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Biomedical subjects

J L Hebert

Publications and source records attributed to J L Hebert.

16 recordsLinked to original sources
PubMed2004

[Arrhythmogenic right ventricular dysplasia].

Congestive cardiac failure could be as important as cardiac arrhythmias in the natural history of arrhythmogenic right ventricular dysplasia. This can be related to the progressive replacement of myocardium by fat and fibrosis of the right ventricle. The left ventricle may also be involved by the same disease process. Moreover, inflammation can be superimposed on ARVD, resulting in a wide spectrum of clinical presentation which can mimick idiopathic dilated cardiomyopathy. Right ventricular cardiac failure has been controlled by anterior dynamic cardiomyoplasty.

Arrhythmogenic Right Ventricular Dysplasia↗
PubMed1998

Mutation of the mouse hepatocyte nuclear factor/forkhead homologue 4 gene results in an absence of cilia and random left-right asymmetry.

Winged helix transcription factors play important roles in cellular differentiation and cell-specific gene expression. To define the role of the winged helix factor hepatocyte nuclear factor/forkhead homologue (HFH)-4, a targeted mutation was created in the mouse hfh-4 gene. No expression of HFH-4 was detected in hfh-4(-)/- mice by RNA blot analysis, in situ hybridization, or RT-PCR. hfh-4(-)/- mice were noted to have abnormalities of organ situs consistent with random determination of left-right asymmetry. In addition, a complete absence of cilia was noted in hfh-4(-)/- mice. The hfh-4 gene is thus essential for nonrandom determination of left-right asymmetry and development of ciliated cells. Homozygous mutant mice also exhibited prenatal and postnatal growth failure, perinatal lethality and, in some cases, hydrocephalus. RT-PCR revealed an absence of left-right dynein (lrd) expression in the embryonic lungs of hfh-4(-)/- mice, suggesting that HFH-4 may act by regulating expression of members of the dynein family of genes. The abnormalities in ciliary development and organ situs in hfh-4(-)/- mice are similar to those observed in human congenital syndromes such as Kartagener syndrome. Targeted mutation of hfh-4 thus provides a model for elucidating the mechanisms regulating ciliary development and determination of left-right asymmetry.

Abnormalities, Multiple↗
PubMed1995

Facilitating changes in exercise behavior: effect of structured statements of intention on perceived barriers to action.

Two groups of worksite employees (58 in a control, 53 in an experimental group) underwent three 90-min. educational sessions designed to increase participation in exercise. At the end of the third session, experimental subjects were asked to complete a structured statement of exercise intention which addressed the major barrier to exercise. Two weeks following the program, chi-squared analysis showed that the two groups were proportionately different in changes in frequency and intensity of exercise such that the experimental group in both cases showed greater changes than the control. Experimental subjects showed a twofold increase in frequency and intensity of exercise over the control group. Pearson r indicated a statistically significant association between the completeness of structured statements of intention and an increase in frequency of exercise. We conclude that structured statements of intention are useful for distinguishing between contrived barriers to exercise (excuses) and actual barriers that require practical solutions.

Adult↗
PubMed1994

Left ventricular function during weaning of patients with chronic obstructive pulmonary disease.

OBJECTIVE: Determine the evolution of left ventricular ejection fraction during weaning. DESIGN: Prospective study. SETTING: Intensive care unit of a university teaching hospital. PATIENTS AND PARTICIPANTS: 12 consecutive mechanically ventilated patients, without documented coronary artery disease, suffering from acute exacerbation of chronic obstructive pulmonary disease and able to be weaned. MEASUREMENTS AND RESULTS: Left ventricular ejection fraction was determined during mechanical ventilation, inspiratory pressure support (10 cmH2O) and spontaneous ventilation with constant inspiratory oxygen fraction using technetium 99m radionuclide angiography. Spontaneous ventilation induced a significant decrease in left ventricular ejection fraction from 54.5 +/- 12.4 to 47.0 +/- 13% (p < 0.01). Inspiratory pressure support induced a slight but non-significant decrease in left ventricular ejection fraction from 55.0 +/- 12.1 to 50.3 +/- 12.4%. Left ventricular ejection fraction was homogeneously reduced by spontaneous ventilation without patent regional wall motion abnormalities of the left ventricle. Myocardial 201thallium imaging performed 15 min after weaning showed a normal perfusion in the left ventricle anterior and posterior free wall. CONCLUSION: Weaning of patients suffering from chronic obstructive pulmonary disease without coronary artery disease induced a significant reduction in left ventricular ejection fraction. The non significant decrease in left ventricular ejection fraction observed with inspiratory pressure support suggested that our results might be explained by a weaning induced increase in afterload.

