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Biomedical subjects

E Teiger

Publications and source records attributed to E Teiger.

47 records · Page 3Linked to original sources
PubMed1995

Comparison of the effects of exercise and cold pressor test on the vasomotor response of normal and atherosclerotic coronary arteries and their relation to the flow-mediated mechanism.

This study was designed to assess the vasomotor response of coronary arteries to exercise and the cold pressor test, and its relationships with the endothelium-mediated dependent mechanism. Twenty-two patients were entered in the study. Group I was composed of 12 patients with a total cholesterol level < 200 mg/dl associated with angiographically smooth, normal coronary arteries. Group 2 consisted of 10 patients with both a cholesterol level > 240 mg/dl and angiographic luminal irregularities of the left anterior descending coronary artery. Coronary blood flow was assessed by a 0.018-inch tip guidewire during Doppler ultrasonography, and analysis of the coronary arterial dimension of the midportion of the left anterior descending coronary artery was performed by quantitative coronary angiography. Catecholamine concentrations were assessed at the different stages of the protocol. The rate-pressure product increased during both the cold pressure test and exercise (p < 0.001). Coronary blood flow velocity increased during the cold pressor and exercise tests by 24.5 +/- 10% and 72 +/- 42%, respectively (p < 0.001), and by 127 +/- 62% (p < 0.0001) after administration of papaverine. In group 1, the cold pressor test had a more pronounced vasodilating effect on epicardial coronary arteries (+11.2 +/- 16%) compared with group 2 (-2 +/- 9%, p < 0.05). Similarly, exercise had a vasodilating action in group 1 (11.3 +/- 15%) compared with group 2 (-1.9 +/- 8%, p < 0.05). Both responses were highly correlated (r = 0.92, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Apoptosis in target organs of hypertension.

Apoptosis or programmed cell death frequently parallels abnormalities in cell proliferation and differentiation. As hypertrophy/hyperplasia or remodeling occurs in organs affected by hypertension, we evaluated the degree of apoptosis in the heart, kidney, and brain in situ in genetically hypertensive mice and rats as well as in cultured vascular smooth muscle cells. Apoptosis was characterized by morphological features, DNA fragmentation, and laddering as well as by terminal deoxynucleotidyl transferase labeling of the 3' OH ends of both extracted DNA and tissue sections. The present report provides the first evidence of increased apoptosis in whole organs of genetically hypertensive rat and mouse strains: in the heart of spontaneously hypertensive rats (SHR) and in the heart (ventricular cardiomyocytes), kidney (inner cortex and medulla), and brain (cortex, striatum, hippocampus, and thalamus) of spontaneously hypertensive mice, with a higher effect of apoptotic inducers in cultured aortic smooth muscle cells derived from SHR. Both types of known apoptotic processes, oligonucleosomal cleavage and large DNA fragmentation, were observed in vascular smooth muscle cells, but only the former appeared to be increased in SHR. This study underlines the importance of cell death dysregulation in hypertension, reveals a new route for investigation of the pathogenesis of hypertension, and suggests novel targets of therapeutic intervention.

Animals↗
PubMed1995

[15 years of coronary angioplasty: focus on the different techniques].

The growth of transcutaneous coronary angioplasty in the 1980s and early 1990s was particularly rapid, as about 42,000 procedures were performed in France in 1994. This treatment for coronary atherosclerosis now constitutes a valid alternative to surgical or medical treatment. New treatment modalities for coronary atherosclerosis have been added to the original balloon technique. Two types of coronary angioplasty can now be performed depending either by flattening and crushing the atheroma against the arterial wall (balloon, stent) or by destroying and fragmenting it (Rotablator, Laser, directional atherectomy). Among these new instruments, vascular stents have reduced the incidence of restenosis and have improved the safety of interventional cardiology, while others, such as Rotablator and Laser, allow the treatment of lesions inaccessible to the balloon. Directional atherectomy, by allowing specific excision, will occupy an important place in future developments of interventional cardiology, which is still a relatively young specialty.

Angioplasty, Balloon, Coronary↗
PubMed1993

Triiodothyronine therapy in open-heart surgery: from hope to disappointment.

