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Biomedical subjects

P Chatelain

Publications and source records attributed to P Chatelain.

At least 73 records · Page 4Linked to original sources
PubMed1996

Palmaz-Schatz Coronary Stent Implantation Without Intravascular Ultrasound and Without Subsequent Anticoagulation: Clinical Outcome.

OBJECTIVES: To determine the safety and efficacy of antiplatelet therapy alone in a selected group of patients following coronary stenting. BACKGROUND: Coronary stent implantation is an effective treatment for abrupt closure, and can also reduce the restenosis rate following percutaneous transluminal coronary angioplasty. However, anticoagulation therapy following stent implantation is associated with a significant incidence of vascular complications and subacute stent thrombosis. METHODS: Between February and November 1994 we implanted 62 Palmaz-Schatz stents in 50 patients with an optimal angiographic result following stent deployment. In these patients, intravascular ultrasound was not used, and a regimen of aspirin 100 mg daily indefinitely and ticlopidine 250 mg twice daily for 3 months was started without anticoagulation. RESULTS: Of these 50 patients (10 females : 40 males, mean age 63 +/- 12 years, LVEF 64 +/- 10%), 39 (78%) were stented for a suboptimal angiographic result post angioplasty, 2 (4%) received stents as a bailout procedure, and 9 (18%) were stented electively. Average hospital stay following stent implantation was 3.7 +/- 3.0 days. After a mean follow-up period of 140 +/- 70 days, there were no instances of stent occlusion, death, stroke, need for coronary bypass surgery, Q-wave myocardial infarction or femoral artery pseudoaneurysm. There was 1 case (2%) of significant puncture site hemorrhage. CONCLUSIONS: Immediate angiographic appearance after stent implantation can be used to define patients at low risk of stent thrombosis who do not require anticoagulation and can safely be discharged early from the hospital.

Journal Article↗
PubMed1996

[Treatment of post-coronarography femoral false aneurysm by compression, guided by Doppler echography].

MATERIAL AND METHODS: We evaluated the role of color Doppler US-guided compression in the non-invasive treatment of femoral artery pseudoaneurysms after cardiac catheterization, including 22 PTCA procedures. The diagnosis of 32 pseudoaneurysms in 32 patients was accomplished by detection of the typical US-Doppler pattern consisting of the swirling color Doppler flow and the "to and fro" pulsed Doppler waveform at a mean 3.6 days (1 to 14) after the cardiac catheterization. Thirteen patients had multiple cavity pseudoaneurysms (2 to 4). All the patients immediately underwent compression therapy. RESULTS: Treatment was successful in 42/49 cavities (86%) and 25/32 patients (78%), usually after 1 to 3 compression cycles of 6 to 8 minutes duration. Only one recurrence was noted at the 24 hour US-Doppler follow-up. In all cases, pain relief during compression was an excellent clinical sign of hemostatic plug formation and conversion from pseudoaneurysm to simple hematoma. Failures occurred among patients under high dose anticoagulants in spite of 4 to 10 compression cycles. COMMENTARY: In conclusion, color Doppler US-guided compression of post-cardiac catheterization pseudoaneurysms should be the first line therapeutic modality, even in cases of multiple cavities and among patients under effective anticoagulation therapy.

Adult↗
PubMed1996

Growth hormone insensitivity syndrome (Laron syndrome): main characteristics and effects of IGF1 treatment.

Growth hormone (GH) insensitivity is a pathological state characterized by a disturbance of the physiological relationship between GH secretion, synthesis of insulin-like growth-factor I (IGF-1) and the biological actions of GH. Laron syndrome, the prototype for GH insensitivity, is most often due to GH receptor deficiency. However, this syndrome is heterogeneous in terms of growth characteristics, bio-chemical features and, most importantly, genetic defects. Recent data have indicated that partial GH receptor deficiency could be involved in children with apparently idiopathic short stature. Laron syndrome, because of extreme growth deficiency and a lack of alternative treatment, was the first clinical situation in which recombinant human IGF-1 was used. IGF-1 accelerates growth rate in most patients, induces subtle modifications of the craniofacies and decreases fat mass. However, it is still too early to evaluate the long-term effects of IGF-1 on final height. Tolerance to the drug has been excellent in all reported trials. The major (but rare) side effects are transient intracranial hypertension and hypokalemia. Generalization of data obtained in Laron syndrome to other clinical situations should take account of the profound alterations in IGF-1 pharmacokinetics resulting from a deficiency in IGF-binding proteins.

