Biomedical subjects
Publications and source records attributed to G Habib.
We report 2 cases (n. 1 and 2) of cerebral infarction caused by a left atrial myxoma, and 1 case (n. 3). of dementia associated with a large left atrial myxoma. Cerebral emboli and neurological symptoms which can occur prior to cardiac obstructive and/or systemic signs require echocardiography. The cardiac post-operative condition was dramatically improved in cases revealed by an hemiplegia.
The authors report a case of isolated double orifice mitral valve in a 20-year old pregnant woman. This exceptional and seldom isolated anomaly is usually discovered at autopsy or surgery. In this particular case it was diagnosed by pulsed doppler ultrasound combined with echocardiography. Data from the literature are reviewed on that occasion, and the echocardiographic images of the malformation are described. Despite its rarity, double orifice mitral valve deserves to be known and its presence should be looked for by echocardiography, notably in patients with complete or partial atrioventricular canal.
In a prospective study of 23 patients who had undergone orthotopic heart transplantation we tried to assess the value of doppler-echocardiography in the detection of acute graft rejection. For this purpose, 220 echocardiographic records were compared with the results of endomyocardial biopsies performed at an interval of less than 12 hours. The parameters investigated by TM and two-dimensional echocardiography were: morphological parameters (including septal echodensity), left ventricular mass and systolic function parameters. Diastolic parameters (isovolumetric relaxation time [IVR], transmitral gradient half-decrease time [T 1/2] and proto-end-diastolic mitral velocity ratio [E/A] were measured by TM echocardiography and pulsed doppler velocimetry. The best doppler-echocardiographic criteria for graft rejection were a more than 15 ms reduction of IVR, a more than 15 p. 100 increase of myocardial mass, and a more than 30 p. 100 increase of teh E/A ratio, the corresponding sensitivities for histological rejection being 82, 76 and 74 p. 100 respectively. In contrast, T 1/2 and systolic function studies seemed to be disappointing. Finally, the increase of septal echodensity enabled rejection to be diagnosed with an excellent (92 p. 100) specificity but an insufficient sensitivity. Thus, none of the parameters measured were sensitive enough, taken separetely, to replace endomyocardial biopsy. However, the combined use of the most sensitive of them should make it possible to reduce the frequency of systematic biopsies.
A case of carcinoid cardiopathy (C.C.) of the right heart, related to liver metastases secondary to a bronchial tumor, is reported. Non-invasive investigative methods have enabled an easy diagnosis of C.C.: liver metastases by scan and abdominal sonogram, restrictive myocardiopathy with typical tricuspid lesions by echocardiography and MRI, magnitude of the tricuspid regurgitation by cardiac Doppler. These extremely performing methods must allow an early diagnosis at a stage when the patient may be still operable, since C.C. is the most frequent cause of death in patients with carcinoid tumors.
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The authors compare three diagnostic-imaging methods (two-dimensional-echography, heart scans and indium-111 platelet scintigraphy) used in the detection of intracardiac thrombi in 82 patients. They attempt to define their respective diagnostic values in the presence of left ventricular and atrial thrombi.
The prognosis of monomorphous, sustained, non-iatrogenic ventricular tachycardia was studied in 86 patients followed up for a mean period of 42.8 months. The patients were divided into three groups as follows: group I, 46 patients with myocardial infarction beyond the acute phase; group II, 30 patients with non-ischaemic heart disease; group III, 10 patients without heart disease detectable at angiography and/or echotomography. Fifty patients died during the follow-up period. Forty (80 p. cent) of these deaths (26 in group I, 14 in group II) were due to cardiac causes: heart failure in 24 cases, sudden death in 15 cases, recurrent myocardial infarction in 1 case. The percentage of cardiac death was higher in patients with left ventricular dysfunction (66 p. 100 versus 15.2 p. 100) and when the ejection fraction was below 0.40 (52.9 p. 100 versus 11.8 p. 100). The proportion of sudden death was 66.7 p. 100 when Lown's grade IV ectopic rhythm persisted under treatment, and only 7.7 p. 100 when this was not the case (p less than 0.001). These results confirm that: ventricular tachycardia has a high mortality rate in patients with heart disease; ventricular tachycardia on a "healthy" heart is of good prognosis; left ventricular dysfunction and persistence of repetitive forms under treatment have a high predictive value for cardiac death.