Acute Disease↗
PubMed1991

[Fortuitous discovery of the association of true and false aneurysm of the left ventricle after cardiogenic shock].

The authors report the fortuitous diagnosis of a true and a false left ventricular aneurysm in a 77 year old man with severe ischaemic heart disease and calcific aortic stenosis, admitted for cardiogenic shock. The association of these two forms of aneurysm is very rare. Clinical and paraclinical diagnosis is difficult. Conventional left ventriculography is the investigation of reference but the diagnosis has been facilitated by Technetium 99 cardiac scintigraphy and color Doppler echocardiography. Surgery may be considered in cases of true aneurysm especially in patients with left ventricular failure, but the indication is formal in cases of false aneurysm.

Aged↗
PubMed1991

[Coronary spasm and diffuse coronary vasoconstriction responsible for transient left ventricular insufficiency].

A 52 year old patient presenting with spontaneous anginal chest pain for 4 days was admitted to hospital for a more intense and prolonged chest pain associated with signs of left ventricular failure (gallop, pulmonary crepitations, hypoxemia). Coronary angiography showed marked septal hypokinesia and spontaneous localised spasm of the left anterior descending and marginal arteries with a variable degree of luminal narrowing of the other segments of these two arteries and of the right coronary artery. These changes regressed after intracoronary injection of molsidomine. The signs of left ventricular failure disappeared in 48 hours. The wall motion abnormality, monitored by 2D echocardiography, regressed slowly over 3 days. On the other hand, the electrocardiogram, which showed anterior wall subendocardial ischaemia with prolongation of the QTc interval during the spasm, remained abnormal for a long time. Therefore, in the absence of organic heart disease, coronary spasms associated with vasoconstriction can induce a sufficiently severe and durable alteration of left ventricular function to create clinical signs of cardiac failure and profound and prolonged ST-T wave changes on the electrocardiogram.

Coronary Angiography↗
PubMed1989

Percutaneous brachial approach for transluminal coronary angioplasty.

Transluminal coronary angioplasty from the arm is performed generally with cutdown and brachial arteriotomy. We describe a brachial percutaneous technique for coronary angioplasty, almost similar to the femoral one, with a special focus on the prevention of induced vasoconstriction. Our preliminary results are satisfactory and without complications: 13 procedures in 11 patients have been performed over a 30 month period, with the sheaths left in place for 4-6 h after the procedure. This method could be an easy alternative to the Sones technique for operators who are essentially familiar with the femoral percutaneous arterial approach.

Aged↗
PubMed1986

Cigarette smoking during coronary angiography: diffuse or focal narrowing (spasm) of the coronary arteries in 13 patients with angina at rest and normal coronary angiograms.

To evaluate the acute effects of cigarette smoking on coronary arteries (CA), repeated coronary angiograms were performed in 13 patients with angina at rest and with normal coronary angiograms at basal state, during smoking, and then after methylergometrine (MEM) and after intracoronary nitroglycerin. Smoking induced anginal pain in three patients, triggered spasm (focal narrowing) in six, and/or an abnormal segmental diffuse narrowing (greater than 30%) in eight. The narrowing of the left CA was on average -21 +/- 13% (P less than 0.001), with more important narrowing of the mid-left anterior descending (-29 +/- 19%, P less than 0.001). The mean of the maximal segmental narrowing by patient was -34 +/- 13% (P less than 0.001). MEM produced similar effects and induced focal CA spasms in nearly the same patients at the same sites. Cigarette smoking may induce vasoconstrictive effects on CA in patients with rest angina and normal coronary angiograms. This action is not dose-dependent and may be initiated by less than one cigarette. These observations offer a new perspective for the understanding of the role of smoking in the precipitation of coronary events.

Adult↗
PubMed1985

Percutaneous brachial approach using the femoral artery sheath for left heart catheterization and selective coronary angiography.

A percutaneous method via the brachial artery for left heart catheterization and selective coronary angiography is described. The technique uses the sheath intended for the femoral artery, continuously infused and introduced following a particular technique. The procedure was performed with minimal complications over 18 months, with multipurpose "Schoonmaker" or preshaped catheters, in all the patients (37) in whom the femoral approach was contraindicated or failed. When a catheterization must be performed from the arm, this method, without cutdown and arteriotomy and allowing a good distal flow during the procedure, appears to have some advantages over the classical Sones technique or the percutaneous arterial axillary approach.

