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Biomedical subjects

S Golf

Publications and source records attributed to S Golf.

At least 37 records · Page 2Linked to original sources
PubMed1989

Intravascular stenting for stenosis of aortocoronary venous bypass grafts.

To test the ability of endoluminal stents to prevent saphenous vein graft restenosis after balloon angioplasty, 13 patients with angina and previous coronary bypass surgery underwent implantation of one or more stents into 14 stenosed grafts. Implantation was technically successful in all cases and there were no major in-hospital complications. During a median follow-up interval of 7 months (range 2 to 26), 10 patients (77%) underwent follow-up angiography. Seven patients remained asymptomatic or in improved condition without further intervention; three patients had further angioplasty with stent implantation for a new stenosis in the same graft. Two patients (20%) developed within-stent restenosis. There was one death from progressive congestive heart failure 7 months after implantation. No patient had a myocardial infarction or needed surgical revascularization during the follow-up period. In selected cases, stent implantation appears to be a promising new technique that may decrease the incidence of restenosis after balloon angioplasty in venous bypass grafts. The rate of complications is low. Further experience and longer follow-up will be needed before definite recommendations can be made about its use.

Aged↗
PubMed1989

Apparent lack of beta 2 adrenergic receptors in porcine myocardium.

The aim of this study was to investigate the relative numbers of myocardial beta 1 and beta 2 receptors in pigs. Membrane particles from left ventricular porcine and mixed ventricular rat myocardium were examined for subtypes of beta adrenergic receptors with a radioligand binding technique using [125I]-cyanopindolol (ICYP) as trace, and the new highly beta 1 selective antagonist Sandoz 204 545 and the beta 2 selective antagonist ICI 118 551 for displacement. Radioligand displacement experiments were also performed using propranolol, isoprenaline and terbutaline. The displacement curves obtained with the subtype selective antagonists and agonist revealed biphasic inhibition of specific ICYP binding in rat preparations, indicating a beta 1/beta 2 ratio of approximately 2/1. In porcine preparations displacement of specific ICYP binding with all agents resulted in monophasic curves, thus sharply contrasting the rat preparations. Affinity constants of displacing drugs derived from these monophasic curves indicated that the specific binding site was a beta 1 receptor. No displacement compatible with beta 2 affinity was found. In the same rat preparations we found that adenylate cyclase activation and inhibition by beta receptor subtype specific agonists and antagonists were mediated by two receptor subtypes, whereas in the pig, adenylate cyclase activation and its inhibition seemed to occur via only one receptor subtype, the beta 1 adrenoceptor.

Adenylyl Cyclases↗
PubMed1988

[Acute coronary occlusion following transluminal angioplasty: the role of an implanted parietal support via transluminal route].

Acute coronary artery occlusion complicates some 5% of balloon angioplasty procedures and often makes emergency surgical revascularization necessary. Initial experience is reported with emergency implantation of endoluminal stents for acute vessel closure following coronary balloon angioplasty. 10 patients received one stent and 2 patients two stents during the study period. In the study group, implantation was technically successful in all cases: there were no deaths, Q-wave infarctions or cases requiring emergency surgery.--2 patients showed a moderate rise in creatinine phosphokinase in the first 48 hours. During a mean follow-up period of 4 months (range 1-21 months) there have been no deaths and no cases requiring elective coronary bypass surgery. 10 patients underwent control angiography and none have developed significant restenosis within the stented segment. For selected patients, coronary artery stenting appears to be a promising technique as an alternative to emergency bypass surgery after acute vessel occlusion during balloon angioplasty.

Angioplasty, Balloon↗
PubMed1988

[Incidence and treatment of coronary restenosis in spite of the implantation of an endoprosthesis].

Between April 1986 and February 1988, 72 endoprosthesis implantations were carried out in the coronary arteries of 65 patients. The indication for implantation was either abrupt closure post angioplasty or prevention of restenosis. The first 3 cases of restenosis within the stented segment are reported. Two were treated by repeat balloon angioplasty, with temporary improvement. The possible mechanisms underlying this particular form of restenosis are discussed.

Angioplasty, Balloon↗
PubMed1988

A transplantable rat Leydig cell tumor--5. Cellular localization of beta-adrenergic and prostaglandin receptors and their effects on testosterone production.

