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Occurrence of the t(2;5)(p23;q35) in non-Hodgkin's lymphoma   总被引:9,自引:3,他引:6  
Primary CD30(Ki-1)-positive anaplastic large-cell lymphoma (ALCL) is considered by some to be a distinct clinicopathologic entity associated with the t(2;5) (p23;q35). However, the specificity of t(2;5) for ALCL has not been carefully studied. Therefore, we performed a detailed analysis of all cases of ALCL with abnormal cytogenetics results in the Nebraska Lymphoma Study Group registry, as well as all other cases of non-Hodgkin's lymphoma with t(2;5) in the registry. We found the t(2;5) in only five of 10 cases of ALCL, four of whom were young patients. However, we also found the t(2;5) in 11 other cases of nonanaplastic lymphoma, including eight children with typical peripheral T-cell lymphomas of various types. The t(2;5) was also found in three older adults with B-cell lymphomas of various types. Thus, the t(2;5) was not specific for CD30+ ALCL. However, t(2;5) may define a clinicopathologic entity in children and young adults characterized by variable morphologies with a T-cell or indeterminate phenotype, CD30-positivity, nodal disease with frequent extranodal involvement, advanced stage, and an excellent response to therapy, including bone marrow transplantation for relapsed disease. The clinical relevance of the t(2;5) in older patients requires further study.  相似文献   
3.
Dural sinus thrombosis: study using intermediate field strength MR imaging   总被引:1,自引:0,他引:1  
The magnetic resonance (MR) images of six patients with thrombosis of a dural sinus were reviewed. The diagnosis had been verified by computed tomographic scans in three patients and arteriograms in two; in the sixth patient, only MR imaging was used to confirm the clinical syndrome. In all patients, high-intensity signal was seen from the thrombus within the affected dural sinus on all echoes. This persistent signal intensity allowed intravascular clot to be distinguished from normal causes of increased signal such as flow-related enhancement (entry phenomenon) and even-echo rephasing. MR imaging demonstrated the cause of the thrombosis in three patients: two were secondary to adjacent tumors, and one was secondary to unsuspected mastoiditis. Complications such as infarction were also demonstrated. Using MR imaging, one can easily and safely diagnose thrombosis of a dural sinus. MR should be the imaging method of choice in patients suspected of having thrombosis of a dural sinus.  相似文献   
4.
Reiman  TH; Heiken  JP; Totty  WG; Lee  JK 《Radiology》1988,169(2):564-566
Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution.  相似文献   
5.
Low-artifact intravascular devices: MR imaging evaluation   总被引:2,自引:0,他引:2  
Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible.  相似文献   
6.
Two effects of Mn2+ on skinned fibers from chicken gizzard smooth muscle were observed, dependent on the presence of absence of dithiothreitol (DTT) reducing agent. One involves protein oxidation (in the absence of DTT) with production of a latch-like state, and the other involves direct Mn2+ activation of contractile proteins. Cells activated by Mn2+ in the presence of ATP and the absence of Ca2+, Mg2+ and DTT did not relax when transferred to normal relaxing solutions. In contrast, when 5 mM DTT was included in the Mn2+ contracting solution to prevent protein oxidation by Mn2+, the cells still contracted when exposed to Mn2+, but relaxed rapidly when the Mn2+ was removed. In the presence of DTT both the Mn2+ activation and the relaxation following removal of Mn2+ were more rapid than normal Ca2+-activated contractions and relaxations. The skinned fibers activated by Mn2+ in the absence of DTT showed little active shortening unless DTT was added. This rigor-like state is probably due to oxidation of contractile proteins since the cells relaxed when exposed to a relaxing solution containing DTT (50mM) and then contracted again in response to Ca2+ and relaxed normally. The Mn2+ activation was not associated with myosin light chain phosphorylation, in contrast to Ca2+-activated contractions.A preliminary report of this work was given at the Biophysical Society Meeting, February 1987: Hoar PE, Kerrick WGL (1987) Mn2+ activates skinned smooth muscle cells directly without myosin light chain phosphorylation and by reversible oxidation. Biophys J 51:332a  相似文献   
7.