Genetic Heterogeneity↗
PubMed1995

Effects of irbesartan (SR47436/BMS-186295) on angiotensin II-induced pressor responses in the pithed rat: potential mechanisms of action.

The effects of two new non-peptide angiotensin receptor antagonists, irbesartan (SR 47436/BMS-186295, (2-n-butyl-4-spirocyclopentane-1-[((2'-tetrazol-5-yl)bipheny l-4-yl)methyl]2 - imidazolin-5-one) and SR 47155A (2-n-butyl-4-spirocyclopentane-1-[((2'-carboxy)biphenyl-4-yl)methy l]2- imidazolin-5-one, trifluoroacetate), on angiotensin II-induced pressor responses were studied in the pithed rat in comparison to losartan, EXP 3174 and [Sar1,Val5,Ala8]angiotensin II. SR 47155A (1-10 mg/kg i.v.) and losartan (1-10 mg/kg i.v.) shifted dose dependently the dose-response curve of angiotensin II to the right without affecting the maximal response. SR 47436 (0.3-10 mg/kg i.v.), EXP 3174 (0.03-1 mg/kg i.v.) and [Sar1,Val5,Ala8]angiotensin II (0.03-1 mg/kg i.v.) induced, at least at high doses, a non-parallel shift to the right of the angiotensin II dose-response curve and this was associated with a reduction of the maximal response. During a 70 min period, the effect of [Sar1,Val5,Ala8]angiotensin II (1 mg/kg i.v.) on the angiotensin II (0.3 microgram/kg i.v.)-induced pressor response was shown to be reversible, the effect of SR 47155A (10 mg/kg i.v.) was partially reversible and the effect of SR 47436 (3 mg/kg i.v.), EXP 3174 (1 mg/kg i.v.) or losartan (6 mg/kg i.v.) was not reversed at the end of this 70 min period. Administration of SR 47155A (10 mg/kg i.v.) before SR 47436 (1-10 mg/kg i.v.) reversed the reduced angiotensin II-maximal response induced by SR 47436. Administration of SR 47436 (10 mg/kg i.v.) before SR 47155A (1-10 mg/kg i.v.) prevented the full development of the pressor response as observed in the absence of SR 47436. In the pithed rat, SR 47436 (30 mg/kg i.v.) and losartan (30 mg/kg i.v.) reduced the change in diastolic blood pressure induced by electrical stimulation of the spinal cord only at low stimulation rates. Taken together these results indicate that SR 47436, under in vivo conditions, is a potent non-peptide angiotensin receptor antagonist. The type of antagonism (partially insurmountable but selective) can be explained by different theoretical models which are discussed.

Angiotensin II↗
PubMed1995

Effect of SR 33805 on arterial smooth muscle cell proliferation and neointima formation following vascular injury.

The possible activity of SR 33805 ([[N-[dimethoxy-3,4-phenethyl]-N- methylamino-propoxyl]-4-benzenesulfonyl]-2-isopropyl-3-methyl-1-in dole), a novel Ca2+ channel blocker, in early atherogenesis was investigated. In vitro, SR 33805 strongly inhibited fetal calf serum-induced proliferation of cultured human aortic smooth muscle cells with an IC50 value of 0.3 +/- 0.1 microM (n = 3). In this respect, SR 33805 was several fold more active than the reference compounds: diltiazem, verapamil, nifedipine and fantofarone. SR 33805 was also a potent inhibitor of platelet-derived growth factor- or basic fibroblast growth factor-induced proliferation of human smooth muscle cells. SR 33805 inhibited serum-stimulated 45Ca2+ uptake in these cells, with an IC50 value of 47 +/- 18 nM. The effect of SR 33805 on intimal smooth muscle hyperplasia in rabbit carotid arteries subjected to air-drying endothelial injury was then investigated. After a 16-day treatment, SR 33805 (6.0 mg/kg/day p.o.) inhibited the development of intimal thickening. Under the same experimental conditions, nifedipine, verapamil, diltiazem (2 x 6 mg/kg/day p.o.--16 days) and fantofarone (12 mg/kg/day p.o.--16 days) were inactive. These results show that SR 33805, a novel and potent Ca2+ channel blocker, can reduce myointimal thickening following endothelial injury.

