Biomedical subjects

G Kneissl

Publications and source records attributed to G Kneissl.

10 recordsLinked to original sources

PubMed2001

Cigarette smoking is independently associated with markers of endothelial dysfunction and hyperinsulinaemia in nondiabetic individuals with coronary artery disease.

BACKGROUND: Oxidative stress and endothelial dysfunction have been introduced as a unifying pathological mechanism for early atherosclerotic disease. They are caused by a variety of stimuli including cigarette smoking (environmental) and type 2 diabetes (disease factor). However, the role of hyperinsulinemia, a marker of insulin resistance, as a risk factor for atherosclerosis remains to be clarified. STUDY OBJECTIVES: To study the relationship of smoking, hyperinsulinaemia and biochemical markers of oxidative stress and endothelial dysfunction, in patients with coronary artery disease. DESIGN: Case-control study of 5-year survivor status in smokers, former smokers and nonsmokers with angiographically documented stable coronary artery disease classified by self-reporting of smoking status together with plasma cotinine measurements. SETTING: Cardiology and cardiac surgery unit of a tertiary care referral centre. PATIENTS AND METHODS: Plasma levels of vitamins C, E and selenium, and the adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were assessed in 214 patients at baseline together with the glucose and insulin response to an oral glucose challenge. Sixty known or newly diagnosed type 2 diabetic patients (28%) were identified and excluded from further analysis. RESULTS: E-selectin and ICAM-1, serving as markers of endothelial dysfunction, significantly correlated with hyperinsulinaemia (p < 0.05). Circulating immunoreactive insulin was elevated in active smokers and former smokers as compared to non-smokers after an oral glucose load (p < 0.05 for the area under the insulin time curve), despite a similar glucose response. Smoking was associated with a decrease in antioxidant vitamins C (p = 0.02) and E (p = 0.03), and an increase of E-selectin (p < 0.05) and ICAM-1 (p < 0.001). Low baseline ICAM-1 and high vitamin C levels emerged as the most significant multivariate predictors of 5-year survival (p < 0.001). CONCLUSIONS: Hyperinsulinaemia in smokers is linked with markers of endothelial dysfunction. Impaired vascular reactivity can thus be a new possible mechanism linking insulin resistance and smoking.

Biomarkers↗

PubMed1996

Persisting effect of Ca(2+)-channel blockers on left ventricular function in hypertrophic cardiomyopathy after 14 years' treatment.

Ca(2+)-channel blockers of the verapamil type have been reported to exert a beneficial effect on clinical symptoms and survival rates in hypertrophic cardiomyopathy. The effects of verapamil have been attributed predominantly to an improved diastolic filling. It is unknown whether an effect on diastolic filling persists in these patients after long-term treatment. Fourteen patients (12 men, 2 women, median age fifty-one [thirty-two to fifty-five] years) with hypertrophic cardiomyopathy were included in the study. Patients had been treated with verapamil 240-480 mg/d or gallopamil 150-200 mg/d for fourteen (seven to seventeen) years. The effect of a withdrawal of Ca(2+)-channel blockers on parameters of left ventricular diastolic function was evaluated at rest and during exercise in patients with hypertrophic cardiomyopathy after long-term therapy. Investigations were performed at rest and during supine ergometric exercise during ongoing Ca(2+)-channel blocking therapy and after five (four to nine) days' withdrawal (control). Pulsed Doppler echocardiography was used to record diastolic mitral flow profiles from an apical four-chamber view. Withdrawal of Ca(2+)-channel blockers of the phenylalkylamine type after long-term treatment of hypertrophic cardiomyopathy resulted in a significant reduction of early diastolic inflow velocity at rest and during exercise. In conclusion, these results indicate a persistent improvement of early diastolic filling by Ca(2+)-channel blockers even after long-term treatment.

Adult↗

PubMed1995

Experimental acute hypoxia in healthy subjects: evaluation of systolic and diastolic function of the left ventricle at rest and during exercise using echocardiography.