Two-dimensional echocardiography and indium 111-labelled platelet scintigraphy have proved helpful in the diagnosis of left intraventricular thrombosis. In this study, both methods were used to investigate the time-related changes undergone by such thrombi in 30 patients (26 with myocardial infarction, 4 with dilated cardiomyopathy) who presented with left intraventricular thrombosis diagnosed by echocardiography and systematically explored by indium scintigraphy. These 30 patients were divided into 2 groups depending on whether the initial scintigraphy was positive (group I, 19 patients) or negative (group II, 11 patients). The follow-up (mean 21.6 months) was clinical and paraclinical, with control echocardiography repeated at 1.5 and 8.5 months in both groups and control scintigraphy at 1.5 month in group I patients. At the 1.5 month echocardiography, the intraventricular thrombosis persisted in 14/16 examinations in group I patients and in only 2/10 examinations in group II patients (p less than 0.01). At the 1.5 month scintigraphy, performed in 16/19 group I patients, this examination had become negative in 8 cases, whereas the 2D-echocardiography remained positive. During the follow-up period 4 patients in group I had an embolic accident, as against none of the group II patients (p less than 0.01); 3 of these 4 patients had persistent uptake at control scintigraphy. At echocardiography, only a protrusion image seemed to be predictive, as it was present in 3 of 4 patients with embolic accident.(ABSTRACT TRUNCATED AT 250 WORDS)
The primary structure of human apolipoprotein (apo) B-48 has been deduced and shown by a combination of DNA excess hybridization, sequencing of tryptic peptides, cloned complementary DNAs, and intestinal messenger RNAs (mRNAs) to be the product of an intestinal mRNA with an in-frame UAA stop codon resulting from a C to U change in the codon CAA encoding Gln2153 in apoB-100 mRNA. The carboxyl-terminal Ile2152 of apoB-48 purified from chylous ascites fluid has apparently been cleaved from the initial translation product, leaving Met2151 as the new carboxyl-terminus. These data indicate that approximately 85% of the intestinal mRNAs terminate within approximately 0.1 to 1.0 kilobase downstream from the stop codon. The other approximately 15% have lengths similar to hepatic apoB-100 mRNA even though they have the same in-frame stop codon. The organ-specific introduction of a stop codon to a mRNA appears unprecedented and might have implications for cryptic polyadenylation signal recognition and RNA processing.
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Studies of the structure and synthesis of cartilage proteoglycan core protein have been carried out. Deglycosylation of completed, secreted proteoglycan by HF-pyridine treatment yielded an intact homogeneous core protein of approximately 210,000 daltons, with a blocked amino-terminus. Greater than 95% of chondroitin sulfate chains and 80% of N- and O-linked oligosaccharides were removed by the procedure, which made the product an excellent xylosyltransferase acceptor. Little alteration of core protein structure occurred during the HF-pyridine treatment as shown by complete immunoreactivity with antiserums prepared against hyaluronidase-digested proteoglycan. In other studies, the initially synthesized precursor for proteoglycan core protein was found to be approximately 376,000 daltons and localized to the rough membrane fractions. This precursor already contained N-linked oligosaccharides, and was also able to accept xylose, thereby initiating chondroitin sulfate chains. The precursor was translocated intact in an energy-dependent manner to smooth membrane-Golgi fractions where further processing of high mannose type of oligosaccharides and addition of glycosaminoglycan chains occurred. The subcellular distribution pattern of the chondroitin sulfate-synthesizing enzymes corroborated the proposed topological modifications of the proteoglycan core protein precursor.
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Pulsed, continuous-wave, and color Doppler were performed in 165 normal mitral prostheses and 58 patients with prosthetic dysfunction (46 regurgitant and 12 obstructive valves) proved by catheterization and/or surgery. Mean mitral gradient (MG) and pressure half-time (PHT) were determined in all cases. Among normal prostheses, a wide range of both MG and PHT was observed in each type of valve and a considerable overlap between valves of different size. St-Jude's valve had the most optimal hemodynamics. Mild mitral insufficiency was detected in 14% of tissue and 24% of mechanical mitral valves. Repeat studies were performed in 30 patients over a 2.4 years period. Nine patients developed Doppler evidence of new prosthetic dysfunction, while Doppler parameters remained unchanged in 21 patients during the follow-up period. Among malfunctioning valves, Doppler correctly identified all cases of prosthetic obstruction (n = 12), and 42 of 46 regurgitant valves. We conclude that Doppler echocardiography is a very useful technique in both non-invasive assessment and follow-up of normal prosthetic valves in the mitral position and in detecting prosthetic dysfunction, especially when prosthetic obstruction is present.
A better knowledge of platelet activation mechanisms has made it possible to develop antiplatelet agents that are capable of inhibiting primary haemostasis at very precise levels. Many of these agents block the synthesis or receptor of an hemostasis I agonist. Thus, the thromboxane A2 receptor can be blocked, or its synthesis can be interrupted, by thromboxane synthetase inhibitors, by cyclooxygenase inhibitors, or by omega 3 fatty acids which are competitive inhibitors. Inhibitors of thrombin (hirudin), PAF acether and serotonin (ketanserin) also are available. Other antiplatelet agents secreted by endothelial cells act as haemostasis I antagonists by elevating platelet cAMP or cGMP levels (prostacyclins and analogues, nitrate derivatives). Monoclonal antibodies and RGD peptides directly inhibit the glycoproteins that are responsible for platelet adhesion or aggregation, but their users are faced with problems of cost and route of administration. Of all these new antiplatelet agents, only ticlopidine, which has an imperfectly known mode of action, has proved effective in multiple situations, but its use is limited by its side-effects.
A 22-year-old man had severe pulmonary congestion and required mechanical ventilation. Endocarditis was suspected because a 2/6 systolic murmur was heard at the apex and because Osler nodes were present. Transthoracic and transesophageal echocardiography allowed correct diagnosis of papillary muscle rupture causing massive mitral regurgitation. To our knowledge, this is the first reported case of papillary muscle rupture caused by bacterial endocarditis diagnosed by transthoracic and transesophageal echocardiography.