Biomedical subjects
Publications and source records attributed to T Tak.
Based on symmetry breaking steps under one-pot conditions, simple molybdenum oxide-based building blocks initially assemble to 'giant molecular wheels' in a fast process followed by further slower assembly processes leading stepwise to more complex mesoscopic architectures including spherical ones and finally to those with a size larger than 500 nm.
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A 29-year-old woman presented with shortness of breath, vague chest pain, and prominent intermittent ejection systolic murmur. Transthoracic echocardiography showed a large mass in the right ventricular outflow tract. Transesophageal echocardiography demonstrated two masses that were adherent to the tricuspid valve and intermittently prolapsed through the pulmonary valve. Computed tomography of the chest corroborated the echocardiographic findings. Currently, there are no definitive guidelines regarding the optimal management of right heart thrombi in patients with antiphospholipid syndrome. Our patient did not respond to a standard dose of rt-PA used in the treatment of pulmonary embolus. She underwent successful surgical resection of the thrombi without complications.
The case of a patient with a prosthetic aortic valve and warfarin hypersensitivity is presented. On rechallenging the patient with warfarin, a spongiotic dermatitis with heavy superficial perivascular lymphocytic infiltrates with eosinophils was seen. The patient was finally discharged on aspirin therapy alone and is doing well to date. Warfarin hypersensitivity is rare, and only incidental reports exist regarding its incidence and management. It is conceivable that newer antiplatelet agents, whether alone or in combination with aspirin, will provide better control of thromboembolic events in patients with warfarin intolerance.
The ability to differentiate active from chronic valvular vegetations (VEGs) by digital image processing and by visual observation was evaluated in 18 patients with a clinical diagnosis of infective endocarditis (IE). Two-dimensional echocardiographic (2-DE) examinations were performed on all patients at diagnosis and after a mean period of 52 days. Two comparable images (active and chronic) from the same patient and in the same phase of the cardiac cycle were digitized, magnified, and displayed on a high resolution monitor. The mean pixel intensity (MPI) was 72+/-14 in the active stage and 143 +/-23 in the chronic stage (P<0.0001). The VEG size was 0.64+/- 0.15 cm(2) in the active stage and decreased to 0.46+/-0.17 cm(2) in the chronic stage (P<0.001). Two experienced echocardiographers, who were blinded to the age of the VEGs, identified each echocardiographic image as active or chronic based on visual observation of density of the VEGs. The VEGs were correctly identified as active or chronic in 17 out of the 18 patients. In summary, although digital image processing of 2-DE may be useful, the density of VEGs assessed by visual inspection will help differentiate between active and chronic VEGs of IE. The standardization procedure at the time of the initial study and use of identical gain settings in subsequent studies are key factors in making this distinction.
Hypertrophic cardiomyopathy is characterized by left or right ventricular hypertrophy that is usually asymmetric and involves the interventricular septum. The condition has numerous genetic, anatomic, and clinical variations and continues to stimulate interest and investigation into causes and treatment options. New genetic forms of the disorder are being identified because of the rapid growth of molecular genetics. However, even with technological advances and a large database of information, risk stratification and treatment of hypertrophic cardiomyopathy remain difficult and controversial. Because of the high risk of sudden death, it is imperative that patients be advised against participation in competitive sports.
A 35-year-old man with a history of polyarteritis nodosa is presented. The patient presented with acute anterolateral myocardial infarction that was complicated by diffuse coronary artery aneurysms found during cardiac catheterization. The complication of acute myocardial infarction in a patient with diffuse coronary artery aneurysms associated with polyarteritis nodosa is rare.
A 61-year-old man was admitted with acute posterior myocardial infarction and, on physical examination, was shown to have a mitral regurgitation (MR) murmur. Transthoracic echocardiography (TTE) showed severe hypokinesis of the posterior wall and severe MR by color flow. Right heart catheterization with a balloon-tipped catheter revealed a pulmonary artery wedge pressure of 30 mmHg. No 'step-up' was seen in blood samples from the right atrium and right ventricle. On angiography, a subtotal occlusion of the mid circumflex artery was found which was angioplastied and stented. As the patient's clinical condition did not improve, he underwent transesophageal echocardiography (TEE) for further evaluation. This showed complete rupture of the posteromedial papillary muscle. The patient underwent urgent surgery with successful mitral valve replacement. The postoperative course was uncomplicated, and clinical improvement seen. This case report underscores the value of TEE in accurate preoperative diagnosis of papillary muscle rupture by providing preoperative anatomic details of the mitral valve apparatus and surrounding structures.