Animals↗
PubMed1995

SR 33589, a new amiodarone-like antiarrhythmic agent: anti-adrenoceptor activity in anaesthetized and conscious dogs.

We have assessed the ability of amiodarone and the new amiodarone-like antiarrhythmic agent, SR 33589 (N,N-dibutyl-3-[4-((2-butyl-5-methylsulphonamido)benzofuran-3-yl-c arbonyl) phenoxy]propylamine), to inhibit the effects of adrenoceptor stimulation in anaesthetized and conscious dogs. In anaesthetized, atropinized dogs, adrenoceptor stimulation was achieved (i) by i.v. administration of adrenaline and measurement of increased blood pressure (ii) by i.v. administration of isoprenaline and measurement of increased heart rate and decreased blood pressure. In conscious dogs, adrenoceptor stimulation was achieved by i.v. administration of isoprenaline and measurement of increased heart rate. In anaesthetized, atropinized dogs, both amiodarone and SR 33589 inhibited to similar extents, alpha-adrenoceptor stimulation (as indicated by attenuation of adrenaline-induced increases in blood pressure). The beta 1-adrenoceptor inhibitory activity of SR 33589 (as demonstrated by blockade of isoprenaline-induced increases in heart rate) was significant, but less marked than amiodarone (heart rate elevation reduced by 39%, P < 0.001 with 10 mg/kg SR 33589 and by 52%, P < 0.01 with 10 mg/kg amiodarone). In contrast, its beta 2-adrenoceptor antagonistic activity (as demonstrated by blockade of isoprenaline-induced reduction in blood pressure) was more marked (mean blood pressure decrease reduced by 69%, P < 0.01 with 10 mg/kg SR 33589 and by 31%, P < 0.05 with 10 mg/kg amiodarone). In conscious dogs, both SR 33589 and amiodarone (12.5, 25 and 50 mg/kg p.o.) inhibited isoprenaline-induced increases in heart rate by approximately the same amount for varying durations depending on the dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

[Percutaneous valvuloplasty in the treatment of mitral stenosis: results in Geneva].

Percutaneous balloon valvotomy is a recognized form of treatment of mitral stenosis. In Geneva between 1986 and 1993, 62 procedures were attempted in 60 patients (87% females) aged 48 +/- 17 years (12 to 80 years). Patient selection was based on symptoms (NYHA class), echocardiography (valve area, Boston score), and hemodynamics. 11 patients (18%) had undergone surgical commissurotomy in the past, 28 patients (47%) were in atrial fibrillation, and 12 patients (30%) had a history of peripheral emboli. Mild or moderate mitral insufficiency was present angiographically in 17 patients (28%) and echographically in 42 patients (70%). Esophageal echocardiography was performed in 37 patients (62%) before the procedure. In 52 patients (84%) a single balloon (Inoue technique) was used. Technical success was obtained in 59 procedures (95%). Following the procedure, mitral valve area increased from 1.1 +/- 0.3 to 1.8 +/- 0.3 cm2 (p < 0.0001) at echocardiography and from 1.1 +/- 0.3 to 1.9 +/- 0.5 cm2 (p < 0.0001) based on invasive hemodynamic data. There were 5 complications directly related to the procedure. In two cases cardiac tamponade developed, one after pericardial perforation during the transseptal approach and one because of left ventricular perforation. The second patient required surgical treatment. In two other cases, a moderate pericardial effusion without clinical consequences was observed. In one case the venous sheath malfunctioned, rendering surgical repair of the right femoral vein necessary. A residual atrial septal defect was observed at echography in 13 patients (22%). Mitral insufficiency was increased in 6 patients (10%) angiographically and in 9 patients (15%) at echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Stenting with the half (disarticulated) Palmaz-Schatz stent.