To clarify whether or not systolic and diastolic function of the human left ventricle (LV) were decreased during acute hypoxia, at rest and with exercise, 14 healthy male volunteers [age 25.9 (SD 3.0) years, height 182.9 (SD 7.1) cm, body mass 75.9 (SD 6.9)kg] were examined using M-mode and 2D-mode echocardiography to determine the systolic LV function as well as Doppler-echocardiography for the assessment of diastolic LV function on 2 separate test days. In random order, the subjects breathed either air on 1 day (N) or a gas mixture with reduced oxygen content on the other (H; oxygen fraction in inspired gas 0.14). Measurements on either day were made at rest, several times during incremental cycle exercise in a supine position (6-min increments of 50 W, maximal load 150 W) and in 6th min of recovery. Corresponding measurements during N and H were compared statistically. Arterial O2 tension (PaO2) was normal on N-day. All subjects showed a marked acute hypoxia at rest [PaO2, 54.5 (SD 4.6) mmHg], during exercise and recovery on H-day. The latter was associated with tachycardia compared to N-day. All echocardiographic measurements at rest were within the limits of normal values on both test days. Ejection time, end-systolic and end-diastolic left ventricular dimensions as well as the thickness of left posterior wall and of interventricular septum showed no statistically significant influence of H either at rest or during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Angiography follow-up after transluminal angioplasty of coronary bypass grafts].

Between January 1979 and October 1991, percutaneous transluminal angioplasty of stenosed or occluded coronary bypass grafts was attempted 180 times in 146 patients (180 lesions in 157 bypass grafts); 6/157 grafts were internal mammary grafts. The procedure was successful in 129/157 grafts (82%) and in 151/180 lesions (84%). Failures occurred almost exclusively in recanalization attempts. Cardiac complications occurred in 4/146 patients (2.7%). Three patients developed an acute myocardial infarction, another patient died after acute occlusion of a native vessel dilated during the same procedure. In successful attempts the severity of stenosis was reduced from 87 +/- 10% to 33 +/- 15%. 113/129 successfully dilated grafts had at least one (mean 2.7) control angiogram. 54/113 (48%) showed recurrence after a mean follow up of 6 months. An additional 15 grafts showed late restenosis in a second control angiogram (mean follow-up 23 months). The total restenosis rate was 61%. Restenoses were dilated again one to six times (mean 1.9) with comparable success and recurrence rate. Two patients died during the sixth angioplasty. Finally, 32/129 (25%) grafts were occluded or presumably occluded, and 97/129 (75%) were angiographically confirmed open without restenosis. Thus, angioplasty of bypass grafts is an alternative to a repeat revascularization surgery. The acute results are comparable to the results of angioplasty in native coronary arteries. The restenosis rate is high. One has to be aware of late restenosis. Restenosis can be dilated repeatedly with a comparable success rate and with no significant increase in restenosis rate.

Adult↗

PubMed1993

[Main branch stenosis after bypass operation. Indications for elective PTCA].

The unprotected left main stenosis still represents one of the contraindications of PTCA; recently developed concepts using percutaneous bypass techniques have not changed this fact so far. However, following bypass grafting the procedure can be done with low risk and may improve prognosis in case of later bypass occlusion. This study should clarify whether a higher rate of bypass occlusion is caused by postsurgical left main PTCA. From October 1981 to January 1991 a left main stenosis was dilated in 41 patients, 2 weeks to 12 years (mean 3.5 years) after bypass grafting. To date, 17/65 venous bypass grafts were already occluded, and 72.4% of the patients suffered from typical angina. In 34/41 patients (82.9%) PTCA was successful, severe complications (death, emergency surgery or myocardial infarction) did not occur and clinical improvement was achieved in 80% of symptomatic patients. Four months later, 26/34 patients (76.5%) had angiographic follow-up. Fifteen restenoses were found and a second PTCA was performed in 9/15. None of the venous bypass grafts, open at the time of the first PTCA, was occluded at follow-up. In one case PTCA of the left main stenosis turned out to be life-saving 7 years later because an occlusion of RCA- and LCX-bypasses occurred and the LAD graft showed a subtotal thrombosis. It is concluded that PTCA of left main stenosis after bypass grafting is a safe procedure and does not lead to a higher rate of venous bypass occlusions. A prognostic indication seems to be justified.

Adult↗

PubMed1992

[Chronic coronary artery occlusion--age, morphology and chance of reopening. An attempt to define indications].