A controversy persists as to whether cardiopulmonary bypass (CPB) decreases plasma levels of triiodothyronine (T3), thereby justifying peri-operative administration of T3 to improve haemodynamic recovery. To examine the effects of T3 therapy on post-CPB haemodynamics and to determine whether the potential inotropic effects of T3 are mediated by an increase in beta-adrenergic responsiveness, a prospective, randomized, double-blind, placebo-controlled study was performed in 20 patients undergoing cardiac surgery with CPB. T3 or placebo solution (10 patients in each group) was given intravenously at the time of aortic unclamping and 4, 8, 12 and 20 h thereafter. End points included (1) thyroid hormone levels measured by radioimmunoassay (2) standard haemodynamic parameters (3) the density of lymphocyte beta-adrenoceptors measured by a radioligand (125I-iodocyanopindolol) binding technique. Post-CPB values (cross clamp removal) of T3 (pg.ml-1) were not significantly decreased compared with pre-CPB values: 3.3 +/- 0.2 vs 3.1 +/- 0.2 in controls and 3.3 +/- 0.4 vs 3.7 +/- 0.6 in T3-treated patients, respectively. The haemodynamic parameters were no different between the two groups at any postoperative time point. Likewise, density and affinity of lymphocyte beta-adrenoceptors were not significantly different from pre-operative values in either group. Thus, there seems to be no sound justification for a routine use of T3 in patients undergoing open-heart procedures.

Adult↗
PubMed1992

[Hemodynamic study of intravenous milrinone in 26 patients with NYHA class III or IV cardiac failure].

The hemodynamic effects of milrinone (WIN 47203) were studied in 26 NYHA Class III or IV patients. The compound was administered intravenously using a protocol including an initial push dose of 50 micrograms/kg in 10 min, followed by a 24 hour infusion at the dose of 0.5 microgram/kg/min. Maximal response was obtained after 15 min and persisted during the infusion: cardiac index increased from 2.08 +/- 0.36 l/min/m2 to 3.09 +/- 0.68 l/min/m2, while capillary pressure fell from 25 mmHg to 16-17 mmHg. These variations were significant (p = 0.01). Heart rate was stable. Mean peripheral blood pressure fell modestly (6%). Systemic vascular resistance fell by 30% and pulmonary vascular resistance by 20%. All these results confirmed the beneficial effect of this inotropic agent administered intravenously. The increase in ventricular premature contractions noted by many justifies the careful surveillance of these patients by monitoring.

Adult↗
PubMed1991

Alterations in beta adrenergic and muscarinic receptors in aged rat heart. Effects of chronic administration of propranolol and atropine.

The cardiac responses to sympathetic and vagal stimulations are attenuated with ageing. To understand these findings, the densities of beta adrenergic (beta R) and muscarinic (MR) receptors in the left ventricles have been quantitated in parallel in male Wistar rats (4- and 24-month-old) using [125I]iodocyanopindolol and [3H]quinuclidinyl benzilate as specific radioligands. The homologous regulation of these receptor densities was also explored after a 7-day continuous infusion of propranolol or atropine. As compared to young rats, the beta R and MR densities in aged animals were decreased (from 31 +/- 2 to 23 +/- 2 fmol/mg protein, P less than 0.05 for beta R; from 104 +/- 7 to 54 +/- 3 fmol/mg protein, P less than 0.001 for MR) but the diminution in MR was more pronounced (-48%) than that in beta R (-26%), resulting in a drop in the beta R/MR ratio. Continuous infusion of propranolol or atropine up-regulated the beta R and MR densities (respectively +50%, P less than 0.01 and +33%, P less than 0.05) in aged but not in young adult rats. We therefore conclude: (i) that the diminution of the cardiac response to the sympathetic and vagal stimulations during ageing may be partly explained by a decrease in the corresponding receptor density; (ii) these changes are reversible and the density of these two groups of receptors can return to adult control values by chronic administration of the appropriate antagonist.

Aging↗
PubMed1990

[Frequency of painless myocardial ischemia during hemodialysis in 50 patients with chronic kidney failure].