The cellular localization of beta-adrenergic and prostaglandin (PG) receptors and their effects on adenylate cyclase activity (AC) and testosterone production in vitro were investigated in a transplantable rat Leydig cell tumor (H-540). Separation of the tumor cells in Percoll gradients revealed that the specific binding of [3H]PGE1 and [125I]Cyanopindolol was found in the same fraction as that of [125I]LH. This fraction--judged by light microscopy of smears--consisted of tumor Leydig cells. In addition, [125I]cyanopindolol was found specifically bound in the red blood cell fraction. In the Leydig tumor cells, approx 25% of the beta-adrenergic receptors was identified as beta 1-receptors, whereas approx 75% of the receptors were of the beta 2-subtype. The AC in Percoll purified Leydig tumor cells was stimulated by hCG (6-fold), PGE1 (2-fold), PGE2 (1.5-fold), PGI1 (2-fold) and isoproterenol (2-fold). The AC in the red blood cell fraction was stimulated by isoproterenol whereas the PGs and hCG had little or no effect. hCG, isoproterenol and PGE1 were able to stimulate testosterone production in vitro. At 44 h incubation, PGE1 was the most potent stimulator of testosterone production. In conclusion, tumor Leydig cells possess hCG, PGE1, PGI2 and beta-adrenergic receptors coupled to the AC. PGE1 and beta-adrenergic agonists stimulate testosterone production after prolonged incubation in vitro.

Alprostadil↗
PubMed1988

Prevention of coronary restenosis by stenting.

Balloon angioplasty fails to provide acceptable long-term results for a significant proportion of patients. An intravascular mechanical support, developed with the aim of preventing restenosis and acute closure of diseased arteries after transluminal angioplasty, was implanted in 44 patients (39 male and five female), aged from 35 to 70 years (mean 56 years) with documented restenosis of native coronary artery (41 stents) and bypass grafts (12 stents). In the group of bypass graft patients there was no local restenosis and no major complication. In patients in whom stents were placed in native coronary arteries, the complication rate was higher (two patients died after coronary bypass surgery). One patient died suddenly at home. Except for one patient, in whom a new lesion developed proximally with extension into the stent, no case of restenosis could be observed. Despite the still relatively high complication rate, we feel that stenting may present a rational approach to the unresolved problem of restenosis after coronary angioplasty.

Adult↗
PubMed1988

Intravenous thrombolytic treatment for acute myocardial infarction. Effects of early intervention and early examination.

Intravenous thrombolytic treatment (streptokinase or anisoylated plasminogen streptokinase activator complex (APSAC) was given to 50 consecutive patients within 3 hours after onset of symptoms of acute myocardial infarction. Left heart catheterisation with coronary angiography and simultaneous double view left ventriculography were performed approximately 4 hours after start of thrombolytic treatment. This examination showed that the acute infarct-related coronary artery was open in 36 patients (72%) and closed in 14 patients (28%). A higher left ventricular ejection fraction was found among patients with open, than among patients with closed infarct-related artery (58.8% vs. 48.4%, p = 0.05). The group with open artery also had a lower score of regional left ventricular dysfunction (1.7 vs. 2.4, p less than 0.05, on a scale from 0-3). Single, double and triple vessel coronary heart disease was found in 22, 14 and 13 patients respectively. Mean age was lower in the group with single vessel disease as compared to double and triple vessel disease (48.4 years vs. 53.4 and 55.4 years, p less than 0.05 and p less than 0.005). Independently of whether the infarct-related artery was open or closed, there tended to be an inverse correlation between number of diseased vessels and preservation of left ventricular function (statistical significance only for single vessel versus triple vessel disease with respect to score of regional left ventricular dysfunction, 1.8 vs. 2.4, p less than 0.05). These findings suggest that early thrombolytic treatment within 3 hours of onset of symptoms may preserve myocardial tissue during the evolution of acute infarction. Furthermore, a presumably better collateralisation from adjacent coronary arteries without stenoses may be important for myocardial preservation. Finally, early angiographic examination can be performed safely and is a good support for determination of further treatment, which in the actual patients was coronary bypass surgery in 8 cases, transluminal angioplasty, PTCA, in 20 cases, and medical treatment alone in 22 cases.

Adult↗
PubMed1988

Emergency stenting for acute occlusion after coronary balloon angioplasty.

Acute coronary artery occlusion complicates 2-12% of the balloon angioplasty procedures, and despite repeat angioplasty, emergency surgical revascularization is often necessary. We report our initial experience with the emergency implantation of endoluminal stents for acute vessel closure after coronary balloon angioplasty. Nine patients received one stent, and two patients received two stents during the study period. Implantation was technically successful in all patients; there were no deaths, no myocardial infarctions as evidenced by Q wave on the electrocardiogram, and no need for emergency surgery. One additional patient, not satisfying the study inclusion criteria, died 16 hours after stent implantation from left ventricular failure and intractable arrythmias. Two patients in the study group had a moderate creatinine phosphokinase rise during the first 48 hours after implantation. During a median follow-up period of 3 months (range, 1-20 months), there have been no deaths and no need for elective coronary bypass surgery. One patient required emergency recanalization 3 months after implantation because of acute occlusion of the stented segment with limited myocardial infarction. Six patients have undergone control angiography, and none has developed chronic restenosis within the stented segment. For selected patients, coronary artery stenting appears to be a promising alternative to emergency bypass surgery after acute vessel occlusion during balloon angioplasty.

