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561.
Renal dysplasia: sonographic findings 总被引:1,自引:0,他引:1
In 38 pediatric patients (predominantly neonates) with a proved pathologic diagnosis of renal dysplasia, a variety of sonographic appearances were seen. When the obstruction was at the level of the ureteropelvic junction (12 patients, 12 kidneys), the typical appearance was of a large kidney containing multiple large or moderate-sized cysts. When the obstruction was at the level of the distal ureter (14 patients, 14 kidneys), a smaller kidney containing a few cysts of variable sizes was usually seen. When the obstruction was at the level of the urethra (eight patients, 13 kidneys), the kidney was typically small with few or no cysts. In four patients (seven kidneys) in whom no cause of the obstruction was evident, the kidneys were small and echogenic. There was one case of segmental dysplasia. 相似文献
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New directions in the development of MR imaging contrast media 总被引:7,自引:0,他引:7
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Schmiedl U; Sievers RE; Brasch RC; Wolfe CL; Chew WM; Ogan MD; Engeseth H; Lipton MJ; Moseley ME 《Radiology》1989,170(2):351-356
The utility of a macromolecular, intravascular contrast agent, albumin-gadolinium diethylenetriaminepentaacetic acid (DTPA), for the differentiation of acutely ischemic and reperfused myocardium on magnetic resonance (MR) images was investigated. Regional, reversible myocardial ischemia was produced in rats and confirmed. After reperfusion, flow to the compromised myocardial segment returned to baseline. Normal myocardium could not be differentiated from ischemic myocardium on nonenhanced MR images (n = 12). After 5 minutes of myocardial ischemia and after administration of albumin-Gd-DTPA, the ischemic zone involving the free wall of the left ventricle was characterized by the absence of significant enhancement. Normal myocardium appeared homogeneously enhanced (by 145%). This pattern persisted for up to 1 hour of myocardial ischemia. In six rats that underwent myocardial reperfusion after 5 minutes of ischemia, the normal and reperfused myocardium became isointense. Radiotracer studies with albumin-Gd-153-DTPA confirmed the decreased distribution of contrast agent to the ischemic myocardium, possibly due to decreased blood pool or a blocked primary delivery system in the ischemic myocardium. 相似文献
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Catechol-O-methyltransferase and breast cancer risk 总被引:5,自引:1,他引:5
Millikan RC; Pittman GS; Tse CK; Duell E; Newman B; Savitz D; Moorman PG; Boissy RJ; Bell DA 《Carcinogenesis》1998,19(11):1943-1947
Recent studies suggest that a polymorphism in catechol-O- methyltransferase
(COMT) is associated with increased risk of breast cancer. Methylation by
COMT is the principal pathway for inactivation of catechol estrogens, which
are hypothesized to participate in estrogen-induced carcinogenesis. We
examined the association of COMT genotype and breast cancer risk in a
population-based, case-control study of invasive breast cancer in North
Carolina. The study population consisted of 654 cases and 642 controls,
with approximately equal numbers of African-American and white women and
women under the age of 50 and aged 50 or over. Contrary to previous
reports, we did not observe an association between one or more copies of
the low activity COMT allele (COMT-L) and breast cancer risk. Multivariate
relative risks (RRs) were 0.8 (95% confidence interval: 0.6-1.1) for
COMT-HL and 0.8 (0.6-1.1) for COMT-LL, compared with the COMT-HH genotype.
RRs for COMT did not differ among African-American and white women and we
did not observe strong modification of RR estimates by menopausal status,
body mass index, physical activity or other covariates. Our results suggest
that COMT genotype is not related to breast cancer risk.
相似文献