[Contribution of Doppler echocardiography in the evaluation of normal and pathologic aortic valve prosthesis]. / Apport de l'échocardiographie-Doppler dans l'évaluation des prothèses aortiques normales et pathologiques.

Doppler echocardiography was performed in 112 patients with normal aortic valve prostheses and 13 patients with dysfunction (3 obstructions, 10 regurgitations) confirmed at catheterisation and/or surgery. The maximum and mean transprosthetic pressure gradients were measured in all patients by continuous wave Doppler. The prosthetic valve surface area was calculated by applying the continuity equation in the last 67 patients and compared with the effective surface area deduced from hemodynamic studies in the literature: --There was a great variability in the values of mean pressure gradient and prosthetic valve area within each group and with each size of prosthesis in patients with normal valves. No significant difference was observed between the gradients of different prostheses. However, for a given size, the St Jude Medical prosthesis had larger calculated surface areas than the other prostheses. The Doppler valve surface area did not differ significantly from the area measured invasively for the different categories of prostheses, and it increased with the size of the prosthesis. Mild aortic regurgitation was observed in 16 per cent of bioprostheses and 30 per cent of mechanical prostheses. The three cases of obstruction were characterised by a high mean pressure gradient (59 +/- 16 mmHg, p less than 0.01 vs normal prostheses) and a reduced Doppler surface area (0.7 +/- 0.2 cm2, p less than 0.005 vs normal prostheses) and were correctly diagnosed by Doppler echocardiography. Eight of the ten prosthetic regurgitations were correctly quantified by Doppler. Cardiac Doppler coupled with echocardiography is a very valuable method of non-invasive assessment of aortic valve prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

[Contribution of Doppler echocardiography to the evaluation and monitoring of normal and pathologic mitral valve prostheses]. / Apport de l'échocardiographie-Doppler dans l'évaluation et la surveillance des prothèses mitrales normales et pathologiques.

Doppler echocardiographic examinations were performed in 146 patients with normal and 42 patients with pathological (31 regurgitations and 11 obstructions) mitral valve prostheses confirmed by catheterisation and/or surgery. The maximum and mean transprosthetic gradients and pressure half times (PHT) were calculated from continuous wave Doppler recordings and regurgitant signals were searched for by continuous and pulsed wave Doppler. In the group of normal mitral valve prostheses, the mean gradients and PHT were very variable even within the subgroups of the same type and size of prosthesis. The best haemodynamic profile was observed with the St Jude prosthesis (mean gradient = 5 +/- 2 mmHg, PHT = 90 +/- 22 ms, p less than 0.05 vs other prostheses). Minimal mitral regurgitation was detected in 12 per cent of bioprostheses and 20 per cent of mechanical prostheses. No correlations were found between the mean pressure gradient or PHT and the size of the prostheses. Regular Doppler echocardiographic follow-up over 2.4 years was obtained in 25 patients and showed a remarkable stability of the Doppler parameters in 17 patients whereas prosthetic valve dysfunction was diagnosed in the other 8 cases. In the group of pathological mitral valve prostheses, regurgitation (N = 31) was associated with a high early diastolic pressure gradient (20.2 +/- 8 mmHg) and a normal or shortened PHT (84 +/- 28 ms). Obstructed prostheses (N = 11) had high mean pressure gradients (17 +/- 5 mmHg) and increased PHT (195 +/- 53 ms). All cases of obstruction were correctly identified by the Doppler but 4 prosthetic valve regurgitations were missed or underestimated (4 mechanical prostheses).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial natriuretic factor regulates the calcium current in frog isolated cardiac cells.

The effect of external application of synthetic atrial natriuretic factor (ANF) on calcium current (ICa) was studied in single cells isolated from frog ventricle using the whole-cell patch-clamp technique. Rat atriopeptin III (APIII) and 3-28 ANF rat (rANF) had negligible effects on basal ICa at concentrations up to 200 nM. However, when ICa was increased by isoprenaline, both peptides had significant inhibitory effects. rANF (3 nM) decreased isoprenaline-elevated ICa by an average of 33% after 3-5 minutes. APIII was slightly less effective than rANF. The effects of rANF and APIII were dose-dependent in a complex manner: one stimulatory and two different inhibitory effects were observed, one being responsible for an irreversible rundown of ICa. The effects of ANF were not blocked by atropine and desensitization of the cells to isoprenaline did not play a significant role in the response to ANF. When ICa was elevated by intracellular perfusion with cyclic adenosine 3',5'-monophosphate, added to the patch electrode solution or using a perfused pipette, rANF or APIII had less inhibitory effect, and no rundown of ICa was observed. It is proposed that adenylate cyclase may be one of several mechanisms by which ANF regulates ICa.

A patch-clamp study of the effects of cicletanine on whole-cell calcium current in ventricular myocytes.

The effects of extracellular application of cicletanine on the voltage-sensitive calcium current (ICa) was studied in isolated cells from frog ventricle. Myocytes were isolated by enzymatic dissociation and ICa was measured using the whole-cell configuration of the patch-clamp technique modified to permit intracellular perfusion with various substances. Cicletanine (10 to 100 microM) had no effect on control ICa. However, when ICa was enhanced by superfusion of the cell with saturating doses of beta-adrenergic agonist (isoprenaline, 2 microM) or by intracellular perfusion with maximal doses of cAMP (20 microM), cicletanine exerted a dual effect on ICa. At 10 microM, cicletanine generally induced a transient or sustained stimulation of ICa (5 to 40%), while 100 microM of the drug generally reduced ICa. The effects of cicletanine were reversible and not voltage-dependent. These results suggest that cicletanine affects ICa by acting on a mechanism occurring after cAMP synthesis, by enhancing cAMP concentration (e.g. through an inhibition of cAMP phosphodiesterase) or facilitating cAMP-dependent phosphorylation of the Ca channels.

ELISA for total IgE and IgG detection in rat serum. Changes with immunization or adjuvants.

Total IgE and IgG serum levels were measured in rats treated with egg albumin (EA), Bordetella pertussis (Bp) and aluminium hydroxide gel (alum), and in rats administered with Bordetella pertussis or alum alone. Two ELISA micromethods have been developed to measure IgE and IgG changes. Immunoglobulin serum levels were evaluated 14 days after immunization. The highest IgE levels were obtained after sensitization with EA suspended in alum s.c. and administered with Bp i.p. The IgE production induced by Bp alone was significantly lower than that of the former. The IgE concentrations from alum treated group were the same as those obtained in the untreated animals. IgG serum levels remained unchanged in the different immunization procedures assayed.