Adult↗
PubMed1988

Risk factors of morbidity and mortality in surgically treated chronic aortic valvular heart disease.

A cohort of 617 patients underwent aortic valve replacement (AVR) the median follow-up time was 3.4 years with a range (0-7.8) years. The incidence of early mortality was 5.0% and the five years survival (77.9 +/- 1.9)%. Risk factors of early mortality and morbidity (Low Output Syndrome) occurring the first 31 days after operation were pinpointed. Another analysis was done to estimate independent predictors of late premature death from all causes, and from specific causes (cardiac related, sudden cardiac). One of the major late morbid events was the appearance of systemic emboli. Its rate was 1.4% pats. Year. Its risk factors were presence of pure aortic regurgitation and advanced age at operation. The relative survival rate was at 5 years of 87.0% for the total cohort, but for our younger patients (age less than 30 years), we reached 99.4%. Our results suggest more aggressive measures to correct the hazard in AVR, and impose carefulness in comparing quality of AVR from different institutions for mortality and morbidity. Finally the results of AVR are rather palliative than curative except for our younger patients where we reached curability.

Adult↗
PubMed1987

Relative selectivity of different beta-adrenoceptor antagonists for human heart beta 1- and beta 2-receptor subtypes assayed by a radioligand binding technique.

The affinity constants of inhibition (Ki values) for both beta 1- and beta 2-receptor subtypes were determined for four different beta-adrenoceptor antagonists by a radioligand binding technique in a human myocardial membrane preparation. The radioligand was the high affinity antagonist [125I]-(-)-iodocyanopindolol (ICYP), and the drugs tested were atenolol, metoprolol, ICI 141,292 and ICI 118,551. Different concentrations of the drugs at test were allowed to compete with a constant concentration of ICYP for the specific binding sites (beta-receptors). Ki values for beta 1- and beta 2-receptors for each beta-adrenoceptor antagonist were developed from these data by computer calculations. Atenolol and metoprolol were found to differ slightly regarding potency (absolute Ki values) and to be practically equal regarding relative selectivity (approx. 40; i.e. ratio between high and low Ki values), while ICI 141,292 was found to have slightly higher relative selectivity (approx. 60) and much higher potency. All these drugs exhibited highest affinity for the beta 1-receptor population. In contrast, ICI 118,551 exhibited a very high relative selectivity (approx. 300) with highest affinity for the beta 2-receptor subtype. The method represents a good supplement to physiological and clinical examinations of selectivity of beta-blockers, and offers several advantages regarding simplicity, specificity and accuracy.

Adrenergic beta-Antagonists↗
PubMed1987

Cardiac stroke volume during exercise measured by Doppler echocardiography: comparison with the thermodilution technique and evaluation of reproducibility.

Cardiac stroke volume was measured simultaneously by Doppler echocardiography and thermodilution in patients with severe coronary artery disease. One group (20 patients) was examined during supine exercise at 25 W and a second group (20 patients) during sitting exercise at 25 W and 50 W. In a third group (10 patients) the reproducibility of the non-invasive stroke volume estimate was determined during upright exercise. There was a considerable variation between results obtained with the invasive and non-invasive technique at rest and during exercise, but no systematic differences were found. Analysis of variance showed that no systematic differences between ultrasonic results were introduced by two observers or by measurements on different days. The coefficient of variation between any pairs of Doppler measurements in each patient was 6%. These findings demonstrate that the ultrasonic technique is suitable for detecting changes in stroke volume induced by low load exercise in patients with severe angina pectoris.

Adult↗
PubMed1987

Increased beta-adrenoceptor-coupled adenylate cyclase response in transplanted human hearts.