In chronic coronary occlusions the rate of successful reopening seems to be improved with the help of new techniques; the chance of success can be judged by the age of occlusion. Frequently this age cannot be fixed exactly. The purpose of the study was therefore to find out, whether the chance of reopening can be judged by morphology. 60 patients in whom the occlusions could not be passed with a conventional wire were treated with the ROTACS system. Cine angios were reviewed carefully, morphological details in at least two projections were evaluated in graphic representations and correlated with the acute success rate and the estimated age of occlusion. Morphological parameters associated with a higher rate of success (type A) were: 1) a clearcut proximal stump with 2) no sidebranches at the site of occlusion, 3) no bridging collaterals and 4) only a slight filling of the distal vessel. Parameters with a low success rate (type B) were: 1) no proximal stump, 2) sidebranches at the site of occlusion, 3) bridging collaterals and 4) a very good distal filling. 48/60 (80%) of occlusions could be classified in type A or type B. The success rate was 17/21 (81%) (type A) versus 5/27 (18.5%) (type B) (p < 0.0002). The estimated age of type B occlusions was significantly higher than in type A: median 8 versus median 4 months (p < 0.002). It is concluded that the rate of success in reopening chronic coronary occlusions can be judged in the majority of patients using morphological parameters.

Atherectomy, Coronary↗

PubMed1991

Semisynthetic epsilon-(iso)rhodomycins: a new glycosylation variant and modification reactions.

Synthesis of 7-O-(3-amino-2,3,6-trideoxy-alpha-L-lyxo-hexopyranosyl)-epsilon-(i so)rhodomycinones 16 and 17, and their 3'-morpholino derivatives are described. Glycosylation (trimethylsilyl triflate, 10:1 dichloro-methane-acetone, -35 degrees) of 1-O-tert-butyldimethylsilyl-2,3-6-trideoxy-4-O-p-nitrobenzoyl-3-trifl uoroacetamido-beta-L-lyxo-hexopyranose (4) with epsilon-rhodomycinone (epsilon-RMN, 5) or epsilon-isorhodomycinone (epsilon-isoRMN, 6) afforded 7-O-alpha-glycosyl-epsilon-RMN (9) and -epsilon-isoRMN (12) in high yield. The glycosyl donors 2,3,6-trideoxy-4-O-p-nitrobenzoyl-3-trifluoroacetamido-L-lyxo++ +-hexopyrano se (2) or its 1-O-trimethylsilylated alpha-anomer 3 were less suitable for the glycosylation of these aglycons. Sapinification of 9 and 12 provided 16 and 17, respectively, which reacted with various 2,2'-oxydiacetaldehydes under conditions of reductive alkylation to give 3'-morpholinyl-epsilon-(iso)rhodomycins.

Anthracyclines↗

PubMed1990

Anthracycline oligosaccharides: facile stereoselective synthesis of 2,6-dideoxy-alpha-L-lyxo-hexopyranosides.

Glycosylation of benzyl-2,3,6-trideoxy-3-trifluoroacetamido-alpha-L-lyxo-h exopyranoside (6) with 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-lyxo-hex-1-enitol (1) or 4-O-acetyl-1,5-anhydro-3-O-benzyl-2,6-dideoxy-L-lyxo-hex-1-enit ol (2) in the presence of trimethylsilyl triflate/triethylamine gave alpha-(1----4)-linked disaccharide derivatives 7 and 8, respectively. In the presence of trimethylsilyl triflate only, 3,4-di-O-acetyl-1-O-tert-butyldimethylsilyl-2,6-dideoxy-beta-L-lyxo++ +-hexopyranose (3) and 6 gave mainly 7. Condensation of 1 or 2 with 9, obtained by O-deacylation of 8, afforded benzyl [O-(3,4-di-O-acetyl-2,6-dideoxy-alpha-L-lyso-hexopyranosyl)-(1----4)-O-( 3-O-benzyl-2,6-dideoxy-2,6-alpha-L-hexopyranosyl)-(1----4)-(2,3,6-tri deo xy-3-trifluoroacetamido-alpha-L-lyxo-hexopyranoside)] (11) and its 3''-benzyl analogue 12, respectively.

Antibiotics, Antineoplastic↗

PubMed1987

[Muscular obstruction of the right ventricular outflow tract. Subvalvular pulmonary stenosis or hypertrophic cardiomyopathy?].

A case is reported of right ventricular outflow obstruction caused by hypertrophic cardiomyopathy. The pressure gradient between the inflow tract and the outflow tract of the right ventricle was 84 mm Hg. Resection of the hypertrophic muscle bundles practically eliminated the obstruction leaving only an insignificant subvalvular gradient of 2 mm Hg. Histologic examination revealed cardiac muscle cell hypertrophy and disorganization.

Adult↗

PubMedDate not supplied

Cardiac volume.

Explore the source record for details and available documents.

Cardiac Volume↗