ABSTRACT
BACKGROUND: Abnormal intracellular Ca2+ homeostasis is an important modulator of chronic atrial fibrillation. Sarcolipin, a homologue of phospholamban, is specifically expressed in the atria, and may play an important role in modulating intracellular Ca2+ homeostasis in the atria. The aim of this study was to investigate the expression of sarcolipin mRNA in the atrial myocardium of patients with chronic atrial fibrillation. METHODS: We analyzed the expression of sarcolipin, phospholamban, cardiac calsequestrin and sodium calcium exchanger mRNAs in the right atrial myocardium from nine patients with mitral valvular disease with atrial fibrillation (MVD/AF), nine patients with MVD who had normal sinus rhythm (MVD/NSR), and 10 control patients with normal sinus rhythm who received open heart surgery (controls). The expression of mRNA was measured using the ABI PRISM 7700 Sequence Detection System (Applied Biosystems, Foster City, CA). RESULTS: Relative expression levels of sarcolipin mRNA were significantly lower in MVD/AF (0.60 +/- 0.11) than in either MVD/NSR (1.28 +/- 0.17, P < 0.01) or controls (1.10 +/- 0.10, P < 0.05). The expression levels of sarcolipin mRNA were significantly lower in the group with high values for right atrial pressure. The expression levels of phospholamban, cardiac calsequestrin and sodium calcium exchanger mRNAs were comparable among all three groups. CONCLUSIONS: Chronic electrical and mechanical overload decreased the expression of sarcolipin mRNA in the right atrial myocardium in patients with chronic atrial fibrillation. Down-regulation of sarcolipin mRNA may be part of atrial fibrillation-induced atrial remodelling.
Subject(s)
Atrial Fibrillation/genetics , Muscle Proteins/genetics , Proteolipids/genetics , RNA, Messenger/analysis , Adult , Aged , Atrial Fibrillation/etiology , Calcium-Binding Proteins/genetics , Calsequestrin/genetics , Chronic Disease , Down-Regulation/genetics , Female , Gene Expression/genetics , Heart Atria/metabolism , Humans , Male , Middle Aged , Mitral Valve Insufficiency/complications , Mitral Valve Insufficiency/genetics , Mitral Valve Stenosis/complications , Mitral Valve Stenosis/genetics , Myocardium/metabolism , Sodium-Calcium Exchanger/geneticsABSTRACT
The purpose of this study was to assess the utility of dynamic MR hepatocholangiography with the Gd-EOB-DTPA enhanced SIP Fast GRE sequence in the hepatobiliary system. The SIP Fast GRE sequence was used for sequential imaging of the hepatobiliary system with a frame rate of 3 sec in a 256 x 192 matrix. Dynamic sequential acquisition was performed for 51 min before and after the injection of 30 mu mol/kg of Gd-EOB-DTPA in a rabbit. Dynamic images of the hepatobiliary system were obtained in the rabbit study. Dynamic MR hepatocholangiography provides better functional information than conventional MR cholangiography.
Subject(s)
Bile Ducts/anatomy & histology , Contrast Media , Gadolinium DTPA , Liver/anatomy & histology , Magnetic Resonance Imaging/methods , Animals , Female , RabbitsABSTRACT
To assess the value of dynamic gadolinium-enhanced MR imaging combined with magnetization transfer contrast (MTC) of breast cancer by SPGR sequence, 15 patients with breast cancer were imaged in the supine position with the newly developed breast coil in a 1.5 Tesla imager. Dynamic gadolinium-enhanced MR imaging combined with MTC (10 cases) and conventional dynamic gadolinium-enhanced MR imaging (5 cases) were performed after the administration of Gd-DTPA (0.2 ml/kg). Sagittal images were obtained every 22 seconds during the first 264 seconds. Thus, a total of 15 images were obtained in each lesion. The signal intensity ratio (SIR) of lesion to mammary glarid was calculated for each image as follows: (SI lesion/SI mammary gland)/(SI (pre)lesion/SI (pre)mammary gland). Dynamic gadolinium-enhanced MR imaging with MTC always allowed better SIR at 88 seconds than conventional dynamic gadolinium-enhanced MR imaging after bolus injection (p < 0.01). Dynamic gadolinium-enhanced MR imaging with MTC improved detection of the boundary of the lesion and mammary gland.
