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排序方式: 共有449条查询结果,搜索用时 15 毫秒
1.
Sonoelasticity imaging of prostate cancer: in vitro results 总被引:2,自引:0,他引:2
2.
Screening for early ovarian cancer 总被引:5,自引:0,他引:5
3.
The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses. 相似文献
4.
Csukly KJ Martineau LC Gardiner PF 《Pflügers Archiv : European journal of physiology》2002,444(6):732-737
Muscle phenotype is regulated by mechanical forces. However, it is not well understood how these forces are translated into intracellular signalling that influences gene expression. The purpose of this study was to test the hypothesis that muscles displaying a wide range of metabolic profiles and fibre-type composition exhibit differences in the detection and transmission of mechanical stimuli. A mechanical challenge in the form of passive stretch normalized to 3 N/g muscle weight was applied to the rat extensor digitorum longus (EDL), soleus (SOL), and plantaris (PLN) in situ for 5 min, following which activities of the mechanically-responsive p54 c-jun NH(2)-terminal kinase (JNK) and extracellular-regulated kinase (ERK) 1/2 were measured. EDL, SOL, and PLN were not different in their stretch-induced JNK (4.5, 5.2 and 6-fold baseline, respectively) or ERK (2.2, 2.2 and 1.9-fold baseline, respectively) responses, in spite of differing fibre-type compositions. The medial gastrocnemius (MG), a compartmentalized muscle with red (MGr) and white (MGw) regions, was subjected to the same normalized mechanical stretch protocol. The resulting JNK and ERK activities were significantly higher in MGr (13 and 4.5-fold baseline, respectively) than in MGw (5 and 1.2-fold baseline, respectively) and all other muscles. In contrast to stimulation by passive stretch, stimulation of the MG by isometric contractile activity did not result in a heterogeneous response between compartments. This study demonstrates an absence of difference among muscles of varying phenotype in their ability to transmit mechanical stimuli to the mitogen-activated protein kinase signalling pathways, and hence in their mechanosensitivity. Furthermore, the results highlight the importance of considering aspects of the functional organization of different muscles, such as compartmentalization and architecture, when studying mechanical signalling in vivo. 相似文献
5.
Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos 总被引:8,自引:2,他引:8
Yang HW; Hwang KJ; Kwon HC; Kim HS; Choi KW; Oh KS 《Human reproduction (Oxford, England)》1998,13(4):998-1002
In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture
environment differs from in-vivo conditions in that the oxygen
concentration is higher, and in such conditions the mouse embryos show a
higher concentration of reactive oxygen species (ROS) in simple culture
media. ROS are believed to cause damage to cell membranes and DNA
fragmentation in somatic cells. This study was conducted to ascertain the
level of H2O2 concentration within embryos and the morphological features
of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31
fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was
obtained from the IVF-embryo transfer programme. The relative intensity of
H2O2 concentrations within embryos was measured using
2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence
imaging and DNA fragmentation was observed with transmission electron
microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations
were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/-
SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and
unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed
only in fragmented embryos, and was absent in non-fragmented embryos.
Electron microscopic findings confirmed apoptotic bodies and cytoplasmic
condensation in the fragmented blastomeres. We conclude that there is a
direct relationship between increased H2O2 concentration and apoptosis, and
that further studies should be undertaken to confirm these findings.
相似文献
6.
7.
Pathways to care for alcohol use disorders 总被引:1,自引:0,他引:1
8.
9.
10.
A Hodgkin cell-specific antigen is expressed on a subset of auto- and alloactivated T (helper) lymphoblasts 总被引:21,自引:0,他引:21
A Hodgkin cell-specific antigen detected by the monoclonal antibody Ki- 1 was found on T helper lymphocytes after activation by autologous and allogeneic stimulator cells. About 50% of lymphoblasts generated by auto- and alloactivation reacted with the antibody. In contrast, only less than 6% of lymphoblasts stimulated with Con-A, phytohemagglutinin (PHA), or protein A, and none of lymphoblasts activated by oxidative mitogenesis, expressed this antigen. Among several permanent cell lines tested, the K562, MOLT-4, HL-60, and EBV transformed B lymphoblastoid cells reacted with the Ki-1 antibody. The results may indicate possible relationships between the autoreactive subset of T lymphocytes and the pathogenesis of Hodgkin's disease. 相似文献