Aged↗
PubMed1985

[Hypertrophic myocardiopathy with isolated obstruction of the right ventricle].

The authors report one case of biventricular hypertrophic cardiomyopathy in a 23 year old female patient with severe localized obstruction of the right ventricle (105 mm Hg gradient, almost complete angiographic disappearance of the middle and apical portions of the right ventricle during systole). Echocardiography, hemodynamic findings, and angiography demonstrated nonobstructive involvement of the left ventricle. Among other family members, only her father was noted to have minimal hypertrophic cardiomyopathy. A favorable response to therapy was obtained over 14 months with 320 mg of propranolol given daily (disappearance of palpitations and ventricular tachycardia which had previously been noted on a continuous 24 hour recording before treatment). Other very rare similar cases in the literature are analyzed. It is not possible to distinguish these cases from those with predominantly left ventricular involvement by clinical and radiological findings alone. However, the ECG can often demonstrate right ventricular involvement (right ventricular hypertrophy and/or right bundle branch block). Lastly, it appears that biventricular hypertrophic cardiomyopathies in young patients can initially be localized to only the right ventricle.

Adult↗
PubMed1980

Comparison of hemodynamic effects of furosemide and piretanide in normovolemic patients.

The effects of furosemide and piretanide (Hoe 118) on the pulmonary hemodynamics in 20 patients recovering from uncomplicated myocardial infarctions were compared in a double-blind study. The diuretic effects and half-lives of the two drugs were not significantly different, so that their hemodynamic actions could be compared directly. Both drugs progressively reduced cardiac output and pressures in the pulmonary circulation, whereas systemic vascular resistance increased significantly. Both drugs slightly increased pulmonary blood volume but not significantly. Total blood volume decreased less rapidly than cardiac output, so that the ratio of cardiac output to total blood volume decreased with time. We conclude that both drugs increase venous compliance in normovolemic subjects and probably increase the compliance of pulmonary vessels.

Blood Pressure↗
PubMedDate not supplied

Effects of intravenous diltiazem on sinus node function and atrioventricular conduction in patients.

We studied the electrophysiologic effects of injectable diltiazem (dosage: bolus of 0.15 mg/kg, maintenance infusion of 0.3 mg/kg/h for 20 min) on sinus node function and atrioventricular function in 33 patients (22 men and 11 women, mean age 63.6 +/- 15.8 years). Seventeen patients had an electrophysiological exploration considered as normal, eight had sinus node dysfunction (corrected sinus recovery time greater than 525 ms), and eight had AV nodal block (PH greater than 160 ms and/or a Wenckebach point less than 125/min). Effects of the drug were assessed 20 min after the beginning of the infusion, which was continued until the end of examination. In normal subjects diltiazem lengthened corrected sinus node recovery time (305 +/- 115 ms leads to 451 +/- 283 ms) and slightly depressed AV nodal conduction (Wenckebach point: 163 +/- 23 leads to 147 +/- 25). In patients with sinus node dysfunction diltiazem provoked a bradycardia without significant changes in corrected sinus node recovery time or in estimated atrio-sino-atrial conduction time. In patients with AV nodal block diltiazem provoked a lowering of the Wenckebach point (137 +/- 47 leads to 122 +/- 38). There was no effect on hissian or infrahissian conduction, even when this was abnormal in the basal state. These data suggest that diltiazem must be utilized with caution in patients with sinus node dysfunction and AV nodal block.

Aged↗
PubMedDate not supplied

Chemoprevention of basal cell carcinomas in the ptc1+/- mouse--green and black tea.

Skin cancers are a rising menace as their incidence increases, attributed in part to increasing ultraviolet radiation exposure. This increasing problem has stimulated efforts to devise useful preventive approaches. The uncertain efficacy of exhortations to avoid sun exposure and to use protective clothing and sunscreens to reduce damage when exposed argue for the development of an oral chemopreventive agent. Bickers and others have studied the effects and mechanisms of tea and of its putative active components on inhibition of skin cancer in experimental models. To continue this work, we have studied the effects of oral green tea and black tea on a new model of ultraviolet-induced skin carcinogenesis - the development of basal cell carcinomas in ptc1+/- mice. To our surprise, we have found that tea preparations which others have used to prevent squamous cell carcinoma formation in mice fail to inhibit basal cell carcinogenesis in our model, suggesting that prevention of this cancer may require special, tumor-specific approaches.

Alleles↗