The mechanism of contraction in rabbit fast-twitch, and bovine and rabbit cardiac muscle was examined using functionally skinned fibers, ATPase activity of myofibrils, and cardiac or skeletal troponintropomyosin regulated actin heavy meromyosin. The Ca2+ and Sr2+ activation properties for the different measures of contraction were evaluated. (1) Tension in rabbit and bovine cardiac skinned fibers and rabbit cardiac myofibrillar ATPase were activated equally well by either Ca2+ or Sr2+. By contrast, rabbit adductor magnus (fast-twitch) skinned fibers required substantially higher [Sr2+] than [Ca2+] for activation, as did rabbit myofibrils from back muscle (fast-twitch). (2) Substantially more Sr2+ than Ca2+ was also required for activation of skeletal muscle actin heavy meromyosin ATPase, controlled by either the skeletal or cardiac troponin-tropomyosin complex, similar to the activation of fast-twitch muscle. (3) The absence of correlation between the divalent cation selectivity properties of actin heavy meromyosin ATPase controlled by cardiac troponin-tropomyosin and cardiac muscle tension or myofibrillar ATPase activation by Ca2+ and Sr2+ suggests that troponin, if primarily responsible for the activation of cardiac muscle, has very different in vivo and in vitro binding properties. (4) The close correlation between percentage of maximal Ca2+- and Sr2+-activated myofibrillar ATPase and tension in skinned fibers strongly justifies the use of myofibrillar ATPase, in contrast to a reconstituted troponin-tropomyosin actin heavy meromyosin ATPase system, as a biochemical measure of contraction.  相似文献   
8.
Changes in the Ca2+ and Sr2+ activation properties of functionally skinned slow-twitch soleus fibers were measured and compared with those of normal fast-twitch extensor digitorum longus (EDL) following cross-reinnervation of soleus with the nerve to EDL. Most of the fibers showed either complete transformation of activation properties (66%) or remained unchanged (34%). The change in sensitivity to divalent cations was correlated with changes in the proteins present in fibers pooled on the basis of their activation properties. The banding patterns of the 35,000- and 37,500-dalton proteins (tropomyosin and troponin T) in cross-reinnervated soleus were correspondingly transformed to those of normal EDL. Slow and fast myosin light chains were present in the pooled cross-reinnervated fibers. Fiber distributions based on activation properties were confirmed by histochemical features. For the first time it has been demonstrated that cross-reinnervation produced changes in the activation properties of soleus fibers and associated changes in the regulatory proteins measured.  相似文献   
9.
It is well known that cardiac troponin C (cTnC) regulates the association of force-generating myosin cross-bridges. We report here evidence for an additional role for cTnC. This hypothesis states that Car2+ binds more strongly to cTnC when force-generating myosin cross-bridges are attached to actin and that removal of this bound Ca2+ accelerates the dissociation of force-generating myosin cross-bridges. Intact Fura-2-loaded rat papillary muscles and skinned (permeabilized) ventricular preparations were used. The preparations were mounted in the Guth Muscle Research System which is capable of measuring simultaneously fluorescence and force in response to length perturbations. All mechanical perturbations of muscle length (isotonic shortening, quick stretches and releases, and length vibrations) which cause dissociation of force-generating myosin cross-bridges during a twitch resulted in Ca2+ being released from troponin as judged from changes in the Ca2+ transients (Fura-2 (340/380) fluorescence ratio). Thus dissociation of force-generating myosin cross-bridges cause Ca2+ to be released from cTnC. Conversely, it would be expected that removal of strongly bound Ca2+ from cTnC would result in an increase in the rate of dissociation of force-generating myosin cross-bridges. To test this hypothesis actomyosin ATPase (NADH fluorescence change) and isometric force were measured in skinned cardiac preparations. The ratio of the ATPase/Force is proportional to the rate constant (gapp) for the dissociation of force-generating myosin cross-bridges. The data showed that decreasing the amount of Ca2+ bound to cTnC in skinned cardiac fibers caused an increase in the ratio of ATPase/Force, the rate of dissociation (gapp) of force-generating myosin cross-bridges.  相似文献   
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