A transplanted (Tx) heart will probably compensate its sympathetic denervation by increasing the sensitivity to adrenergic stimulants. To evaluate whether this also engages the myocardial adenylate cyclase (AC) system, small endomyocardial biopsies were collected at right heart catheterization both from patients with heart Tx with no signs of rejection and from a group of patients serving as controls. In crude homogenates from these biopsies, AC activity was measured at basal conditions and following in vitro stimulation with optimal concentrations of beta-receptor agonists, histamine and sodium fluoride (NaF). The Tx group exhibited a 75% (p = 0.01) higher activation of AC with isoproterenol, and a 62% (p less than 0.05) higher AC activation with terbutaline compared with the control group. The differences in AC activation by histamine and NaF were insignificant. Thus, sympathetic denervation leads to increased activation of the beta-adrenoceptor-coupled AC system, leaving the histaminergic system unaltered. The upregulation does probably engage the receptor part of the receptor-AC system exclusively, since no elevation of NaF stimulation of AC was found in the Tx hearts.

Adenylyl Cyclases↗
PubMed1986

Beta adrenoceptor density and adenylate cyclase response in right atrial and left ventricular myocardium of patients with mitral valve disease.

Beta adrenoceptor density, measured by radioligand binding techniques, is reportedly much higher in atrial than in ventricular myocardium of patients with mitral valve disease. In the present study adenylate cyclase activity, both basal and in response to beta adrenergic agonists and sodium fluoride, in biopsy preparations from these same patients was significantly lower in atrial than in ventricular tissue when stimulated with either isoproterenol, noradrenaline, isoproterenol combined with terbutaline, or sodium fluoride. Terbutaline stimulated and basal adenylate cyclase activity was not significantly different in the two cardiac regions. The ratios of receptor density to isoproterenol stimulated and to sodium fluoride stimulated adenylate cyclase activity were 4-5 times higher in atrial than in ventricular biopsy specimens. Thus ventricular beta receptors, although present in comparatively low concentrations, are coupled to considerably more catalytic moieties of the receptor-adenylate cyclase complex than their atrial counterparts. The reason for this is probably a relative lack of coupling proteins (N components) in atrial tissue. A weak positive correlation between receptor density and isoproterenol stimulated adenylate cyclase activity was found in atrial but not in ventricular tissue. This may indicate individual variation in receptor-adenylate cyclase coupling. Furthermore, no correlation was found between atrial and ventricular values for any variable. One reason for this may be the different haemodynamic stresses in the two cardiac chambers.

Adenylyl Cyclases↗
PubMed1986

Effects of beta blocking agents on the density of beta adrenoceptors and adenylate cyclase response in human myocardium: intrinsic sympathomimetic activity favours receptor upregulation.

The density of beta adrenoceptors, the relative number of beta 1 and beta 2 adrenoceptor subtypes, and adenylate cyclase activity were studied in preparations from atrial biopsy specimens of 32 patients with coronary heart disease. Six patients were not receiving beta blocking agents, whereas the others were treated with different beta blocking drugs (timolol, propranolol, pindolol, metoprolol, and atenolol). Clinical and haemodynamic variables were similar in the different groups of patients. Beta adrenoceptor density was 17% significantly lower in the non-treated group than in the groups treated with beta blocking drugs. Among these, the group treated with pindolol, a drug with intrinsic sympathomimetic activity, had receptor densities that were 38% significantly higher than those treated with other beta blocking drugs and 51% significantly higher than the non-treated group. The relative numbers of beta 1 and beta 2 adrenoceptor subtypes were very similar in the different groups (beta 1 receptors 75-80%, beta 2 receptors 20-25%). A significant increase in the ratios of terbutaline stimulated to basal and terbutaline stimulated to isoproterenol stimulated adenylate cyclase activities was found in patients treated with beta 1 selective blockers (metoprolol, atenolol), indicating that beta 1 selective drugs may improve beta 2 receptor-adenylate cyclase coupling. In contrast, pindolol caused a significant reduction in the ratio of terbutaline stimulated to isoproterenol stimulated adenylate cyclase activity, indicating that this drug may cause a reduction in beta 2 receptor-adenylate cyclase coupling efficacy. Thus treatment with beta blocking agents causes upregulation of human myocardial beta receptor density. Intrinsic sympathomimetic activity seems to favour receptor upregulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1986

Congenital swallowing-induced symptomatic heart block: a case report of a probably hereditary disorder.

A 15-year-old girl had had syncope induced by swallowing since infancy. An ECG recorded during food intake revealed SA block with very slow junctional and ventricular escape rhythms. No symptoms or signs of other cardiac disorders or gastrointestinal diseases were present. Activation of a strong vagal reflex, able to inhibit impulse formation and propagation in an otherwise normal heart, is the most likely explanation of the disorder in this patient. Furthermore, ECGs of her close relatives which were recorded during food intake as compared with the findings in a reference group (n = 20), indicated that a genetic factor could be involved.

Adolescent↗