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Biomedical subjects

A Bloch

Publications and source records attributed to A Bloch.

At least 55 records · Page 3Linked to original sources
PubMed1995

Mitral regurgitation in patients with coronary artery disease and low left ventricular ejection fractions. How should it be treated?

In recent years, coronary artery bypass grafting has been extended to include patients with very low left ventricular ejection fractions. Should concomitant mitral valve regurgitation be corrected simultaneously? Between January 1990 and July 1994, 43 patients with preoperative left ventricular ejection fractions < or = 25% and echocardiographic evidence of concomitant mitral valve regurgitation (grade I, 18 patients; II, 19 patients; and III, 6 patients) underwent primary coronary artery bypass grafting. None of these patients underwent simultaneous mitral valve surgery. Twenty-four patients (56%) had pulmonary artery pressures > or = 40 mmHg (pulmonary hypertension). The mean preoperative left ventricular ejection fraction was 18.7% +/- 4.4% (range, 10% to 25%), and the mean pulmonary artery pressure was 45.6 +/- 15.8 mmHg. The average of number of grafts per patient was 4.5 +/- 1.5. Five patients underwent simultaneous repair of a left ventricular aneurysm. The hospital mortality rate was 4.7% (2/43). Transient low cardiac output occurred postoperatively in 13 patients (30%). Sixteen patients (37%) had no postoperative complications. The average follow-up of the 41 hospital survivors was 6 months (range, 1 to 32 months). One patient died 8 months after surgery for an overall mortality rate of 7%. Another 2 patients had graft occlusions that did not require reoperation. In the 40 surviving patients, follow-up echocardiography revealed that 37 patients (93%) had either no mitral valve regurgitation or only very mild mitral valve regurgitation (grade I). Three patients had grade II mitral valve regurgitation, but none required mitral valve surgery. The New York Heart Association functional class improved significantly in all hospital survivors (from 3.4 +/- 0.6 to 1.7 +/- 0.7; p > 0.001), and left ventricular ejection fractions rose from 19.0% +/- 4.6% to 42.0% +/- 8.3%. Coronary artery bypass grafting is possible in patients with very low left ventricular ejection fractions who present with 2- or 3-vessel disease, significant coronary artery stenoses (less than or equal 70%), and angina. The mortality rate is acceptable and morbidity is low. If there is no rupture of papillary muscle or chordae, concomitant ischemic mitral regurgitation (grades I through III) seems to return to normal after coronary artery bypass grafting and, therefore, does not need to be corrected surgically during the primary operation.

Adult↗
PubMed1995

Effect of low left ventricular ejection fractions on the outcome of primary coronary by-pass grafting in end-stage coronary artery disease.

Advanced ischemic heart disease (HID) with very low left ventricular ejection fraction (LVEF), pulmonary hypertension (PHT) with or/without left ventricular aneurysm (LVA) are criteria for defining end-stage coronary artery disease (ESCAD). Coronary artery by-pass grafting is often denied to these patients. Between January 1990 and December 1993, 91 patients with ESCAD, significant 2 or 3-vessel disease (stenosis > or = 70%) and LVEF < or = 25% underwent primary CABG at our institutions. The mean age was 62.5 +/- 8.0 years (41-81), 89% were men. Eighty-one patients were in preoperative NYHA (New York Heart Association) functional class 3 and 4. Mean LVEF was 21.3 +/- 3.8% (10-25). Mitral regurgitation (MR) was present in 39/91 (43%). The systolic pulmonary artery pressure (PAP) was 33.2 +/- 17.1 mmHg (11-75) and the wedge pressure was 19.0 +/- 10.8 mmHg (5-47). Twenty-two patients had significant PHT with a systolic PAP > or = 40 mmHg. The overall perioperative mortality was 14.3% (13/91). Low postoperative cardiac output occurred in 33 patients, requiring intraaortic balloon support in 13. Gastrointestinal complications occurred in 6 patients and neurological events in one. Fifteen patients had additional left ventricular aneurysm repair. There was a good correlation between LVEF and PAP (r = 0.782). Surprisingly, in a subset of patients with preoperative PHT and LVEF < or = 25% the mortality rate was only 4.6% (1/22). Other perioperative complications did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Should a mild to moderate ischemic mitral valve regurgitation in patients with poor left ventricular function be repaired or not?

