
There is a recent need to study glucose metabolism of the heart in ischemic, as well as in "hibernating or stunned" myocardium, and compare it with that in perfusion studies. In non-positron emission tomography centers, positron imaging is possible with a standard Anger-type camera if proper collimation and adequate shielding of the camera crystal can be achieved. For the study with fast-decaying isotopes, seven-pinhole tomography (7PHT), a limited-angle method designed for transaxial tomography of the left ventricle using a nonrotating camera, is well suited, because projections are acquired simultaneously. Individual adjustment (patient supine) of the camera's view axis (CAx) with the left ventricular axis (LVAx) gives excellent results: sensitivity for CHD 82%, specificity 72% in a prospective 201TI study (48 patients, x-ray coronarography as reference). Good alignment of CAx with LVAx is also achieved with the patient prone in LAO in a hammock above the camera surface. In this setting additional lead shielding of the camera is possible using a table reinforced with 5 cm of lead with a central hole for the 7PH-collimator, which has a special lead inlay. This allows utilization of the 511 KeV emitter 18F-FDG, which with a half-life of 109 minutes, can be transported a reasonable distance from the production site. System sensitivity and resolution for 18F was found comparable to 201Tl, 99mTc, and 123I using a phantom. First clinical examinations after 201Tl stress/redistribution studies showed increased 18F-FDG uptake in ischemic heart segments, as well as in "hibernating" nonperfused or "stunned" myocardium. 相似文献
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Gene conversion is a likely cause of mutation in PKD1 总被引:3,自引:0,他引:3
Watnick TJ; Gandolph MA; Weber H; Neumann HP; Germino GG 《Human molecular genetics》1998,7(8):1239-1243
Approximately 70% of the gene responsible for the most common form of
autosomal dominant polycystic kidney disease ( PKD1 ) is replicated in
several highly homologous copies located more proximally on chromosome 16.
We recently have described a novel technique for mutation detection in the
duplicated region of PKD1 that circumvents the difficulties posed by these
homologs. We have used this method to identify two patients with a nearly
identical cluster of base pair substitutions in exon 23. Since pseudogenes
are known to be reservoirs for mutation via gene conversion events for a
number of other diseases, we decided to test whether these sequence
differences in PKD1 could have arisen as a result of this mechanism. Using
changes in restriction digest patterns, we were able to show that these
sequence substitutions are also present in N23HA, a rodent-human somatic
cell hybrid that contains only the PKD1 homologs. Moreover, these changes
were also detected in total DNA from several affected and unaffected
individuals that did not harbor this mutation in their PKD1 gene copy. This
is the first example of gene conversion in PKD1 , and our findings
highlight the importance of using gene-specific reagents in defining PKD1
mutations.
相似文献
8.
Two types of phantoms were developed with which to evaluate the overall performance of digital subtraction angiography (DSA) systems. A dynamic phantom, called a "fish bone" phantom, consists of polyethylene tubes that simulate blood vessels with various lesions, such as stenoses, ulcers, and aneurysms. With this phantom, washout curves were obtained representing the relationship between iodine content and time. It will be useful for qualitative assessment of DSA images, evaluation of different image-processing schemes, and studies of blood flow analysis. A static phantom, called a "C-D" phantom, can be used for measurement of quantitative contrast-detail (C-D) diagrams and for daily monitoring of DSA systems. This was constructed of tubes of seven different diameters (2.15-0.28 mm) and 14 different concentrations of contrast medium (100%-1.1% Renografin-76 [meglumine and sodium diatrizoate]). The C-D diagrams were determined from an observer performance study using C-D phantom images obtained at four different DSA settings. 相似文献
9.
Fuchs P Haefeli WE Ledermann HR Wenk M 《European journal of clinical pharmacology》1999,54(11):869-876
Objectives: To evaluate the in vivo effect of xanthine oxidase (XO) inhibition by allopurinol on the determination of polymorphic N-acetyltransferase 2 (NAT2) and cytochrome P450 1A2 (CYP1A2) with urinary caffeine metabolic ratios.
Methods: In an open, prospective study involving 21 healthy subjects (eight fast, 13 slow NAT2 acetylators) allopurinol (300 mg perday)
was administered orally on trial days 1–8, followed by a wash-out period of 8 days. Urinary caffeine tests (200 mg caffeine
p.o.) were performed repetitively. Urine was collected for 8 h and venous blood samples for the determination of allopurinol,
oxypurinol and uric acid were drawn. The urinary caffeine metabolites 1-methyluric acid (1MU), 1-methylxanthine (1MX), 1,7-dimethyluric
acid (17MU), 1,7-dimethylxanthine (17MX), 5-acetylamino-6-formylamino-3-methyluracil (AFMU), plasma allopurinol and oxypurinol
were analysed using high-performance liquid chromatography (HPLC).
Results: During XO inhibition by allopurinol, the formation of 1MU from 1MX and therefore the XO ratio 1MU/1MX decreased to 15.9
(1.2)% [mean with (SEM)] of baseline values (P < 0.005). The NAT2 ratio AFMU/1MX decreased likewise to 56.7 (6.3)% (P < 0.005). AFMU/(AFMU + 1MX + 1MU), an alternative NAT2 ratio, remained constant, but the CYP1A2 ratio (AFMU + 1MX + 1MU)/17MU,
used to express CYP1A2 activity, transiently increased to 167 (13)% (P < 0.005). The NAT2 phenotype did not influence CYP1A2 and XO ratios or plasma oxypurinol pharmacokinetics.
Conclusions: Several caffeine metabolic ratios are commonly used to express the activities of NAT2, CYP1A2 and XO both in healthy volunteers
and in polymedicated patients, although their reliability has not been evaluated thoroughly during concurrent drug administration.
The findings of this study suggest that NAT2 phenotyping should be performed using the ratio AFMU/(AFMU + 1MX + 1MU) if an
XO inhibitor may be present. It also shows that the determination of CYP1A2 activity with caffeine as a metabolic probe is
considerably altered under these conditions. Thus, concomitant drug administration may impair the robustness of multiple pathways
of the complex caffeine test. This points to the need for alternative probes, designed to assess only the activity of a single
enzyme because, in contrast to healthy volunteers, in patients known or unknown drug interactions may often be present.
Received: 10 August 1998 / Accepted in revised form: 5 October 1998 相似文献
10.