A total of 110 half (disarticulated) Palmaz-Schatz coronary stents were implanted in 102 patients. Procedural success rate was 98%. Elective stenting was performed in five patients. The others received half stents for bail-out situations, including short dissections, relapsing stenoses, dissections not adequately covered by a full stent, ostial stenoses, and thrombus containing lesions. Seventeen patients received no anticoagulation except aspirin. Complications included one procedural death, three acute occlusions (resulting in one Q and two non-Q wave myocardial infarctions), and one non-Q wave infarction related to side branch closure. Stenting with the half Plamaz-Schatz coronary stent is an effective technique. It allows stenting in situations where a full stent may not be ideally suited. Use of only half a stent reduces thrombogenicity and halves costs.

Adult↗
PubMed1995

Randomized evaluation of six French voda-type guiding catheters for left coronary artery balloon angioplasty.

In order to evaluate 6 French (6F) Voda-type guiding catheters for left coronary artery balloon angioplasty, we randomized the choice of the guiding catheter in 100 consecutive patients between a Voda (group 1, n = 50) and a Judkins or Amplatz curve (group 2) guiding catheter. Angioplasty success rate (98% for both), need for guiding catheter crossover exchange (2 in group 1 vs. 1 in group 2), fluoroscopy time, and volume of injected contrast were similar in both groups, but the operator's appreciation of good back-up support was better with the Voda-type guiding catheter (90% vs. 74%, P < 0.05). No complications attributed to the guiding catheter were noted in either group. Efficiency of the Voda-type guiding catheter appeared similar for both left anterior descending (n = 35, success rate 100%) and circumflex (n = 18, success rate 94%) coronary artery angioplasty. Voda-type guiding catheters are an efficient and safe approach to routine left coronary angioplasty. They appear to be as effective as a choice between a Judkins or an Amplatz configuration and could be of particular use when a double angioplasty of the left anterior descending and circumflex arteries is attempted during the same procedure.

Angioplasty, Balloon, Coronary↗
PubMed1995

Bailout coronary stenting with 6F guiding catheters for failed balloon angioplasty.

Between July 1992 and February 1994, we attempted bailout Palmaz-Schatz stent implantation through a 6F guiding catheter after 52 failed coronary balloon angioplasty procedures to reverse (14 [27%] cases) or prevent (38 [73%] cases) abrupt vessel closure. The stents or half-stents were manually crimped onto a monorail balloon catheter for delivery. Thirty-nine (75%) procedures involved a single stent, and 13 (25%) involved two or three stents. Technical success was achieved in 50 (96%) procedures, and clinical success without major complications was obtained in 45 (87%) cases. Target vessel occlusion was documented angiographically or suggested clinically in 2 (4%) cases. Two (4%) patients underwent semielective bypass surgery, and in 4 (8%) patients a non-Q-wave and in 1 (2%) a Q-wave myocardial infarction developed. There were no deaths. Major bleeding occurred in 2 patients: 1 had an important groin hematoma that was treated with local surgery followed by coronary bypass surgery, and one had macroscopic hematuria that required interruption of anticoagulation therapy on day 4. Three (6%) femoral pseudoaneurysms were diagnosed by ultrasound and could be obliterated by external compression alone. Bailout coronary stent implantation through 6F guiding catheters after failed balloon angioplasty is technically reliable, safe, and cost-efficient. As a consequence, use of 6F guiding catheters is a good option for a large majority of routine balloon angioplasty procedures.

Aged↗
PubMed1995

New drug binding sites in Ca2+ channels.

New classes of drugs modifying Ca2+ channel activity have become available, this may enlarge the clinical utilities that have been associated with established Ca2+ channel antagonists such as the dihydropyridines (for example, nifedipine). Two such classes are reviewed by Michael Spedding, Barry Kenny and Pierre Chatelain. Fantofarone is a non-dihydropyridine with a novel site of action in the L-type Ca2+ channel that appears to yield a distinct cardiovascular profile. In contrast, fluspirilene and related Na+ and Ca2+ channel inhibitors have a distinct site of action in Ca2+ channels, which is not specific for one channel type. The utility of Na+ and Ca2+ channel inhibitors in ischaemic stroke is compared with new and more selective Na+ channel inhibitors.

Animals↗
PubMed1995

Acute coronary occlusion secondary to radiofrequency catheter ablation of a left lateral accessory pathway.