In recent years coronary artery bypass grafting (CABG) has been extended to include patients with very low left ventricular ejection fractions (LVEF), also frequently with co-existing mild to moderate mitral valve regurgitation (MR). The question is, should such a MR be corrected simultaneously with a myocardial revascularization or not? Between January 1989 and November 1994, 56 patients with preoperative LVEF < or = 25% and echocardiographic evidence of co-existing MR (Grade I: 41%, II: 46%, III: 13%) underwent primary CABG. None of them had simultaneous mitral valve surgery. Twenty-nine patients (52%) had a pulmonary artery pressure (PAP) > 40 mmHg. The mean preoperative LVEF was 17.9 +/- 4.6 (10-25), mean PAP 44.2 +/- 16.1 mmHg. An average of 4.5 +/- 1.5 grafts/patient were placed and five patients had simultaneous repair of a post-infarction left ventricular aneurysm. The overall mortality was 3.6% (2/56). Transient post-operative low cardiac output syndrome occurred in 16 patients (29%). Twenty-one patients (38%) had no postoperative complications at all. The 54 hospital survivors were followed up over a mean period of 12 months (3-36 months). There was one death (eight months postoperatively) and two graft occlusions, not requiring reoperation. At the end of the follow up echocardiography showed that 50 patients (93%) had no (31 patients) or only a very mild Grade I MR (19 patients). Four patients had Grade II MR, none of them requiring mitral valve surgery. All patients improved their NYHA functional class, from 3.4 +/- 0.8 to 1.9 +/- 0.7 and LVEF from 17.9 +/- 4.6 to 44.2 +/- 7.4 (p < 0.001). Coronary artery bypass grafting is a possible treatment for patients with very low LVEF, provided the patient has a two- or three-vessel disease with significant coronary artery stenosis (> 70%) and angina. Mortality and morbidity are low. Moderate co-existing MR (Grade I-III) seems to normalize after myocardial revascularization and should not be surgically corrected therefore at the primary operation.

Adult↗
PubMed1994

Differential effect of growth- and differentiation-inducing factors on the release of eicosanoids and phospholipids from ML-1 human myeloblastic leukemia cells.

In the absence of serum, growth of ML-1 human myeloblastic leukemia cells is induced by the insulin-like growth factor-1 (IGF1) together with transferrin (Tf), whereas monocytic differentiation is initiated by the transforming growth factor-beta (TGF-beta) in combination with Tf. Initiation of growth was followed by the rapid release of arachidonic acid (AA), hydroxyeicosatetraenoic acids (HETEs) and phospholipids into the culture medium. In contrast, induction of differentiation occurred without the release of these lipids beyond the level present in control. Inhibitors of enzymes involved in the formation of AA and of HETEs, including phospholipase A2 and lipoxygenases, caused interference with growth but not with differentiation, and an inhibitor of the cyclooxygenase path affected neither growth nor differentiation. These results indicate that the initiation of ML-1 cell growth but not of cell differentiation is dependent upon the increased formation of AA and its derivatives formed primarily via the lipoxygenase path.

Arachidonic Acid↗
PubMed1994

Differential binding of nuclear c-ets-1 protein to an intron I fragment of the c-myb gene in growth versus differentiation.

For growth, ML-1 human myeloblastic leukemia cells require insulin-like growth factor 1 together with transferrin, whereas for differentiation they depend upon transforming growth factor beta in combination with transferrin. As shown in this study, growth stimulation is accompanied by c-myb expression, whereas initiation of differentiation results in the cessation of c-myb expression through premature termination of transcription in the first intron of the myb gene. Growth factor-stimulated c-myb elongation was found to correlate with an elevated level of nuclear c-ets-1 protein and with increased binding of this protein to an 18-base pair sequence in intron 1 of the c-myb gene containing the putative regulatory element PEA 3. In contrast, differentiation factor-initiated ML-1 cell maturation was accompanied by a very low level of nuclear c-ets-1 protein, by the inability to detect binding of the protein to the 18-base pair sequence, and by the cessation of c-myb expression. These results show a correlation to exist between c-ets-1 binding to intron 1 of the c-myb gene and c-myb expression. The mechanism underlying this correlation is under further study.