The authors carried out a prospective study to determine the frequency of silent ischemia (SI) in 50 consecutive patients with end stage renal failure during dialysis by Holter monitoring. Twenty patients had SI (40%). This event was related to the number of cardiovascular risk factors (p = 0.0025), principally diabetes, smoking and the underlying renal disease (p = 0.018), and to a history of coronary artery disease (p = 0.0015). Two patients died during the nine months follow-up period and both had SI on Holter monitoring. Dialysis therapy in anaemic patients may predispose to and facilitate the detection of myocardial ischemia by the simultaneous interplay of hypotension, hypovolemia, hypoxia and tachycardia. The detection of these ischemic events may allow identification of a subgroup of dialysis patients with a high cardiovascular risk. The prognosis of these patients and best therapeutic approach require further study.

Adult↗
PubMed1990

Iron chelation by deferoxamine inhibits lipid peroxidation during cardiopulmonary bypass in humans.

Iron catalysis is involved in oxygen-derived free radical generation and subsequent lipid peroxidation, which have been reported to occur during cardiopulmonary bypass in humans. We assessed the effects of the iron chelator deferoxamine on the susceptibility of circulating low density lipoproteins (LDLs) to induced peroxidation in 20 adult patients (10 controls and 10 treated) undergoing cardiopulmonary bypass for coronary or valve procedures. Deferoxamine was given both intravenously (30 mg/kg body wt, starting 30 minutes before bypass and extending for the next 4 hours) and as an additive to the cardioplegic solution (250 mg/l). Blood samples were taken from both atria before and immediately after the end of cardiopulmonary bypass. Plasma lipid peroxidation was assessed by measuring spectrophotometrically the thiobarbituric acid reactive substances (TBARS) content of selectively isolated LDLs after their exposure to a peroxidizing agent. Before cardiopulmonary bypass, the right and left atrial blood values of LDL-TBARS were not significantly different between the two groups. Cardiopulmonary bypass resulted in a lipid peroxidation of significantly greater magnitude in control than in treated patients. Postbypass right atrial values for LDL-TBARS (expressed in mumol/mmol LDL-phospholipids) were 45.7 +/- 17.2 (mean +/- SEM) in control patients and 6.9 +/- 2.9 in treated patients (p less than 0.02), whereas in the left atrial blood, LDL-TBARS yielded values of 62.7 +/- 20.5 and 10.3 +/- 3.9, respectively (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Bypass↗
PubMedDate not supplied

[Physiopathology of unstable angina].

The major risk of atherosclerotic disease is the occurrence of an acute coronary syndrome. The pathogenesis of instable angina involves the formation of an arterial thrombus as a consequence of the rupture of an atheromatous plaque. This risk of plaque rupture appears to depend on plaque morphology rather than plaque size or severity of stenosis. Ratio of lipid core to fibrous determined by the balance between smooth muscle cells proliferation and extracellular matrix synthesis stabilizing the plaque and macrophages which degrade collagen, determine the plaque vulnerability. The fibrous cap weakness leads to the plaque activation, plaque fissure or erosion activating a thrombotic cascade. A general inflammation or prothrombotic states are probably involved suggesting the need for a systemic therapeutic in addition with the treatment of the culprit lesion.

Angina, Unstable↗
PubMedDate not supplied

[Silent myocardial ischemia during hemodialysis in patients with chronic renal insufficiency].

A prospective search for episodes of silent myocardial ischaemia (SMI) was carried out during sessions of haemodialysis in 62 patients with chronic renal failure and was positive in 37.1% of the cases. The occurrence of SMI is correlated with the number of cardiovascular risk factors (p = 0.008) and particularly with diabetes (p = 0.012), smoking (p = 0.007) and age (p = 0.02), as well as with the type of nephropathy that had caused the renal failure (p = 0.02). During a 6-month follow-up two patients died; both had silent myocardial ischaemia on Holter recordings. In these anaemic patients, haemodialysis might sensitize the detection of ischaemia by the concomitant occurrence of hypotensive, hypovolaemic or hypoxic episodes, thus playing a aggravating role. The existence of such episodes characterizes a subgroup of patients at high cardiovascular risk for whom the prognosis and the best therapeutic approach remain to be determined.

Adult↗