A case of asymptomatic acute coronary occlusion secondary to radiofrequency catheter ablation of a left lateral accessory pathway is reported. Due to post-procedural ST modifications of the surface ECG, a coronary angiography was performed which disclosed total occlusion of the first marginal branch of the left circumflex coronary artery. Acute myocardial infarction was confirmed by moderate cardiac enzyme release, abnormal myocardial perfusion scan and mild lateral hypokinesia at echocardiography. This rare but potentially harmful complication of interventional electrophysiology should be kept in mind and coronary angiography performed immediately when coronary occlusion related to radiofrequency application is suspected.

Catheter Ablation↗
PubMed1995

SR 33589, a new amiodarone-like antiarrhythmic agent: electrophysiological effects in anesthetized dogs.

We compared the electrophysiological effects of a new amiodarone-like agent, SR 33589, with those of amiodarone. Mongrel dogs were anesthetized with chloralose, and electrodes were implanted in right atrium and ventricle for electrical stimulation and regional ECG measurement. Sinus cycle length (CL), AH interval, Wenckebach CL (WCL), atrial, atrioventricular node, and ventricular effective refractory periods (AERP, AVNERP, VERP), and parameters calculated from surface ECG were measured. SR 33589 was administered intravenously (i.v.) at 1, 2.5, or 5 mg/kg followed 60 min later by a second similar dose. The same protocol was followed with amiodarone 5 mg/kg, which reduced heart rate (HR) by 19% (p < 0.05), increased WCL by 31% (p < 0.01), AH interval by 14% (p < 0.05) and AERP, AVNERP, and VERP by 13% (p < 0.05), 19% (p < 0.05), and 11% (p < 0.01) respectively. No effect was observed on HV or PQ intervals. A second administration of 5 mg/kg changed these indexes further. SR 33589 (2.5 mg/kg) reduced HR by 21% (p < 0.001), increased WCL by 44% (p < 0.001), AH interval by 24% (p < 0.01), and AERP, AVNERP, and VERP by 17% (p < 0.001), 63% (p < 0.01), and 15% (p < 0.01) respectively, with an 18% increase in PQ interval (p < 0.05) but no significant effect on HV interval. Higher doses (5 mg/kg) and/or administration of a second dose both resulted in greater changes. Both amiodarone and SR 33589 prolonged VERP more at longer CL than at shorter CL, but the degree of reduction at shorter CL was less with SR 33589 than with amiodarone. Results suggest that acute administration of SR 33589 results in electrophysiological actions similar to those produced by amiodarone.

Amiodarone↗
PubMed1995

Effects of a new amiodarone-like agent, SR 33589, in comparison to amiodarone, D,L-sotalol, and lignocaine, on ischemia-induced ventricular arrhythmias in anesthetized pigs.

We compared the ability of a new amiodarone-like agent, SR 33589, with that of amiodarone, D,L-sotalol, and lignocaine to reduce the incidence of ventricular fibrillation (VF) and associated arrhythmias caused by acute coronary artery occlusion in anesthetized pigs. Ischemia was induced by occlusion of the left coronary descending artery (LAD) for 30 min. Premature ventricular complexes (PVCs), ventricular tachycardia (VT), and ventricular fibrillation (VF) were recorded during coronary occlusion. SR 33589 (1.25, 2.50, and 5 mg/kg intravenously, i.v.) markedly reduced the occurrence of ventricular arrhythmias during ischemia. The incidence of VF was reduced from 90% in the control group to 30% (p < 0.05) with 1.25 mg/kg, to 10% (p < 0.001) with 2.50 mg/kg, and to 20% (p < 0.01) with 5 mg/kg. In addition, SR 33589, especially at the two higher doses, caused a sustained reduction in both the incidence of VT and the number of PVCs per minute. In comparison, amiodarone 10 and 20 mg/kg i.v. reduced the incidence of VF (40 and 50%, respectively), but these reductions never reached a level of statistical significance. The incidence of VT and the number of PVCs per minute were also decreased significantly by amiodarone. D,L-sotalol 3 mg/kg i.v. exerted significant anti-arrhythmic activity; the incidence of VF was reduced 20% (p < 0.01), and both the incidence of VT and number of PVC per minute were also reduced. In contrast, lignocaine given as a 2-mg/kg bolus followed by an infusion at 70 micrograms/kg/min had no antiarrhythmic or antifibrillatory activity in this preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiodarone↗
PubMed1995

Interaction of the antiarrhythmic agents SR 33589 and amiodarone with the beta-adrenoceptor and adenylate cyclase in rat heart.