Base Sequence↗
PubMed1993

[Who should perform echocardiograms?].

This question falls into two parts: 1. Should echocardiography be reserved to cardiologists? We believe that only physicians with extensive training in cardiology and echocardiography are able to derive maximum information from echocardiograms. 2. Should echocardiography be performed by technicians, under the control and responsibility of well-trained physicians? This practice prevails in the majority of big centers in the United States. However, a study performed among the members of the Swiss Working Group of Echocardiography shows that this is rarely the case in Switzerland (14/145 = 10%). This situation has several reasons: most Swiss cardiologists think that echocardiography should be reserved to themselves, that their annual number of studies is not sufficient to warrant a technician, and/or that they are unable to find trained technicians. Experience of physicians used to working with technicians is however very positive. A prospective study reported here shows that the percentage of mistaken recordings or interpretations is low. Cooperation with well-trained technicians allows good-quality work, saves the physicians' time, facilitates research projects and contributes to the training of future cardiologists in echocardiography.

Cardiology↗
PubMed1993

[From cardiac auscultation to echo-Doppler. Limitations of both methods].

Physiological tricuspid and pulmonary regurgitations are very often found by Echo-Doppler. They are generally slight, inaudible and devoid of significance. Tricuspid insufficiency nevertheless has the great advantage of enabling the calculation of pulmonary pressures. Auscultation is a good method for the diagnosis of rheumatic mitral insufficiency or related to prolapse, but is not reliable in other situations. Doppler is an excellent method for the qualitative and etiological diagnosis of mitral insufficiency but enables only semi-quantification. It also has the disadvantage of discovering minimal mitral insufficiency, the significance of which is uncertain. In contrast to auscultation, Doppler enables precise quantification in mitral stenosis. Auscultation is a good method for the diagnosis of aortic valve disease with the exception of slight insufficiency and stenosis in the elderly. Doppler enables the quantification of stenosis and semi-quantification of insufficiency. The existence of physiological aortic regurgitation is by no means certain. In conclusion, auscultation remains an important tool in cardiological diagnosis but has notable limitations. Echo-Doppler is a major advance but it is important to be aware of its limitations.

Echocardiography, Doppler↗
PubMed1993

[Mid-term clinical and prognostic evaluation of idiopathic atrial fibrillation].

Forty-six patients with idiopathic or lone atrial fibrillation (AF) underwent clinical evaluation in the cardiology outpatient department. The follow-up period was 4.6 +/- 2.5 years. The prevalence of idiopathic AF was 19% (89% paroxysmal and 11% permanent) in a population of 244 patients with atrial fibrillation. The global prevalence was 1.15% out of 4,000 patients examined over the same period. A history of paroxysmal atrial fibrillation over a 6 +/- 4 year period was obtained in 61% of the patients with idiopathic AF before the study. At inclusion, 24% of patients were asymptomatic. During follow-up, 12 patients (26%) developed cardiovascular disease and/or hypertension. The size of the left atrium was measured by echocardiography in 45 patients and reevaluated in 30 of them during follow-up without any statistically significant difference being observed between the two values. There were no thromboembolic complications or deaths during follow-up. These results show that idiopathic AF is not uncommon in cardiology clinics. The evolution of the paroxysmal forms is variable--but the medium-term prognosis is excellent. In some cases, idiopathic AF may be a manifestation of asymptomatic coronary artery disease but the relationship between the two pathologies has not been definitely established.

Adult↗
PubMed1993

Dynamics of interaction between DNA-specific antitumor agents and serum-contained cytokines in the initiation of ML-1 human myeloblastic leukemia cell differentiation.