Assessment of patients with valvular heart disease has undergone many changes in the past few decades with the introduction of noninvasive techniques such as echocardiography. Along with the history, physical examination, electrocardiogram, and chest films, echocardiography is an important component of the assessment, providing essential information for diagnosis and follow-up.
Transesophageal echocardiography was used to image bypass grafts and measure flow reserve in these conduits. Imaging and measurement of flow reserve were feasible in most patients.
Unless thrombolytic or surgical therapy is rapidly available, massive pulmonary embolism in both pulmonary arteries invariably results in instantaneous death. A patient is presented with congenital atrial septal defect and right ventricular thrombus who developed extensive bilateral pulmonary embolism with an apparently prolonged survival. The ante- and postmortem findings represent the unusual and interesting aspects of this particular case.
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Reparative surgery for valvular insufficiency is attempted frequently. The success of surgery depends partly on the underlying etiology. To establish the morphological characteristics of rheumatic mitral valve disease (insufficiency) (n = 12), mitral insufficiency due to infective endocarditis (n = 12), mitral insufficiency postinfarction (n = 6), rheumatic (predominant) mitral insufficiency postinfarction (n = 6), rheumatic (predominant) mitral stenosis (n = 12) and normal patients (n = 12) were examined retrospectively. In the groups of patients with mitral insufficiency< the mobility of the posterior leaflet tip (change in angle from the annular plane) was significantly less than normal 48 +/- 9 degrees only in the rheumatic group (12 +/- 7 degrees, P < 0.01). The posterior mitral leaflet tip had greater than normal mobility in the other mitral insufficiency groups: infective endocarditis 53 +/- 15 degrees (P = 0.35 versus normals), postinfarction 63 +/- 11 degrees (P = 0.02 versus normals), myxomatous 63 +/- 19 degrees (P = 0.03 versus normals). The mobility of the posterior mitral leaflet tip was also significantly less than normal in the rheumatic mitral stenosis group: 16 +/- 7 degrees, P < 0.01 versus normals. In the two rheumatic groups, diastolic doming of the anterior mitral leaflet was seen solely in mitral stenosis. In the predominant regurgitant group, the tip of the anterior mitral leaflet was much more mobile than in the stenosis group. Doming of the anterior mitral leaflet was absent from the predominant regurgitant group (2.1 +/- 0.9 cm, P < 0.001). The stenotic mitral valves domed 0.75 +/- 0.15 cm.(ABSTRACT TRUNCATED AT 250 WORDS)
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The authors report the case of a 36-year-old male who, following investigations for dyspnea, othopnea and peripheral cyanosis, was found to have metastatic intracardiac plasmacytoma. Diagnosis was made initially with transesophageal echocardiography and emergent cardiac surgery was performed. Postoperative transthoracic and transesophageal echocardiograms revealed residual masses in the right and left atrium. The patient was subsequently treated with systemic chemotherapy and was symptom-free within three months of treatment, with rapid decline of paraproteins in the serum and urine. This case of intracardiac metastatic plasmacytoma is deemed unique because cardiac involvement with multiple myeloma has not been studied in detail, largely due to the rarity of such a presentation.
Catheter balloon valvulotomy (CBV) is useful in the relief of rheumatic mitral stenosis. Morphologic scoring of the mitral valve by transthoracic echocardiography is predictive of success with CBV. Horizontal plane transesophageal echocardiography can obtain high quality images of the mitral valve and left atrium, but its value with routine use in the pre and post CBV setting is unknown. We prospectively examined 14 patients with mitral stenosis, pre and post CBV, noting scores, complications of mitral stenosis, and complications of CBV. Mitral valve scoring was similar by TTE and TEE pre and post CBV, but TEE did tend to underestimate scores pre CBV. There was a single thrombus, it was detected only by TEE. Post CBV, both TTE and TEE detected one of two torn chordae. Of three patients with ASD's by colour flow mapping, TTE and TEE each detected two. Increases in mitral insufficiency post CBV were seen equally frequently by TTE and TEE. The increases appeared to be of a higher grade (NS) by TEE. TTE and TEE yielded complementary findings, pre and post CBV. Other than for the detection of thrombi through, the net clinical contribution of routine use of TEE appears small, and large series would be needed to establish its contribution.
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