1. The effects of SR 33589 and amiodarone on the cardiac beta-adrenoceptor were studied in vitro and after chronic treatment by means of [125I]-(-)-iodocyanopindolol ([125I]-(-)-CYP) binding and measurement of adenylate cyclase activity. 2. Binding of [125I]-(-)-CYP was inhibited in a dose-dependent manner by SR 33589 (IC50=1.8 +/- 0.4 microM, nH=0.93 +/- 0.06) and amiodarone (IC50=8.7 +/- 2.0 microM, nH=9.2 +/- 0.03). Saturation binding experiments indicated a non-competitive interaction such that SR 33589 (1 and 3 microM) and amiodarone (5 and 10 microM) reduced the Bmax of [125I]-(-)-CYP binding without any effect on the KD. Kinetic studies showed that the rate of association of [125I]-(-)-CYP was unchanged while the rate of dissociation was increased both in the presence of SR 33589 (10 microM) and amiodarone (30 microM).3. Under the same conditions, the receptor stimulated adenylate cyclase activity was inhibited in a dose-dependent, but non-competitive manner, by SR 33589 (isoprenaline-, glucagon- and secretin-stimulated enzyme inhibited 50% at 6.8 +/- 0.6 microM, 31 +/- 10 microM and 12 +/- 3 microM, respectively) while the basal, GTP- and GPP(NH)p-stimulated enzyme was inhibited by 5-10% and the NaF and forskolin-stimulated enzyme by 50% at 500 microM. Amiodarone exhibited a similar pattern of inhibition. 4. After chronic oral treatment (50, 100, 150 mg kg(-1) per day, 14 days), both SR 33589 and amiodarone produced a dose-dependent decrease in Bmax without any effect on KD as determined from [125I]-(-)-CYP saturation experiments and a decrease of the isoprenaline- and glucagon-stimulated adenylate cyclase activity without any effect on basal enzyme activity or activity when stimulated by agents acting directly on regulatory catalytic units. 5. Unlike amiodarone, SR 33589 does not contain iodine substituents. Plasma levels of T3, T4, and rT3 were changed after SR 33589 treatment except a decrease in T4 level at the highest dose whilst the T4 T3 ratio and the level of rT3 were dose-dependently increased by amiodarone treatment. 6. In vitro, SR 33589 and amiodarone were characterized as non-competitive beta-adrenoceptor antagonists. Chronic treatment led to a down-regulation of the beta-adrenoceptor; the down-regulation cannot be attributed to an indirect effect mediated by the thyroid hormones. To reconcile these opposing observations, we propose that SR 33589 and amiodarone interact with the beta-adrenoceptor at a site close to the intracellular loops which are involved in the coupling with Gs and contain the phosphorylable sites.

Adenylyl Cyclases↗
PubMed1995

Final height in Turner syndrome patients treated with growth hormone.

The first treatment trials on patients presenting with Turner syndrome were successful in accelerating growth velocity. It is therefore essential to know the final height of the patients who were treated in order to ascertain whether or not growth hormone treatment increases final height. We are reporting on a group of 117 patients with Turner syndrome whose growth hormone treatment was initiated in 1986. The mean growth hormone dose was 0.74 IU/kg/week for an average period of 4 years. At the start of treatment, the patients' chronological age was 129/12 years, height -3.8 +/- 1.0 standard deviation scores (SDS) and bone age 10.5 +/- 2.1 years. Mean final height was 147.7 +/- 5.6 cm, i.e. a gain of 1.5 SDS. We noted no significant difference due to the type of chromosomal abnormality, nor to oxandrolone or estrogen-associated treatment. A significant correlation was found between final height, mean parental height, the duration of the treatment, height SDS at the start of treatment and growth hormone peak during pharmacological stimulation tests. However, there was no correlation between growth hormone dosage, chronological age and bone age at the start of treatment. These results show that the growth hormone treatment improves the final heights of patients with Turner syndrome.

Age Determination by Skeleton↗