When added to RPMI-1640 medium containing fetal bovine serum, DNA-directed antineoplastic agents such as cytosine arabinoside (araC), daunorubicin, and actinomycin D induce the monocytic differentiation of ML-1 human myeloblastic leukemia cell populations to an extent that depends upon both drug and serum concentration. Differentiation is not induced in the absence of serum or when antibodies to tumor necrosis factor-alpha and transforming growth factor-beta are added to the cultures, indicating that these serum-contained cytokines participate in initiating the differentiation process. The drug- and cytokine-dependent cell maturation, which results in the inhibition of leukemic cell growth, is achieved at much lower concentrations of drug than is required for growth-inhibition through drug-mediated cell kill. RNA- and protein-targeted agents cannot replace DNA-specific agents in the process of differentiation-induction. The DNA-specific agents render the leukemic cells responsive to the low concentrations of differentiation-inducing cytokines that are present in serum, causing them to mature, and subsequently, to cease growth. This sensitization may be a component of the clinically selective action of DNA-specific antitumor agents.

Animals↗
PubMed1992

[Complementary information from Doppler echocardiography in the electrocardiogram in the basic assessment of chronic coronary heart disease, especially following a myocardial infarct. Observations from an ambulatory cardiology clinic].

In chronic ischemic heart disease, Doppler echocardiography (DE) at rest permits semiquantitative evaluation of scarring and remodelling processes, global ventricular function and, frequently, regional wall motion state. Late complications are detected, namely infarct expansion, true and false ventricular aneurysm, mitral insufficiency, thrombus formation, and associated valvular and aortic diseases are discovered. We studied 100 patients with known chronic coronary artery disease referred for noninvasive evaluation, including electrocardiogram (ECG) and DE. In all patients, the global left-ventricular function was satisfactorily assessable. In roughly two thirds of the documented infarctions. DE confirmed the ECG diagnosis and permitted a more precise diagnosis in the majority of them in terms of localization and/or dimension of the necrosis. In one third of the patients. DE clarified inconclusive ECG tracings. Thus, the baseline noninvasive investigation with ECG and DE is a potent tool in the management of chronic ischemic heart disease, serving as a guide to further investigation and to treatment adjustments.

Adult↗
PubMed1992

[Do dentists enforce correctly the recommendations for prophylaxis of bacterial endocarditis?].

Recommendations for the prophylaxis of infective endocarditis have been published by working groups in several countries. We performed an enquiry amongst 276 dentists in Geneva to evaluate how the Swiss recommendations were applied. Of the 183 dentists who answered, the majority knew that extraction (85%) or scaling (76%) required prophylaxis. They correctly prescribed antibiotics to patients with valve prostheses (84%), to those with rheumatic heart disease (80%), a previous history of endocarditis (73%) or congenital heart disease (49%). Not conforming to the recommendations, many dentists considered that coronary bypass surgery (40%), mitral valve prolapse without mitral regurgitation (30%) or previous myocardial infarction (22%) also required antibiotic prophylaxis. Only 34% of dentists used the recommended 3 g of amoxicillina, the others preferring a lower dose of another antibiotic. About one third started prophylaxis 1 to 3 days too early and less than 20% used the suggested single dose of antibiotics. These results showed that dentists caring for cardiac patients should be better informed of the risks of endocarditis and its prevention. We make a few suggestions to improve antibiotic prophylaxis.

Amoxicillin↗
PubMed1991

Identification of transferrin as a progression factor for ML-1 human myeloblastic leukemia cell differentiation.

We have previously demonstrated (Guan X.-P., Hromchak, R. A., and Bloch, A. (1989) Cancer Commun. 1, 111-115) that ML-1 human myeloblastic leukemia cells differentiate to monocyte/macrophage-like cells by the sequential action of competence and progression factors. Tumor necrosis factor-alpha, transforming growth factor-beta, and the phorbol ester tetradecanoylphorbol acetate were found to induce competence, whereas a 77-kDa glycoprotein (DF77) isolated from mitogen-stimulated human leukocyte-conditioned medium initiated progression. In this communication we show DF77 to be an isoform of human transferrin. Hemin or soluble iron complexes did not induce differentiation progression, suggesting that the participation of transferrin in ML-1 cell differentiation may not be related to its iron-carrying capacity.

Amino Acid Sequence↗